DE102010000783A1 - Piezoelectric ceramics for piezoelectric element, contain crystal grain comprising shell and core phases, each differing in composition and having preset amount of crystal lattice defects - Google Patents

Abstract

Piezoelectric ceramics contain crystal grain (20) comprising a shell phase (22) covering a core phase (21), each differing in composition. The ceramics contain a polycrystal having specific isotropic perovskite type compound as main phase. The ratio of amount of crystal lattice defects in shell phase and core phase is less than 1.2. Piezoelectric ceramics contain crystal grain comprising a shell phase covering a core phase, each differing in composition. The ceramics contain a polycrystal having isotropic perovskite type compound as main phase. The ratio of amount of crystal lattice defects in shell phase and core phase is less than 1.2. The perovskite type compound is of formula: (Li x(K 1 - yNa y) 1 - x) a(Nb 1 - z - wTa zSb w)O 3, where x,w are 0-0.2, y is 0-1, z is 0-0.4, x+z+w is more than 0 and a is 0.93-1. Independent claims are included for the following: (1) lamination-type piezoelectric element; (2) manufacture of piezoelectric ceramics; and (3) manufacture of lamination-type piezoelectric element.

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The The invention relates to a piezoceramic of a polycrystalline Material consisting mainly of an isotropic perovskite compound there is a method for producing such a piezoceramic, to a method for producing a multilayer piezoelectric element, and a method of manufacturing the multilayer piezoelectric element. The multilayer piezoelectric element has a layer structure in which piezoceramic layers and internal electrodes are alternately stacked. The The invention also relates to a crystal-oriented ceramic made of a polycrystalline material, mainly consists of an isotropic perovskite compound. The specific one {100} crystal plane of each crystal grain containing the polycrystalline Material of the crystal-oriented ceramic forms is oriented in parallel. The invention also relates to methods for producing the crystal-oriented ceramic and multilayer piezoelectric elements.

2. Description of the stand of the technique

One ceramic polycrystalline material is different Types of sensors, such as a temperature sensor, a thermocouple, a gas sensor and an ion sensor, widely used. The end Ceramic existing polycrystalline material will be added as well as part of electronic circuits, such as capacity, Resistor and substrate of an integrated circuit, used. In addition, the existing polycrystalline ceramic Material used as an optical or ceramic recording element. As such (referred to as "piezoceramics") Ceramics, which consists of a polycrystalline material containing a piezoelectric effect shows high performance and is freely editable in terms of material design, this piezoceramic is particularly in the field of electronics and mechatronics widely used. Mechatronics is the combination from mechanical engineering, electrical engineering, computer technology, control engineering and system design to produce useful products.

The piezoceramic is generally used in a multilayer piezoelectric element. For example, the Japanese script discloses JP 2007-258280 A Such a multilayer piezoelectric element in which a plurality of piezoceramic layers and electrode formation layers are alternately stacked. Each piezoceramic layer is made of a piezoelectric material that can expand or contract when a voltage is applied to the piezoelectric material. Each electrode formation layer has one or more electrode portions forming one or more internal electrodes. Such a multilayer piezoelectric element is produced by the following method. An electrode material containing an AgPd alloy, etc. is printed on a green sheet of the piezoceramic. The printed green sheets are stacked to produce a laminate. The laminated body of the printed green sheets is then fired.

Since there has recently been a demand in this technical field to increase the amount of deformation or the amount of expansion of such a multilayer piezoelectric element, various types of piezoelectric materials have been developed. In particular, it has been strongly demanded to develop a piezoelectric material containing a lead-free material for environmental protection and to reduce the impact on the environment. For example, the Japanese writings reveal JP 2002-68835 A . JP 2002-68836 A . JP 2004-244299 A . JP 2004-323325 A and JP 2006-56778 A such lead-free piezoelectric materials. However, since these conventional lead-free piezoelectric materials have low piezoelectric properties, a multilayer piezoelectric element composed of these lead-free piezoelectric materials can not provide the necessary deformation characteristics.

In order to solve this known problem in the filed piezoelectric material, for example, the Japanese document discloses JP 2006-28001 A a piezoelectric element of a piezoceramic containing ceramic crystal grains with an anisotropic form, in which a spontaneous polarization is oriented in front of other crystal planes in exactly one crystal plane.

In general, the piezoelectric properties of an isotropic perovskite compound change according to the direction of the crystal axis of each crystal grain in a polycrystalline material. By orienting the crystal axis of each crystal grain forming the polycrystalline material of an isotropic perovskite compound in a certain direction, its piezoelectric properties can be increased as much as possible. This can increase the performance of the piezoceramic. As in the Japanese font JP 2006-28001 A is disclosed, it is possible to produce a high-performance crystal-oriented ceramic in which a specific crystal plane is oriented by using as a reactive master a plate-shaped powder having a predetermined chemical composition and orienting the specific crystal plane of each powder grain. That in Japanese writing JP 2006-28001 A The disclosed method produces such a crystal-oriented ceramic with high performance by sintering a mixture of the plate-shaped powder and a piezoceramic starting powder.

If the multilayer piezoelectric element using these previously described conventional, consisting of the polycrystalline material Piezoceramic is produced and the polycrystalline material mainly consists of an isotropic perovskite compound falls However, it the piezoceramic layers in the multilayer piezoelectric element heavy, to a sufficient extent electrical insulation resistance to have. Because of the insufficient extent of electrical insulation resistance Therefore, it is difficult to use in electrical components.

Namely, the conventional piezoceramic composed mainly of an isotropic perovskite compound expressed by the general formula ABO ₃ often causes a crystal lattice defect at an A-site or O-site during a burning step. Due to the presence of such a crystal lattice defect, there is therefore the possibility that the electrical insulation resistance in the piezoceramic decreases as the end product.

Furthermore has the method of manufacturing a multilayer piezoelectric element the problem is that a conductive metal like Ag that is in an electrode part is included in the piezoceramic diffused when the electrode part is formed on the green sheets before the green sheets be fired with the electrode part to the multi-layered piezoelectric element to create. This leads to a drastic reduction the electrical insulation resistance of the piezoceramic.

As previously described is such a polycrystalline ceramic material with different types of sensors, such as a temperature sensor, a thermocouple, a gas sensor and an ion sensor, far common. The ceramic polycrystalline material is also considered as part of electronic circuits, such as capacity, Resistor and substrate of an integrated circuit, used. Further, the ceramic polycrystalline material becomes as an optical recording element and as a ceramic recording element used. As such, consisting of a polycrystalline material (called "piezoceramics") ceramics, the shows a piezoelectric effect, high performance has and is relative to material design is free to work, this piezoceramic is particular widely used in the field of electronics and mechatronics. Mechatronics is the combination of mechanical engineering, electrical engineering, Computer technology, control technology and system design for production useful products.

A such piezoceramic is produced by a polarization treatment, when applied to a ferroelectric ceramic an electric field becomes the direction of the ferroelectric domains in one to orient specific direction. To the spontaneous polarization in the piezoceramic by the polarization treatment in a specific Orienting direction, it is preferable that the piezoceramic has a crystal structure of an isotropic perovskite compound, when the spontaneous polarization in a three-dimensional space arises. Therefore, most are available in the market Piezoceramics areotropic ferroelectric perovskite ceramics.

The following materials are well known and widely used in the market as isotropic perovskite ferroelectric ceramics: for example, Pb (Zr · Ti) O ₃ (hereinafter referred to as "PZT"), a ternary PZT system in which a complex perovskite on lead is used. (Pb-) base is added as a third component to PZT, and BiTiO ₃ , Bi _0.5 Na _0.5 TiO ₃ (hereinafter referred to as "BNT").

There the lead-based piezoceramics, representing the PZT is high piezoelectric compared to other piezoceramics Have characteristic values are the most available piezoceramics Lead-based piezoceramics. Because these piezoceramics based on lead However lead oxide (PbO) containing a high vapor pressure, lead pollution, that is the entry of pollutants into the environment, causing instability, disruption, Damage or damage to the ecosystem, d. H. of physical systems or living organisms. It is therefore required piezoceramics with low lead content or lead-free Piezoceramics produce the same piezoelectric Have characteristic values like PZT.

On the other hand, a BaTiO ₃ ceramic as a lead-free piezoelectric material is relatively high piezoelectric characteristics. For example, a BaTiO ₃ ceramic is used in sonar equipment (sonar: sound navigation and distance determination).

In addition, there is a mixed crystal with high piezoelectric characteristics, which consists of a BaTiO ₃ ceramic and a lead-free perovskite compound (for example BNT). However, this lead-free piezoceramic has low piezoelectric characteristics compared to PZT.

In order to solve the above known problem, various types of piezoceramics have been proposed. For example, there are isotropic perovskite-type niobium-potassium peroxide and a piezoceramic composed of a mixed crystal of isotropic perovskite-type niobium-potassium-sodium oxide (see the Japanese patents JP 2000-313664 A . JP 2002-300776 A . JP 2003-306479 A . JP 2003-327472 A . JP 2003-342069 A and JP 2003-342071 A ). However, these lead-free piezoceramics have low piezoelectric characteristics compared to PZT-based piezoceramics.

In order to solve this known problem with the registered piezoceramics, for example, the Japanese document discloses JP 2004-7406 A a piezoelectric element with an anisotropic structure of a crystal-oriented ceramic, which contains ceramic crystal grains in which a preferred orientation of a spontaneous polarization occurs in a plane.

It is generally well known that the piezoelectric properties of an isotropic perovskite compound change according to the direction of the crystal axis of each crystal grain. The orientation of the axis of each crystal grain along a specific direction can strengthen the piezoelectric properties of the isotropic perovskite compound as much as possible. As a result, the performance of the piezoceramic can increase. As in Japanese writing JP 2004-7406 A is disclosed, a high-performance crystal-oriented ceramic can be prepared in which a specific crystal plane is oriented when a plate-like powder having a predetermined chemical composition is used as the reactive master and the specific crystal plane of each powder grain is oriented by sintering the plate-like powder and a piezoceramic starting powder becomes.

These Crystal-oriented ceramics is exemplified by the following Process produced.

anisotropic Powder with a predetermined composition is called reactive Template prepared. Initial powder is prepared to be used during a firing step by the reaction between the starting powder and the anisotropic powder is an isotropic perovskite compound produce.

When Next, by mixing the plate-like powder, the starting powder, a solvent, a binder, a plasticizer, a dispersant, etc., a mixed slurry produced.

By Forming the mixed sludge into a sheet-like shaped Body (or a sheet-like molding) is a molded body produced. During this form step can be caused by the shear stress on the mixed slurries is applied, the anisotropic powder approximately in one Direction.

When Next is the sheet-like molded body Fired sintered. Inside the layer-like shaped body The plate-like powder serves during the sintering step as a reactive template and reacts with the starting powder. The plate-like Powder grows during this reaction and generates the isotropic perovskite compound.

If the sintering step is continued, the plate-like grows Powder continues during the reaction with the starting powder, and it is the crystal-oriented ceramics that are made Crystal grains composed in which a specific Crystal plane is oriented.

If However, the conventional piezoelectric element using a crystal-oriented ceramic of a polycrystalline material which is made up mainly of an isotropic Composed perovskite compound, has crystal-oriented ceramics not adequately electrical insulation resistance. It is therefore difficult to incorporate the conventional piezoelectric element use electrical components such as a multilayer piezoelectric element.

As in the conventional crystal-oriented ceramic manufacturing process during the In fact, if an insufficient reaction between the anisotropic powder and the starting powder occurs during the firing step, the end product of the crystal-oriented ceramic will have lower insulation characteristics.

BRIEF SUMMARY OF THE INVENTION

A The object of the invention is to provide a crystal-oriented ceramic excellent electrical insulation characteristics, a multi-layered piezoelectric element with excellent electrical insulation characteristics and each method for producing the crystal-oriented ceramic and the multilayer piezoelectric element to deliver.

A Another object of the invention is a method for manufacturing a crystal-oriented ceramic with excellent electrical Insulation properties and a multilayer piezoelectric element to provide.

- First to tenth Embodiment of the invention

In order to achieve the above objects, the invention as a first aspect of the invention provides a polycrystalline piezoceramic material mainly composed of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≤ x ≤ 0.2, 0 ≤ y ≤ 1,
0≤z≤0.4, 0≤w≤0.2, x + z + w> 0, 0.95≤a≤1.

In the multilayer piezoelectric element of the first embodiment of the invention each crystal grain forming the piezoelectric ceramic is composed of one Core phase (or a core part) and a shell phase (or a shell layer), which are a different Composition, wherein the shell phase, the core phase and the piezoceramic satisfies the relationship ds / dc <1.2, where "ds" is a lot of one in the shell phase generated crystal lattice defect and "dc" one Amount of a crystal lattice defect generated in the core phase.

According to one Second embodiment of the invention is a multilayer piezoelectric element in which a plurality of piezoceramic layers and electrode formation layers, which have an electrode part having one or more internal electrodes forms containing a conductive metal, alternately stacked are. In the multilayer piezoelectric element of the second embodiment According to the invention, the piezoceramic layers consist of the piezoceramic according to the first embodiment of the invention.

• (a) Mischen eines anisotropen Pulvers mit einem reaktiven Ausgangspulver, um ein Ausgangsgemisch herzustellen, wobei das anisotrope Pulver aus einer Perowskitverbindung besteht, das anisotrope Pulver aus orientierten anisotropen Körnern besteht, die eine orientierte Ebene bilden, in der eine Kristallebene, die bezüglich des Gitters zu der spezifischen Kristallebene A passt, orientiert ist, und das reaktive Ausgangspulver durch eine Reaktion mit dem anisotropen Pulver die durch die allgemeine Formel (1) ausgedrückte isotrope Perowskitverbindung erzeugt;
• (b) Formen des Ausgangsgemisches zu einem lagenartigen Formkörper (oder einem lagenartig geformten Körper), so dass die orientierte Ebene jedes orientierten anisotropen Korns in dem anisotropen Pulver ungefähr in einer gleichen Richtung orientiert ist; und
• (c) Brennen des Formkörpers, um die Piezokeramik herzustellen.

According to a third aspect of the present invention, there is provided a method of manufacturing a piezoceramic of a polycrystalline material mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zx Ta _z Sb _w ) O ₃ (1) where 0 ≤ x ≤ 0.2, 0 ≤ y ≤ 1,
0≤z≤0.4, 0≤w≤0.2, x + z + w> 0, 0.95≤a≤1. The piezoceramic of the third aspect of the invention is made of a crystal-oriented ceramic in which a specific crystal plane A is oriented in crystal grains constituting the polycrystalline material. The method of the third aspect of the invention comprises the following steps (a), (b) and (c):

• (a) mixing an anisotropic powder with a starting reactive powder to produce a starting mixture, the anisotropic powder consisting of a perovskite compound consisting of anisotropic powders of oriented anisotropic grains forming an oriented plane in which a crystal plane relative to the lattice to the specific crystal plane A, oriented, and the reactive starting powder by reaction with the anisotropic powder produces the isotropic perovskite compound expressed by the general formula (1);
• (b) forming the starting mixture into a sheet-like shaped body (or a sheet-like shaped body) so that the oriented plane of each oriented anisotropic grain in the anisotropic powder is oriented approximately in a same direction; and
• (c) firing the shaped body to produce the piezoceramic.

In the method of the third aspect of the invention, the mixing step further mixes a K starting powder and / or an Li starting powder as an additive into the starting mixture so that the addition amount per 1 mol of the isotropic perovskite compound expressed by the general formula (1) on the element K and / or Li is not more than 0.05 mol. The firing step carries out the firing for a period of not less than two hours at a temperature of not lower than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50%.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a piezoceramic of a polycrystalline material mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≤ x ≤ 0.2, 0 ≤ y ≤ 1,
0≤z≤0.4, 0≤w≤0.2, x + z + w> 0, 0.95≤a≤1.

• (a) Mischen von ein oder mehr aus eine Li-Quelle, einer K-Quelle, einer Na-Quelle, einer Nb-Quelle, einer Ta-Quelle und einer Sb-Quelle gewählter Elemente in einem stöchiometrischen Verhältnis, das die durch die allgemeine Formel (1) ausgedrückte Verbindung erzeugt, um ein Ausgangsgemisch herzustellen, und Kalzinieren des erzielten Ausgangsgemisches, um ein reaktives Ausgangspulver zu erzeugen;
• (b) Formen des Ausgangsgemisches zu einem Formkörper; und
• (c) Brennen des Formkörpers, um die Piezokeramik herzustellen.

The method of the fourth aspect of the invention comprises the following steps (a), (b) and (c):

• (a) mixing one or more of a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source of selected elements in a stoichiometric ratio similar to that of the general Formula (1) to produce a starting mixture and calcining the obtained starting mixture to produce a reactive starting powder;
• (b) shaping the starting mixture into a shaped body; and
• (c) firing the shaped body to produce the piezoceramic.

In the method of the fourth aspect of the invention, the mixing step further mixes a K starting powder and / or an Li starting powder as an additive in the starting mixture so that the addition amount per 1 mol of the isotropic perovskite compound expressed by the general formula (1) on the element K and / or Li is not more than 0.05 mol. The firing step carries out the firing for a period of not less than two hours at a temperature of not less than 900 ° C under an atmosphere under an oxygen partial pressure P ₀₂ of not less than 50%.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a piezoceramic of a polycrystalline material mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≤ x ≤ 0.2, 0 ≤ y ≤ 1,
0≤z≤0.4, 0≤w≤0.2, x + z + w> 0, 0.95≤a≤1.

• (a) Mischen eines anisotropen Pulvers mit einem reaktiven Ausgangspulver, um ein Ausgangsgemisch herzustellen, wobei das anisotrope Pulver aus einer aus einem anisotropen Pulver bestehenden Perowskitverbindung besteht, das anisotrope Pulver aus orientierten anisotropen Körnern besteht, die eine orientierte Ebene bilden, in der eine Kristallebene, die bezüglich des Gitters zu der spezifischen Kristallebene A passt, orientiert ist, und das reaktive Ausgangspulver durch eine Reaktion mit dem anisotropen Pulver die durch die allgemeine Formel (1) ausgedrückte isotrope Perowskitverbindung erzeugt;
• (b) Formen des Ausgangsgemisches zu einem lagenartigen Formkörper, so dass die orientierte Ebene jedes orientierten anisotropen Korns in dem anisotropen Pulver ungefähr in einer gleichen Richtung orientiert ist; und
• (c) Brennen des lagenartigen Formkörpers, um die Piezokeramik herzustellen.

The method of the fifth aspect of the invention comprises the following steps (a), (b) and (c):

• (a) mixing an anisotropic powder with a starting reactive powder to produce a starting mixture, the anisotropic powder consisting of an anisotropic powder perovskite compound consisting of anisotropic powder of oriented anisotropic grains forming an oriented plane in which a crystal plane oriented with respect to the grating to the specific crystal plane A, and the reactive starting powder produces, by reaction with the anisotropic powder, the isotropic perovskite compound expressed by the general formula (1);
• (b) forming the starting mixture into a sheet-like shaped body such that the oriented plane of each oriented anisotropic grain in the anisotropic powder is oriented approximately in a same direction; and
• (c) firing the sheet-like shaped body to produce the piezoceramic.

In the method of the fifth aspect of the invention, the reactive starting powder has a specific surface area in a range of 2 to 5 m ² / g, and the firing step includes a temperature increasing step, a first temperature holding step, a temperature decreasing step, and a second temperature holding step. Namely, the temperature raising step raises the temperature to T ₁ ° C (1050 ° C <T ₁ ≤ 1150 ° C). The first temperature keeping step keeps the temperature T ₁ ° C for a period of t ₁ hour (t ₁ ≤ 5 hours). The temperature reduction step lowers the temperature from T ₁ ° C to T ₂ ° C (950 ° C ≤ T ₂ ≤ 1050 ° C). The second temperature keeping step keeps the temperature T ₂ ° C for t ₂ hours (2 hours ≤ t ₂ ≤ 20 hours). If the temperature increase rate at least between T ₂ ° C and T ₁ ° C D ₁ ° C / hour and the temperature lowering rate D ₂ ° C / hour, the firing step controls the firing temperature to have the relationship (T ₁ -T ₂ ) / t ₂ ≤D ₁ ≤200 and (T ₁ -T ₂ ) / t ₂ ≤D ₂ ≤ 200 fulfilled.

• (a) Mischen von ein oder mehr aus einer Li-Quelle, einer K-Quelle, einer Na-Quelle, einer Nb-Quelle, einer Ta-Quelle und einer Sb-Quelle gewählter Elemente in einem stöchiometrischen Verhältnis, das die durch die allgemeine Formel (1) ausgedrückte Verbindung erzeugt, um ein Ausgangsgemisch herzustellen, und Kalzinieren des erzielten Ausgangsgemisches, um ein reaktives Ausgangspulver zu erzeugen;
• (b) Formen des Ausgangsgemisches zu einem Formkörper; und
• (c) Brennen des Formkörpers, um die Piezokeramik herzustellen.

According to a sixth aspect of the present invention, there is provided a method of manufacturing a piezoceramic of a polycrystalline material mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≤ x ≤ 0.2, 0 ≤ y ≤ 1,
0≤z≤0.4, 0≤w≤0.2, x + z + w> 0, 0.95≤a≤1. The method of the sixth aspect of the invention comprises the following steps (a), (b) and (c):

• (a) mixing one or more of a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source of selected elements in a stoichiometric ratio similar to that of the general Formula (1) to produce a starting mixture and calcining the obtained starting mixture to produce a reactive starting powder;
• (b) shaping the starting mixture into a shaped body; and
• (c) firing the shaped body to produce the piezoceramic.

In this process, the starting reactive powder has a specific surface area in a range of 2 to 5 m ² / g. The firing step includes, in the method of the sixth aspect of the invention, a temperature increasing step, a first temperature holding step, a temperature decreasing step, and a second temperature holding step. Namely, the temperature raising step raises the temperature to T ₁ ° C (1050 ° C <T ₁ ≤ 1150 ° C). The first temperature keeping step keeps the temperature T ₁ ° C for a period of t ₁ hour (t ₁ ≤ 5 hours), the temperature decreasing step lowers the temperature from T ₁ ° C to T ₂ ° C (950 ° C ≤ T ₂ ≤ 1050 ° C). The second temperature keeping step keeps the temperature T ₂ ° C for t ₂ hours (2 hours ≤ t ₂ ≤ 20 hours). When the temperature raising rate is at least ₁ ° C / hour and the temperature decreasing rate D is ₂ ° C / hour at least between T ₂ ° C and T ₁ ° C, the firing step controls the firing temperature to determine the relationship (T ₁ -T ₂ ) / t ₂ ≤ D ₁ ≤ 200 and (T ₁ - T ₂ ) / t ₂ ≤ D ₂ ≤ 200.

• (a) Mischen eines anisotropen Pulvers mit einem reaktiven Ausgangspulver, um ein Ausgangsgemisch herzustellen, wobei das anisotrope Pulver aus einer Perowskitverbindung besteht, das anisotrope Pulver aus orientierten anisotropen Körnern besteht, die eine orientierte Ebene bilden, in der eine Kristallebene, die bezüglich des Gitters zu der spezifischen Kristallebene A passt, orientiert ist, und das reaktive Ausgangspulver durch eine Reaktion mit dem anisotropen Pulver die durch die allgemeine Formel (1) ausgedrückte isotrope Perowskitverbindung erzeugt;
• (b) Formen des Ausgangspulvers zu einem lagenartigen Formkörper, so dass die orientierte Ebene jedes orientierten anisotropen Korns in dem anisotropen Pulver ungefähr in einer gleichen Richtung orientiert ist;
• (c) Aufdrucken eines das leitende Metall enthaltenden Elektrodenmaterials, das nach einem folgenden Brennschritt den Elektrodenteil bildet;
• (d) Aufschichten der Formkörper nach Abschluss des Druckschritts; und
• (e) Brennen des Schichtkörpers, um das mehrlagige Piezoelement zu erzeugen, das sich aus den abwechselnd aufeinandergeschichteten Piezokeramikschichten und Elektrodenbildungsschichten zusammensetzt.

According to a seventh embodiment of the invention, a method for producing a multilayer piezoelectric element is provided, in which piezoceramic layers and electrode-forming layers are alternately stacked on one another. The piezoceramic layer is made of a polycrystalline material of a crystal-oriented ceramic mainly composed of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, where a specific crystal plane A is oriented in crystal grains constituting the polycrystalline material, and the electrode formation layer has one or more electrode portions forming internal electrodes containing conductive metal. The method of the seventh aspect of the invention comprises the following steps (a), (b), (c), (d) and (e):

• (a) mixing an anisotropic powder with a starting reactive powder to produce a starting mixture, the anisotropic powder consisting of a perovskite compound consisting of anisotropic powders of oriented anisotropic grains forming an oriented plane in which a crystal plane relative to the lattice to the specific crystal plane A, oriented, and the reactive starting powder by reaction with the anisotropic powder produces the isotropic perovskite compound expressed by the general formula (1);
• (b) forming the starting powder into a sheet-like shaped body so that the oriented plane of each oriented anisotropic grain in the anisotropic powder is oriented approximately in a same direction;
• (c) printing an electrode material containing the conductive metal, which forms the electrode part after a subsequent firing step;
• (d) coating the moldings after completion of the printing step; and
• (e) firing the laminated body to produce the multi-layered piezoelectric element composed of the alternately stacked piezoceramic layers and electrode forming layers.

In the method of the seventh aspect of the invention, the mixing step further mixes a K starting powder and / or a Li starting powder as an additive in the starting mixture so that the addition amount per 1 mol of the isotropic perovskite compound expressed by the general formula (1) is applied to the Element K and / or Li is not more than 0.05 mol. The burning step leads to the burning for a period of not less than 2 hours at a temperature of not less than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50%.

• (a) Mischen von ein oder mehr aus einer Li-Quelle, einer K-Quelle, einer Na-Quelle, einer Nb-Quelle, einer Ta-Quelle und einer Sb-Quelle gewählter Elemente in einem stöchiometrischen Verhältnis, das die durch die allgemeine Formel (1) ausgedrückte Verbindung erzeugt, um ein Ausgangsgemisch herzustellen, und Kalzinieren des erzielten Ausgangsgemisches, um ein reaktives Ausgangspulver zu erzeugen;
• (b) Formen des reaktiven Ausgangspulvers zu einem lagenartigen Formkörper;
• (c) Aufdrucken eines das leitende Metall enthaltenden Elektrodenmaterials, das nach einem folgenden Brennschritt den Elektrodenteil bildet;
• (d) Aufschichten der Formkörper nach dem Druckschritt; und
• (e) Brennen des Schichtkörpers, um das mehrlagige Piezoelement zu erzeugen, das sich aus den abwechselnd aufeinandergeschichteten Piezokeramikschichten und Elektrodenbildungsschichten zusammensetzt.

According to an eighth embodiment of the invention, a method for producing a multilayer piezoelectric element is provided, in which piezoceramic layers and electrode-forming layers are alternately stacked on one another. The piezoceramic layer is made of a polycrystalline material of a crystal-oriented ceramic mainly composed of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb ₁ Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1. The method of the eighth aspect of the invention comprises the following steps (a), (b), (c), (d) and (e):

• (a) mixing one or more of a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source of selected elements in a stoichiometric ratio similar to that of the general Formula (1) to produce a starting mixture and calcining the obtained starting mixture to produce a reactive starting powder;
• (b) forming the starting reactive powder into a sheet-like shaped body;
• (c) printing an electrode material containing the conductive metal, which forms the electrode part after a subsequent firing step;
• (d) coating the shaped bodies after the printing step; and
• (e) firing the laminated body to produce the multi-layered piezoelectric element composed of the alternately stacked piezoceramic layers and electrode forming layers.

In the method of the eighth aspect of the invention, the mixing step further mixes a K starting powder and / or a Li starting powder as an additive into the starting mixture so that the addition amount per 1 mol of the isotropic perovskite compound expressed by the general formula (1) is applied to the Element K and / or Li is not more than 0.05 mol. The firing step carries out the firing for a period of not less than 2 hours at a temperature of not lower than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50%.

• (a) Mischen eines anisotropen Pulvers mit einem reaktiven Ausgangspulver, um ein Ausgangsgemisch herzustellen, wobei das anisotrope Pulver aus einer Perowskitverbindung besteht, das anisotrope Pulver aus orientierten anisotropen Körnern besteht, die eine orientierte Ebene bilden, in der eine Kristallebene, die bezüglich des Gitters zu der spezifischen Kristallebene A passt, orientiert ist, und das reaktive Ausgangspulver durch eine Reaktion mit dem anisotropen Pulver die durch die allgemeine Formel (1) ausgedrückte isotrope Perowskitverbindung erzeugt;
• (b) Formen des Ausgangsgemisches zu einem lagenartigen Formkörper, so dass die orientierte Ebene jedes orientierten anisotropen Korns in dem anisotropen Pulver ungefähr in einer gleichen Richtung orientiert ist;
• (c) Aufdrucken eines das leitende Metall enthaltenden Elektrodenmaterials, das nach einem folgenden Brennschritt den Elektrodenteil bildet;
• (d) Aufschichten der Formkörper nach dem Druckschritt; und
• (e) Brennen des Schichtkörpers, um das mehrlagige Piezoelement zu erzeugen, das sich aus den abwechselnd aufeinandergeschichteten Piezokeramikschichten und Elektrodenbildungsschichten zusammensetzt.

According to a ninth embodiment of the invention, a method for producing a multilayer piezoelectric element is provided, in which piezoceramic layers and electrode-forming layers are alternately stacked on one another. The piezoceramic layer is made of a polycrystalline material of a crystal-oriented ceramic mainly composed of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb ₁ Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, where a specific crystal plane A in crystal grains forming the polycrystalline material is oriented. The electrode formation layer has an electrode part forming internal electrodes containing a conductive metal. The method of the ninth aspect of the invention comprises the following steps (a), (b), (c), (d) and (e):

• (a) mixing an anisotropic powder with a starting reactive powder to produce a starting mixture, the anisotropic powder consisting of a perovskite compound consisting of anisotropic powders of oriented anisotropic grains forming an oriented plane in which a crystal plane relative to the lattice to the specific crystal plane A, oriented, and the reactive starting powder by reaction with the anisotropic powder produces the isotropic perovskite compound expressed by the general formula (1);
• (b) forming the starting mixture into a sheet-like shaped body such that the oriented plane of each oriented anisotropic grain in the anisotropic powder is oriented approximately in a same direction;
• (c) printing an electrode material containing the conductive metal, which forms the electrode part after a subsequent firing step;
• (d) coating the shaped bodies after the printing step; and
• (e) firing the laminated body to produce the multi-layered piezoelectric element composed of the alternately stacked piezoceramic layers and electrode forming layers.

In the process of the ninth aspect of the invention, the reactive starting powder has a specific surface area in a range of 2 to 5 m ² / g. The firing step has a temperature increase step, a first temperature holding step, a temperature lowering step and a second temperature holding step. Namely, the temperature raising step raises the temperature to T ₁ ° C (1050 ° C <T ₁ ≤ 1150 ° C). The first temperature keeping step keeps the temperature T ₁ ° C for a period of t ₁ hour (t ₁ ≤ 5 hours). The temperature reduction step lowers the temperature from T ₁ ° C to T ₂ ° C (950 ° C ≤ T ₂ ≤ 1050 ° C). The second temperature keeping step keeps the temperature T ₂ ° C for t ₂ hours (2 hours ≤ t ₂ ≤ 20 hours). When the temperature raising rate is at least ₁ ° C / hour and the temperature decreasing rate D is ₂ ° C / hour at least between T ₂ ° C and T ₁ ° C, the firing step controls the firing temperature to determine the relationship (T ₁ -T ₂ ) / t ₂ ≤ D ₁ ≤ 200 and (T ₁ - T ₂ ) / t ₂ ≤ D ₂ ≤ 200.

• (a) Mischen von ein oder mehr aus einer Li-Quelle, einer K-Quelle, einer Na-Quelle, einer Nb-Quelle, einer Ta-Quelle und einer Sb-Quelle gewählter Elemente in einem stöchiometrischen Verhältnis, das die durch die allgemeine Formel (1) ausgedrückte Verbindung erzeugt, um ein Ausgangsgemisch herzustellen, und Kalzinieren des erzielten Ausgangsgemisches, um ein reaktives Ausgangspulver zu erzeugen;
• (b) Formen des reaktiven Ausgangspulvers zu einem lagenartigen Formkörper;
• (c) Aufdrucken eines das leitende Metall enthaltenden Elektrodenmaterials, das nach einem folgenden Brennschritt den Elektrodenteil bildet;
• (d) Aufschichten der lagenartigen Formkörper nach dem Druckschritt; und
• (e) Brennen des Schichtkörpers, um das mehrlagige Piezoelement zu erzeugen, das sich aus den abwechselnd aufeinandergeschichteten Piezokeramikschichten und Elektrodenbildungsschichten zusammensetzt.

According to a tenth aspect of the invention, there is provided a method of manufacturing a multilayer piezoelectric element in which piezoceramic layers and electrode forming layers are alternately stacked, wherein the piezoceramic layer consists of a polycrystalline material of a crystal oriented ceramic consisting mainly of an isotropic perovskite compound represented by the general formula (1) expressed: {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta ₂ Sb _w ) O ₃ (1) where 0 ≤ x ≤ 0.2, 0 ≤ y ≤ 1,
0≤z≤0.4, 0≤w≤0.2, x + z + w> 0, 0.95≤a≤1. The method of the tenth aspect of the invention comprises the following steps (a), (b), (c), (d) and (e):

• (a) mixing one or more of a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source of selected elements in a stoichiometric ratio similar to that of the general Formula (1) to produce a starting mixture and calcining the obtained starting mixture to produce a reactive starting powder;
• (b) forming the starting reactive powder into a sheet-like shaped body;
• (c) printing an electrode material containing the conductive metal, which forms the electrode part after a subsequent firing step;
• (d) coating the sheet-like shaped bodies after the printing step; and
• (e) firing the laminated body to produce the multi-layered piezoelectric element composed of the alternately stacked piezoceramic layers and electrode forming layers.

In the method of the tenth aspect of the invention, the reactive starting powder has a specific surface area in a range of 2 to 5 m ² / g. The firing step includes a temperature increasing step, a first temperature holding step, a temperature decreasing step, and a second temperature holding step. Namely, the temperature raising step raises the temperature to T ₁ ° C (1050 ° C <T ₁ ≤ 1150 ° C). The first temperature keeping step keeps the temperature T ₁ ° C for a period of t ₁ hour (t ₁ ≤ 5 hours). The temperature reduction step lowers the temperature from T ₁ ° C to T ₂ ° C (950 ° C ≤ T ₂ ≤ 1050 ° C). The second temperature keeping step keeps the temperature T ₂ ° C for t ₂ hours (2 hours ≤ t ₂ ≤ 20 hours). When the temperature raising rate is at least ₁ ° C / hour and the temperature decreasing rate D is ₂ ° C / hour at least between T ₂ ° C and T ₁ ° C, the firing step controls the firing temperature to determine the relationship (T ₁ -T ₂ ) / t ₂ ≤ D ₁ ≤ 200 and (T ₁ - T ₂ ) / t ₂ ≤ D ₂ ≤ 200.

- effects of the first to the tenth embodiment of the invention -

The piezoceramic of the first aspect of the invention is composed of a polycrystalline material mainly composed of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb ₁ Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1. The piezoceramic therefore has excellent piezoelectric characteristics and shows excellent deformation properties.

Of Further, each crystal grain constituting the piezoceramic is set the first embodiment of the invention of a core phase (or a core part) and a shell phase together, the one have different composition.

In particular, the shell phase takes up the core phase. The piezoceramic satisfies the relationship ds / dc <1.2, where "ds" is the amount of a crystal lattice defect generated in the shell phase and "dc" is the amount of a crystal lattice defect generated in the core phase. If the above relationship is ds / dc <1.2 fills, this ensures a piezoceramic with a high electrical insulation resistance. When an electrode part is formed on the piezoceramic, the electrical insulation resistance of the piezoceramic can be prevented from decreasing. This means that the piezoceramic of the first embodiment of the invention provides for the property of high electrical insulation. The piezoceramic according to the invention can be used in various types of electronic components.

In the method according to the other embodiments The invention will be the core phase and the shell phase in the polycrystalline, mainly from the isotropic Perovskite compound produced existing material in the firing step. The core phase and the shell phase generally have different characteristics in the composition, the crystallization, the orientation characteristics and the density.

In addition, the perovskite compound is expressed by the general formula ABO ₃ . It is well known that the firing step causes a crystal lattice defect in the A-site element and / or O-site element. The presence of the crystal lattice defect further reduces the electrical insulation resistance of the piezoceramic. When most crystal lattice defects are generated in the cladding phase, this noticeably reduces the electrical insulation resistance. Based on this phenomenon, the fulfillment of the relationship ds / dc <1.2 ensures a piezoceramic with an excellent and sufficient electrical insulation resistance.

The multilayer piezoelectric element according to the second embodiment of the invention is composed of the piezoceramic layers, that from the piezoceramic of the first embodiment of the invention consist. The multilayer piezoelectric element having the above construction The second embodiment of the invention can be based on the excellent Characteristics of the piezoceramic of the first embodiment of the invention excellent deformability and excellent have electrical insulation properties.

The third, fourth, fifth and sixth embodiments of the invention refer to methods for producing the piezoceramic. These Procedures lead the mixing step, the molding step and through the firing step.

at The third and fourth aspects of the invention become a K output powder and / or a starting Li powder as an additive to the starting mixture or a reactive starting powder, so that the addition amount per 1 mole of that expressed by the general formula (1) isotropic perovskite compound based on the element K and / or Li is not more than 0.05 mol.

The molding step forms the starting mixture into a shaped body. The firing step carries out the firing for a period of not less than two hours at a temperature of not lower than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50%.

The Piezoceramic produced by the above method consists of a polycrystalline material consisting mainly of the isotropic one expressed by the general formula (1) Perovskite compound exists. Each crystal grain of the polycrystalline Material consists of the core phase and the shell phase together, wherein the sheath phase takes up the core phase. The piezoceramic fulfills the relationship ds / dc <1.2, where "ds" is a Crystal lattice defect quantity in the shell phase and "dc" a Crystal lattice defect amount in the core phase. This means, that the methods of the third and fourth embodiments of the invention make it possible, the piezoceramic according to the first embodiment of the invention.

The perovskite compound is expressed by the general formula ABO ₃ . The firing step often causes a crystal lattice defect at A-site or O-site, especially in the shell phase. The mixing step in the processes of the third and fourth aspects of the invention adds a K starting powder and / or a Li starting powder as an additive to the starting mixture or reactive starting powder. Therefore, it is possible to suppress the generation of the crystal lattice defects of the A-site element during the burning step.

Moreover, the firing step in the methods of the third and fourth aspects of the invention results in firing for a period of not less than two hours at a temperature not lower than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50%. by. This may also suppress the generation of a crystal lattice defect of the O-site element during the firing step.

As a result, an increase in the crystal lattice defects that occur in the firing step can be suppressed Piezoceramic be produced. Since most crystal lattice defects are generated in the shell phase, the method of the invention can reduce the amount of crystal lattice defects in the shell phase.

Accordingly can the methods of the invention produce the piezoceramic of the first embodiment of the invention, the relationship ds / dc <1,2 met, where "ds" is the amount of an in the shell phase generated crystal lattice error and "dc" the Amount of a crystal lattice defect generated in the core phase.

The Piezoelectric ceramic according to the invention has both excellent Deformation properties as well as excellent electrical Insulation resistance. Even if in the piezoceramic electrode parts can be formed, a decrease in the electrical insulation resistance the piezoceramic be suppressed. this makes possible it, the piezoceramic in different types of electronic Use components.

The Method of the fifth embodiment of the invention leads the mixing step, the molding step and the firing step.

In particular, the methods of the fifth and sixth aspects of the invention use a reactive starting powder having a specific surface area, and perform the firing at a temperature having the relationship (T ₁ -T ₂ ) / t ₂ ≦ D ₁ ≦ 200 and (T ₁ - T ₂ ) / t ₂ ≤ D ₂ ≤ 200. This can suppress generation of a crystal lattice defect in the A-space element and O-space element.

The Piezoceramic, by the above method of the fifth and sixth embodiment of the invention is made made of a polycrystalline material, mainly consists of a perovskite compound by the general Formula (1) is expressed. Each crystal grain of the polycrystalline material consists of the core phase and the shell phase, wherein the shell phase accommodates the core phase. The piezoceramic satisfies the relationship ds / dc <1.2, where "ds" is the Amount of crystal lattice defect generated in the shell phase and "dc" the amount of one generated in the core phase Crystal lattice defect is. That means it's the procedure the fifth and sixth embodiments of the invention allow the Piezoceramic according to the first embodiment of Invention produce.

The Piezoelectric ceramic according to the invention has both excellent Deformation properties as well as excellent electrical Insulation resistance. Even if in the piezoceramic electrode parts can be formed, a decrease in the electrical insulation resistance the piezoceramic be suppressed. this makes possible it, the piezoceramic in different types of electronic Use components.

at the method of the third and fifth embodiment of Invention mixes the mixing step, the anisotropic powder with the reactive starting powder. The molding step forms the reactive mixture to a sheet-like shaped body (or a sheet-like shaped body), so that the oriented plane in the Anisotropic powder in approximately the same direction is oriented. This allows one from the crystal-oriented ceramic existing piezoceramic be prepared in which the crystal grains, which form the polycrystalline material, in the specific crystal plane A are oriented.

on the other hand use the methods of the fourth and sixth embodiments of Invention no anisotropic powder, as in the method of the third and fifth embodiment of the invention is used. Of the Mixing step in the methods of the fourth and sixth embodiments at least one of a Li source, a K source, a Na source, a Nb source, a Ta source, and a Sb source Element in a stoichiometric ratio, that is the compound expressed by the general formula (1) produced to produce a starting mixture, and then calcined the resulting starting mixture to a reactive starting powder to produce. When the firing step by the above mixing step obtained molded body burns, it can be a piezoceramic obtained from a non-oriented body consists.

The disclose seventh, eighth, ninth and tenth embodiments of the invention as the next method of manufacturing the multilayer piezoelectric element. The methods of the seventh and eighth embodiments of the invention lead the mixing step, the molding step, the printing step, the laminating step and the firing step.

These methods can produce a multilayer piezoelectric element in which the piezoceramic layers and the electrode-forming layers are alternately stacked with each other, the piezoceramic layers being made of a polycrystalline material of a crystal-oriented ceramic composed mainly of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≤ x ≤ 0.2, 0 ≤ y ≤ 1,
0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0.95 ≦ a ≦ 1, and the electrode formation layer has an internal electrode forming electrode portion containing conductive metal.

In the mixing step in the processes of the seventh and eighth embodiments of the invention are as in the methods of the third and fourth Embodiment of the invention, a K output powder and / or Li output powder as an additive to the starting mixture or reactive starting powder added so that the addition amount per 1 mol of the by the general Formula (1) expressed isotropic perovskite compound based on the element K and / or Li is not more than 0.05 mol.

Of the Forming step forms the starting mixture or the reactive starting powder to a sheet-like shaped body. The printing step prints the electrode material containing the conductive metal, on the sheet-like shaped body. The burning step is burning the shaped body. The electrode material forms after completion of the printing step, the electrode parts.

Of the Aufschichtungsschritt produces the composite, at the molded body after the completion of the printing step stacked to produce the laminate in which the electrode materials and the moldings consisting of the starting mixture are alternately stacked.

The firing step burns the laminated body to produce the multilayer piezoelectric element in which the piezoceramic layers and the electrode forming layers are alternately stacked. The firing step is performed for a period of not less than two hours at a temperature of not lower than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50%.

Accordingly can the procedures of the seventh and eighth embodiment invention as the methods of the third and fourth embodiment of the invention suppress an increase in the amount of crystal lattice defects, in the crystal grains, the piezoceramic layer form, are generated. This allows piezoceramic layers are made from the piezoceramic of the first embodiment of the invention satisfying the relationship ds / dc <1.2, where "ds" is the amount of one in the shell phase generated crystal lattice defect and "dc" the amount is a crystal lattice defect generated in the core phase. The The multilayer piezoelectric element according to the invention has both excellent deformation properties as well as excellent electrical insulation resistance.

It In particular, there is often the possibility that the electrical insulation resistance of the piezoceramic layer by a diffusion of the conductive metal in the electrode parts reduced in the electrode formation layer to the piezoceramic layer, when the piezoceramic layers and the electrode formation layers are stacked together by the previously described methods. The methods of the seventh and eighth embodiments of the invention can such a decrease in electrical insulation resistance of the multilayer piezo element appropriately suppress. This makes it possible to produce a multilayer piezoelectric element, which is suitable for electronic components.

The ninth and tenth embodiments of the invention see next Procedures in which, as in the procedures of the seventh and eighth Embodiment of the invention, the mixing step, the molding step, the printing step, the laminating step and the firing step are performed be used to produce the multilayer piezoelectric element.

Specifically, the methods of the ninth and tenth embodiments of the invention use a reactive starting powder having a specific surface area and perform the firing step at a temperature indicative of the relationship (T ₁ -T ₂ ) / t ₂ ≦ D ₁ ≦ 200 and (T ₁ - T ₂ ) / t ₂ ≤ D ₂ ≤ 200. This can suppress the generation of a crystal lattice defect in the A-space element and O-space element.

As in the methods of the fifth and sixth embodiments of the invention, piezoceramics made of the piezoceramic, which satisfies the relationship ds / dc <1.2. Therefore, the multilayer piezoelectric element having the piezoceramic layers produced by the methods of the present invention can have excellent deformation properties and excellent electrical insulation properties.

About that There is also the possibility that the electric Insulation resistance of the piezoceramic layer by diffusion of the conductive material in the electrode parts in the electrode formation layer reduced to the piezoceramic layer when the piezoceramic layers and the electrode formation layers in the above-described Processes are stacked together. The procedures of the ninth and tenth embodiment of the invention can as the method the seventh and eighth embodiments of the invention, this decrease the electrical insulation resistance of the multilayer piezoelectric element appropriately suppress. This allows one Produce multilayer piezoelectric element, which is used for electronic Components is suitable.

at the method of the seventh and ninth embodiments of the invention The mixing step mixes the anisotropic powder with the reactive one Starting powder. The molding step forms the reactive mixture into a sheet-like one Shaped body, leaving the oriented plane in the anisotropic Powder is oriented approximately in a same direction. As a result, a piezoceramic can be produced that is made of the crystal-oriented Ceramics in which the crystal grains that form the polycrystalline Form material, oriented in the specific crystal plane A. are.

on the other hand use the methods of the eighth and tenth embodiments of Invention no anisotropic powder, as in the method of the seventh and ninth embodiment of the invention is used. The mixing step in the methods of the fourth and sixth embodiments of the invention mixes at least one of a Li source, a K source, a Na source, Nb source, Ta source and Sb source selected element in a stoichiometric ratio, that is the compound expressed by the general formula (1) produced to produce a starting mixture, and then calcined the resulting starting mixture to a reactive starting powder to produce. When the firing step by the above mixing step obtained molded body burns, it can be a piezoceramic obtained from a non-oriented body consists.

- Eleventh embodiment and twelfth Embodiment of the invention

It Now follows a description of the eleventh and twelfth embodiment the invention.

• (a) erstes Vorbereiten eines anisotropen Pulvers aus orientierten anisotropen Körnern, in denen die {100}-Kristallebene orientiert ist;
• (b) zweites Vorbereiten eines reaktiven Ausgangspulvers, um durch eine Reaktion mit dem anisotropen Pulver die isotrope Perowskitverbindung zu erzeugen;
• (c) Mischen des anisotropen Pulvers mit dem reaktiven Ausgangspulver, um ein Ausgangsgemisch herzustellen;
• (d) Formen des Ausgangsgemisches zu einem lagenartigen Formkörper, so dass die orientierte Ebene jedes orientierten anisotropen Korns in dem anisotropen Pulver ungefähr in einer gleichen Richtung orientiert ist; und
• (e) Brennen des Formkörpers, um die kristallorientierte Keramik zu erzeugen.

According to the eleventh aspect of the present invention, there is provided a method of producing a crystal-oriented polycrystalline ceramics composed mainly of an isotropic perovskite compound in which a {100} crystal plane is oriented in crystal grains constituting the polycrystalline material. The method comprises the following steps (a), (b), (c), (d) and (e):

• (a) first preparing an anisotropic powder of oriented anisotropic grains in which the {100} crystal plane is oriented;
• (b) secondly preparing a starting reactive powder to produce the isotropic perovskite compound by reaction with the anisotropic powder;
• (c) mixing the anisotropic powder with the starting reactive powder to produce a starting mixture;
• (d) shaping the starting mixture into a sheet-like shaped body such that the oriented plane of each oriented anisotropic grain in the anisotropic powder is oriented approximately in a same direction; and
• (e) firing the shaped body to produce the crystal oriented ceramic.

In the method of the eleventh embodiment of the invention uses the second preparation step (b) a reactive starting powder, the a half width of a pseudocubic {002} plane in one Range of 0.4 ° to 0.8 °.

• (a) erstes Vorbereiten eines anisotropen Pulvers aus orientierten anisotropen Körnern, in denen die {l00}-Kristallebene orientiert ist;
• (b) zweites Vorbereiten eines reaktiven Ausgangspulvers, das eine Halbwertsbreite einer pseudokubischen {002}-Ebene in einem Bereich von 0,4° bis 0,8° hat, um durch eine Reaktion mit dem anisotropen Pulver die isotrope Perowskitverbindung zu erzeugen;
• (c) Mischen des anisotropen Pulvers mit dem reaktiven Ausgangspulver, um ein Ausgangsgemisch herzustellen;
• (d) Formen des Ausgangsgemisches zu einem lagenartigen Formkörper, so dass die {l00}-Kristallebene jedes orientierten anisotropen Korns in dem anisotropen Pulver ungefähr in einer gleichen Richtung orientiert ist;
• (e) Aufdrucken eines das leitende Metall enthaltenden Elektrodenmaterials, das nach Abschluss eines folgenden Brennschritt zu den Innenelektroden wird;
• (f) Aufschichten einer Vielzahl der Formkörper nach Abschluss des Druckschritts, um einen Schichtkörper herzustellen; und
• (g) Brennen des Schichtkörpers, um durch die Reaktion zwischen dem anisotropen Pulver und dem reaktiven Ausgangspulver in den Formkörpern das mehrlagige Piezoelement zu erzeugen, in dem die piezoelektrischen Schichten und die Innenelektroden abwechselnd aufeinandergeschichtet sind.

According to the twelfth aspect of the invention, there is provided a method of manufacturing a multilayer piezoelectric element in which piezoceramic layers and internal electrodes including a conductive metal are alternately stacked. The piezoceramic layer consists of a crystal-oriented ceramic, which consists of a polycrystalline material. The polycrystalline material mainly consists of an isotropic perovskite compound in which a {100} crystal plane is oriented in crystal grains constituting the polycrystalline material. The process comprises the following steps (a), (b), (c), (d), (e), (f) and (g):

• (a) first preparing an anisotropic powder of oriented anisotropic grains in which the {100} crystal plane is oriented;
• (b) second preparing a starting reactive powder having a half width of a pseudocubic {002} plane in a range of 0.4 ° to 0.8 ° to produce the isotropic perovskite compound by a reaction with the anisotropic powder;
• (c) mixing the anisotropic powder with the starting reactive powder to produce a starting mixture;
• (d) shaping the starting mixture into a sheet-like shaped body such that the {100} crystal plane of each oriented anisotropic grain in the anisotropic powder is oriented approximately in a same direction;
• (e) printing an electrode material containing the conductive metal which becomes the internal electrodes upon completion of a subsequent firing step;
• (f) coating a plurality of the molded articles after completion of the printing step to produce a laminated body; and
• (g) firing the laminated body to produce the multilayer piezoelectric element in which the piezoelectric layers and the internal electrodes are alternately stacked by the reaction between the anisotropic powder and the reactive source powder in the moldings.

- effects of the eleventh Embodiment and twelfth embodiment of the invention

The Method of the eleventh embodiment of the invention leads the first preparation step, the second preparation step, the mixing step, the molding step and the firing step to produce the crystal-oriented ceramics.

Of the most important point in the eleventh embodiment of the invention is that the second preparation step is the reactive starting powder prepared and used, which has a half width in one area from 0.4 ° to 0.8 °. The reactive starting powder with the half width in a range of 0.4 ° to 0.8 ° has a excellent reactive effect on the anisotropic powder in which the {100} crystal plane is oriented. Because this reactive starting powder during the firing step adequately with the anisotropic Powder reacts, therefore, may decrease the electrical insulation resistance suppressed and the density of crystal-oriented ceramics be increased as the final product.

conventional reactive starting powder with a low half - width of the pseudocubic {001} plane promotes crystal growth. This conventional reactive starting powder has during of the firing step has a bad reactive effect on the anisotropic Powder in which the {100} crystal plane is oriented and obstructed the production of a compact product. As a result, the crystal-oriented Ceramics as a final product a low electrical insulation resistance.

On the other hand has the reactive starting powder with the half width of the pseudocubic {002} plane of not less than 0.4 °, in the process the eleventh embodiment of the invention used in the preparation step is, a low crystallization and a superior reactive Effect on the anisotropic powder. Therefore, the use of the above reactive starting powder for a crystal-oriented Ceramic with an excellent electrical insulation resistance.

About that In addition, the method of the eleventh embodiment of the invention make a crystal-oriented ceramic using the {100} crystal plane every crystal grain is oriented. Therefore, the {100} plane is the crystal-oriented one Ceramic perpendicular to the polarization axis of the perovskite compound and lies in the same direction as the deformation direction of oriented crystal grains in the crystal oriented Ceramics. The crystal-oriented ceramic therefore shows a high deformability.

The Method according to the twelfth embodiment The invention leads the first preparation step, the second preparation step, the mixing step, the molding step, the printing step, the laminating step and the firing step through to produce the multilayer piezoelectric element.

The Method of the twelfth embodiment of the invention can the same steps except for the printing step and the firing step as the above-described method of the eleventh embodiment of Carry out invention.

The most important point of the twelfth embodiment of the invention is that the second preparation step as in the previously described eleventh embodiment of the invention comprises a reactive starting powder a half width in a range of 0.4 ° to 0.8 ° prepared and used. Therefore, since this reactive source powder adequately reacts with the anisotropic powder during the firing step, a decrease in the electrical insulation resistance can be suppressed and the density of the crystal-oriented ceramic can be increased.

If the piezoceramic layers and the internal electrodes are stacked and the layered body as a single body Incidentally, the conductive metal diffuses from the inner electrode to the piezoceramic layer and reduces it often the electrical insulation resistance of the piezoceramic layer. However, the structure of the multilayer piezoelectric element suppresses that by the method of the twelfth embodiment of Invention, adequately the decrease of the electrical Insulation resistance. Therefore, the procedure represents the twelfth Embodiment of the invention, the multilayer piezoelectric element as electrical Components ago.

The Method according to the twelfth embodiment The invention can also produce a piezoceramic layer which consists of the crystal-oriented ceramic in which the {100} crystal plane every crystal grain is oriented. Therefore, the oriented level the piezoceramic layer perpendicular to the polarization axis of the perovskite compound and takes the same direction as the deformation direction of oriented crystal grains in the crystal oriented Ceramics. Therefore, this can be done by the twelfth embodiment The invention achieved multilayer piezoelectric element has a high deformability demonstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

Under Reference to the accompanying drawings will be given by way of example a preferred, non-limiting embodiment of the invention. Show it:

1A a view showing an overall structure of a multilayer piezoelectric element according to a first embodiment of the invention;

1B a sectional view of the in 1A shown multilayer piezoelectric element along its Aufschichtungsrichtung;

2 a view showing a structure of crystal grains forming a piezoceramic layer formed in the multi-layered piezoelectric element between electrode parts;

3 a SEM photograph showing a piezoceramic layer formed between electrode parts of the multilayer piezoelectric element in accordance with a first experiment;

4 a photograph of a cathodoluminescence (CL) spectral analysis showing the piezoceramic layer of the multilayer piezoelectric element according to the first attempt;

5 4 is a graph showing a relationship between the wavelength and the CL intensity of a core phase (or a core portion) and a cladding phase (or cladding layer) of the piezoceramic layer determined by the cathodoluminescence (CL) spectral analysis according to the first experiment ;

6 a schematic view showing a structure of a Perowskitverbindung according to a second embodiment of the invention;

7 a view showing a temperature control during a burning step in a method according to a third embodiment of the invention;

8th a photograph of a CL spectral analysis showing the piezoceramic layer of the multilayer piezoelectric element according to a second experiment;

9 FIG. 4 is a graph showing a relationship between the wavelength and a CL intensity of a core phase and a cladding phase in the piezoceramic layer determined by the CL spectral analysis according to the second experiment; FIG.

10 a view showing a structure of a starting mixture according to a fourth embodiment of the invention by mixing an anisotropic powder and a reactive output powder was achieved;

11 10 is a view showing an internal structure of a molded article in which the anisotropic powder according to the fourth embodiment of the invention is oriented approximately in a specific direction;

12 a view showing according to the fourth embodiment of the invention, a crystal growth of the anisotropic powder in the molding during the firing step;

13 a view showing a crystal-oriented ceramic according to the fourth embodiment of the invention;

14A a view showing the reactive starting powder according to the fourth embodiment of the invention;

14B a view showing the reactive starting powder after completion of the calcination step;

15A a view showing an overall structure of a multilayer piezoelectric element according to a fifth embodiment of the invention; and

15B a sectional view of the in 15A shown multilayer piezoelectric element along its Aufschichtungsrichtung.

DETAILED DESCRIPTION THE PREFERRED EMBODIMENTS

in the The following will be with reference to the accompanying drawings various embodiments of the invention described. In the following description of the various embodiments denote in the various representations like reference numerals or numbers are the same or corresponding components.

It follows a description of the preferred embodiments the invention in terms of the first to tenth embodiment the invention.

The piezoceramic is made of a polycrystalline material mainly composed of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb ₁ Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1.

The technical term "isotropic" means that the relative ratio of the axial lengths a, b and c has a value in a range of 0.8 to 1.2 and that their respective axial angle α, β and γ in a range of 80 ° to 100 ° lies when the perovskite structure ABO _{3 has} a pseudo-cubic primitive lattice.

When a compound expressed by the above general formula (1) is applied to the composition equation ABO _{3 of} the perovskite structure, the A-site atom may have a composition ratio to a composition ratio of the A-site element and the B-site element from 1: 1 by 5%. This means that the relationship 0.95 ≤ a ≤ 1, better still 0.97 ≤ a ≤ 1, is satisfied.

In of the above general formula (1), the relationship "x + z + w> 0 ", that it is sufficient if at least one selected from Li, Ta and Sb Element is included as a substitution element.

Of Further, the value "y" in the above general Formula (1) the ratio of K and Na, which is in the isotropic Perovskite compound is included. It is enough if in the through the general formula (1) expressed isotropic perovskite compound at least one element selected from K and Na as the A-space element is included.

It is preferable that the value "y" in the general formula (1) has a range of 0 <y ≦ 1. In this case, Na is an essential ingredient in the compound expressed by the general formula (1) part. As a result, the piezoelectric constant g _{31 of} the piezoceramic can be further increased.

In addition, the value "y" in the general formula (1) may have a range of 0 ≦ y <1. In this case, K is an essential ingredient in the compound expressed by the general formula (1). This ₃₁ may further enhance the piezoelectric characteristics such as the piezoelectric constant d. Since the piezoceramic can be sintered at a low temperature according to the higher amount of added K, it is thereby possible to produce the piezoceramic with lower manufacturing costs and to reduce the amount of energy used.

Moreover, it is preferable that the value "y" in the general formula (1) is in a range of 0.05 ≦ y ≦ 0.75, and more preferably in a range of 0.20 ≦ y ≦ 0.70 , As a result, the piezoelectric constant d ₃₁ and the electromechanical coupling factor K _{p of} the crystal-oriented ceramic can be further increased.

It It is further preferable that the value "y" in of the general formula (1) in a range of 0.20 ≦ y <0.70, better yet in a range of 0.35 ≦ y ≦ 0.65 and still better in a range of 0.35 ≦ y <0.65. He is best in a range of 0.42 ≦ y ≦ 0.60.

In the general formula (1), the value "x" indicates the substitution amount of Li with which the A-site element such as K and / or Na is substituted. The substitution of K and / or Na with Li can increase the piezoelectric properties and the Curie temperature T _C and promote the density.

It is preferable that the value "x" in the general formula (1) is in a range 0 <x ≦ 0.2. In this case, since Li is an essential ingredient in the isotropic perovskite compound expressed by the general formula (1), the firing step during the production of the piezoceramic is easier to perform. Furthermore, the piezoelectric characteristics can thereby be improved and, in addition, the Curie temperature (T _C ) of the piezoceramic can be further increased. Since Li in the general formula (1) becomes an essential component in the region of the value "x", the firing temperature can be lowered and Li, as a fuel, can produce a piezoceramic having a smaller number of pores.

When the value "x" is more than 0.2, there is a possibility of decreasing the piezoelectric characteristics (such as the piezoelectric constant d ₃₁ , the electromechanical coupling factor K _p and the piezoelectric constant g ₃₁ ).

The value "x" may be zero (x = 0) in the general formula (1). In this case, the general formula (1) can be expressed by (K _1-y Na _y ) _a (Nb _1-zw Ta _z Sb _w ) O _3-k . In this case, in the case of producing the crystal-oriented ceramic, since there is no compound such as LiCO ₃ containing the maximum light Li, variations in characteristics caused by a change in the starting powders can be reduced when the starting materials are mixed. Furthermore, in this case, a piezoceramic having excellent relative permeability and a relatively large piezoelectric constant "g" can be produced. It is preferable that the value "x" in the general formula (1) has a range of 0 ≦ x ≦ 0.15, and more preferably a range of 0 ≦ x <0.10.

The value "z" in the general formula (1) indicates the amount of Ta substituted with Nb as the B-site element. The substitution of a part of Nb with Ta has the effect of increasing the piezoelectric characteristics of the piezoceramic. When the value "z" in the general formula (1) is more than 0.4, the Curie temperature T _{C of} the crystal oriented ceramics decreases. This leads to the possibility that it is difficult to use the piezoceramic in household applications and automotive components.

It It is therefore preferable that the value "z" in the general formula (1) has a range of 0 <z ≦ 0.4. In this case Ta is expressed by the general formula (1) isotropic perovskite compound an essential component. This lowers the sintering temperature accordingly, with Ta serving as the fuel and reduce the number of pores produced in the piezoceramic can.

The value "z" can be zero (z = 0). In this case, the general formula (1) is expressed by {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-w Sb _w ) O ₃ . In this case, since the compound expressed by the general formula (1) does not contain Ta, the compound expressed by the general formula (1) can have excellent piezoelectric characteristics without using expensive Ta in the preparation of this compound.

It It is preferable that the value "z" in the general Formula (1) has a range of 0 ≦ z ≦ 0.35 and better still has a range of 0 ≤ x ≤ 0.30.

Of Further, the value "w" in the general Formula (1) the amount of Sb, substituted with the Nb as B-site element becomes. The substitution of a part of Nb with Sb ensures that that increases the piezoelectric characteristics of the piezoceramic become. Since the piezoelectric characteristics and / or the Curie temperature of the crystal oriented ceramic when the value "w" in of the general formula (1) is more than 0.2, it is avoided that the value "w" is more than 0.2.

It It is therefore preferable that the value "w" in the general formula (1) has a range of 0 <w ≦ 0.2. In this case Sb is as expressed by the general formula (1) Compound an integral part. Accordingly, you can thereby lowering the sintering temperature, improving the sintering characteristics and also the stability of the dielectric Loss tanδ the crystal-oriented ceramics are increased.

The value "w" may be zero (w = 0) in the general formula (1). In this case, the general formula (1) can be expressed by {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-z Ta _z ) O ₃ . Since this compound expressed by the above general formula (1) contains no Sb, the compound expressed by the general formula (1) can do without Sb and have a relatively high Curie temperature. It is therefore preferable that the value "w" in the general formula (1) has a range of 0 ≦ w ≦ 0.15, and more preferably a range of 0 ≦ w ≦ 0.10.

It Although it is preferable that the piezoceramic from the above general formula (1) expressed isotropic perovskite compound but it can also be another element and phase as long as they do not have a bad influence, the sintering characteristics and the piezoelectric characteristics and other characteristics deteriorated.

The Crystal grains that form the piezoceramic have one Core phase (or core part) and shell phase (or a shell layer) containing various chemical compositions have, with the sheath phase surrounding the core phase. The means that the crystal grains containing the piezoceramic have a core and sheath structure.

The Core phase consists of an isotropic perovskite compound compared with the average composition of the whole from the isotropic perovskite compound existing piezoceramic more elemental components Na, Ta and Sb contains.

on the other hand the shell phase consists of one by the general Formula (1) expressed isotropic perovskite compound, which compared with the average composition of the whole Piezoceramic contains more elemental components K and Nb.

If the chemical composition of the core phase with that of the shell phase is compared, the difference is the chemical Composition between them about 3% to 25%.

The different composition between the core phase and the Sheath phase in the piezoceramic forming crystal grains can be determined by the following procedure.

First is used as element mapping analysis by means of an X-ray microprobe an EPMA (electron beam microanalysis) performed, while applying an acceleration voltage of 15 kV becomes. Then, a ZAF correlation is performed to the Composition of the core phase and the shell phase in the To determine crystal grains. There is a complete Element mapping analysis based on the determined element distribution to identify the core phase and the sheath phase. This gives elemental analysis results for different species of crystal grains. For more precise analysis results To achieve this, the EPMA must be responsible for the core phase and the sheath phase are performed. It follows then a ZAF correlation to each of the detailed composition the core phase and the shell phase.

It may also be a microscopic observation using the BSE image a SEM (Scanning Electron Microscope) are used with the the core phase and the shell phase are slightly independent can be detected by each other. Such a REM observation can be the Core phase and the shell phase clearly independent capture each other.

The Piezoceramic satisfies the relationship ds / dc <1.2, where dc the Amount of a crystal lattice defect generated in the core phase and ds is the amount of a crystal lattice defect generated in the shell phase is.

Of the Context ds / dc ≥ 1.2 gives the possibility that the electrical insulation resistance of the piezoceramic decreases.

The the piezoceramic polycrystalline material may be oriented Body (crystal-oriented ceramics) in which a specific Crystal plane A is oriented, or an unoriented body in which no crystal plane is oriented.

With In other words, the piezoceramic, if made of a crystal-oriented Ceramic or a non-oriented ceramic, with a high electrical insulation resistance can be achieved, provided they the relationship ds / dc <1,2 Fulfills.

It is preferable that the piezoceramic of a crystal-oriented Ceramic in which a specific crystal plane A in crystal grains, which form the polycrystalline material is oriented. Thereby can the piezoelectric characteristics of the piezoceramic be further increased. It is preferable that the crystal plane A is a {100} level. If this {100} plane is oriented or aligned is, the piezoceramic can have a high dislocation performance, because the {100} plane is perpendicular to the polarized axis of a perovskite compound is and the direction of deformation of the oriented grains and the {100} plane have the same direction.

In The crystal-oriented ceramic is a specific crystal plane A of the crystal grains containing the polycrystalline material The crystal-oriented ceramic form, oriented or aligned. That means the specific levels A of the crystal grains in the isotropic perovskite compound are oriented parallel to each other. (This structure is called "surface orientation.")

The Type of crystal plane A oriented can according to the direction the spontaneous polarization, the field of application of the crystal-oriented Ceramic and the required characteristics are selected. The means that depending on the purpose or need either a pseudocubic {100} plane, a pseudocubic {200} plane, a pseudocubic {101} plane and a pseudocubic {111} plane can be chosen.

pseudocubic {HKL} means that the structure of the isotropic perovskite compound Although in general it has a structure that is opposite one quadrangular grid, an oblique grid, a trigonal Grid and a cubic grid is slightly shifted, that this Shift amount, however, is small, so pseudo-cubic as a treated cubic lattice and therefore using the Miller indices {HKL} can be expressed.

When a specific crystal plane A is plane-oriented, the plane orientation degree can be expressed by the following Mathematical Equation (1) by means of a mean orientation degree F (HKL): F (HKL) = [{Σ'I (HKL) / ΣI (hkl)} - {Σ'Io (HKL) / ΣIo (hkl)}] / [1 - {Σ'Io (HKL) / ΣIo (hkl) }] × 100 (%) Mathematical equation (1), where ΣI (hkl) is the sum total of the detected X-ray diffraction intensities of all crystal planes (hkl) of a crystal oriented ceramic, ΣIo (hkl) is the sum total of the detected XRD intensities of all crystal planes (hkl) of a non-crystal oriented ceramic having the same composition as the crystal oriented ceramics, Σ ' I (HKL) is the sum total of the detected X-ray diffraction intensities of a specific crystal plane (HKL) corresponding to the crystal oriented ceramics in a crystallographic analysis, and Σ'Io (HKL) is the sum total of the detected XRD intensities of the specific crystal plane (HKL) Crystallographic analysis of the non-crystal-oriented ceramic with the same composition as the crystal-oriented ceramic corresponds.

If none of the crystal grains containing the polycrystalline material is oriented in a specific level their mean orientation degree F (HKL) corresponding to 0%. On the other hand each of the crystal grains containing the polycrystalline material is oriented in a specific crystal plane is their mean orientation degree F (HKL) 100%.

ever more the ratio of the crystal grains, the are oriented in a specific crystal plane, in the crystal-oriented one Ceramic increases, the higher the deformation effect the piezoceramic layers.

It is also preferable that the specific crystal plane to be oriented is a plane that is perpendicular to a polarized axis.

There the crystal-oriented ceramics generally made of a polycrystalline Material consists mainly of an isotropic material Perovskite compound, it can with a lead-free piezoceramic ensure high piezoelectric characteristics. Because the specific Crystal plane in crystal-oriented ceramic in every crystal grain, which forms the polycrystalline material, in a same direction Oriented or aligned, can also be compared with a non-oriented sintered body (an unoriented Body) with the same composition as the crystal-oriented Ceramic for high piezoelectric characteristics are taken care of.

The Ceramics consisting of the isotropic perovskite compound, the a complicated composition like that by the general formula (1) has expressed link can through the following Process are produced.

It a variety of compounds are mixed, each one of which simple composition that has an elemental component of a planned composition has to have a planned reaction stoichiometry to achieve the planned composition. That achieved Mixture is shaped and calcined. The mixture is then broken. The break is reshaped and then sintered. By the above method a piezoceramic is produced, which consists of a non-oriented Body exists.

Indeed it is difficult with the above method, a crystal-oriented Ceramics in which a specific crystal plane each Crystal grain is oriented or aligned in a specific direction.

While the manufacturing process for the piezoceramic, the crystal-oriented ceramic, the anisotropic powder can be oriented or aligned during the molding step. By using the anisotropic powder as a template or reactive template can also be expressed by the general formula (1) isotropic perovskite compound synthesized and then sintered. By this method, a crystal-oriented ceramic can be produced in which a specific level of each polycrystalline Material forming crystal grain oriented in a same direction or is aligned. The method for producing the from crystal-oriented ceramic existing piezoceramic will be later explained.

It But it is also possible to use the piezoceramic which does not oriented body exists. This ensures during the production of piezoceramic for easy preparation of the starting material. This means that the piezoceramic easy to manufacture.

The from a non-oriented body or a crystal-oriented one Ceramic existing piezoceramic can be produced by the method of manufacture the piezoceramic according to the third and fourth Embodiment of the invention are prepared, previously in the Section "Summary of the invention" has been described and described in the following embodiments becomes.

In the mixing step of the method according to the invention for producing the piezoceramic are an anisotropic powder and a reaction starting powder mixed to form a starting powder mixture with a stoichiometric ratio to produce which produces the compound expressed by the general formula (1), or at least one element from a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source mixed and calcined to produce the reactive starting powder. Calcination takes place for a period of 2 to 5 hours in a temperature range of 600 ° C to 720 ° C.

Of Further, in the mixing step, a K starting powder is also added and / or a starting Li powder as an additive in the starting powder mixture or given the reactive starting powder, so this added amount per 1 mole of that expressed by the general formula (1) isotropic perovskite compound based on the element K and / or Li is not more than 0.05 mol. It means that the K-starting powder and / or the Li-starting powder mixed in this way be that the amount of the element K in the K starting powder and / or the amount of element Li in the Li starting powder per 1 mole of isotropic perovskite compound not more than 0.05 mole.

If the amount of addition of K starting powder and / or Li starting powder based on the element K and / or Li is more than 0.05 mol, there is a possibility that the chemical composition the generated isotropic perovskite compound of the predetermined Moved composition or that in the piezoceramic as the final product an anisotropic phase is generated. This makes it possible that a piezoceramic with worse piezoelectric properties will be produced.

It It is preferable that the K starting powder and / or the Li starting powder be selected from carbonate, bicarbonate and borate. This makes it possible to use crystal lattice defects of an A-space element repair and also serve as a sintering agent. This reduces during the production of the piezoceramic, the sintering temperature.

In the forming step of the method for producing the piezoceramic according to third and fourth embodiment of the invention, previously in the Section "Summary of the Invention" described was, are the starting mixture and the reactive starting powder shaped so that the shaped body is produced. While of the molding step, the starting mixture is introduced by, for example Doctor blade method, a pressing method or a rolling method to a shaped sheet-like shaped body. It is preferable that the shaped body, the starting mixture to a sheet-like Shaped body with a thickness of not less than 30 microns shaped. A sheet-like molding having a thickness of less than 30 microns difficult during production the piezoceramic handling of the molding.

In the firing step of the method for producing the piezoceramic according to the third and fourth aspects of the invention, the shaped body is fired to produce the piezoceramic. The burning takes place for a duration of not less than 2 hours at a firing temperature of not lower than 900 ° C under the condition of an oxygen partial pressure P _{02 of} the ambient atmosphere of not less than 50%.

When the oxygen partial pressure P _{02 of} the ambient atmosphere is less than 50% or the firing temperature is less than 900 ° C or the firing time is less than 2 hours, the amount of defects generated at the O-site of the piezoceramic is generated after completion of the firing step are, higher. This reduces the electrical insulation resistance of the piezoceramic.

The Piezoceramic can also by the method according to the Fifth and sixth embodiments of the invention beforehand, in the "Summary" section of the Invention "has been described and in the following embodiments is described.

The method uses the starting reactive powder having a specific surface area in a range of 2 to 5 m ² / g.

If a starting reactive powder having a specific surface area of less than 2 m ² / g is used, the firing temperature lowers, whereby there is a possibility that large crystal grains are generated in the piezoceramic. This deteriorates the piezoelectric properties of the piezoceramic. In addition, this makes the production of a piezoceramic with the relationship ds / dc <1.2 more difficult.

On the other hand, when a reactive starting powder having a specific surface area of more than 5 m ² / g is used, the firing temperature increases. As a result, there is the possibility that internal electrodes melt, which are formed in a multi-layered piezo element that uses the piezoceramic.

The firing step of the method according to the fifth and sixth aspects of the invention is composed of a temperature increasing step, a first temperature holding step, a temperature decreasing step, and a second temperature holding step performed while the relationship (T ₁ -T ₂ ) / t ₂ ≦ D ₁ ≤ 200 and (T ₁ -T ₂ ) / t ₂ ≤ D ₂ ≤ 200, where 1050 <T ₁ ≤ 1150, t ₁ ≤ 5, 950 ≤ T ₂ ≤ 1050, and 2 ≤ t ₂ ≤ 20.

In the piezoceramic can during the first temperature holding step the core phase and during the second temperature holding step the sheath phase grow.

The holding temperature T ₁ of not more than 1050 ° C during the first temperature holding step often generates a piezoceramic of insufficient density. As a result, there is a possibility that a piezoceramic having an insufficient density is produced.

On the other hand, there is the possibility that the number of errors generated in the piezoceramic increases when the holding temperature T ₁ during the first temperature holding step is more than 1050 ° C. This reduces the electrical insulation resistance of the piezoceramic.

Moreover, if the holding time t _{1 of} the holding temperature T ₁ during the first temperature holding step is more than 5 hours, there is also a possibility of increasing the number of errors generated in the piezoceramic. It is therefore preferable that the first temperature holding step has a holding time t ₁ of not less than 0.1 hours (t ₁ ≥ 0.1 hours).

During the second temperature holding step, a holding temperature of T ₂ less than 950 ° C in the piezoceramic often creates an insufficient sheath phase.

On the other hand, when the holding temperature T _{2 is} more than 1050 ° C during the second temperature-holding step, there is a possibility that the core phase is generated during the second temperature-holding step while the casing phase is prevented from easily growing.

When the holding period t _{2 of} the holding temperature T ₂ during the second temperature-holding step is less than 2 hours, there is a possibility of preventing the casing phase from easily growing.

On the other hand, if the holding time t _{2 of} the holding temperature T ₂ during the second temperature-holding step is more than 20 hours, there is a possibility that a piezoceramic is produced whose casing phase is very thick. This leads to a change in temperature to a fluctuation of the piezoelectric properties. That is, there is the possibility that a poor dependence of the piezoelectric properties on a temperature change arises.

If the firing step takes place with the relationship D ₁ <(T ₁ -T ₂ ) / t ₂ or D ₂ <(T ₁ -T ₂ ) / t ₂ , there is the possibility that the relationship ds / dc is not less than 1, 2. On the other hand, if D ₁ > 200 or D ₂ > 200, there is a possibility that the piezoelectric properties of the piezoceramic will decrease due to generation of an insufficient amount of liquid phase.

It is therefore preferable that the relationship D ₁ ≦ 100 and D ₂ ≦ 100 holds.

In the method for producing the piezoceramic, which is a crystal-oriented Ceramics used in a specific crystal plane A each Crystal grain, which forms the polycrystalline material, oriented is, the starting mixture as in the previously described third and fourth embodiment of the invention by mixing an anisotropic Powder and a reactive starting powder generated. The anisotropic Powder consists of a perovskite compound, which is oriented from anisotropic grains that one is oriented Form surface in which a crystal plane to the grid the specific crystal plane A fits, and it comes to the reaction between the anisotropic powder and the reactive starting powder, such that expressed by the general formula (1) isotropic perovskite compound is produced.

While of the molding step, the starting mixture is formed into a layer so that the oriented surface of the anisotropic powder oriented or oriented in a same direction is. As a result, one consisting of a crystal-oriented ceramic Piezoceramic be produced in the specific crystal plane A of each crystal grain forming the polycrystalline material, is oriented. This structure of the piezoceramic ensures even better piezoelectric properties.

It Now follows a description of the method for producing the the crystal-oriented ceramic existing piezoceramic.

When Anisotropic powder can be a powder of oriented grains can be used, which consist of a Perowskitverbindung. The Oriented grains have an anisotropic shape, the one oriented surface in which a crystal plane, the with respect to the lattice to the specific crystal plane A of the crystal grains fits, is oriented.

Of the Lattice degree can be determined by means of a lattice matching percentage be expressed. The meshing degree will now be explained. In the case of a metal oxide as oriented grain, a lattice match to the Example given when the from an oxygen atom or a metal atom existing lattice point in a two-dimensional crystal lattice the specific oriented in the polycrystalline material Crystal plane A has a similar relationship.

Of the Grid Fit is expressed as the percentage of a value which is achieved by first the grid dimension of oriented surface in the oriented grain of the Grid dimension at the corresponding point (or an analogue) of the subtracted specific crystal plane A in the polycrystalline material and by taking the absolute value of this subtraction result the grid dimension of the oriented surface in the divided grain is divided.

The Grid dimension is the distance between grid points in the two-dimensional Crystal lattice structure in a crystal plane. The grid dimension (or the lattice spacing) can be determined by a crystal structure analysis be determined using the X-ray diffraction method or the electron diffraction method. In general the oriented grain is more likely to have a high degree of meshing with the specific crystal plane A, the lower the lattice mating degree is. These oriented grains act as a high performance template.

Around a crystal-oriented ceramic with a high degree of orientation To achieve, it is preferable that the lattice degree does not more than 20% is that the lattice pass better not more than 10% and that the lattice pass rate even better not more than 5%.

It It is preferable that the oriented surface of the oriented Korns the same as the specific crystal plane A is. In this Case can easily be one made of a crystal-oriented ceramic Piezoceramic be produced in the specific crystal plane A is oriented. So can the oriented grains In particular, grains are used in which a pseudocubic Oriented {100} plane and / or a pseudocubic {200} plane is. As a result, a piezoceramic with improved temperature dependency characteristics a large electric field in a square grid in which the oriented axis is equal to the axis of polarization is.

The "anisotropic Form "denotes a form in which the dimension in the Longitudinal direction longer than the dimension in latitude or thickness direction. Such an anisotropic structure has in particular a plate shape, a columnar shape, a flake shape or a needle shape. The type of crystal plane that the oriented surface can form, as needed from different types of crystal planes to get voted.

It is preferable than the oriented grains a material to use, which has a form, with which the crystal plane during the molding step easily in a specific direction orient. For this reason, it is preferable that the oriented grain has a mean aspect ratio of not less than 3 has.

If the mean aspect ratio is less than 3, lets the anisotropic powder during the molding step difficult to orient in a specific direction. To the out Crystal-oriented ceramic existing piezoceramic with a higher Orientation degree, it is preferable that the oriented Grain an aspect ratio of not less than 5 has. The mean aspect ratio is an average of maximum dimension to the minimum dimension of the oriented grains.

ever greater the mean aspect ratio which is oriented grains, the easier it can be the oriented grains during the forming step orientate. If the mean aspect ratio however, is extremely high, there is a possibility that the oriented grains during the mixing step break. This makes it difficult to produce a shaped body, in which the oriented grains are oriented. It is therefore, it is preferable that the oriented grains have a middle Aspect ratio of not more than 100 have. It is better if the oriented grains are a medium Have aspect ratio of not more than 50, and even better, they have a medium aspect ratio of not more than 30.

The oriented grains consist of a perovskite compound. In a concrete example can be considered oriented grains A compound can be used that has the same chemical composition as the desired isotropic perovskite compound has, such as by the general formula (1) expressed compound.

It is not always necessary to connect with the same chemical Composition like the desired isotropic perovskite compound to use, such as those expressed by the general formula (1) Connection. It can also be used as a material Main component generates the desired isotropic perovskite compound, about the compound expressed by the general formula (1), by using the reactive starting powder described later is sintered.

Accordingly either a mixed crystal or a compound can be chosen be one or more positive interior elements (or positively charged Internal elements) contained in the perovskite compound to be produced are included.

As these oriented grains satisfying the above condition, for example, the following compounds may be used:
NaNbO ₃ (hereinafter referred to as "NN"), KNbO ₃ (hereinafter referred to as "KN") and (K _1-y Na _y ) NbO ₃ (0 <y <1) which are an isotropic perovskite compound type, or in the above Materials are substituted or dissolved by a predetermined amount of Li, Ta and / or Sb, which is expressed by the following general formula (2): {Li _x (K _1-y Na _y ) _1-x } (Nb ₁ Ta _z Sb _w ) O ₃ (2) where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, and 0 ≦ w ≦ 1 holds.

The compounds expressed by the general formula (2) have a good and high lattice matching function the isotropic one expressed by the general formula (1) Perovskite. Therefore, this is oriented from the above Grains consisting of anisotropic powder (hereinafter referred to as the "anisotropic Powder A "), represented by the general formula (2) is expressed as a reactive template to the to produce crystal-oriented ceramics. In the above oriented Grains is the plane that is relative to the grid to the crystal plane A in the polycrystalline material, the oriented level.

About that In addition, the anisotropic powder A consists essentially of positive Ionic elements (or positively charged ionic elements) used in the expressed by the general formula (1) isotropic Perovskite compound are included. This can be a crystal-oriented Ceramics are made containing a smaller amount of impurity elements Has.

When Anisotropic powder can also be a layered perovskite compound in which, for example, a crystal plane with less Surface energy with respect to the grid to the Crystal plane A in which expressed by the general formula (1) polycrystalline material fits.

There a layered perovskite compound is a large anisotropic Crystal lattice, this can be from the layered Perovskite compound existing anisotropic powder (hereinafter referred to as referred to as "anisotropic powder B"), referred to as oriented plane has a low surface energy, easy to make.

An example which can be used for the layered perovskite compound is, for example, a bismuth layer perovskite compound expressed by the following general formula (3): (Bi ₂ O ₂ ) ²⁺ {Bi _0.5 Me _m-1.5 NbmO _{3m + 1} } ^2- (3) wherein m is an integer of not less than 2 and Me is one or more of Li, K and Na.

Unlike the other planes in the compound expressed by the general formula (3), a {001} crystal plane generally has a low surface energy. The use of the compound expressed by the general formula (3), therefore, facilitates the work of synthesizing the above anisotropic powder B having the {001} oriented layer. The oriented {001} plane is parallel to the (Bi ₂ O ₂ ) ²⁺ layer of the bismuth layer perovskite compound expressed by the general formula (3). Further, the {001} plane in the compound expressed by the general formula (3) greatly matches the {100} plane of the isotropic perovskite compound expressed by the general formula (1).

The anisotropic powder B, which is characterized by the general formula (3) consists of an expressed {001} crystal plane has, provides a good reactive template or a good anisotropic powder to produce the crystal-oriented ceramic.

If the compound expressed by the general formula (3) is used, the anisotropic powder B can be adjusted that it contains essentially no Bi as an A-space element, by adjusting the composition of the reactive starting powder will be explained later.

Accordingly, even if the anisotropic powder B is used, a piezoceramic made of the crystal-oriented ceramic can be produced, which is mainly composed of the one obtained by the all consists of the general formula (1) expressed isotropic perovskite compound.

A preferred second example of the layered perovskite compound as the anisotropic powder B is, for example, Sr ₂ Nb ₂ O ₇ . The {010} plane of Sr ₂ Nb ₂ O ₇ has a low surface energy compared to the other planes. Further, the {010} plane of Sr ₂ Nb ₂ O ₇ highly matches the {110} plane of the isotropic perovskite compound expressed by the general formula (1). Therefore, an anisotropic powder consisting of Sr ₂ Nb ₂ O ₇ in which the {010} plane is an oriented plane can be used as a reactive template to produce a crystal oriented ceramic having an oriented {110} plane.

A preferred third example of the layered perovskite compound as anisotropic powder B is, for example, Na _1.5 Bi _2.5 Nb ₃ O ₁₂ , Na _2.5 Bi _2.5 Nb ₄ O ₁₅ , Bi ₃ TiNbO ₉ , Bi ₃ TiTaO ₉ , K _0.5 Bi _2.5 Nb ₂ O ₉ , CaBi ₂ Nb ₂ O ₉ , SrBi ₂ Nb ₂ O ₉ , BaBi ₂ Nb ₂ O ₉ , BaBi ₃ Ti ₂ NbO ₁₂ , CaBi ₂ Ta ₂ O ₉ , SrBi ₂ Ta ₂ O ₉ , Na _0.5 Bi _2.5 Ta ₂ O ₉ , Bi ₇ Ti ₄ NbO ₂₁ , Bi ₅ Nb ₃ O ₁₅ , etc.

The {001} plane in the above compounds fits of the lattice to a high degree to the pseudocubic {100} plane the isotropic one expressed by the general formula (1) Perovskite. Accordingly, an anisotropic powder from one of these links, where the {001} plane is an oriented one Level is to be used as a reactive template to be a crystal-oriented To produce ceramic with an oriented pseudocubic {100} plane.

A preferred third example of the layered perovskite compound as the anisotropic powder B is, for example, Ca ₂ Nb ₂ O ₇ and Sr ₂ Ta ₂ O ₇ , etc.

The {010} plane in the above links fits of the lattice to a high degree to the pseudocubic {110} plane the isotropic one expressed by the general formula (2) Perovskite. Accordingly, an anisotropic powder from one of these compounds in which the {010} plane is oriented Level is to be used as a reactive template to be a crystal-oriented To produce ceramic with an oriented pseudocubic {110} plane.

When Next follows a description of a method of manufacturing of the above anisotropic powder.

The anisotropic powder (ie, the anisotropic powder B) consisting of the layered perovskite compound can be easily prepared by the following steps with a predetermined composition, a predetermined average grain size, and / or a predetermined aspect ratio:
Preparing an oxide, carbonate, nitrate, etc. (hereinafter referred to as the "anisotropic powder raw material") containing its constituent elements; and
Heating the anisotropic powder starting material with a liquid or material that becomes liquid upon heating.

If the anisotropic powder starting material is heated in a solution is allowed, which allows for easy diffusion easily synthesize an anisotropic powder B in which the Low surface energy level (for example, the {001} plane in the compound expressed by the general formula (3)) growing with priority. In this case, you can the mean aspect ratio and the mean Grain size of the anisotropic powder B by selection be set to an optimal synthesis condition.

There are the following methods for producing the anisotropic powder B: a method in which an optional flux (for example, NaCl, KCl, a mixture of NaCl and KCl, BaCl ₂ , KF, etc.) is added to the anisotropic powder starting material and the mixture is then heated, or a method in which an irregularly shaped powder having the same composition as the produced anisotropic powder B and an alkali solution are heated in an autoclave. The former method is called "flux method". The latter method is called "hydrothermal method".

There the compound expressed by the general formula (2) it is, on the other hand, a crystal lattice with very little anisotropy difficult, the anisotropic powder (i.e., the anisotropic powder A), that expressed by the general formula (2) Compound in which the specific crystal plane oriented one Level is to synthesize directly. However, this can be anisotropic Powder A are prepared while the above described Anisotropic powder B is used as a reactive template by it in a flux with a reactive starting material B heated which satisfies a predetermined condition.

If the anisotropic powder A using the anisotropic powder B as a reactive template is synthesized under optimal conditions Reaction conditions are changed its crystal structure without affecting the shape of the powder.

Around the anisotropic powder A, which during the molding step in to be oriented in a specific direction it is preferable that during the anisotropic powder B to be used in the synthesizing step has a shape that is easy during the shaping step oriented in the specific direction.

If the anisotropic powder A using the anisotropic powder B is synthesized as a reactive template, it is therefore preferable to the anisotropic powder A has an average aspect ratio not less than 3, better still not less than 5 and even better of not less than 10 has. Furthermore It is preferable that the anisotropic powder A has an average aspect ratio of not more than 100, to prevent the product from being in to break a next step.

The previously described reactive starting material B is a compound with the anisotropic powder A, which is made by the general Formula (2) is composed by one Reaction with the anisotropic powder B can produce. In this case it is for the reactive starting material B acceptable if it is due to the reaction with the anisotropic powder B only those expressed by the general formula (2) Connection created. It is also acceptable if it is due to the reaction with the anisotropic powder B both an excess Material as well as those expressed by the general formula (2) Connection created. The "excess Material "means a different material than the material the general formula (2) expressed compound as the planned product. If the excess material by the reaction between the anisotropic powder B and the reactive one It is also preferable that the excess material through a thermal or to easily remove chemical treatment from the product.

When Reactive starting material B may be, for example, an oxide powder, a Mixed oxide powder, a carbonate, a nitrate, an oxalate, an alkoxide etc. are used. The chemical composition of the reactive Starting material B may be based on the manufactured and by the general formula (2) and compound expressed the composition of the anisotropic powder B.

If an anisotropic powder A is prepared consisting of NaNbO ₃ (NN) as one kind of the compounds expressed by the general formula (2) by using an anisotropic powder B composed of Bi _2.5 Na _{0, 5} Nb ₂ O ₉ as a kind of the bismuth layer-perovskite compound expressed by the above general formula (3), as the reactive raw material B, a Na-containing compound (such as an oxide, a hydroxide, a carbonate, a Nitrate, etc.).

When in the anisotropic powder B and the reactive starting material B having the above composition, a suitable flux in a range of 1 wt .-% to 500 wt .-% (for example, NaCl, KCl, a mixture of NaCl and KCl, BaCl ₂ , KF, etc.) and the mixture is heated to a temperature considering a eutectic point and a melting point, the excess material consists mainly of NN and Bi ₂ O ₃ . Since Bi ₂ O _{3 has} a low melting point and low acid resistance, the N-anisotropic powder A in which the {100} plane is an oriented plane can be prepared by eliminating the flux from the obtained reaction product then heated or rinsed with acid.

Further, in synthesizing an anisotropic powder A consisting of (K _0.5 Na _0.5 ) NbO ₃ (hereinafter referred to as "KNN") as one kind of the compound expressed by the general formula (2), by one of BINN ₂ existing anisotropic powder B is used as the reactive starting material B, a Na-containing compound (an oxide, a hydroxide, a carbonate, a nitrate, etc.) or a mixture of Na and K.

When an appropriate flux in a range of 1 wt% to 500 wt% is added to the anisotropic powder B and the reactive raw material B having the above composition, and the mixture is heated to a temperature considering a eutectic point and a melting point , the excess material consists mainly of KNN and Bi ₂ O ₃ .

By doing the flux is removed from the reaction product obtained, For example, an anisotropic powder A consisting of KNN can be produced. where the {100} plane is an oriented plane.

Of the Case that by the reaction between the anisotropic powder B and the reactive starting material B only those through the general Formula (2) expressed compound has the same procedure. That means it's enough, that Anisotropic powder B with a specific composition and the reactive starting material B with a specific composition in a suitable flux to heat. This can be done in the Fluxes expressed by the general formula (2) Connection can be generated with the predetermined composition. By removing the flux from the reactive product can then the anisotropic expressed by the general formula (2) Powder A can be achieved in which a specific crystal plane a oriented level is.

There the compound expressed by the general formula (2) has a crystal lattice with low anisotropy leaves The anisotropic powder A, as described above, is difficult synthesize directly. It is also difficult to get an anisotropic To synthesize powder A directly in which an optional crystal plane to an oriented level becomes.

There on the other hand, the layered perovskite compound as described above was, has a crystal lattice with great anisotropy leaves The anisotropic powder can easily and directly synthesize. Furthermore, the most oriented levels in the anisotropic Powder of the layered perovskite compound the effect, with respect of the lattice to the specific crystal plane in the by the general Formula (2) to match. About that In addition, the compound expressed by the general formula (2) is thermodynamically compared to the layered perovskite compound stable.

Out For this reason, the anisotropic powder B serves as a reactive template, when the reaction between the anisotropic powder B and the reactive Starting material B is carried out in a suitable flux wherein the anisotropic powder B is made of the layered perovskite compound in which the oriented plane with respect to the grid to the specific level in which by the general formula (2) Expressed connection fits.

Thereby can be easily an anisotropic powder A from the through synthesize the compound expressed by the general formula (2), the same crystal plane orientation direction as the anisotropic powder B has.

About that In addition, an optimization of the composition allows of the anisotropic powder B and the reactive starting material B it, the A-space element (hereinafter referred to as the "excess A-space element") from the anisotropic powder B and an anisotropic powder A is as expressed by the general formula (2) Make connection that no excess A-space element contains.

In particular, when the anisotropic powder B is the bismuth layer-perovskite compound expressed by the general formula (3), Bi is removed as the excess A-site element and an excess of mainly Bi ₂ O _{3 is} synthesized. By thermally or chemically removing the excess ingredient, the anisotropic powder A can be prepared from the compound expressed by the general formula (2) in which the specific crystal plane is oriented.

The oriented grain consists of an isotropic perovskite compound expressed by ABO ₃ . It is preferable that the A-space element in the isotropic perovskite compound mainly consists of at least one of K, Na and Li, and that the B-space element therein is mainly composed of at least one of Nb, Sb and Ta. In this case, in a potassium niobate-sodium system for isotropic perovskite, a crystal-oriented ceramic having comparatively high piezoelectric characteristics which is lead-free can be produced.

It It is also preferable that the oriented grain is the compound expressed by the general formula (2) consists. This allows a crystal-oriented ceramic with a high degree of orientation.

And although the one expressed by the general formula (2) fits Compound as described above with respect to Lattice to a great extent to that by the general formula (1) expressed connection. Therefore, the anisotropic serves Powder B, that of those expressed by the general formula (2) oriented grains in which the specific Crystal plane is the oriented plane, as a good template for the production of crystal-oriented ceramics.

When Next, the reactive starting material will be described. that is the connection with which through the reaction with the Anisotropic powder expressed by the general formula (1) isotropic perovskite compound.

It it is preferable that the reactive starting material is a grain size of not more than 1/3 of the grain size of the anisotropic Powder has.

If the grain size of the reactive starting material more than 1/3 of the grain size of the anisotropic powder There is a possibility that the Starting mixture difficult to shape so that the oriented Level in the anisotropic powder approximately in a same Direction is oriented. It is preferable that the grain size of the reactive starting material not more than 1/4 of the grain size of the anisotropic powder, better still not more than 1/5 of the grain size of the anisotropic powder.

The Grain size between the reactive starting material and the anisotropic powder can be compared by their mean Grain size is compared. The grain size of the anisotropic powder and the reactive starting material each its long diameter.

The Chemical composition of the reactive starting material may be appropriate the composition of the anisotropic powder and the composition the isotropic perovskite compound such as that by the general Formula (1) or (2) to be prepared and expressed compound, be determined.

When For example, reactive raw material may be an oxide powder Mixed oxide powder, a hydroxide powder, a carbonate, a nitrate, a Oxalate or an alkoxide, etc. can be used.

When For example, reactive starting material may be a material such as compound expressed by the general formula (1) used to put the planned isotropic perovskite compound under Sintering by reaction with the anisotropic powder.

It It is preferable to use the isotropic perovskite compound in the firing step by a reaction between the anisotropic powder and the reactive one Make starting powder, wherein the anisotropic powder and the reactive starting powders have a different composition. This makes it easy to make a crystal-oriented ceramic produce with complicated composition.

When reactive starting powder uses a calcined powder, by mixing at least one of a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source selected element and by calcination of the mixture is achieved. It is preferable to use this mixture with a stoichiometric Ratio so that using the anisotropic Powder and the reactive starting powder by the general Formula (1) is generated.

Thereby may be the reactive starting powder during the firing step react under good conditions with the anisotropic powder while the generation of a by-product is suppressed.

Of the The above calcination step takes place for a duration of 2 to 5 hours at a temperature in the range of 600 ° C up to 750 ° C.

When Li Source, K Source, Na Source, Nb Source, Ta Source and Sb Source For example, an oxide powder or a carbonate powder may be used contains at least one of the elements Li, K, Na, Nb, Ta and Sb.

Furthermore is preferable for each oxide powder and carbonate powder, that there are one or two types of elements Li, K, Na, Nb, Ta and Sb contains. In this case, there is a slight preparation of the reactive starting powder. As a reactive starting powder can also a calcined powder can be used by calcination of the mixing powder containing these elements is achieved.

It Powders can also be combined with these elements contain the planned perovskite compound by sintering the anisotropic powder and the reactive starting powder.

It is acceptable that the reactive starting powder produces the intended perovskite compound by reaction with the anisotropic powder, or that it produces both the planned perovskite compound and an excess component. If due to the reaction between the anisotropic powder and the reactive end powder, the excess ingredient is generated, it is preferable that the excess ingredient is removed thermally or chemically.

at the production of the crystal-oriented ceramic Piezoceramic become the anisotropic powder and the reactive starting powder mixed to produce the starting mixture.

In the mixing step may be irregular to the mixture shaped fine powder (hereinafter referred to as "fine compound powder") be given, resulting from a predetermined composition the anisotropic powder and the reactive starting powder, wherein the irregularly shaped fine powder a compound that has the same composition as the has isotropic perovskite compound, which is due to the reaction between the anisotropic powder and the reactive starting powder becomes. It is also possible to add to the above mixture To give sintering agents such as CuO.

The Addition of the fine compound powder or the sintering agent increases the density of the sintered body.

If the composition ratio of the fine compound powder too strong is increased, the compositional proportion of the anisotropic increases Powder in the entire starting material from. This is the Possibility that the degree of orientation of the specific Crystal plane decreases. It is therefore preferable to have the optimum compositional proportion according to the requirements, taking into account the Density of the sintered product and the degree of orientation to choose.

It It is preferable that the compositional proportion of the anisotropic Powder is chosen so that the occupancy rate of the A-space element by at least one element in which by the general formula (1) expressed anisotropic powder a value in one area from 0.01 to 70 atomic%, more preferably within a range of 0.1 to 50 atomic%, and more preferably in a range of 1 to 10 atomic%. The unit "atom%" defines the percentage the number of atoms.

It it is preferable that the starting mixture contains one or more additional elements contains from the to the groups 2 to 15 in the periodic table associated metal elements, semi-metal elements, transition elements, Noble metal elements and alkaline earth metals belongs.

By including the auxiliary element, a piezoceramic consisting of a crystal-oriented ceramic containing the above additive element can be produced, whereby piezoelectric characteristics such as piezoelectric d ₃₃ constant, electromechanical coupling factor K _p and piezoelectric d ₃₁ constant, and dielectric characteristics such as the specific one inductive capacitance and the dielectric loss factor of the piezoceramic can be increased.

In the compound expressed by the general formula (1) may be the A-space element or the B-space element through the above Additional element to be replaced. It is also possible the above additional element in the grains or grain boundary of compound expressed by the general formula (1) without substitution.

• (a) ein Verfahren, bei dem das Zusatzelement zugegeben wird, wenn das anisotrope Pulver synthetisiert wird;
• (b) ein Verfahren, bei dem das Zusatzelement zugegeben wird, wenn das reaktive Ausgangspulver synthetisiert wird; und
• (c) ein Verfahren, bei dem das Zusatzelement während des Mischschritts mit dem reaktiven Ausgangspulver und dem anisotropen Pulver zugegeben wird.

For example, there are the following methods (a), (b) and (c) for incorporating the above additive element in the starting mixture:

• (a) a method in which the additive element is added when the anisotropic powder is synthesized;
• (b) a method in which the additive element is added when the reactive starting powder is synthesized; and
• (c) a method in which the additive element is added during the mixing step with the starting reactive powder and the anisotropic powder.

By the above methods for adding the additional element leaves easily produce a starting mixture, which is the additional element contains.

The Piezoceramic containing the above additional element crystal-oriented Contains ceramic is by molding and sintering of the starting mixture produced.

And Although as additional elements elements such as Mg, Ca, Sr, Ba, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Hf, W, Re, Pd, Ag, Ru, Rh, Pt, Au, Ir, Os, B, Al, Ga, In, Si, Ge, Sn and Bi be used.

The Although additional element can be added directly, but can also an oxide or compound is added, which is the additive element contains.

It It is preferable that 0.0001 to 0.15 moles of the additive element per 1 mole of that expressed by the general formula (1) Isotropic perovskite compound to be added after completion of the firing step is achieved.

Become Added less than 0.0001 mol of the additive element, there is the Possibility that by the presence of the Additional element caused effect, the piezoelectric characteristics too improve, difficult to reach sufficiently.

If In contrast, more than 0.15 mol of the additive element are added the possibility that the piezoelectric characteristics and remove the dielectric characteristics of the piezoceramic.

The Mixing ratio of the additive element may be in the mixing step be adjusted so that the additional element in a range of 0.01 to 15 atom to at least one element of the A-place and B-place elements in the isotropic perovskite compound in the firing step becomes.

As a result, a crystal-oriented ceramic can be achieved, in which the additional element replaces the isotropic perovskite compound. This crystal-oriented ceramic has piezoelectric characteristics such as an excellent piezoelectric d ₃₃ constant and excellent electromechanical coupling factor K _p and dielectric characteristics such as excellent specific inductive capacity ε _33T / ε ₀ .

Become If less than 0.01 atom of the additive element is used, the Possibility that it is hard to get a sufficient improvement the piezoelectric characteristics and the dielectric characteristics to achieve the crystal-oriented ceramic. Will be more used as 15 atom of the additive element, it is possible that the piezoelectric characteristics and the dielectric characteristics remove the crystal-oriented ceramic. It is therefore preferable the additional element in a range of 0.01 to 5 atom better yet in a range of 0.01 to 2 atom and even better in one range from 0.05 to 2 atom.

The Unity "Atom is the percentage of the number of substitutes Atoms to the number of Li, K, Na, Nb, Ta and Sb in the by the general formula (1) expressed compound.

Of the Mixing step can be through a dry process or a wet Process be performed, wherein the wet process Dispersants such as water, alcohol or an organic solvent used. One or more of the substances may be binders, plasticizers and dispersing agents are added.

When Next follows a description of the shaping step for molding the crystal-oriented ceramic piezoceramic.

As in the third embodiment and the fifth embodiment the invention is shown, the sheet-like (or belt-like) Shaped body formed by the starting mixture so shaped will that approximate the oriented plane in the anisotropic powder oriented in a same direction.

It is sufficient if the molding process, the anisotropic powder to a specific Crystal plane oriented. In particular, molding processes such as For example, a doctor blade method, a pressing method and a rolling method prefers. These methods allow the anisotropic Powder in the molding in about the same Direction to orient by applying an applied to the anisotropic powder Shearing stress is used.

It it is preferable that the starting mixture becomes a sheet-like Product with a thickness in a range of 30 microns to 200 microns is formed.

When layered product makes it a shaped body with a thickness of less than 30 μm extremely difficult to handle the molding. On the other hand, more difficult than layer-shaped product a shaped body with a Thickness of more than 200 microns it, the anisotropic powder about to orient in a same direction.

With the molded article (hereinafter referred to as "plane-oriented Shaped "referred to) can also be multi-layer pressing, pressing and rolling (hereinafter be referred to as "level orientation process") be performed to the thickness and the degree of orientation of the plane-oriented shaped body.

The Although the above method performs the level-orientation process with a plane in the plane-oriented shaped body, but it can also be done with two or more types of levels become. It is also possible to use the level orientation process repeat for a single level. In addition, the level orientation process can be repeated be carried out for two or more levels.

It Now follows a description of the burning step for producing the from the crystal-oriented ceramic existing piezoceramic. Of the Firing step burns the anisotropic powder and the reactive starting powder.

While the firing step proceeds by heating the shaped body (or the plane-oriented shaped body) the sintering, and it becomes mainly from the isotropic perovskite compound existing polycrystalline material produced. This can (as piezoceramic) a crystal-oriented ceramic made of a polycrystalline material getting produced. By the reaction between the anisotropic Powder and the reactive powder output results from the general formula (1) expressed isotropic perovskite compound. In addition, during the firing step accordingly the composition of the anisotropic powder and / or the reactive Exit powder at the same time the excess Component generated.

Corresponding the composition of the anisotropic powder, the starting reactive powder and the crystal-oriented ceramic to be produced can during the firing step also selected an optimal firing temperature so that the reaction and / or sintering proceed efficiently, and the reactant has a planned composition.

If the crystal-oriented ceramics that are made by the general Formula (1) expressed compound, using of the anisotropic powder A having the KNN composition as the anisotropic Powder is prepared, the firing step, for example, at a firing temperature in a range of 900 ° C to 1300 ° C. The optimum temperature in the above temperature range of 900 ° C to 1300 ° C is determined by the composition of the general formula (1) expressed as component the planned material. In addition, can according to the firing temperature, the burning time in the firing step are set to a predetermined density of the sintered body to reach.

In the third aspect of the invention, the firing step as described above is performed for a period of not less than 2 hours at a temperature of not lower than 900 ° C under an ambient atmospheric partial pressure P ₀₂ of not less than 50% Reduction of the electrical insulation resistance to suppress.

If by the reaction between the anisotropic powder and the reactive one Starting powder an excess ingredient The surplus ingredient can be generated as a minor phase in the sintered body. In addition, it is also possible the excess Remove component from the sintered body. There are various methods for thermal or chemical removal the excess ingredient is known.

To the For example, there is a method for removing the excess Component in which a thermal process is used in that from that expressed by the general formula (1) Component and the excess ingredient produced sintered body (hereinafter referred to as "intermediate sintered body") is heated and the excess ingredient volatilized. There is in particular a method in which the intermediate sintered body for a long period of time under a lower pressure in the atmosphere or in an oxidizing gas is heated at a temperature to that is able to remove the excess ingredient to evaporate.

The optimum heating temperature for thermally removing the excessive ingredient may be selected according to the composition of the compound expressed by the general formula (1) and / or the composition of the excess ingredient, so that the volatilization of the excess ingredient proceeds efficiently and the generation of by-products is suppressed , For example, when the excess ingredient is single phase bismuth oxide, it is preferable that the Heating temperature in a range of 800 ° C to 1300 ° C and better still in a range of 1000 ° C to 1200 ° C.

on the other hand There is a method of chemically removing the excess Component in which the intermediate sintered body in a Dipping treatment solution capable of doing so is to just erode the excess ingredient, to extract the excess ingredient. The optimal treatment solution can be adjusted according to the the general formula (1) expressed compound and / or the Composition of the excess ingredient to get voted. If the excess Constituent of, for example, single-phase bismuth oxide, it is preferable as a treatment solution nitric acid, hydrochloric acid etc. to use. In particular nitric acid is one optimal treatment solution capable of mainly consisting of bismuth oxide excess Chemically extract ingredient.

The Reaction of the anisotropic powder and the reactive starting powder and removing the excess ingredient can be simultaneous, sequential or independent respectively. The molding is, for example, directly below heated to a lower pressure or in vacuo to a temperature in which the reaction of the anisotropic powder and the reactive starting powder and the volatilization of the excess Component progress efficiently to the reaction and removal to carry out the excess ingredient at the same time. The additional ingredient substitutes during the reaction of the anisotropic powder and the reactive starting powder by the general formula (1) expressed compound as the planned material or is found in crystal grains and / or the grain boundary again.

The excess Ingredient can be removed by adding the molding in the atmosphere or in an oxygen atmosphere is heated at a temperature at which the reaction of the anisotropic Powder and the reactive starting powder efficiently, to generate the intermediate sintered body, and by the obtained intermediate sintered body then under a lower Pressurized or heated in vacuo at a temperature at which the volatilization of the excess Component progresses efficiently. In addition, can the excess ingredient will be removed by the intermediate sintered body in the atmosphere or in an oxygen gas for a long period of time a temperature is heated, which volatilizes the excess Connection after the generation of the intermediate sintered body efficiently promotes.

Of the Intermediate sintered body can also be used in a treatment solution be dipped to the excess ingredient chemically after the intermediate sintered body produced cooled to room temperature. It is also possible, the intermediate sintered body after generation of the intermediate sintered body to cool to room temperature, and the intermediate sintered body then again under a predetermined atmosphere to a to heat the predetermined temperature to the excess Thermally remove component.

If the molded article produced by the molding step has a resin component as a binder, can be a thermal treatment be performed to remove the resin component. In this case, the temperature to carry out the above thermal treatment are adjusted to a temperature which is sufficient to cause the thermal decomposition of at least the binder perform. It is preferable that the thermal Treatment for removing the resin at a temperature of not more than 500 ° C takes place when the starting mixture a volatile component (such as a Na compound).

It there is a possibility that the degree of orientation of the anisotropic powder decreases in the molding or that the volume of the molding increases when the thermal Treatment for removing the resin component from the molding is carried out. To avoid this phenomenon, It is preferable with the molding after completion of the molding thermal treatment cold isostatic pressing (a CIP treatment) perform. Carrying out the CIP treatment prevents a caused by the volatilization treatment Decrease in the degree of orientation and one by the volume expansion (or spatial extent) of the molded body caused Decrease in the density of the sintered body.

In the case of removing the excess ingredient produced by the reaction between the anisotropic powder and the starting reactive powder, the CIP treatment and the baking process may also be performed for the intermediate sintered body without the excess ingredient which has been removed. In order to increase the density of the sintered body and the degree of orientation, a hot pressing method may be performed on the sintered body after completion of the firing step. Furthermore, a combination of the above-described method for adding fine compound powder, the CIP treatment ment and hot pressing.

As As described above, the crystal-oriented ceramic existing piezoceramic according to the invention Process be prepared when the anisotropic powder A as reactive Template is used after the anisotropic powder A with the help the anisotropic powder B was synthesized as a reactive template, wherein the anisotropic powder B is the layered isotropic perovskite compound which is easily synthesized and anisotropic Powder A from the expressed by the general formula (2) Connection exists. In this case, even then, when the compound expressed by the general formula (1) is used with a crystal lattice of low anisotropy, easily produce crystal-oriented ceramics at a low price, in which an optional crystal plane is oriented.

If an optimal composition of the anisotropic powder B and the reactive starting material B is used, the anisotropic Powder A can be synthesized even if the anisotropic powder contains no excess A-space ingredient. Because of this, the composition of the A-space element is simple it is possible to get one out of the crystal-oriented ceramic to produce existing piezoceramics, which mainly consists of one through the general formula (1) expressed by no conventional method can be achieved.

When anisotropic powder may also be an anisotropic powder B used are made of a layered isotropic perovskite compound consists. This can be done simultaneously during sintering the compound expressed by the general formula (1) be synthesized. With the help of an optimal composition of the anisotropic powder B and the reactive starting material (the Reaction between them) can be a through the general Synthesize formula (1) expressed planned compound and from the anisotropic powder B an excess A place element as surplus ingredient remove, with the anisotropic powder B during the molding step is oriented in the molding.

If as anisotropic powder, the anisotropic powder B is used, the produces an excess ingredient that can be easily removed thermally or chemically can a substantially the excess A-space element containing piezoceramics are produced, which from the by the general formula (1) expressed compound existing crystal-oriented piezoceramic exists in which the specific Crystal plane is oriented.

According to the Fourth and sixth embodiments of the invention may be a piezoceramic are made from an unoriented body consists of preparing the reactive starting powder, wherein the reactive starting powder by calcination of the starting mixture is prepared and the starting mixture by mixing at least one from a Li source, a K source, a Na source, a Nb source, a Ta source and a Sb source selected element is prepared so that the starting mixture reaction stoichiometry has to those expressed by the general formula (1) Create connection.

If a piezoceramic is made, which does not consist of such oriented body, the starting mixture can be prepared by including at least one of a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source selected starting powder is mixed, so that the starting mixture a has predetermined composition to the isotropic perovskite compound to produce. The starting mixture is calcined to (as the "reactive Starting powder ") to produce a calcined powder. With This calcined powder becomes the molding step and the firing step carried out.

When Li Source, K Source, Na Source, Nb Source, Ta Source and Sb Source For example, an oxide, a mixed oxide, a chloride, a carbonate, a hydrogencarbonate, a hydroxide and a nitrate be used. It can in particular the materials according to the third embodiment described above and fifth embodiment of the invention.

It one or more of the metals Li, K, Na, Nb, Ta and Sb as Li source, K source, Na source, Nb source, Ta source and Sb source.

It Now follows a description of a multilayer piezoelectric element according to the second embodiment of the invention.

The multilayer piezoelectric element consists of piezoceramic layers and electrode-forming layers, each electrode-forming layer having an electrode part which contains a conductive metal having an inside forms electrode, and the piezoceramic layers and the electrode formation layers are alternately stacked.

The Piezoceramic layers in the multilayer piezoelectric element consist of the piezoceramic according to the first embodiment the invention.

In The multi-layered piezoelectric element can be a piezoceramic layer used be that from an unoriented body or out an oriented body (as crystal-oriented ceramics) exists, being in the oriented body as the crystal-oriented Ceramic is oriented to a specific crystal plane.

It It is preferable to use an AgPd alloy as the conductive metal. This case shows especially clearly the effect and the effect of the invention, a decrease in electrical insulation resistance suppress.

And although the conductive metal can easily diffuse when the electrode formation layers and the piezoceramic layers during manufacture of the multilayer piezoelectric element formed together to form a unit become. Since the invention as a piezoceramic layers a piezoceramic used, which satisfies the relationship ds / dc <1.2, can itself when the conductive metal diffuses into the piezoceramic layers, be adequately prevented that the electrical insulation resistance decreases.

The multilayer piezo element can by the method according to the Seventh to tenth embodiments of the invention are produced.

The Method according to the seventh and ninth embodiment of the invention carry out the mixing step, the molding step, the printing step, the laminating step and the firing step through to produce the multilayer piezoelectric element.

In the mixing step in the seventh and ninth embodiments of the invention the starting mixture is prepared by adding the anisotropic powder and mixing the reactive starting powder. This mixing step in the method according to the seventh embodiment and the ninth embodiment of the invention is the same as in the method according to the third embodiment and the fifth embodiment of the invention.

As in the methods of the third and fifth embodiments According to the invention, it is preferable that the methods of the seventh Embodiment and the ninth embodiment of the invention, the calcined Use powder by mixing and then adding Calcining at least one of a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source selected element to the calcined powder each of the sources being mixed so that shows a stoichiometry with which by the reaction between the reactive starting powder consisting of the calcined powder and the anisotropic powder expressed by the general formula (1) Connection is generated.

In the mixing step in the method according to the eighth and tenth embodiment of the invention, the starting mixture produced by including at least one of a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source selected element is mixed to a stoichiometry to achieve that expressed by the general formula (1) Connection is generated. The reactive starting powder is then passed through Calcination of the starting mixture obtained above. The eighth embodiment and the tenth embodiment of the invention lead the same mixing step as the fourth embodiment and the sixth Embodiment of the invention.

In the mixing step in the method according to the eighth and tenth embodiment of the invention are also as in the methods of the third and fourth embodiments of the invention a K starting powder and / or a Li starting powder in the starting mixture or the reactive starting powder is given.

In the method according to the seventh and ninth embodiment It is also preferable, according to the invention, as a K source powder and / or Li source powder, a carbonate, a hydrogen carbonate or to use a borate.

In the methods according to the seventh and ninth embodiments of the invention, the starting mixture is shaped or formed so that it generates the sheet-like molded body, so that the oriented Level is oriented in the anisotropic powder approximately in a same direction.

In the method according to the eighth and tenth embodiment By contrast, the reactive starting powder of the invention is shaped in this way or formed, that generates the sheet-like molded body becomes. In the molding step, it is preferable that the thickness of the Shaped body in a range of 30 microns to 200 microns is set.

When Next, in the printing step, in the methods according to the Seventh and tenth embodiments of the invention on the sheet-like Shaped body (or a green sheet) an electrode material printed. The electrode material contains a conductive Metal that becomes the electrode part after completion of the firing step.

When For example, electrode material may be painted on an AgPd alloy become. It can also be a metal or an alloy such as Ag, Pd, Cu, Ni and Cu / Ni are used.

It It is preferable to use an AgPd alloy as the conductive metal. This provides for the enhanced effects and effects of Invention, with which suppresses the decrease of the electrical insulation resistance can be.

And while using a AgPd alloy containing leads Electrode material during the firing step slightly too a diffusion of Ag into the piezoceramic. This can be easy reduce the electrical insulation resistance of the piezoceramic layer.

The mixing step of the method of the invention uses a K starting powder and / or a Li starting powder, and its firing step is carried out for a period of not less than 2 hours at a temperature not lower than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50% (see seventh and eighth aspects of the invention).

In addition, these methods use a reactive starting powder having a specific surface area and perform a temperature control having the relationship (T ₁ -T ₂ ) / t ₂ ≦ D ₁ ≦ 200 and (T ₁ -T ₂ ) / t ₂ ≦ D ₂ ≤ 200 fulfilled.

Therefore can be the decrease of the electrical insulation resistance suppress the piezoceramic layers even if Ag, which is contained in the electrode material, into the interior of the Piezoceramic layers diffused.

The Electrical material is at a desired area printed on the green sheet, after completion of the firing step becomes an electrode part.

The In particular, electrode material can be printed in such a way that the electrode part in the entire area between the piezoceramic layers is formed in the multilayer piezoelectric element. The electrode material can also be printed so that between the piezoceramic layers a partial electrode is formed. When the partial electrode is formed is the electrode material is on a desired Area printed on the green sheet that on the sides the multi-layered piezoelectric element formed an electrode-free part becomes.

In the Aufschichtungsschritt be the moldings after completion the printing step (as green sheets) stacked, to create the multilayer piezoelectric element.

The Green areas can on both sides, that is in the laminating direction of the multilayer piezoelectric element the top and bottom side, without the printed electrode material to be placed. Due to this structure can be used for a multi-layered Piezo element are taken care of in which after completion of the firing step on both sides (the top and bottom side) of piezoelectric Ceramic existing blind layers are placed.

On the top and bottom side of the multilayer piezoelectric element can As blanks each one or more layers placed become.

After completion of the laminating step, the above-obtained laminated body can be pressed in the laminating direction to press the electrode materials in the laminated body into the green sheets sen. The above pressing step is thermally carried out by thermocompression bonding to press it under heating.

By Degreasing of the composite body before the firing step can also organic components such as a binder are removed.

When Next, the laminate will be during burned the firing step to produce the multilayer piezoelectric element in which the piezoceramic layers and the electrode layers alternate are stacked on top of each other.

The Method of the seventh embodiment and the eighth embodiment of the invention can the same firing step as in the Method of the third embodiment and the fourth embodiment perform the invention.

The Method of the ninth embodiment and the tenth embodiment of the invention can the same firing step as in the Method of the fifth embodiment and the sixth embodiment perform the invention.

At the outer peripheral side surface of the multilayer piezoelectric element two outer electrodes can be formed, which consist of a conductive material such as Ag. The two external electrodes become in the Aufschichtungsrichtung alternately electrically with the electrode part formed in the interior of the multilayer piezoelectric element connected.

It follows a description of first to third embodiments, which correspond to the first to tenth embodiments of the invention.

- First embodiment -

Under Referring now to the drawings, a description of the first follows Embodiment of the invention.

1A FIG. 15 is a view showing an overall structure of the multilayer piezoelectric element according to the first embodiment of the invention. 1B is a sectional view of the in 1A shown multilayer piezoelectric element along its Aufschichtungsrichtung.

As in 1A and 1B is shown, a multi-layer piezoelectric element 1 made of the piezoceramic layers 2 consisting of the piezoceramic and the electrode forming layers 3 composed of the electrode parts 31 comprising the conductive metal-containing internal electrodes. In the multilayer piezoelectric element are the piezoceramic layers 2 and the electrode formation layers 3 alternately stacked.

Each piezoceramic layer 2 It consists of a polycrystalline material consisting mainly of an isotropic perovskite compound expressed by the following general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1.

In the first embodiment, the piezoceramic layers exist 2 mainly of an isotropic perovskite compound expressed in particular by {Li _0.08 (K _0.5 Na _0.5 ) _0.92 } (Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ .

2 FIG. 14 is a view showing the structure of crystal grains containing the piezoceramic layer. FIG 2 form, between the electrode parts 31 is formed in the multilayer piezoelectric element.

As in 2 shown has every crystal grain 20 that the piezoceramic of the piezoceramic layer 2 forms, a core phase 21 and a wrapper phase 22 that have a different composition.

The shell phase 22 is designed to be the core phase 21 surrounds. The crystal grain 20 satisfies the relation ds / dc <1.2, where "dc" is a crystal lattice defect amount in the core phase 21 and "ds" one Crystal lattice defect quantity in the shell phase 22 designated.

In the structure of the multilayer piezoelectric element 1 According to the first embodiment, the piezoceramic layers are made 2 from the crystal-oriented ceramic, in which a specific crystal plane A of the crystal grains 20 that form the polycrystalline material is oriented. The piezoelectric layers 2 of the multilayer piezoelectric element 1 According to the first embodiment, in particular, consist of a crystal-oriented ceramic, in which a pseudocubic {100} plane is oriented.

As in 1A . 1B and 2 is shown, there are the electrode parts 31 in the electrode formation layer 3 from an AgPd alloy.

The method for producing the multilayer piezoelectric element 1 According to the first embodiment, the mixing step, the molding step, the printing step, the laminating step and the firing step are composed.

The mixing step produces the starting mixture by combining starting powders with a mixing ratio producing the isotropic perovskite compound expressed by the general formula (1). In this case, a K starting powder and / or a starting Li powder are added as an additive to the starting mixture, so that this addition amount is not more than 0.05 mol per 1 mol of the expressed by the general formula (1) isotropic perovskite compound. In the first embodiment, in particular 0.05 mol K ₂ CO _{3 are added} as starting K powder to the starting mixture.

Of the Mixing step mixes the anisotropic powder with the reactive starting powder, the anisotropic powder being oriented anisotropic grains exists, in which a crystal plane is oriented and an oriented one Surface and in which the crystal plane re of the lattice matches the {100} specific crystal plane, where the reactive starting powder produces the isotropic perovskite compound, when it reacts with the anisotropic powder.

Of the Forming step next forms from the starting mixture a layer form to a sheet-like shaped body (or a green sheet) so that the oriented plane in the anisotropic powder in approximately the same direction is oriented.

Of the Printing step prints the electrode material on the green sheet, wherein the electrode material contains the conductive metal, which becomes the electrode parts after the firing is completed. In The first embodiment is used as a conductive metal used an AgPd alloy.

Of the Stratification step stratifies after completion of the printing step the moldings as green sheets on each other to the Produce laminated body.

The firing step burns the layered body around the multilayer piezoelectric element 1 in which the piezoceramic layers 2 and the electrode formation layers 3 (as in 1A and 1B shown) are alternately stacked. The reaction between the anisotropic powder and the starting reactive powder produces the isotropic perovskite compound.

The firing step is carried out for a period of not less than 2 hours at a temperature of not lower than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50%.

There now follows a detailed description of the manufacturing process for the multilayer piezoelectric element 1 according to the first embodiment.

(1) Preparation of Anisotropic Powder

First, the anisotropic powder was prepared by the following method, wherein the anisotropic powder consisted of oriented grains having the oriented plane in which a specific crystal plane was oriented and the oriented plane of the anisotropic powder with respect to the lattice to the specific {100}. -Kristallebene adapted to form a planned, polycrystalline material. More specifically, the first embodiment produces an anisotropic powder B consisting of Bi _2.5 Na _3.5 Nb ₅ O ₁₈ . Then, using the anisotropic powder B as the anisotropic powder A, an NaNbO ₃ anisotropic powder having a plate shape (or a plate-like anisotropic powder) was prepared.

Namely, an Na ₂ CO ₃ powder and an Nb ₂ O ₅ powder having the stoichiometry of a planned composition of Bi _2.5 Na _3.5 Nb ₅ O ₁₈ (hereinafter also referred to as "BINN5") were weighed out and then wet mixed to make a starting powder.

When Next, to the starting powder was added 50% by weight of a NaCl flux and the mixture was dry blended for one hour.

When Next, the mixture was placed in a Pt crucible and Heated at 850 ° C for 1 hour to complete the flux to melt. The mixture contained in the Pt crucible was further heated at 1100 ° C for two hours to synthesize BINN5.

The Temperature increase rate was 200 ° C / hour, and the temperature lowering rate was the oven cooling rate.

To On cooling, the flux component was washed by hot water removed from the reactant to the BINN5 powder (as the anisotropic To achieve powder B).

The obtained BINN5 powder was a plate-like powder, which oriented one Had {001} level.

Next, to the plate-like BINN5 powder (as the starting reactive powder) was added an Na ₂ CO ₃ powder of the required amount sufficient to synthesize NaNbO ₃ (hereinafter referred to as "NN"). These powders were mixed and the resulting mixture was placed in a Pt crucible and then heated at 950 ° C for 8 hours for thermal treatment.

As a result, since the reactant contained Bi ₂ O _{3 in} addition to the Na ₂ CO ₃ powder, after removing the flux from this reactant, the reactant was placed in an HNO ₃ solution to dissolve Bi ₂ O ₃ as an excessive ingredient. The resulting solution was filtered to separate the NN powder and then washed using 80 ° C warm ion-exchanged water. By the above processes, the NN powder (as the anisotropic powder) was obtained.

The obtained NaNbO ₃ powder had the plate-like powder with the oriented pseudocubic {100} plane, an average grain size of 15 μm and an aspect ratio in a range of 10 to 20.

(2) Preparation of the reactive starting powder

Of the following process produced the reactive starting powder. The reactive Starting powder had a mean grain size, not more than 1/3 of the mean grain size of the anisotropic powder was, and it was able to To produce isotropic perovskite compound, than it is with anisotropic Powder was sintered.

In the first embodiment, the NN powder was prepared so that by the NN powder (as the anisotropic powder), 5 mol% of the A-site element in the planned ceramic composition of {Li _0.08 (K _0.5 Na _0.5 ) _0.92 } (Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ .

In the preparation of the reactive starting powder were first a Na ₂ CO ₃ powder, a K ₂ CO ₃ powder, a Li ₂ CO ₃ powder, a Nb ₂ CO ₅ powder, a Ta ₂ O ₅ powder and a Sb ₂ O ₅ powders having a purity of not less than 99.99% were weighed out to obtain the composition achieved when the NN powder component of the intended ceramic composition of {Li _0.08 (K _{0, 5} Na _0.5 ) _0.92 } (Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ . Then, they were wet mixed with ZrO ₂ balls using an organic solvent for 20 hours.

They were then calcined for 5 hours at 750 ° C and then wet-crushed for 20 hours with the ZrO ₂ spheres. Thereby, (as the reactive starting powder), a calcined powder having an average grain size of about 0.5 μm was obtained.

(3) mixing step

Next, the anisotropic powder obtained in the above steps and the starting reactive powder were mixed to obtain the starting mixture in the composition ratio containing the is produced by the proposed ceramic composition of isotropic perovskite compound expressed as {Li _0.08 (K _0.5 Na _0.5 ) _0.92 } (Nb _0.84 Ta _0.06 Sb _0.06 ) O ₃ . The mixing step was carried out so that of elements in the anisotropic powder 5 mol% of the A-site element in the planned ceramic composition of {Li _0.08 (K _0.5 Na _0.5 ) _0.92 } (Nb _{0 , 84} Ta _0.1 Sb _0.06 ) O ₃ .

Further, to the starting mixture was added a K starting powder (K ₂ CO ₃ ) so that the additive was 0.05 mol per 1 mol of the intended ceramic composition of {Li _0.08 (K _0.5 Na _0.5 ) _{O, 92} } (Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ .

Next, to the above starting mixture was added 1% by weight of a polyoxyalkylene polymer dispersing agent and then wet-blended with ZrO ₂ balls for 20 hours to obtain a raw material slurry.

After that were added to the starting mixture slurry based on the weight of the powder 15 wt .-% polyvinyl butyral (PVB) as a binder and dibutyl phthalate as plasticizer and then for one hour through an impeller stirrer mixed.

(4) molding step

When Next was the starting mixture slurries with Assisted by a doctor blade method or to a sheet-like molded body (as a green sheet) having a thickness of about 100 microns had. The grains of the anisotropic were Powder by a shear stress applied to the anisotropic powder oriented in approximately the same direction.

(5) printing step

Next, an AgPd alloy containing 30 mol% Pd was prepared. The AgPd alloy powder and the starting reactive powder were mixed at a volume ratio of 9: 1. Ethyl cellulose and terpineol were added to the mixture to prepare an electrode material paste. The obtained electrode material paste was printed on the electrode area, which should be formed on the green sheet. In the multi-layer piezo element 1 According to the first embodiment, the electrode material paste was printed to the electrode part 31 after the following firing step on the entire surfaces between the piezoceramic layers 2 to train (see 1A and 1B ).

It is also possible or acceptable to print the electrode material paste on the surface of the green sheet at a desired area, so that on an outer peripheral part of the multilayer piezoelectric element 1 an electrode-free part is formed. As a result, partial electrodes can be formed on the surface of the green layer.

(6) Layering step

To Completion of the above printing step were the green sheets, on which the electrode material paste was printed (after firing to the electrode forming layers) and pressed to produce a plate-like laminate, measured in its Aufschichtungsrichtung a thickness of 1.5 mm has.

On the cover side and the bottom side of the multilayer piezoelectric element 1 In each case a green layer without electrode part was placed. These greensheets placed on the top and bottom side formed blank layers after the completion of the following firing step 30 (please refer 1A and 1B ).

Next, the composite was removed to remove a fat ingredient 5 Degreased for hours at a temperature of 600 ° C under a temperature raising rate of 50 ° C / hour and the Ofenabkühlgeschwindigkeit.

(7) firing step

After completion of the degreasing step, the laminate was next fired to the multilayer piezoelectric element 1 produce as end product.

More specifically, the composite was placed in a furnace after removing the grease and then heated at a temperature raising rate of 200 ° C / hour to a temperature of 1120 ° C. The composite was then left in the oven for one hour at the temperature of 1120 ° C. The composite was cooled to 900 ° C at a cooling rate of 75 ° C / hour. Thereafter, the composite was cooled to room temperature at a cooling rate of 200 ° C / hr. This eventually became the multilayer piezoelectric element 1 generated. The burning time in this case was five hours at a temperature of not lower than 900 ° C.

Next, the multilayer piezoelectric element obtained by the above method became 1 finished by a machining process to complete the in 1A and 1B shown circular disc of the multilayer piezoelectric element 1 to achieve.

The multilayer piezoelectric element produced by the above method 1 was used as sample E1, in which the piezoceramic layers consisting of a crystal-oriented ceramic 2 and the electrode parts made of Ag / Pd alloy 31 (Electrode formation layers 3 ) were alternately stacked as described above.

Table 1 described later shows the conditions of production of various kinds of samples E1 and E2 and comparative samples C1, C2 and C3, such as the addition amount of K starting powder (K ₂ CO ₃ ) used in the mixing step, oxygen partial pressure P ₀₂ in the firing step , the firing temperature and the heating time at not less than 900 ° C (hereinafter referred to as the "burning time under the predetermined condition").

The Samples E2, C1, C2 and C3 were in the first embodiment prepared under conditions other than sample E1, such as with other types and additions of the K starting powder or Li starting powder, with a different oxygen partial pressure in the firing step, a another burning temperature or another burning time under the predetermined condition. The remaining conditions are in samples E1, E2, C1, C2 and C3 are the same.

Namely, the mixing step used a Li starting powder (LiBO ₂ ) instead of the K starting powder in preparation of the sample E2, and added this Li starting powder to the starting mixture so that the Li starting powder as an additive was 0.02 mol per 1 mol which was the isotropic perovskite compound expressed by the composition {Li _0.08 (K _0.5 Na _0.5 ) _0.92 } (Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ .

The firing step for producing the sample E2 was carried out in the oven at an oxygen partial pressure P ₀₂ of 50%. The firing temperature was 1100 ° C for one hour. The temperature raising rate to 1100 ° C was 200 ° C / hour. The cooling rate was 200 ° C / hour to room temperature. After completion of the firing step, the multilayer piezo element was 1 taken out of the oven as sample E2. The burning time under the predetermined condition was 3 hours.

In the preparation of Comparative Sample C3, the mixing step used a K starting powder (K ₂ CO ₃ ), and this K starting powder was added to the starting mixture so that the K starting powder as an additive was 0.5 mol per 1 mol of the composition {Li _0.08 (K _0.5 Na _{0.5) 0.92}} (Nb _0.84 Ta _0.1 Sb _0.06) O ₃ was expressed isotropic perovskite compound.

The firing step for preparing the comparative sample C1 was carried out in the oven at an oxygen partial pressure 202 from 20%. The firing temperature was 1140 ° C for 2 hours. The temperature raising rate to 1140 ° C was 200 ° C / hour. The cooling rate was 200 ° C / hour to room temperature. After completion of the firing step, the multilayer piezo element was 1 taken as a reference sample C1 from the oven. The burning time under the predetermined condition was 5 hours.

In the preparation of Comparative Sample C2, the mixing step used a K starting powder (K ₂ CO ₃ ) as in the preparation of Comparative Sample C1, and this K starting powder was added to the starting mixture such that the K starting powder as an additive was 0.5 mol per 1 mole of the isotropic perovskite compound expressed by the composition {Li _0.08 (K _0.5 Na _0.5 ) _0.92 } (Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ .

The firing step for preparing the comparative sample C2 was carried out in the oven at an oxygen partial pressure 202 from 0%. The firing temperature was 1140 ° C for one hour. The temperature raising rate to 1140 ° C was 200 ° C / hour. The cooling rate was 30 ° C / hr to 900 ° C, and the cooling rate was 200 ° C / hr from 900 ° C to room temperature. After completion of the firing step, the multilayer piezo element was 1 taken as a comparative sample C2 from the oven. The Burning time under the predetermined condition was 10 hours.

at For the preparation of comparative sample C3, the mixing step was used no K starting powder or Li starting powder as additive. The means that in the mixing step in the production of Comparative sample C3 no additive added to the starting mixture has been. The firing step in the preparation of the comparative sample C3 was the same as the firing step in the production of Sample E1.

The following Table 1 shows the conditions in the preparation of the samples E1 and E2 and the comparative samples C1, C2 and C3, such as the addition amount of K starting powder (K ₂ CO ₃ ) or Li starting powder (LiBO ₂ ) used in the mixing step. the oxygen partial pressure P ₀₂ in the firing step, the firing temperature and the firing time under the predetermined condition as the heating time at not less than 900 ° C. Table 1 Sample No. K output powder / Li output powder Oxygen partial pressure P ₀₂ (%) Burning temperature (° C) Burning time (hours) under a predetermined condition kind Addition amount (mol) E1 K ₂ CO ₃ 0.05 100 1120 5 E2 Li ₈ O ₂ 0.02 50 1100 3 C1 K ₂ CO ₃ 0.5 20 1140 5 C2 K ₂ CO ₃ 0.5 0 1140 10 C3 - - 100 1120 5

First try

When Next follows a description of the characteristics of the multilayer Piezoelectric element according to each sample E1 and E2 and each comparative sample C1 to C3. The characteristic values of these samples E1, E2, C1, C2 and C3 were determined as follows.

- Crystal lattice defect amount in the core phase and the shell phase in the piezoceramic layer -

First was manufactured by Hitachi High-Technologies Corporation's "S-4300SE" -REM (Scanning Electron Microscope) the structure of the crystal grains in the piezoceramic layer detected in each sample E1, E2, C1, C2 and C3.

3 is a SEM photograph, which according to the first attempt the piezoceramic layer 2 shows that between electrode parts 31 of the multilayer piezoelectric element 1 is trained. 2 shows schematically the structure of the between the electrode parts 31 in the multilayer piezoelectric element 1 formed piezoceramic layers 2 in the in 3 shown photograph.

As in 3 is shown, each crystal grain exists 20 from the core phase 21 and the shell phase 22 , wherein the crystal grains 20 between the electrode parts 31 of the multilayer piezoelectric element 1 formed piezoceramic layer 2 form.

By Cathodoluminescence spectral analysis each became the crystal lattice defect amount the core phase and the shell phase in the piezoceramic layer determined. The detection device was one from Jobin Yvon Corporation prepared Kathodolumineszenzanlage used.

The Detection was carried out under the following conditions: the room temperature (RT) as temperature, a 1 mm slot, a C lens 2, an objective aperture of 2, an acceleration voltage of 15 kV, 3000 times magnification, W.D. of 10 mm and 5 seconds exposure (per point).

The Crystal lattice defect quantity in the core phase and the shell phase could with the help of the highest peak intensity in the Wavelength range from 500 nm to 700 nm are compared.

4 is a photograph of a cathodoluminescence (CL) spectral analysis corresponding to Er results of the CL spectral analysis shows the piezoceramic layer of the multilayer piezoelectric element.

In 4 The parts shown in black indicate the electrode parts 31 and the parts shown in white and gray color the piezoceramic 2 (the piezoceramic layer 2 ).

In the in 4 The amount of crystal lattice defects increases as the intensity of the white color increases. As from the in 4 shown photograph has the shell phase 22 a stronger white color than the core phase 21 , This shows that the number of crystal lattice defects in the shell phase 22 greater than in the core phase 21 is.

5 shows a graphical representation of the relationship between the wavelength and the CL intensity of the core phase 21 and the shell phase 22 in the piezoceramic layer 2 as a result of the cathodoluminescence (CL) spectral analysis according to the first experiment.

The detection by the CL spectral analysis was made at two points in the core phase 21 and the shell phase 22 , The average of the highest peak intensities at the detection points was used as the amount of crystal lattice defect (see 5 ).

The Table 2 below, which will be described later, gives the Crystal lattice defect quantity dc of the core phase, the crystal lattice defect amount ds of the shell phase and the ratio "ds / dc" between to them.

- bulk density -

When Next, the bulk density of each sample was E1 and E2 and each comparative sample C1, C2 and C3 determined.

And Although the weight (or dry weight) of each sample E1, E2, C1, C2 and C3 determined in the dry state.

To the immersion of these samples in water, that is after Water in the open pores in each sample E1, E2, C1, C2 and C3 had penetrated the weight (wet weight) of each sample E1, E2, C1, C2 and C3 detected.

When Next was based on the difference between the Dry weight and wet weight the volume of open pores determined in each sample E1, E2, C1, C2 and C3.

By the Archimedes method was used in each sample E1, E2, C1, C2 and C3 determines the volume without the volume of open pores.

When Next, the bulk density of each sample E1, E2, C1, C2 and C3 calculated by dividing the dry weight of each sample E1, E2, C1, C2 and C3 by the total volume of each sample (sum of the volume of the open pores and the volume without the open pores) was divided. Table 2 gives the bulk densities of each sample E1, E2, C1, C2 and C3 as calculation result.

When Next was the resistivity of each sample E1, E2, C1, C2 and C3 are determined by the specific resistances to compare from them.

More specifically, the inner electrode part was taken out of the multilayered piezoelectric element via the side surface of each sample E1, E2, C1, C2 and C3. A voltage was applied to the internal electrode parts so that 2 kV / mm was applied across the distance between the internal electrodes. By a resistance measuring device, the resistivity of the piezoceramic layer of each sample E1, E2, C1, C2 and C3 was detected. Table 2 indicates the detection resistivity results of each sample E1, E2, C1, C2 and C3. Table 2 Sample No. Crystal lattice defect quantity dc (b.E.) in the core phase Crystal lattice defect quantity ds (b.E.) in shell phase ds / dc Bulk density (g / cm ³ ) resistivity (Ω · m) E1 280 300 1.07 4.71 4.7 × 10 ⁹ E2 300 340 1.13 4.68 1.3 × 10 ⁹ C1 320 480 1.50 4.76 8.4 × 10 ⁷ C2 850 1200 1.41 4.41 5.5 × 10 ⁵ C3 400 560 1.40 4.85 6.0 × 10 ⁶

• (a) in dem Mischschritt wurden ein K-Ausgangspulver und/oder ein Li-Ausgangspulver zu dem Ausgangsgemisch gegeben, so dass diese Zugabemenge pro 1 mol der durch die allgemeine Formel (1) ausgedrückten isotropen Perowskitverbindung nicht mehr als 0,05 mol betrug, und dieses Pulver wurde dann als Zusatzstoff mit dem Ausgangsgemisch gemischt; und
• (b) in dem Brennschritt wurde der Schichtkörper nicht weniger als 2 Stunden bei einer Temperatur von nicht weniger als 900°C unter einer Atmosphäre mit einem Sauerstoffpartialdruck 202 von nicht weniger als 50% gebrannt, um (als Proben E1 und E2) das mehrlagige Piezoelement zu erzeugen.

As is apparent from Table 1 and Table 2, the multilayer piezoelectric element produced by the following conditions (a) and (b) has piezoceramic layers made of piezoceramic, which satisfy the relationship of ds / dc <1.2:

• (a) in the mixing step, a K starting powder and / or a Li starting powder was added to the starting mixture so that this addition amount per 1 mol of the isotropic perovskite compound expressed by the general formula (1) was not more than 0.05 mol, and this powder was then mixed as an additive with the starting mixture; and
• (b) In the firing step, the laminated body was not less than 2 hours at a temperature of not lower than 900 ° C under an atmosphere with an oxygen partial pressure 202 of not less than 50% to produce (as samples E1 and E2) the multilayer piezoelectric element.

The multilayer piezoelectric element produced by the above method has an extremely high resistivity of 4.7 × 10 ⁹ Ω · m (Sample E1) and 1.3 × 10 ⁹ Ω · m (Sample E2) as shown in Table 2. ,

On the other hand, the sample C1 was prepared under the condition that the mixing step used 0.5 mol K starting powder as an additive and the firing step was conducted under an atmosphere having an oxygen partial pressure P ₀₂ of 20%. The sample C2 was prepared under the condition that the mixing step used 0.5 mol K starting powder as an additive and the firing step was carried out under an atmosphere without oxygen partial pressure (P ₀₂ = 0%). Sample C3 was prepared in the mixing step without K starting powder and Li starting powder.

Thereby the samples C1, C2 and C3 have a value ds / dc of the piezoceramic layer of not less than 1.2, that is, that the samples C1, C2 and C3 compared to the samples E1 and E2 a lower specific Have resistance.

• (a) in dem Mischschritt werden ein K-Ausgangspulver und/oder ein Li-Ausgangspulver zu dem Ausgangsgemisch gegeben, so dass diese Zugabemenge pro 1 mol der durch die allgemeine Formel (1) ausgedrückten isotropen Perowskitverbindung nicht mehr als 0,05 mol beträgt, und dieses Pulver wird dann als Zusatzstoff mit dem Ausgangsgemisch gemischt; und
• (b) in dem Brennschritt wird der Schichtkörper für nicht weniger als 2 Stunden bei einer Temperatur von nicht weniger als 900°C unter einer Atmosphäre mit einem Sauerstoffpartialdruck P₀₂ von nicht weniger als 50% gebrannt, um (als Proben E1 und E2) das mehrlagige Piezoelement zu erzeugen. Das mehrlagige Piezoelement (Probe E1 und E2) mit diesen Piezokeramikschichten hat einen hohen elektrischen Isolationswiderstand.

Under the following conditions (a) and (b), therefore, it is possible to manufacture a multilayer piezoelectric element having piezoceramic layers composed of piezoceramic, which satisfy the relationship of ds / dc <1.2:

• (a) in the mixing step, a K starting powder and / or a Li starting powder are added to the starting mixture so that this addition amount per 1 mol of the isotropic perovskite compound expressed by the general formula (1) is not more than 0.05 mol, and this powder is then mixed as an additive with the starting mixture; and
• (b) in the firing step, the laminate is fired for not less than 2 hours at a temperature not lower than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50% to obtain (as samples E1 and E2) to produce multilayer piezoelectric element. The multilayer piezoelectric element (sample E1 and E2) with these piezoceramic layers has a high electrical insulation resistance.

Furthermore have the samples E1 and E2 as the samples C1, C2 and C3 sufficient high density. The piezoceramic layers in samples E1 and E2 show excellent piezoelectric characteristics by the general Formula (1) expressed isotropic perovskite compound and excellent deformation characteristics.

In addition, the first embodiment shows a piezoceramic (as piezoceramic layers), which consists of a crystal-oriented ceramic, which uses an anisotropic powder. However, the invention is not limited to the disclosure of the first embodiment. For example, (as a piezo ceramic layers), a piezoceramic consisting of an unoriented body having at least one selected from a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source Element having a stoichiometry capable of producing the compound expressed by the general formula (1). The multilayer piezoelectric element produced by this method and these conditions can achieve the same effects and effects as the multilayer piezoelectric element according to the first embodiment.

Second Embodiment

It Now follows a description of the method for producing a Piezoceramic according to the second embodiment the invention.

As previously described, generates the first embodiment (as samples E1 and E2) a multilayer piezoelectric element consisting of a Piezoceramic existing piezoceramic layers having the context satisfy ds / dc <1.2, where "ds" is the amount of crystal lattice defects in the shell phase and "dc" the amount at crystal lattice defects in the core phase.

The second embodiment produces a piezoceramic, the the relationship ds / dc <1,2 Fulfills.

In the second embodiment, a piezoceramic is made, which consists of a polycrystalline material, which consists mainly of an isotropic perovskite compound, by the chemical composition {Li _0.08 (K _0.5 Na _0.5 ) _0.92 ) ( Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ .

The second embodiment also generates a crystal-oriented ceramics in which the {100} crystal plane is specific A is oriented by crystal grains, which is the polycrystalline Form material.

The Piezoceramic according to the second embodiment is determined by a specific combination of the mixing step and the Burning made.

In the mixing step, a starting mixture is prepared or prepared, by using the starting powder with a composition ratio is mixed, which produces the isotropic perovskite compound. there For example, a K starting powder and / or a Li starting powder are used as an additive added to the starting mixture, so that the addition amount per 1 mol the isotropic perovskite compound is not more than 0.05 mol. Furthermore, in the mixing step, an anisotropic powder and a reactive starting powder mixed together, the anisotropic Powder consists of a perovskite compound containing oriented grains has an anisotropic shape, in which crystal planes with respect to of the lattice to the specific {100} crystal plane A, so are oriented, that they form an oriented plane, and that reactive starting powder through a reaction with the anisotropic Powder produces the isotropic perovskite compound.

In the molding step, the starting mixture is molded to the sheet-like To produce shaped bodies (or the green sheet), see above that the oriented plane of each grain of the anisotropic powder is approximately oriented in a same direction.

Of the Burning step burns the sheet-like shaped body for not less than 2 hours at a temperature of not less as 900 ° C under an atmosphere with an oxygen partial pressure of not less than 50%.

It Now follows a detailed description of the procedure for producing the piezoceramic according to the second Embodiment.

As in the method of the first embodiment made the anisotropic powder and the reactive starting powder.

When Next were the anisotropic powder and the reactive one Starting powder as in the method of the first embodiment mixed to produce a Ausgangsgemischschlämme. Into this starting mixture slurry became a K starting powder as an additive, so that this addition amount per 1 mol of the isotropic perovskite compound 0.05 mol.

Next, the starting mixture slurry was molded or discharged by a doctor blade device formed to produce the sheet-like molded body. In this case, the grains in the anisotropic powder in the forming step were oriented approximately in a same direction by a shearing stress applied to the anisotropic powder.

To Completion of the molding step became the molding next degreased. The degreasing step took five hours long in atmosphere at a temperature of 600 ° C at a temperature raising rate of 50 ° C / hour and the oven cooling rate.

To the degreasing step, the shaped body was next fired to produce the piezoceramic.

More accurate said molding was after the fat removal (the Degreasing step) as in the method of the first embodiment placed in an oven and then at a temperature raising rate from 200 ° C / hour to a temperature of 1120 ° C (the firing temperature) heated. The mold in the oven was fired at the temperature of 1120 ° C for one hour. The shaped body then became at a cooling rate cooled from 75 ° C / hour to 900 ° C. Thereafter, the molded body was at a cooling rate from 200 ° C / hour further cooled to room temperature. After all This produced the piezoceramic. The burning time at one Temperature of not less than 900 ° C was in this Case five hours. The produced by the above method Piezoceramic is referred to as sample "e1".

As in the first attempt in the first embodiment the structure of the sample "e1" using a SEM analyzed. Each crystal grain in the sample "e1" consisted from the core phase and the shell phase.

As in the first attempt in the first embodiment by the cathodoluminescence (CL) spectral analysis, respectively, the crystal lattice defect amount the core phase and the shell phase in the sample "e1" determined. Then, based on the detection result, the value ds / dc was calculated. The result was that the piezoceramic as sample "e1" according to the second embodiment, the relationship ds / dc <1.2 sufficient Fulfills.

The second embodiment also produced a piezoceramic as sample "e2" by using an additive consisting of a Li starting powder (LiBO ₂ ) instead of the K starting powder. In this starting mixture slurry, the starting Li powder was added as an additive, so that this addition amount per 1 mole of the isotropic perovskite compound was 0.05 mole.

As in the first attempt in the first embodiment the structure of the sample "e2" also with the help of the REM determined. Every crystal grain in the sample "e2" existed from the core phase and the shell phase.

As in the first attempt in the first embodiment by the cathodoluminescence (CL) spectral analysis, respectively, the crystal lattice defect amount of the core phase and the shell phase in the sample "e2". Then, based on the detection results, the value ds / dc calculated. The result was that the piezoceramic sample "e2" according to the second embodiment, the relationship ds / dc <1.2 sufficient Fulfills.

The prepared by the above method as sample "e1" and sample "e2" Piezoceramic satisfies the relationship ds / dc <1.2, where "dc" is the Amount of crystal lattice defects generated in the core phase and "ds" the Amount of crystal lattice defects generated in the shell phase is. Therefore, the piezoceramic sample e1 and e2 has a high electrical insulation resistance. It is very suitable for a piezoceramic, which is used in electronic components.

6 Fig. 12 is a schematic view showing the structure of the perovskite compound according to the second embodiment of the invention.

Such a perovskite compound is generally expressed by the general formula ABO ₃ . It is well known that during the firing step in the perovskite compound, crystal lattice defects are often generated in the A-site element and / or O-site element (see US Pat 6 ). These crystal lattice defects reduce the electrical insulation resistance of the piezoceramic. In addition, the concentration of the crystal lattice defects generated in the shell phase further increases the decrease in the electrical insulation resistance of the piezoceramic. The piezoceramic according to the second embodiment may suffice have the electrical insulation resistance as long as it satisfies the relationship ds / dc <1.2.

Third Embodiment

It Now follows a detailed description of the procedure for producing the multilayer piezoelectric element according to the third embodiment. The procedure of the third Embodiment differs from the method of the first embodiment satisfying the relationship ds / dc <1.2.

While the method of the first embodiment piezoelectric Layers used, made of a crystal-oriented ceramic consist uses the method of the third embodiment Piezoceramic layers made of a non-oriented body (or a non-oriented crystal) exist.

The multilayer piezoelectric element according to the third embodiment is made up of piezoceramic layers, which consist of a piezoceramic and electrode formation layers together, the electrode parts comprising the internal electrodes containing a conductive metal form. In the multilayer piezoelectric element are the piezoceramic layers and the electrode formation layers are alternately stacked.

In the multilayer piezoelectric element according to the third embodiment, the piezoceramic layer is made of a polycrystalline material mainly composed of an isotropic perovskite compound represented by the {Li _0.08 (K _0.5 Na _0.5 ) _0.92 } (Nb _{0 , 84} Ta _0.1 Sb _0.06 ) O ₃ expressed in chemical formula. The crystal plane of the crystal grains constituting the polycrystalline material is not oriented. That is, the polycrystalline material consists of an unoriented body. The other constituents of the multilayer piezoelectric element according to the third embodiment are the same as those of the multilayered piezoelectric element according to the first embodiment.

The Method for producing the multilayer piezoelectric element according to the third embodiment consists of the mixing step, the molding step, the printing step, the laminating step and the firing step together.

The mixing step produces the starting mixture by combining at least one stoichiometric element selected from a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source, which is the produced by the general formula (1) compound generated. The starting mixture is then calcined to produce the starting reactive powder. The third embodiment uses a reactive starting powder having a specific surface area in a range of 2 to 5 m ² / g.

Of the Forming step shapes the reactive starting powder to the sheet-like Shaped body (or green layer).

Of the Printing step prints the electrode material on the green sheet on, wherein the electrode material contains the conductive metal, which becomes the electrode parts after the firing is completed. In The third embodiment is referred to as a conductive metal used an AgPd alloy.

Of the Aufschichtungsschritt layers the moldings after the Pressure step as green sheets on each other to the composite body manufacture.

Of the Burning step burns the laminate to the piezoceramic manufacture.

7 FIG. 14 is a view showing the temperature control during the burning step in the method according to the third embodiment of the invention. FIG.

As in 7 11, the firing step of the method according to the third embodiment is composed of a temperature increasing step, a first temperature holding step, a temperature lowering step, and a second temperature holding step.

The temperature raising step raises the temperature to T ₁ ° C (1050 ° C <T ₁ ≤ 1150 ° C). The first temperature keeping step keeps the temperature T ₁ ° C for a period of t ₁ hour (t ₁ ≤ 5 hours). The temperature reduction step lowers the temperature from T ₁ ° C to T ₂ ° C (950 ° C ≤ T ₂ ≤ 1050 ° C). The second temperature keeping step keeps the temperature T ₂ ° C for t ₂ hours (2 hours ≤ t ₂ ≤ 20 hours).

When the temperature raising rate is at least T ₂ ° C and T ₁ ° C D ₁ ° C / hour and the temperature lowering rate D ₂ ° C / hour, the method of the third embodiment controls the firing temperature to determine the relationship (T ₁ -T ₂ ) / t ₂ ≤ D ₁ ≤ 200 and (T ₁ - T ₂ ) / t ₂ ≤ D ₂ ≤ 200 (see 7 ).

It Now follows a detailed description of the multilayer Piezoelectric element according to the third embodiment.

In the mixing step in the process of the third embodiment, Na ₂ CO ₃ powder, K ₂ CO ₃ powder, Li ₂ CO ₃ powder, Nb ₂ O ₅ powder, Ta ₂ O ₅ powder, and a Sb ₂ O ₅ powder, which had a purity of not less than 99.99%, weighed to a planned ceramic composition of {Li _0.08 (K _0.5 Na _{0.5) 0.92}} (Nb _{0 , 84} Ta _0.1 Sb _0.06 ) O ₃ . Then, they were wet mixed with ZrO ₂ balls using an organic solvent for 20 hours.

Thereafter, the starting mixture obtained above was calcined at 700 ° C for 5 hours and then wet-cracked for 20 hours with an organic solvent having ZrO ₂ balls. As a result, a calcined powder having a mean grain size of about 0.5 μm and a specific surface area of 3.2 m ² / g was obtained (as a starting reactive powder).

Next, was added to the above reactive starting powder 1 wt .-% polyoxyalkylene polymer dispersing agents, and then wet-mixed for 20 hours with ZrO ₂ balls using an organic solvent to obtain a reactive Ausgangspulverschlämme.

After that were incorporated into the starting reactive powder slurries the powder weight 15% by weight of polyvinyl butyral (PVB) as a binder and dibutyl phthalate as a plasticizer and then for one hour mixed with an impeller stirrer.

In the forming step became the reactive starting powder slurry shaped or by means of a doctor blade method to a shaped body formed with a band shape (green sheet) having a thickness of about 100 microns had.

In In the printing step, an AgPd alloy containing 30 mol% was prepared. Pd contained. The AgPd alloy powder and the reactive starting powder were mixed at a volume ratio of 9: 1. In the Mixture was ethyl cellulose and. Terpineol given to an electrode material paste to create. The obtained electrode material paste was on the Printed electrode area, which formed on the green layer should be. As with the printing step in the method of the first Embodiment was the electrode material paste on the green sheets having a predetermined electrode formation pattern printed.

When Next, the lamination step and the degreasing step, to remove a fat ingredient from the laminate.

To Completion of the degreasing step became the laminated body burned next to the multilayer piezo element as Produce end product.

More specifically, after the fat removal, the laminate was placed in an oven and then, as in 7 is shown at a temperature raising rate of not more than 200 ° C / hour to a temperature T ₂ ° C (T ₂ = 1000 ° C in the third embodiment) heated. The temperature raising rate can be chosen optionally.

Next, the laminate was heated from the temperature T ₂ ° C at a temperature raising rate D ₁ ° C / hour (D ₁ = 50 in the third embodiment) to a temperature T ₁ ° C and for ₁ hour (t ₁ = 1 hour in FIG third embodiment) at the temperature T ₁ ° C held (first temperature holding step). The composite was cooled from T ₁ ° C to T ₂ ° C at a cooling rate D ₂ ° C / hour (D ₂ = 100 in the third embodiment) (temperature decreasing step) and t for ₂ hours (t ₂ = 5 hours in the third embodiment) maintained at the temperature T ₂ ° C (second temperature holding step). Thereafter, the laminate was cooled to room temperature at a cooling rate of not more than 200 ° C / hr. Finally, the multilayer piezoelectric element was produced thereby. The temperature reduction rate can be chosen optionally.

Next, the multilayer piezoelectric element obtained by the above method was replaced by a ma schinellen machining process finished, as in the previously described method of the first embodiment to achieve a circular disc of the multilayer piezoelectric element.

The by the above method of the third embodiment produced multilayer piezo element is used as sample E3.

Table 3 gives the specific surface area of the starting reactive powder used in the sample E3, the temperature raising speed D ₁ in the temperature increasing step, the holding temperature T ₁ in the first temperature holding step, the holding time t ₁ , the temperature lowering speed D ₂ in the temperature decreasing step, the holding temperature T ₂ im second temperature holding step, the holding time t ₂ and the value (T ₁ - T ₂ ) / t ₂ on.

The third embodiment also produced a sample E4 and comparative samples C4, C5, C6 and C7 having different production conditions, such as the specific surface area of the starting reactive powder, the temperature raising rate D ₁ ° C / hour in the temperature raising step, the holding temperature T ₁ ° C in the first temperature holding step, the holding time t ₁ , the temperature lowering rate D ₂ ° C / hour in the temperature decreasing step, the holding temperature T ₂ ° C in the second temperature holding step, the holding time t ₂ and the value (T ₁ -T ₂ ) / t ₂ . The other conditions were the same for the preparation of these samples E4, C4, C5, C6 and C7 as for the preparation of sample E3.

In particular, in the preparation of Comparative Sample C5, the second temperature-holding step was not used. That is, in the preparation of the comparative sample C5 in the firing step, the firing temperature (in the temperature increasing step) was increased from the room temperature to the temperature T ₁ ° C, and the temperature T ₁ ° C (in the first temperature holding step) was kept for ₁ hour. Next, the temperature (in the temperature decreasing step) was lowered from the temperature T ₁ ° C to the room temperature at a temperature lowering rate D ₂ ° C / hour.

The following Table 3 indicates the conditions in the preparation of the samples E3 and E4 and the comparative samples C5, C6 and C7, such as the specific surface of the reactive starting powder, the temperature increase rate D ₁ ° C / hour in the temperature increasing step, the holding temperature T ₁ ° C. in the first temperature holding step, the holding time t is ₁ hour, the temperature lowering speed D is ₂ ° C / hour in the temperature decreasing step, the holding temperature T is ₂ ° C in the second temperature holding step, the holding time t ₂ , and the value (T ₁ -T ₂ ) / t ₂ .

Second try

When Next follows a description of the characteristics of the multilayer Piezoelectric element according to each sample E3 and E4 and each comparative sample C4, C5, C6 and C7. The characteristics of these samples E3, E4, C4, C5, C6 and C7 were determined as follows.

As the first attempt was the amount of crystal lattice defects the core phase and the shell phase in each sample E3, E4, C4, C5, C6 and C7 determined.

The Table 4 gives the crystal lattice defect quantity dc of the core phase which Crystal lattice defect quantity ds of the shell phase and the ratio ds / dc of them in each sample E3, E4, C4, C5, C6 and C7.

In particular shows 8th a photograph of a CL spectral analysis showing the piezoceramic layer of sample E3.

As with the first attempt (see 4 ), the parts shown in white and gray indicate the piezoceramic 2 (as piezoceramic layer 2 ). In the piezoceramic 2 The more the intensity of the white color is, the higher the amount of crystal lattice defects. As can be seen from the in 8th shown photograph has the hull phase 22 (as in the in 4 shown photograph) a stronger white color than the core phase 21 , This shows that the number of crystal lattice defects in the shell phase 22 greater than in the core phase 21 is.

9 shows a graphical representation of the relationship between the wavelength and the CL intensity of the core phase 21 and the shell phase 22 sample E3 as a result of cathodoluminescence (CL) spectral analysis according to the first experiment.

The following Table 4 indicates the bulk density and the resistivity of the samples E3 and E4 and the comparative samples C4, C5, C6 and C7, respectively. Table 4 Sample No. Crystal lattice defect quantity dc (b.E.) in the core phase Crystal lattice defect quantity ds (b.E.) in shell phase ds / dc Bulk density (g / cm ³ ) resistivity (Ω · m) E3 220 240 1.09 4.82 1.2 × 10 ¹¹ E4 260 300 1.15 4.78 6.9 × 10 ¹⁰ C4 420 560 1.33 4.71 8.1 × 10 ⁸ C5 260 560 2.15 4.52 4.3 × 10 ⁶ C6 620 800 1.29 4.74 2.6 × 10 ⁸ C7 260 390 1.5 4.68 5.0 × 10 ⁷

As is clear from Table 3 and Table 4, the multilayer piezoelectric element (such as the sample E3 and the sample E4) has the specific surface area using the starting reactive powder in the range of 2 to 5 m ² / g under a firing condition which satisfies the relationship (T ₁ -T ₂ ) / t ₂ ≦ D ₁ ≦ 200 and (T ₁ -T ₂ ) / t ₂ ≦ D ₂ ≦ 200, piezoceramic layers made of a piezoceramic which satisfy the condition ds / dc <1.2. Table 4 also shows that the multilayer piezoelectric element with these piezoceramic layers has an extremely high specific resistance.

There each of the samples C4, C5, C6 and C7 produced under one condition one that did not fulfill the above burning condition Value ds / dc of less than 1.2, on the other hand, each of these samples has C4, C5, C6 and C7 have a low resistivity.

As can be seen from Table 4, have the samples E3 and E4 a high bulk density as the samples C4, C5, C6 and C7. This shows that the piezoceramic layer in samples E3 and E4 excellent piezoelectric characteristics of the general Formula (1) expressed isotropic perovskite compound and has excellent deformation characteristics.

The third embodiment shows a method for manufacturing a piezoceramic (or piezoceramic layers) consisting of a non-oriented body exists (made of random oriented ceramic exists). As in the method of the first embodiment It is possible to make one from a crystal-oriented ceramic produce existing piezoceramic by anisotropic powder and a reactive starting powder of stoichiometry the composition expressed by the general formula (1) be combined. In this case, a piezoceramic can be generated which satisfies the relationship ds / dc <1.2 by the specific Surface of the reactive starting powder and the firing conditions as set the conditions of the third embodiment become. The piezoceramic produced under these conditions can the same effects and effects as the multilayer piezo element (Sample E3 and Sample E4) according to the third embodiment to have.

- Eleventh embodiment and twelfth Embodiment of the invention

It Now follows the description of preferred embodiments the invention in terms of the eleventh and twelfth embodiment the invention.

The Method according to the eleventh embodiment of the invention produces a crystal-oriented ceramic from a polycrystalline Material consisting mainly of an isotropic perovskite compound in which the {100} crystal plane of each crystal grain, the forming the polycrystalline material is oriented. The crystal-oriented Ceramic is made by a first preparation step, a second Preparation step, a mixing step, a molding step and made a burning step.

It is preferable that the mixing step mixes an anisotropic powder with a starting reactive powder to produce, after completion of the firing step, an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≤ x 5 0.2, 0 ≤ y ≤ 1, 0 ≤ z ≤ 0.4, 0 ≤ w ≤ 0.2, x + z + w> 0, 0.95 ≤ a ≤ 1. The process of the present invention can thus produce a crystal-oriented ceramic of a polycrystalline material consisting mainly of the isotropic perovskite compound expressed by the general formula (1). Therefore, since the crystal-oriented ceramic has the characteristics of the isotropic perovskite compound, it has excellent piezoelectric characteristics.

The technical term "isotropic" means that the relative ratio of the axial lengths a, b and c has a value in a range of 0.8 to 1.2 and that their respective axial angle α, β and γ in a range of 80 ° to 100 ° lies when the perovskite structure ABO _{3 has} a pseudo-cubic primitive lattice.

When a compound expressed by the above general formula (1) is applied to the composition equation ABO _{3 of} the perovskite structure, the A-site atom may have a composition ratio to a composition ratio of the A-site element and the B-site element from 1: 1 by 5%. This means that the relationship 0.95 ≤ a ≤ 1, better still 0.97 ≤ a ≤ 1, is satisfied.

In of the above general formula (1), the relationship "x + z + w> 0 ", that it is sufficient if at least one selected from Li, Ta and Sb Element is included as a substitution element.

Of Further, the value "y" in the above general Formula (1) the ratio of K and Na, which is in the isotropic Perovskite compound is included. It is enough if in the through the general formula (1) expressed isotropic perovskite compound at least one element selected from K and Na as the A-space element is included.

It is preferable that the value "y" in the general formula (1) has a range of 0 <y <1. In this case, Na is an essential ingredient in the compound expressed by the general formula (1). As a result, the piezoelectric constant g _{31 of} the piezoceramic can be further increased.

In addition, the value "y" in the general formula (1) may have a range of 0 ≦ y <1. In this case, K is an essential ingredient in the compound expressed by the general formula (1). This ₃₁ may further enhance the piezoelectric characteristics such as the piezoelectric constant d. Since the piezoceramic sintered according to the higher amount of K added at a low temperature can be in this case, it is possible to produce the piezoceramic with lower production costs and to reduce the amount of energy used.

Moreover, it is preferable that the value "y" in the general formula (1) is in a range of 0.05 ≦ y ≦ 0.75, and more preferably in a range of 0.20 ≦ y 5 0.70 , As a result, the piezoelectric constant d ₃₁ and the electromechanical coupling factor K _{p of} the crystal-oriented ceramic can be further increased.

It It is further preferable that the value "y" in of the general formula (1) in a range of 0.20 ≦ y <0.70, better yet in a range of 0.35 ≦ y ≦ 0.65 and still better in a range of 0.35 ≦ y <0.65. He is best in a range of 0.42 ≦ y ≦ 0.60.

In the general formula (1), the value "x" indicates the substitution amount of Li with which the A-site element such as K and / or Na is substituted. The substitution of K and / or Na with Li can increase the piezoelectric properties and the Curie temperature T _C and also promote the density.

It is preferable that the value "x" in the general formula (1) is in a range 0 <x ≦ 0.2. In this case, since Li is an essential ingredient in the isotropic perovskite compound expressed by the general formula (1), the firing step during the production of the piezoceramic is easier to perform. Furthermore, the piezoelectric characteristics can thereby be improved and the Curie temperature (T _C ) of the piezoceramic can be further increased. Since Li in the general formula (1) becomes an essential component in the region of the value "x", the firing temperature can be lowered and Li, as a fuel, can produce a piezoceramic having a smaller number of pores.

When the value "x" is more than 0.2, there is a possibility of decreasing the piezoelectric characteristics (such as the piezoelectric constant d ₃₁ , the electromechanical coupling factor Kp and the piezoelectric constant g ₃₁ ).

The value "x" may be zero (x = 0) in the general formula (1). In this case, the general formula (1) can be expressed by (K _1-y Na _y ) _a (Nb _1-zw Ta _z Sb _w ) O ₃ . In this case, in the case of producing the crystal-oriented ceramic, since there is no compound such as LiCO ₃ containing the maximum light Li, variations in characteristics caused by a change in the starting powders can be reduced when the starting materials are mixed. Furthermore, in this case, a piezoceramic having excellent relative permeability and a relatively large piezoelectric constant "g" can be produced. It is preferable that the value "x" in the general formula (1) has a range of 0 ≦ x ≦ 0.15, and more preferably a range of 0 ≦ x <0.10.

The value "z" in the general formula (1) indicates the amount of Ta substituted with Nb as the B-site element. The substitution of a part of Nb with Ta has the effect of increasing the piezoelectric characteristics of the piezoceramic. When the value "z" in the general formula (1) is more than 0.4, the Curie temperature T _{C of} the crystal oriented ceramics decreases. This leads to the possibility that it is difficult to use the piezoceramic in household applications and automotive components.

It It is therefore preferable that the value "z" in the general formula (1) has a range of 0 <z ≦ 0.4. In this case Ta is expressed by the general formula (1) isotropic perovskite compound an essential component. This lowers the sintering temperature accordingly, with Ta serving as the fuel and reduce the number of pores produced in the piezoceramic can.

The value "z" can be zero (z = 0). In this case, the general formula (1) is expressed by {Li _x (K _1-y Na _y ) 1-x} _a (Nb _1-w Sb _w ) O ₃ . In this case, since the compound expressed by the general formula (1) does not contain Ta, the compound expressed by the general formula (1) can have excellent piezoelectric characteristics without using expensive Ta in the preparation of this compound.

It It is preferable that the value "z" in the general Formula (1) has a range of 0 ≦ z ≦ 0.35 and better still has a range of 0 ≤ x ≤ 0.30.

Further, the value "w" in the general formula (1) indicates the amount of Sb substituted with Nb as the B-site element. The substitution of a part of Nb with Sb ensures that the piezoelectric characteristics of the piezoceramic are increased. Since the piezoelectric characteristics and / or the Cu When the value "w" in the general formula (1) is more than 0.2, it is avoided that the value "w" is more than 0.2.

It It is therefore preferable that the value "w" in the general formula (1) has a range of 0 <w ≦ 0.2. In this case Sb is as expressed by the general formula (1) Compound an integral part. Accordingly, you can thereby lowering the sintering temperature, improving the sintering characteristics and also the stability of the dielectric Loss tanδ the crystal-oriented ceramics are increased.

The value "w" may be zero (w = 0) in the general formula (1). When w = 0, the general formula (1) can be expressed by {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-z Ta _z ) O ₃ . Since this compound expressed by the above general formula (1) contains no Sb, the compound expressed by the general formula (1) can do without Sb and have a relatively high Curie temperature. It is therefore preferable that the value "w" in the general formula (1) has a range of 0 ≦ w ≦ 0.15, and more preferably a range of 0 ≦ w ≦ 0.10.

The crystal phase of the crystal-oriented ceramic changes according to a temperature change from a high temperature to a low temperature in the following three stages:
first stage: from a cubic lattice to a quadrangular lattice (at a first crystal phase change temperature = Curie temperature);
second stage: from the quadrangular grid to an oblique grid (at a second crystal phase change temperature;
third stage: from the oblique lattice to a rhombohedral lattice (at a third crystal phase change temperature).

The Crystal-oriented ceramic loses the deformation characteristics a temperature of not less than the first crystal phase change temperature, because their crystal phase is shifted to the cubic lattice phase.

The Crystal phase of the crystal-oriented ceramic changes in a temperature range of not less than the first crystal phase change temperature to the second crystal phase change temperature to the oblique Grid phase, the deformation characteristics and the electrostatic Capacity of the crystal-oriented ceramics strongly of the Depend on temperature change. It is therefore preferable that the first crystal phase change temperature higher is the working temperature of the crystal-oriented ceramic and that the second crystal phase change temperature is lower than the working temperature of the crystal-oriented ceramic.

However, the relevant literature, for example the "Journal of American Ceramic Society", pp. 438-442, [9] of vol. 42, 1959 , and the American patent US 2,976,246 discloses that niobium-potassium-sodium oxide (K _1-y Na _y NbO ₃ ), which is a basic component of the crystal-oriented ceramic, has the following phase change corresponding to a decrease from a high temperature to a low temperature:
from a cubic lattice to a quadrangular lattice (at a first crystal phase change temperature = Curie temperature);
from the quadrangular grid to an oblique grid (at a second crystal phase change temperature); and
from the oblique lattice to a rhombohedral lattice (at a third crystal phase change temperature), where for y = 0.5 the first crystal phase change temperature is about 420 ° C, the second crystal phase change temperature is about 190 ° C, and the third crystal phase change temperature is about -150 ° C. In other words, the temperature holding the square grid has a range of 190 ° C to 420 ° C, which does not match the general temperature range of -40 ° C to 160 ° C where general industrial products work.

On the other hand, the first crystal phase change temperature and the second crystal phase change temperature in the crystal oriented ceramic of the present invention can be freely changed by using the amount of Li, Ta, Sb, etc. as a substitution element for such a niobium-potassium-sodium oxide (K _1-y Na _y NbO ₃ ) is changed as a primitive.

The The following formulas B1 and B2 give calculation results of a multiple regression analysis the amount of substitution elements Li, Ta and Sb and detection values the crystal phase change temperature for the Range y = 0.4 to 0.6 with the largest piezoelectric Characteristics.

From the formulas B1 and B2, it is understood that the substitution amount of Li increases the first crystal phase change temperature and decreases the second crystal phase change temperature. In addition, it is clear from the formulas B1 and B2 that the presence of Ta and Sb reduces the first crystal phase change temperature and also the second crystal phase change temperature. first crystal phase change temperature = (388 + 9x - 5z - 17w) ± 50 [° C] Formula B1; and second crystal phase change temperature = 190 - 18.9x - 3.9z - 5.8w) ± 50 [° C] Formula B2.

The first crystal phase change temperature is a temperature in which the crystal-oriented ceramic, the piezoelectric characteristics completely loses. Because the dynamic capacity the crystal-oriented ceramic drastically changes it is preferable that the first crystal phase change temperature a temperature range within the working temperature of a product + 60 ° C has.

There the second crystal phase change temperature only a temperature at which the crystal phase changes, but no piezoelectric characteristics change it is preferable that the second crystal phase change temperature a temperature range of not more than the working temperature of a product + 60 ° C.

On the other hand changes the working temperature of a product according to its conditions of use. For example, the upper limit temperature of a product is about either 60 ° C, 80 ° C, 100 ° C, 120 ° C, 140 ° C or 160 ° C and the lower limit temperature of the product about -30 ° C or -40 ° C.

Accordingly it is preferable that the values x, z, and w are related (388 + 9x - 5z - 17w) ± 50 ≥ 120 [° C], since it is preferable that the expressed by the formula B1 first crystal phase change temperature not less than 120 ° C.

Furthermore it is preferable that the values x, z and w are the relationship (190 - 18.9x - 3.9z - 5.8w) - 50 ≥ 10 fulfill, since it is preferable that through the formula B2 expressed second crystal phase change temperature not more than 10 ° C.

The means that it is preferable that the previously described general formula (1) the relationship 9x - 5z - 17w ≥ -318, and 18.9x - 3.9z - 5.8w ≤ -130 Fulfills.

It Although it is preferable that the crystal-oriented ceramics one expressed by the above general formula (1) Isotropic perovskite compound is produced, but it can also contain another element and another phase as long as these lead to no bad influence, the sintering characteristics and piezoelectric characteristics and other characteristics deteriorated.

In The crystal-oriented ceramic is a specific crystal plane A of the crystal grains containing the polycrystalline material The crystal-oriented ceramic form, oriented or aligned. This means that the specific levels A of the crystal grains in the isotropic perovskite compound are oriented parallel to each other. (This structure is called "surface orientation.")

pseudocubic {HKL} means that the structure of the isotropic perovskite compound Although in general it has a structure that is opposite one quadrangular grid, an oblique grid, a trigonal Grid and a cubic grid is slightly shifted, that this Shift amount, however, is small, so pseudo-cubic as a treated cubic lattice and therefore using the Miller indices {HKL} can be expressed.

When a specific crystal plane A is plane-oriented, the plane orientation degree can be expressed by the following Mathematical Equation (1) by means of a mean orientation degree F (HKL): F (HKL) = [{Σ'I (HKL) / ΣI (hkl)} - {Σ'Io (HKL) / ΣIo (hkl)}] / [1 - {Σ'Io (HKL) / ΣIo (hkl) }] × 100 (%) Mathematical equation (1), where ΣI (hkl) is the sum total of the detected x-ray diffraction intensities of all crystal planes (hkl) of a crystal-oriented ceramic, ΣIo (hkl) is the sum total of the detected X-ray diffraction intensities of all crystal planes (hkl) of a non-crystal oriented ceramic having the same composition as the crystal oriented ceramic, Σ'I (HKL) is the sum total of detected X-ray diffraction intensities of a specific crystal plane (HKL) which corresponds to the crystal oriented ceramics in a crystallographic analysis, and Σ'Io (HKL) is the sum total of the detected X-ray diffraction intensities of the specific crystal plane (HKL) corresponding to crystallographic analysis of the non-crystal oriented ceramics having the same composition as the crystal oriented ceramics.

If none of the crystal grains containing the polycrystalline material is oriented in a specific level their mean orientation degree F (HKL) corresponding to 0%. On the other hand each of the crystal grains containing the polycrystalline material is oriented in a specific crystal plane is their mean orientation degree F (HKL) 100%.

ever more the ratio of the crystal grains, the are oriented in a specific crystal plane, in the crystal-oriented one Ceramic increases, the higher the deformation effect the piezoceramic layers.

There The crystal-oriented ceramics generally made of a polycrystalline Material consists mainly of an isotropic material Perovskite compound can exist in a lead-free piezoceramic ensure high piezoelectric characteristics. Because the specific Crystal plane in each of the crystal grains, which is the polycrystalline Material in the crystal-oriented ceramic form, in a same Direction oriented or oriented, can also compared with a non-oriented sintered body (not oriented body), which has the same composition The crystal-oriented ceramic has, for high piezoelectric Characteristics are taken care of.

When Next follows a description of each step in the Method for producing the inventive crystal-oriented ceramic.

Of the first preparation step prepares an anisotropic powder oriented anisotropic grains in which a {100} crystal plane is oriented.

The "anisotropic Form "indicates a shape in which the dimension in the longitudinal direction longer than the dimension in width or thickness direction is. More specifically, such an anisotropic form has a plate shape, a columnar shape, a dandruff shape or a needle shape. The type of crystal plane that the oriented surface can, according to the needs of different types of Crystal planes are chosen.

It is preferable than the oriented grains a material to use, which has a form, with which the crystal plane during the molding step easily in a specific direction orient. For this reason, it is preferable that the oriented grain has a mean aspect ratio of not less than 3 has.

If the mean aspect ratio is less than 3, lets the anisotropic powder during the molding step difficult to orient in a specific direction. To the out Crystal-oriented ceramic existing piezoceramic with a higher Orientation degree, it is preferable that the oriented Grain an aspect ratio of not less than 5 has. The mean aspect ratio is an average of maximum dimension to the minimum dimension of the oriented grains.

ever greater the mean aspect ratio which is oriented grains, the easier it can be the oriented grains during the forming step orientate. If the mean aspect ratio however, is extremely high, there is a possibility that the oriented grains during the mixing step break. This makes it difficult to produce a shaped body, in which the oriented grains are oriented. It is therefore, it is preferable that the oriented grains have a middle Aspect ratio of not more than 100 have. It is better if the oriented grains are a medium Have aspect ratio of not more than 50, and even better, they have a medium aspect ratio of not more than 30.

The oriented grains consist of a perovskite compound. In a concrete example can be considered oriented grains A compound can be used that has the same chemical composition as the desired isotropic perovskite compound has, such as by the general formula (1) expressed compound.

It is not always necessary to connect with the same chemical Composition like the desired isotropic perovskite compound to use, such as those expressed by the general formula (1) Connection. It can also be used as a material Main component generates the desired isotropic perovskite compound, about the compound expressed by the general formula (1), by using the reactive starting powder described later is sintered.

Accordingly either a mixed crystal or a compound can be chosen be one or more positive interior elements (or positively charged Internal elements) contained in the perovskite compound to be produced are included.

As these oriented grains satisfying the above condition, for example, the following compounds may be used:
NaNbO ₃ (hereinafter referred to as "NN"), KNbO ₃ (hereinafter referred to as "KN") and (K _1-y Na _y ) NbO ₃ (0 <y <1) which are an isotropic perovskite compound type, or in the above Materials are substituted or dissolved by a predetermined amount of Li, Ta and / or Sb, which is expressed by the following general formula (2): {Li _x (K _1-y Na _y ) _1-x } (Nb _{1-1 -t} Ta _z Sb _w ) O ₃ (2), where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, and 0 ≦ w ≦ 1 holds.

The compounds expressed by the general formula (2) have a good and high lattice matching function the isotropic one expressed by the general formula (1) Perovskite. Therefore, this is oriented from the above Grains consisting of anisotropic powder (hereinafter referred to as the "anisotropic Powder A "), represented by the general formula (2) is expressed as a reactive template to the to produce crystal oriented ceramics, where the {100} crystal plane in the above oriented grains, the oriented plane is.

About that In addition, the anisotropic powder A consists essentially of positive Ionic elements (or positively charged ionic elements) used in the expressed by the general formula (1) isotropic Perovskite compound are included. This can be a crystal-oriented Ceramics are made containing a smaller amount of impurity elements Has.

When Anisotropic powder can also be a layered perovskite compound in which, for example, the {100} crystal plane is one Crystal plane with low surface energy is. Because the layered perovskite compound a large anisotropic Crystal lattice, this can be from the layered Perovskite compound existing anisotropic powder (hereinafter referred to as referred to as "anisotropic powder B"), referred to as oriented plane has a low surface energy, easy to make.

An example which can be used for the layered perovskite compound is, for example, a bismuth layer perovskite compound expressed by the following general formula (3): (Bi ₂ O ₂ ) ²⁺ {B _10.5 Me _m-1.5 Nb _m O _{3m + 1} } ^2- (3) wherein m is an integer of not less than 2 and Me is one or more of Li, K and Na.

Unlike the other planes in the compound expressed by the general formula (3), a {001} crystal plane generally has a low surface energy. The use of the compound expressed by the general formula (3), therefore, facilitates the work of synthesizing the above anisotropic powder B having the {001} oriented layer. The oriented {001} plane is parallel to the (Bi ₂ O ₂ ) ²⁺ layer of the bismuth layer perovskite compound expressed by the general formula (3). Further, the {001} plane in the compound expressed by the general formula (3) greatly matches the {100} plane of the isotropic perovskite compound expressed by the general formula (1).

The anisotropic powder B, which is characterized by the general formula (3) composed connection and the oriented {001} crystal plane has, provides a good reactive template or a good anisotropic powder to produce the crystal-oriented ceramic.

When the compound expressed by the general formula (3) is used, the anisotropic powder B can be adjusted so that it contains substantially no Bi as the A-site element by the Composition of the reactive starting powder is set (will be explained later).

Accordingly even if the anisotropic powder B is used, a produced from the crystal-oriented ceramic piezoceramic which are mainly made by the general Formula (1) expressed isotropic perovskite compound consists.

A preferred second example of the layered perovskite compound as the anisotropic powder B is, for example, Sr ₂ Nb ₂ O ₇ . The {010} plane of Sr ₂ Nb ₂ O ₇ has a low surface energy compared to the other planes. Further, the {010} plane of Sr ₂ Nb ₂ O ₇ highly matches the {110} plane of the isotropic perovskite compound expressed by the general formula (1). Therefore, an anisotropic powder consisting of Sr ₂ Nb ₂ O ₇ in which the {010} plane is an oriented plane can be used as a reactive template to produce a crystal oriented ceramic having an oriented {110} plane.

A preferred third example of the layered perovskite compound as anisotropic powder B is, for example, Na _1.5 Bi _2.5 Nb ₃ O ₁₂ , Na _2.5 Bi _2.5 Nb ₄ O ₁₅ , Bi ₃ TiNbO ₉ , Bi ₃ TiTaO ₉ , K _0.5 Bi _2.5 Nb ₂ O ₉ , CaBi ₂ Nb ₂ O ₉ , SrBi ₂ Nb ₂ O ₉ , BaBi ₂ Nb ₂ O ₉ , BaBi ₃ Ti ₂ NbO ₁₂ , CaBi ₂ Ta ₂ O ₉ , SrBi ₂ Ta ₂ O ₉ , Na _0.5 Bi _2.5 Ta ₂ O ₉ , Bi ₇ Ti ₄ NbO ₂₁ , Bi ₅ Nb ₃ O ₁₅ , etc.

The {001} plane in the above compounds fits of the lattice to a high degree to the pseudocubic {100} plane the isotropic one expressed by the general formula (1) Perovskite. Accordingly, an anisotropic powder from one of these links, where the {001} plane is an oriented one Level is to be used as a reactive template to be a crystal-oriented To produce ceramic with an oriented pseudocubic {100} plane.

A preferred third example of the layered perovskite compound as the anisotropic powder B is, for example, Ca ₂ Nb ₂ O ₇ and Sr ₂ Ta ₂ O ₇ , etc.

The {010} plane in the above links fits of the lattice to a high degree to the pseudocubic {110} plane the isotropic one expressed by the general formula (2) Perovskite. Accordingly, an anisotropic powder from one of these compounds in which the {010} plane is oriented Level is to be used as a reactive template to be a crystal-oriented To produce ceramic with an oriented pseudocubic {110} plane.

When Next follows a description of a method of manufacturing of the above anisotropic powder.

The anisotropic powder (ie, the anisotropic powder B) consisting of the layered perovskite compound can be easily prepared by the following steps with a predetermined composition, a predetermined average grain size, and / or a predetermined aspect ratio:
Preparing an oxide, carbonate, nitrate, etc. (hereinafter referred to as the "anisotropic powder raw material") containing its constituent elements; and
Heating the anisotropic powder starting material with a liquid or material that becomes liquid upon heating.

If the anisotropic powder starting material is heated in a solution is allowed, which allows for easy diffusion easily synthesize an anisotropic powder B in which the Low surface energy level (for example, the {001} plane in the compound expressed by the general formula (2)) growing with priority. In this case, you can the mean aspect ratio and the mean Grain size of the anisotropic powder B by selection be set to an optimal synthesis condition.

There are the following methods for producing the anisotropic powder B: a method in which an optional flux (for example, NaCl, KCl, a mixture of NaCl and KCl, BaCl ₂ , KF, etc.) is added to the anisotropic powder starting material and the mixture is then heated, or a method in which an irregularly shaped powder having the same composition as the produced anisotropic powder B and an alkali solution are heated in an autoclave. The former method is called "flux method". The latter method is called "hydrothermal method".

On the other hand, since the compound expressed by the general formula (2) has a crystal lattice with very little anisotropy, it is difficult to obtain the anisotropic powder (ie, the anisotropic powder A) consisting of the compound expressed by the general formula (2) the specific crystal plane one oriented level is to synthesize directly. However, the anisotropic powder A can be produced while using the above-described anisotropic powder B as a reactive master by heating in a flux having a reactive raw material B satisfying a predetermined condition.

If the anisotropic powder A using the anisotropic powder B as a reactive template is synthesized under optimal conditions Reaction conditions are changed its crystal structure without affecting the shape of the powder.

Around the anisotropic powder A, which during the molding step in to be oriented in a specific direction it is preferable that during the anisotropic powder B to be used in the synthesizing step has a shape that is easy during the shaping step oriented in the specific direction.

If the anisotropic powder A using the anisotropic powder B is synthesized as a reactive template, it is therefore preferable to the anisotropic powder A has an average aspect ratio not less than 3, better still not less than 5 and even better of not less than 10 has. Furthermore It is preferable that the anisotropic powder A has an average aspect ratio of not more than 100, to prevent the product from being in to break a next step.

The previously described reactive starting material B is a compound with the anisotropic powder A, which is made by the general Formula (2) is composed by one Reaction with the anisotropic powder B can produce. In this case it is for the reactive starting material B acceptable if it is due to the reaction with the anisotropic powder B only those expressed by the general formula (2) Connection created. It is also acceptable if it is due to the reaction with the anisotropic powder B both an excess Material as well as those expressed by the general formula (2) Connection created. The "excess Material "means a different material than the material the general formula (2) expressed compound as the planned product. If the excess material by the reaction between the anisotropic powder B and the reactive one It is also preferable that the excess material through a thermal or to easily remove chemical treatment from the product.

When Reactive starting material B may be, for example, an oxide powder, a Mixed oxide powder, a carbonate, a nitrate, an oxalate, an alkoxide etc. are used. The chemical composition of the reactive Starting material B may be based on the manufactured and by the general formula (2) and compound expressed the composition of the anisotropic powder B.

For example, when an anisotropic powder A is prepared consisting of NaNbO ₃ (NN) as one kind of the compounds expressed by the general formula (2) by using an anisotropic powder B composed of Bi _2.5 Na _0.5 Nb ₂ O ₉ as one kind of the bismuth layer-perovskite compound expressed by the above-explained general formula (3), as the reactive raw material B, a Na-containing compound (such as an oxide, a hydroxide, a carbonate , a nitrate, etc.).

When in the anisotropic powder B and the reactive starting material B having the above composition, a suitable flux in a range of 1 wt .-% to 500 wt .-% (for example, NaCl, KCl, a mixture of NaCl and KCl, BaCl ₂ , KF, etc.) is added and the mixture is heated to the temperature of an eutectic point and a melting point, the excess material is mainly composed of NN and Bi ₂ O _3. Since Bi ₂ O _{3 has} a low melting point and low acid resistance, the N-anisotropic powder A in which the {100} plane is an oriented plane can be prepared by eliminating the flux from the obtained reaction product then heated or rinsed with acid.

Further, in synthesizing an anisotropic powder A consisting of (K _0.5 Na _0.5 ) NbO ₃ (hereinafter referred to as "KNN") as one kind of the compound expressed by the general formula (2), by one of BINN2 existing anisotropic powder B is used as the reactive starting material B, a Na-containing compound (an oxide, a hydroxide, a carbonate, a nitrate, etc.) or a mixture of Na and K.

When an appropriate flux in a range of 1 wt% to 500 wt% is added to the anisotropic powder B and the reactive raw material B having the above composition, and the mixture is heated to the temperature of a eutectic point and a melting point, is that over schüssige material mainly from KNN and Bi ₂ O ₃ .

By doing the flux is removed from the reaction product obtained, For example, an anisotropic powder A consisting of KNN can be produced. where the {100} plane is an oriented plane.

Of the Case that by the reaction between the anisotropic powder B and the reactive starting material B only those through the general Formula (2) expressed compound has the same procedure. That means it's enough, that Anisotropic powder B with a specific composition and the reactive starting material B with a specific composition in a suitable flux to heat. This can be done in the Fluxes expressed by the general formula (2) Connection can be generated with the predetermined composition. By removing the flux from the reactive product can then the anisotropic expressed by the general formula (2) Powder A can be achieved in which a specific crystal plane a oriented level is.

There the compound expressed by the general formula (2) has a crystal lattice with low anisotropy leaves The anisotropic powder A, as described above, is difficult synthesize directly. It is also difficult to get an anisotropic To synthesize powder A directly in which an optional crystal plane to an oriented level becomes.

There on the other hand, the layered perovskite compound as described above was, has a crystal lattice with great anisotropy leaves The anisotropic powder can easily and directly synthesize. Furthermore, the most oriented levels in the anisotropic Powder of the layered perovskite compound the effect, with respect of the lattice to the specific crystal plane in the by the general Formula (2) to match. About that In addition, the compound expressed by the general formula (2) is thermodynamically compared to the layered perovskite compound stable.

Out For this reason, the anisotropic powder B serves as a reactive template, when the reaction between the anisotropic powder B and the reactive Starting material B is carried out in a suitable flux with the oriented plane in the layered perovskite compound with respect to the grid to the specific level in the compound expressed by the general formula (2) fits. This makes it easy to get the anisotropic powder A is as expressed by the general formula (2) Synthesize the compound that has the same crystal plane orientation direction as the anisotropic powder B has.

About that In addition, an optimization of the composition allows of the anisotropic powder B and the reactive starting material B it, the A-space element (hereinafter referred to as the "excess A-space element") from the anisotropic powder B and an anisotropic powder A is as expressed by the general formula (2) Make connection that no excess A-space element contains.

In particular, when the anisotropic powder B is the bismuth layer-perovskite compound expressed by the general formula (3), Bi is removed as the excess A-site element and an excess of mainly Bi ₂ O _{3 is} synthesized. By thermally or chemically removing the excess ingredient, the anisotropic powder A can be prepared from the compound expressed by the general formula (2) in which the specific crystal plane is oriented.

The oriented grain consists of an isotropic perovskite compound expressed by ABO ₃ . It is preferable that the A-space element in the isotropic perovskite compound mainly consists of at least one of K, Na and Li, and that the B-space element therein is mainly composed of at least one of Nb, Sb and Ta. In this case, in a potassium niobate-sodium system for isotropic perovskite, a lead-free, crystal-oriented ceramic having relatively high piezoelectric characteristics can be produced.

It It is also preferable that the oriented grain is the compound expressed by the general formula (2) consists. This allows a crystal-oriented ceramic with a high degree of orientation.

Namely, the compound expressed by the general formula (2) described above, with respect to the lattice, greatly matches the compound expressed by the general formula (1). Therefore, the anisotropic powder B consisting of the oriented grains expressed by the general formula (2) in which the specific crystal plane is the oriented plane serves as a good template for the production of crystal-oriented ceramics.

Of the second preparatory step next prepares the reactive one Starting powder before to react by reaction with the anisotropic powder to produce the isotropic perovskite compound.

Of the second preparation step prepares a reactive starting powder with a half width in a range of 0.4 ° to 0,8 ° before and use it.

Becomes a reactive starting powder with a half width of less used as 0.4 °, there is a possibility that during the firing step the reactivity the reaction between the reactive starting powder and the anisotropic Powder decreases. As a result, it can be difficult to bulk density of the product. This reduces the electrical Insulation resistance of the crystal-oriented ceramic as a product.

Becomes by contrast, a reactive starting powder having a half-width of more than 0.8 °, it is possible to that it is at uniformity after completion of the firing step in the crystal-oriented ceramic as the product obtained lacks.

The Half width of the {002} plane of the reactive starting powder can be determined by the following method.

And indeed, the X-ray patterns of the reactive starting powder become separated at each of its peak values, and it is based on the {002} plane the peak width as half width (as full width at half height: engl. FWHM) at one intensity which determines half the highest peak intensity at the peak value (θ = about 45 °).

It it is preferable that the reactive starting material is a grain size of not more than 1/3 of the grain size of the anisotropic Powder has.

If the grain size of the reactive starting material more than 1/3 of the grain size of the anisotropic powder There is a possibility that the Starting mixture difficult to shape so that the oriented Level in the anisotropic powder approximately in a same Direction is oriented. It is preferable that the grain size of the reactive starting material not more than 1/4 of the grain size of the anisotropic powder, better still not more than 1/5 of the grain size of the anisotropic powder.

The Grain size between the reactive starting material and the anisotropic powder can be compared by their mean Grain size is compared. The grain size of the anisotropic powder and the reactive starting material each its long diameter.

The Chemical composition of the reactive starting material can for Example according to the composition of the anisotropic powder and the composition expressed by the general formula (1) and isotropic perovskite compound to be prepared.

And Although the first through the general Formula (1) expressed planned composition and the Composition of the anisotropic powder are set, and then can set the composition of the reactive starting powder to be so by the reaction between the anisotropic powder and the reactive starting powder represented by the general formula (1) to produce expressed isotropic perovskite compound.

It it is preferable that the isotropic perovskite compound is in the firing step by the reaction between the anisotropic powder and the reactive one Starting powder is produced, wherein the anisotropic powder and the reactive starting powders have a different composition. This makes the crystal-oriented ceramic easy with a complicated composition.

It is preferable to use a starting reactive powder consisting of an isotropic perovskite compound expressed by the following general formula (4): {Li _p (K _1-q Na _q ) _1-p } _c (Nb _1-rs Ta _r Sb _s ) O ₃ (4) where 0≤p≤1, 0≤q≤1, 0≤r≤1,0≤≤≤1,0,95≤c≤1.05.

The Use of the reactive starting powder with the above, by general formula (4) can be expressed in the firing step the reactivity with the anisotropic Increase powder, making it easily a crystal-oriented Ceramic with uniform composition and Density can be produced.

It it is preferable that the second preparation step includes a mixing preparation step and performing a calcination step. The preparation step produces the reactive starting mixture by mixing starting elements. The calcining step calcines the reactive starting mixture, to make the reactive starting powder.

Thereby can be easily generated a reactive starting powder that the compound expressed by the general formula (4) which is excellent in reacting with the reaction the anisotropic powder. It is then possible, the reactive Starting powder after completion of the calcination step accordingly to generate the demand.

When Output sources can be one or more from a Li source, a K source, a Na source, a Nb source, a Ta source and an Sb source of selected elements.

When Starting sources may be an oxide powder, a mixed oxide powder, a hydroxide powder, an alkoxide or a salt. As a salt, a carbonate, a bicarbonate, a nitrate, etc. be used.

The reactive starting powder can be prepared in a composition be the desired isotropic perovskite compound in the Firing step produced by a reaction with the anisotropic powder.

Of the Calcination step can be performed so that the reactive starting mixture at a temperature of not more calcined as 700 ° C.

If the calcination temperature is more than 700 ° C, there is a possibility that it will be difficult in the second preparation step with a reactive starting powder a half width of the pseudocubic {002} plane in one area from 0.4 ° to 0.8 °.

The means that the calcination step is the half width set the pseudocubic {002} plane of the starting reactive powder can. The reaction of the reactive starting mixture occurs during the calcination step for both the production of the isotropic perovskite compound as well as to a crystal growth. However, that leads Calcination at a temperature of more than 700 ° C easily to excessive calcination. If it in the reactive starting powder to excessive Crystal growth comes, there is a possibility that out Most reactive starting powder produces a perovskite compound which has a high crystal fit.

Consequently the reactive starting powder has a high crystal matching what the half-width of the pseudocubic {002} plane is slightly less reduced by 0.4 °. Besides, that has reactive Starting powder at an excessive Calcining a larger average grain size. A reactive starting powder with a half width of less as 0.4 ° and an extremely large mean grain size has in the firing step against the anisotropic powder a low reactivity and difficult high density. There is a possibility that the electrical insulation resistance the crystal-oriented ceramic decreases.

It It is therefore preferable for the reactive starting powder to be a primary one mean grain size of not more than 2.5 microns Has.

It is even better if the calcination temperature is not more than 650 ° C is.

In Considering the optimal calcination temperature to a long Calcination time to avoid the optimal composition of the obtained after completion of the firing step crystal-oriented Ceramics, to avoid insufficient calcination, and the optimal density of the achieved after completion of the firing step crystal-oriented ceramics to make a nonuniform To avoid density, it is preferable that the calcination temperature is not less than 600 ° C.

It is acceptable if the reactive starting powder by the reaction with the anisotropic powder generates only the planned perovskite compound or both the planned perovskite compound and an excess ingredient. When the excess ingredient is generated by the reaction between the anisotropic powder and the starting reactive powder, it is preferable that the excess ingredient be removed thermally or chemically.

Of the Mixing step produces the starting mixture by mixing the anisotropic Powder with the reactive starting powder.

In the mixing step may be added to the mixture resulting from a predetermined Composition of the anisotropic powder and the reactive starting powder composed, an irregularly shaped fine powder (hereinafter referred to as "fine compound powder") be given, with the irregular shaped fine powder consists of a compound that has the same composition as the isotropic perovskite compound has, by the reaction between the anisotropic powder and the reactive starting powder is achieved. To the above mixture, a sintering agent such as CuO be given.

The Addition of the fine compound powder or the sintering agent increases the density of the sintered body.

If the composition ratio of the fine compound powder is excessive is increased, the compositional proportion of the anisotropic increases Powder throughout the starting material from. This makes it possible that the degree of orientation of the specific crystal plane decreases. It is therefore preferable to have the optimum composition ratio according to the requirements of the density of the sintered product and to select the degree of orientation.

It it is preferable that the mixing step comprises the anisotropic powder the reactive starting powder in a composition ratio (Molar ratio) of anisotropic powder to reactive starting powder of 0.02 to 0.10: 0.98 to 0.90 mixes (the total of the anisotropic Powder and the starting reactive powder is 1 mol).

If the ratio of the anisotropic powder in the composition ratio (Molar ratio) is less than 1.12 or the ratio of reactive starting powder more than 0.98 There is a possibility that the crystal-oriented Ceramic in use is difficult to achieve a sufficient degree of orientation.

If the ratio of the anisotropic powder is more than 0.10 or the ratio of the reactive starting powder less 0.9, on the other hand, it is possible to that the crystal-oriented ceramic has a high density.

It It is preferable that the composition ratio of the anisotropic powder is adjusted so that the occupancy rate of the A-space element by at least one element in which by the general formula (1) expressed anisotropic powder a value in a range of 0.01 to 70 atom better still in a range of 0.1 to 50 atom and even better in one range from 1 to 10 atoms. The unit "atomic%" is the percentage of the number of atoms.

Of the Mixing step can be the anisotropic powder, the reactive starting powder and an optional additive, such as the fine compound powder and the sintering agent, by a dry process or a wet one Mixing process, where the wet process is a dispersant like Water, alcohol or an organic solvent used. It may contain one or more of the substances binder, plasticizer and dispersing agents are added.

Of the Forming step shapes the starting mixture next to one layer-like shaped body, so that the {100} -Kristallebene of the anisotropic powder in approximately the same direction is oriented.

It is sufficient if the molding process the anisotropic powder in a specific Crystal plane oriented. Preferred molding methods are, for example in particular a doctor blade method, a pressing method and a rolling method. These methods make it possible to use the anisotropic powder in the shaped body with the help of an anisotropic powder applied shear stress in about a same To orient direction.

It it is preferable that the starting mixture becomes a sheet-like Product with a thickness in a range of 30 microns to 200 microns is formed.

When layered product makes it a shaped body with a thickness of less than 30 μm extremely difficult to handle the molding. On the other hand, more difficult than layer-shaped product a shaped body with a Thickness of more than 200 microns it, the anisotropic powder about to orient in a same direction.

With the molded article (hereinafter referred to as "plane-oriented Shaped "referred to) can also be multi-layer pressing, pressing and rolling (hereinafter be referred to as "level orientation process") be performed to the thickness and the degree of orientation of the plane-oriented shaped body.

The Although the above method performs the level-orientation process with a plane in the plane-oriented shaped body, but it can also be done with two or more types of levels become. It is also possible to use the level orientation process repeat for a single level. In addition, the level orientation process can be repeated be carried out for two or more levels.

It A thermal treatment can be performed to to remove the resin component. In this case, the temperature for carrying out the above thermal treatment be set to a temperature sufficient to the thermal Decomposition of at least the binder to perform. It It is preferable that the thermal treatment for removing the Resin at a temperature of not more than 500 ° C, when the starting mixture is a volatile component contains (about a Na compound).

It there is a possibility that the degree of orientation of the anisotropic powder decreases in the molding or that the volume of the molding increases when the thermal Treatment for removing the resin component from the molding is carried out. To avoid this phenomenon, It is preferable with the molding after completion of the molding thermal treatment cold isostatic pressing (a CIP treatment) perform. Carrying out the CIP treatment prevents a caused by the volatilization treatment Decrease in the degree of orientation and one by the volume expansion (or spatial extent) of the molded body caused Decrease in the density of the sintered body.

When Next comes in the firing step by heating the Shaped body to the reaction between the anisotropic powder and the starting reactive powder, wherein the shaped body It also sinters to the crystal-oriented ceramics manufacture.

With in other words, the burning step sinters the anisotropic powder and the reactive starting powder, which form the shaped body, by heating the shaped body. This can be a crystal-oriented Ceramics are produced from a polycrystalline material, the mainly consists of the isotropic perovskite compound.

Of the Firing step can be at a firing temperature of not less than 900 ° and not more than 1300 ° C take place. The optimal Burning time can be selected according to the firing temperature become, with a sintered body of desired density or raw density can be produced.

It is preferable to burn a molded article in which a Variety of moldings stacked or stacked are. This allows a crystal-oriented ceramic with large Thickness can be produced.

It Now follows a description of the multilayer piezoelectric element according to the Eleventh embodiment of the invention.

The multilayer piezoelectric element consists of piezoceramic layers and electrode forming layers, wherein each electrode forming layer has an electrode part which has a contains conductive metal that forms an internal electrode, and the piezoceramic layers and the electrode formation layers are alternately stacked. The piezoceramic layer consists of a polycrystalline material, which consists mainly of an isotropic perovskite compound in which the {100} crystal plane every crystal grain forming the polycrystalline material is oriented is.

The method according to the twelfth aspect of the invention performs the first preparation step, the second preparation step, the mixing step, the molding step, the printing step, the lamination Step and the firing step to produce the multilayer piezoelectric element.

The Method of the twelfth embodiment of the invention leads the same except for the printing step and the firing step Steps like the above-described method of the eleventh embodiment of the invention.

Accordingly, as in the method of the eleventh aspect of the invention, it is preferable that the anisotropic powder in the method of the twelfth aspect of the invention is mixed with the starting reactive powder in a stoichiometry which, after completion of the firing step, is represented by the following general formula (1). Expressed isotropic perovskite compound produces: {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1.

It is also preferable to use, as the starting reactive powder, a powder consisting of an isotropic perovskite compound expressed by the general formula (4): {Li _p (K _1-q Na _q ) _1-p } _c (Nb _1-rs Ta _r Sb _s ) O ₃ (4) where 0 ≦ p ≦ 1, 0 ≦ q ≦ 1, 0 ≦ r ≦ 1, 0 ≦ s ≦ 1,
0.95 ≤ c ≤ 1.05 applies.

Of the second preparation step may be the preparation mixing step and Perform the calcination step. The mixing preparation step produces the reactive mixture by mixing sources. The calcining step calcines the reactive starting mixture, to achieve the reactive starting powder.

It it is preferable to use one or more of a Li source as the output sources, a K source, a Na source, a Nb source, a Ta source and an Sb source of selected elements.

When Starting sources may be an oxide powder, a mixed oxide powder, a hydroxide powder, an alkoxide or a salt.

Of the Calcination step can be performed so that the reactive starting mixture at a temperature of not more calcined as 700 ° C.

About that In addition, in the calcination step, it is preferable that the reactive starting powder is a primary mean grain size of not more than 2.5 μm.

When Next will be in the printing step in the method of the twelfth Embodiment of the invention on the sheet-like molded body (or a green sheet) an electrode material printed. The electrode material contains a conductive metal that after completion of the firing step becomes the electrode part.

Of the Although printing step prints the electrode material on one the molding step obtained molded body having a thickness in a range of about 30 μm to 200 μm has, but can the molded body produced by the molding step also be stacked, and the electrode material can then printed on the laminate.

Thereby Piezoceramic layers can be formed, which consist of a crystal-oriented ceramic with a relative great thickness exist while a decrease in the Orientierungsgrads the piezoceramic layer forming crystal-oriented Ceramic is suppressed.

When conductive metal can be an AgPd alloy, Ag, Pd, Cu, Ni and a CuNi alloy are used. It is preferable to use an AgPd alloy as the conductive metal.

Thereby result in the improved effects and effects of the invention, by suppressing the decrease of the electrical insulation resistance can be.

Namely, the use of an electrode material containing an AgPd alloy as a conductive metal tion during the firing step easily for the diffusion of Ag in the piezoceramic. This could easily reduce the electrical insulation resistance of the piezoceramic layer.

There the method of the twelfth embodiment of the invention a reactive starting powder with a half width of the pseudocubic {002} plane used in a range of 0.4 ° to 0.8 °, a refinement of the product can be supported. This can cause a decrease in the electrical insulation resistance the piezoceramic layers are prevented even if the Ag contained in the electrode material into the interior of the piezoceramic layers diffused.

The Electrode material can be made by placing in the conductive Metal powder the reactive starting powder, a binder and a Solvent, etc. is given.

The Electrode material will be on a desired area printed on the green sheet after completion of the firing step becomes an electrode part.

More accurate said electrode material can be printed so that the Electrode part on the entire area between the piezoceramic layers is formed in the multilayer piezoelectric element as an inner electrode. The electrode material can also be printed so that between the piezoceramic layers as the inner electrode a partial electrode is trained. When the sub-electrode is formed, is the electrode material to a desired area printed on the green sheet, leaving on the sides of the multilayer Piezoelectric element is formed an electrode-free part.

To Completion of the printing step will be in the laminating step (as green sheets), the shaped bodies stacked, to create the multilayer piezoelectric element.

In the Aufschichtungsrichtung of the multilayer piezoelectric element can on both sides, that is on the top and bottom side, a green layer without the printed electrode material to be placed. This construction can be multi-layered Piezo element take care in the after completion of the firing step Both sides (the top and bottom side) placed blind layers are made of crystal-oriented ceramics.

On the top and bottom side of the multilayer piezoelectric element can one or more layers are placed as blotches.

To Completion of the lamination step may be the above-obtained composite in the lamination direction to the electrode materials to press into the green sheets in the laminate. The above pressing step is carried out thermally by thermocompression bonding, to squeeze it under heating.

In front the firing step can be achieved by degreasing the layered body also removes an organic ingredient such as a binder become.

When Next, the burning step burns the laminate, to produce the multilayer piezoelectric element in which the piezoceramic layers and the electrode layers are alternately stacked. The firing step carries out the reaction between the anisotropic Powder and the reactive starting powder and sintered the shaped body.

Of the Firing step takes place at a firing temperature of not less as 900 ° C and not more than 1300 ° C. The optimal Burning time may be in the firing step according to the firing temperature be selected with which a predetermined density of the sintered body can be achieved.

At the outer peripheral side surface of the multilayer piezoelectric element Two external electrodes can be made of a conductive one Metal like Ag are formed. The two external electrodes are each electrically and alternately in the Aufschichtungsrichtung connected to the electrode part inside the multilayer Piezoelectric element is formed.

It Now follows a description of fourth and fifth embodiments, the eleventh and twelfth embodiments of the invention correspond.

Fourth Embodiment

The fourth embodiment discloses a method for Producing a crystal-oriented ceramic of a polycrystalline Material consisting mainly of an isotropic perovskite compound in which the {100} crystal plane of each grain is polycrystalline Material forms, is oriented.

As in 10 to 13 is shown, the process performs the first preparation step, the second preparation step, the mixing step, the molding step, and the firing step to produce the crystal-oriented ceramic.

10 Fig. 13 is a view showing a construction of a starting mixture obtained by mixing an anisotropic powder and a reactive starting powder according to the fourth embodiment of the invention. 11 Fig. 12 is a view showing an internal structure of a molded article in which the anisotropic powder according to the fourth embodiment of the invention is oriented approximately in a specific direction. 12 Fig. 13 is a view showing crystal growth of the anisotropic powder in the molded body during the firing step according to the fourth embodiment of the invention. 13 Fig. 13 is a view showing the crystal-oriented ceramic according to the fourth embodiment of the invention.

As in 10 is shown, the first preparation step prepares the anisotropic powder 101 which consists of oriented grains with an oriented {100} crystal plane. The second preparation step prepares the reactive starting powder 102 in front. The reaction between the reactive starting powder 102 and the anisotropic powder 101 produces the isotropic perovskite compound. The second preparation step used as a reactive starting powder 102 a powder having a half width in a range of 0.4 ° to 0.8 °.

14A FIG. 14 is a view showing the reactive starting powder according to the fourth embodiment of the invention. FIG. 14B Figure 11 is a view showing the reactive starting powder after calcination as a thermal treatment.

As in 14A and 14B is shown, the second preparation step performs the mixing preparation step and the calcining step. The mixing preparation step prepares the reactive starting powder 102 by mixing the output source 121 in front. The calcining step calcines the reactive starting mixture 120 ,

As in 10 is shown, the mixing step mixes the anisotropic powder 101 and the reactive starting powder 102 to the starting mixture 103 to create. In the method of the fourth embodiment, the mixing step mixes the anisotropic powder 101 and the reactive starting powder 102 in stoichiometry to produce an isotropic perovskite compound expressed by the general formula {Li _0.08 (K _0.5 Na _0.5 ) _0.92 } (Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ .

As in 11 is shown, the forming step forms the starting mixture 103 to a sheet-like shaped body 135 so that the {100} crystal plane of the anisotropic powder 101 oriented in approximately the same direction.

As in 12 and 13 is shown, the burning step burns the shaped body 135 to stop the reaction between the anisotropic powder 101 and the reactive starting powder 102 takes place, and sinters them to the crystal-oriented ceramics 104 manufacture.

A description will now be given of the method for producing the crystal-oriented ceramic 104 according to the fourth embodiment of the invention.

- First preparation step -

First, the following steps produced the anisotropic powder. The anisotropic powder consisted of oriented anisotropic grains oriented in the {100} crystal plane. More specifically, the fourth embodiment produced an anisotropic powder B consisting of Bi _2.5 Na _3.5 Nb ₅ O ₁₈ and, using the anisotropic powder B, produced a plate-shaped anisotropic powder (or plate-like anisotropic powder) of NaNbO ₃ as anisotropic Powder A.

Namely were initially a Bi ₂ O ₃ powder, a NaHCO ₃ powder and Nb ₂ O ₅ powder, which we do not niger than 99.9% pure and commercially available, weighed in stoichiometry of a planned composition of Bi _2.5 Na _3.5 Nb ₅ O ₁₈ (hereinafter also referred to as "BINN5") and then wet blended to give a starting powder manufacture.

When Next, to the starting powder was added 50% by weight of a NaCl flux and the mixture was dry blended for one hour.

When Next, the mixture was placed in a Pt crucible and heated at 850 ° C for one hour to the flux completely melt. The mixture contained in the Pt crucible was further heated at 1100 ° C for two hours to BINN5 to synthesize.

The Temperature increase rate was 200 ° C / hour, the temperature lowering rate was the oven cooling rate.

To the flux became the reactant from the reactant by hot water washing to remove the BINN5 powder (as anisotropic powder B).

The obtained BINN5 powder was a plate-like powder with an oriented {001} plane.

Next, to the plate-like BINN5 powder (as a starting reactive powder) was added a NaHCO ₃ powder of a necessary amount sufficient to synthesize NaNbO ₃ (hereinafter referred to as "NN"). These powders were mixed and the resulting mixture was placed in a Pt crucible and then heated at 950 ° C for 8 hours for thermal treatment.

As a result, since the reactant contained Bi ₂ O ₃ in addition to Na ₂ CO ₃ powder, after removing the flux from this reactant, the reactant was placed in an HNO ₃ solution to dissolve the Bi ₂ O ₃ as an excessive ingredient. The resulting solution was filtered to separate NN powder and then washed using 80 ° C warm ion-exchanged water. Through the above process, (as anisotropic powder), the NN powder was obtained (see 10 ).

The obtained NaNbO ₃ powder was a plate-like powder having an oriented plane of a pseudocubic {100} plane, an average grain size of 15 μm and an aspect ratio in a range of 10 to 20.

- second preparation step -

When Next, the second preparation step generated in the Method of the fourth embodiment by the following Steps the reactive starting powder.

In the fourth embodiment, in the following mixing step, the NN powder was mixed so that by the NN powder (as the anisotropic powder) 5 mol% of the A-site element in the planned ceramic composition of {Li _0.08 (K _0.5 Na _0.5 ) _0.92 } (Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ .

In the preparation of the reactive starting powder were first a Na ₂ CO ₃ powder, a K ₂ CO ₃ powder, a Li ₂ CO ₃ powder, a Nb ₂ O ₅ powder, a Ta ₂ O ₅ powder and a Sb ₂ O ₅ powders having a purity of not less than 99.99% were weighed to obtain a composition obtained when the NN powder component of the intended ceramic composition of {Li _0.08 (K _{0, 5} Na _0.5 ) _0.92 } (Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ . Then, they were wet mixed with ZrO ₂ balls using an organic solvent for 20 hours.

Thereafter, the reactive starting mixture 120 Calcined at 600 ° C for five hours to (as a reactive starting powder 102 ) to produce the calcined powder (calcination step, see 14A ).

Of the Calcination step increased the temperature with a temperature raising rate of 200 ° C / hour and held the calcination temperature (600 ° C in the fourth embodiment) five For hours, with the calcination temperature at a temperature lowering rate cooled from 200 ° C / hour to 100 ° C. has been.

It became the primary average grain size (D50) of the starting reactive powder achieved by the above steps 102 determined.

More accurate That is, the reactive starting powder was in a range of 0.1 to 0.15 wt .-% in an ethanol solution.

When Next, the reactive starting powder became three minutes long through an ultrasonic distributor (SUS-103, manufactured by Shimadzu Rika Corporation) at 28 kHz evenly distributed in the ethanol solution. The primary middle one Grain size of in this dispersion solution The starting reactive powder contained was then passed through a laser diffraction particle size analyzer (SALD-7000, manufactured by Shimadzu Rika Corporation). The detection results of the primary mean grain size of the starting reactive powder are shown in Table 5 below.

In addition, by the 2θ method, the half-width of the {002} crystal plane of the reactive starting powder became 102 determined. Namely, the X-ray diffraction intensity of the reactive starting powder disposed on a substrate became 102 detected. The X-ray diffraction intensity was determined by X-ray diffraction (RINT-TTR, manufactured by Rigaku Corporation) by X-ray diffraction (2θ method) with CuKα radiation, 50 kV / 300 mA in a possible angular range of 0 ° to 180 ° (5 ° to 60 ° in the fourth embodiment).

When The next step was the {002} crystal plane achieved in the X-ray diffraction intensity pattern the peak width (or full width at half height: engl. FWHM) at the peak value (θ = about 45 °) determined. This Peak area (width) at half height of the highest Peak intensity was used as the "half width". Table 5 below gives these results.

After the above detection step, the reactive starting powder was then wet-cracked for 20 hours using an organic solvent with the ZrO ₂ spheres. As a result, a calcined powder (as a starting reactive powder) having an average grain size of about 0.5 μm was obtained.

- mixing step -

Next, the anisotropic powder obtained in the above steps and the starting reactive powder 102 mixed to the starting mixture 103 (please refer 10 ) in the composition ratio producing the isotropic perovskite compound formed by the planned ceramic composition of {Li _0.08 (K _0.5 Na _0.5 ) _0.92 } (Nb _0.84 Ta _0.1 Sb _0.06 ) O _{3 is} expressed. In this case, the mixing step was carried out so that of the elements in the anisotropic powder 5 mol% of the A-site element in the planned ceramic composition of {Li _0.08 (K _0.5 Na _0.5 ) _0.92 ) (Nb _0.84 Ta _0.1 Sb _0.06 ) O ₃ .

Next, using the ZrO ₂ balls and an organic solvent in the wet state, a process was carried out for 20 hours to produce the starting mixture powder.

After that to the starting mixture slurry obtained above were polyvinyl butyral (PVB) as a binder and dibutyl phthalate added as a plasticizer and then mixed for one hour by an impeller stirrer. To the starting mixture were added 8.0 g of binder and 4.0 g of plasticizer per 100 g of the starting mixture (powder ingredient) given.

As in 10 was shown, the Ausgangsgemischschlämme 103 achieved in which the anisotropic powder 101 and the reactive starting powder 102 in the dispersion medium consisting of the organic solvent, the binder and the plasticizer 130 dispersed.

- forming step -

Next, the starting mixture slurry was molded by the doctor blade method or into a sheet-like molded body 135 (or a green sheet) formed with a thickness of about 80 microns. In addition, a plurality of the sheet-like shaped bodies were stacked and then pressed to form a shaped body by the doctor blade method 135 to produce with a thickness of 1.2 mm. The grains of the anisotropic powder were oriented in approximately the same direction by a shear stress applied to the anisotropic powder.

When Next became the above laminated body, the one Thickness of 1.2 mm, at 400 ° C in the atmosphere degreased to remove a fat ingredient.

- burning step -

The above-described molded body 135 After completion of the degreasing treatment, it was placed in an oven and fired at 1120 ° C for 20 minutes, then cooled to 1050 ° C and held at 1050 ° C for 10 hours. Finally, the molding became 135 cooled down to the planned crystal-oriented ceramics 104 to produce (see 12 and 14 ).

During the firing step, the anisotropic powder grew 101 in the shaped body 135 by a reaction with the reactive starting powder 102 That's about the anisotropic powder 101 around, to a crystal, whereby sintering took place (see 12 ). As a result, could be made of a polycrystalline material crystal-oriented ceramic 104 which consisted mainly of the isotropic perovskite compound in which the {100} crystal plane of each crystal grain 141 , which was the polycrystalline material, was oriented (see 13 )

In the firing step became the firing temperature at a temperature elevation rate increased from 200 ° C / hour to 1120 ° C and then at a temperature lowering rate of 50 ° C / hour Cooled to 1050 ° C. Cooling to 1000 ° C was carried out at a temperature reduction rate of 50 ° C / hour, and cooling to below 1000 ° C was carried out with a temperature reduction rate of 200 ° C / hour.

The achieved by the above steps crystal-oriented ceramic is referred to as "sample E11".

Furthermore The fourth embodiment set the following five Types of crystal oriented ceramics, namely sample E12, sample E13 and comparative samples C11, C12 and C13. These Samples E12, E13, C11, C12 and C13 were prepared using five different types of reactive starting powder with different Half-width of the {002} crystal plane produced that produced were determined by the calcination temperature in the preparation of reactive starting powder in a range of 650 ° C to 1000 ° C was changed.

Namely, these samples E12, E13, C11, C12 and C13 were prepared as follows:
Sample E12: Calcination temperature of 650 ° C, wherein the crystal oriented ceramic was prepared using the starting reactive powder having a half width of 0.648 ° (primary mean grain size of 2.24 μm);
Sample E13: Calcination temperature of 700 ° C, wherein the crystal oriented ceramic was prepared using the starting reactive powder having a full width at half maximum of 0.419 ° (primary mean grain size of 2.48 μm);
Comparative Example C11: calcining temperature of 800 ° C, wherein the crystal-oriented ceramic was prepared using the starting reactive powder having a half-width of 0.371 ° (primary mean grain size of 2.77 μm);
Comparative Example C12: calcination temperature of 900 ° C, wherein the crystal oriented ceramic was prepared using the starting reactive powder having a half width of 0.295 ° (primary mean grain size of 6.03 μm); and
Comparative Example C13: Calcining temperature of 1000 ° C, wherein the crystal-oriented ceramic was prepared using the starting reactive powder having a half-width of 0.261 ° (primary average grain size of 8.53 μm).

The Table 5 gives the calcination temperature, the half width the {002} crystal plane and the primary mean grain size of the starting reactive powder used in the preparation of the crystal-oriented Ceramics of Samples E11, E12 and E13 and Samples C11, C12 and C13 was used.

When Next, the electrical insulation characteristics of the prepared by the above method E11, E12, E13 and Comparative samples C11, C12 and C13 determined.

More accurate said one surface of each sample E11, E12, E13, C11, C12 and C13 ground to 150μm surface area Depth parallel to the surface of the layer. After graduation of the above grinding step was applied to the surface of each Sample as external electrodes, an Ag resin paste (Dotite, manufactured by Fujikura Kasei Co., Ltd.). The sample was then Baked for 30 minutes at 150 ° C to the Remove in the Ag resin paste contained solvents. Through the above steps, the outer electrodes on each sample became educated.

Next, a 2.0 kV / mm electric field was applied between the outer electrodes of each sample, and at a temperature of 20 ° C., the resistance of each sample was measured by an ohmmeter. Based on the detected electrical resistance value, the insulation resistance value of each sample E11, E12, E13, C11, C12 and C13 was calculated. The following Table 5 gives the calculation results of the insulation resistance value (as the resistivity) of each sample E11, E12, E13, C11, C12 and C13. Table 5 Sample No. reactive starting powder crystal-oriented ceramic resistivity (Ω · m) Calcination temperature (° C) Half width (°) of the (002} plane primary mean grain size (μm) E11 600 0.75 1.96 3.68 × 10 ¹⁰ E12 650 0.648 2.24 1.52 × 10 ¹⁰ E13 700 0.419 2.48 6.80 × 10 ⁹ C11 800 0.371 2.77 2.82 × 10 ⁹ C12 900 0,295 6.03 7.19 × 10 ⁸ C13 1000 0.261 8.53 2.11 × 10 ⁸

Out Table 5 shows that the crystal-oriented ceramics (as samples E11, E12 and E13) by the reactive starting powder with the half width of the {002} crystal plane in one area from 0.4 ° to 0.8 °, a high resistivity and excellent electrical insulation resistance Has.

on the other hand has the crystal-oriented ceramic (as Comparative Examples C11, C12 and C13) passing through the reactive starting powder of half width the {002} crystal plane has been made less than 0.4 °, low resistivity and inadequate electrical insulation resistance.

Accordingly It is understood that a crystal-oriented ceramic with outstanding Electrical resistance can be produced by a reactive Starting powder with a half width of the {002} crystal plane is used in a range of 0.4 ° to 0.8 °.

It It is also understood that calcining at a temperature in a range of 600 ° C to 700 ° C the reactive Starting powder with the half width of {002} crystal plane in a range of 0.4 ° to 0.8 ° generated (see Samples E11, E12 and E13 in Table 5).

If calcining at a calcination temperature of more than 700 ° C takes place, the obtained crystal-oriented ceramic has a half width less than 0.4 °. It is therefore preferable to use the reactive starting powder at a calcination temperature of not more than 700 ° C, better still at a temperature of not more than 650 ° C to calcine.

As is apparent from Table 5, the higher the calcination temperature, the higher the primary average particle size of the starting reactive powder. That means the crystal of the reactive starting powder 102 the more it grows the more the calcination temperature is increased (see 14A and 14B ).

Accordingly may perform the calcination step at a Calcination temperature of not more than 700 ° C, the crystal growth of the reactive starting powder and suppress it easily reactive starting powder with a half width in one range from 0.4 ° to 0.8 °.

- Fifth Exemplary embodiment

It Now follows a description of the method for producing the multilayer Piezoelectric element according to the fifth embodiment the invention.

15A is a view showing the overall structure of the multilayer piezoelectric element according to the fifth Embodiment of the invention shows. 15B is a sectional view of the in 15A shown multilayer piezoelectric element along its Aufschichtungsrichtung.

As in 15A and 15B is shown, sets the multilayer piezoelectric element 105 according to the fifth embodiment of a laminated body together, in the piezoceramic layers 151 and internal electrodes 152 containing conductive metal are alternately stacked. The piezoceramic layers 151 consist mainly of a polycrystalline material consisting mainly of the isotropic perovskite compound. In particular, the {100} crystal plane is oriented by crystal grains constituting the polycrystalline material.

As in 15A and 15B is shown is at both end portions of the multilayer piezoelectric element 105 a blindfold 150 formed without internal electrodes. The blind layer 150 exists like the piezoceramic layers 151 made of piezoelectric ceramic.

The Method for producing the multilayer piezoelectric element according to the fifth embodiment is made of the first preparation step, the second preparation step, the Mixing step, the molding step, the printing step, the laminating step and the firing step together.

It Now follows a detailed description of the procedure for producing the multilayer piezoelectric element according to the fifth embodiment.

As in the method according to the fourth embodiment introduced the method of the fifth embodiment the first preparation step, the second preparation step, the mixing step and the molding step to a sheet-like Shaped body (or green sheet) with a thickness of 80 μm.

- printing step -

When Next, an AgPd alloy powder was prepared Contained 30 mol% Pd. A mixture was made by adding the AgPd alloy powder and that by the first preparation step and the second preparation step achieved reactive starting powders with a volume ratio of 9: 1 were mixed.

To the mixture was then added ethyl cellulose and terpineol to prepare an electrode material paste. The obtained electrode material paste was then printed on the area corresponding to the electrode area to be formed on the green sheet. In the multi-layered piezoelectric element to be produced after completion of the firing step described later, the electrode material paste was printed to form the electrode part (as an inner electrode 152 ) on the entire surfaces between the piezoceramic layers 151 to train (see 15A and 15B ).

It is also possible or acceptable to print the electrode material paste on the surface of the green sheet on a desired area so that on an outer peripheral part of the multilayer piezoelectric element 105 an electrode-free part is formed. As a result, partial electrodes can be formed on the surface of the green layer.

- layering step -

After completion of the above printing step, the green sheets on which the electrode material paste had been printed were stacked and pressed to prepare a plate-like composite composed of six layers having a thickness of 1.2 mm in its lapping direction (which after firing) the electrode formation layers were). On the cover side and the bottom side of the multilayer piezo element, a green layer without electrode part was placed in each case. These greensheets placed on the top and bottom side formed the blind layers after completion of the following firing step 150 (please refer 15A and 15B ).

When Next became the above obtained laminate degreased at a temperature of 400 ° C to form a fat ingredient to remove.

- burning step -

To Completion of the degreasing step became the laminated body burned next to the multilayer piezo element as Produce end product.

Namely, after the fat removal, the laminate was placed in an oven and then heated at a temperature of 1120 ° C for 20 minutes. The composite in the oven was cooled to a temperature of 1050 ° C and then in the oven 10 Heated at the temperature of 1050 ° C for hours. The laminate was then cooled to room temperature. The production of the multilayer piezoelectric element was completed.

In the firing step was the temperature raising speed at 1120 ° C 200 ° C / hour and the temperature cooling rate at 1050 ° C 50 ° C / hour. The temperature cooling rate to 1000 ° C was 50 ° C / hour, and the temperature cooling rate to less than 1000 ° C was 200 ° C / hour.

Next, the multilayer piezoelectric element obtained by the above method was finished by a machining process to obtain the in 15A to achieve shown circular disc of the multilayer piezoelectric element.

As described above, the above method becomes a multilayer piezoelectric element 105 achieved in which the crystal-oriented ceramic piezoceramic layers 151 and the internal electrodes made of AgPd alloy 152 (Total electrode formation layers 3) are alternately stacked.

In The fifth embodiment was as in the fourth embodiment, six types of multilayer Piezo elements (Samples E16, E17 and E18 and Samples C16, C17 and C18) to be used in a comparative experiment to become. The six multilayer piezoelectric elements (samples E16, E17 and E18 and comparative samples C16, C17 and C18) were reactive Starting powders with different half widths of {002} crystal plane.

It The resistivity of each sample was E16, E17 and E18 as well each comparative sample C16, C17 and C18 is determined to be the electrical Compare insulation resistance of the piezoceramic layer.

And though, between the inner electrode layers than the inner electrodes of the multilayer piezo element of each sample E16, E17, E18, C16, C17 and C18 applies a predetermined voltage. The predetermined voltage was 2 kV / mm for the electrode spacing of each sample.

As in the fourth embodiment, Table 6 gives the detection results of these samples E16, E17, E18, C16, C17 and C18 for the half-width, the primary average grain size, the calcination temperature in the preparation of the starting reactive powder and the resistivity. Table 6 Sample No. reactive starting powder crystal-oriented ceramic resistivity (Ω · m) Calcination temperature (° C) Half width (°) of the {002} plane primary mean grain size (μm) E14 600 0.75 1.96 6.44 × 10 ⁹ E15 650 0.648 2.24 3.66 × 10 ⁹ E16 700 0.419 2.48 8,20 × 10 ⁸ C14 800 0.371 2.77 2.10 × 10 ⁸ C15 900 0,295 6.03 3.00 × 10 ⁷ C16 1000 0.261 8.53 1.10 × 10 ⁷

It is apparent from Table 6 that the method of the fifth embodiment makes possible, like the method of the fourth embodiment, piezoceramic layers having excellent to produce electrical insulation resistance by using a starting reactive powder having a half width of {002} crystal plane in a range of 0.4 ° to 0.8 °.

About that In addition, by comparison, the results in Table 5 and Table 6 shows detection results that the multilayer piezo element, in which the piezoceramic layers consisting of the crystal-oriented ceramic and the internal electrodes are stacked, under the same Conditions a smaller electrical insulation resistance than which has crystal-oriented ceramics. It is assumed that the conductive metal such as AgPd during the firing step diffused from the inner electrode to the piezoceramic layer.

Consequently Table 6 shows that the electrical insulation resistance is increased when the reactive starting powder with the half width the {002} crystal plane is used in a range of 0.4 ° to 0.8 ° becomes.

It Although certain embodiments in detail the skilled person will recognize that to these details in the light of the whole doctrine of Revelation various modifications and alternatives can be made. Accordingly, the particular arrangements disclosed are merely are illustrative and not intended to be within the scope of the invention restrict, by the full breadth of the following claims and all its equivalents.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

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Cited non-patent literature

• - "Journal of American Ceramic Society", pp. 438-442, [9] of vol. 42, 1959 [0521]

Claims (40)

Piezoceramic of a polycrystalline material consisting mainly of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb ₁ Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, where each crystal grain constituting the piezoceramic is composed of a core portion and a cladding layer having a different composition, the cladding phase surrounding the core portion, and the piezoceramic satisfying the relationship ds / dc <1.2, where ds is a quantity of a crystal lattice defect generated in the shell phase and dc is an amount of crystal lattice defect generated in the core part. Piezoceramic according to claim 1, wherein the piezoceramic consists of a crystal-oriented ceramic, in which a specific Crystal plane A in the crystal grains containing the polycrystalline Form material, is oriented. Piezoceramic according to claim 1, wherein the piezoceramic from a non-oriented body as randomly oriented Ceramic exists. Multi-layered piezoelectric element in which a plurality of Piezoceramic layers and electrode forming layers comprising a Have electrode part that forms internal electrodes, which is a conductive Contain metal, alternately stacked, being the piezoceramic layers of the piezoceramic according to a of claims 1 to 3 exist. A multilayer piezoelectric element according to claim 4, wherein said conductive metal is an AgPd alloy. A method of producing a piezoceramic of a polycrystalline material mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, the piezoceramic is made of a crystal-oriented ceramic in which a specific crystal plane A is oriented in crystal grains constituting the polycrystalline material, and the method comprises the steps of: mixing an anisotropic powder with a starting reactive powder to prepare a starting mixture, wherein the anisotropic powder is composed of a perovskite compound and consists of oriented anisotropic grains forming an oriented plane in which a crystal plane matching with respect to the lattice to the specific crystal plane A is oriented, and the reactive starting powder by the reaction with the anisotropic powder passing through the general formula (1) expressed isotropic perovskite compound; Forming the starting mixture into a sheet-like shaped body so that the oriented plane of each oriented anisotropic grain in the anisotropic powder is oriented approximately in a same direction; and firing the molded body to produce the piezoceramic, wherein the mixing step further mixes a K starting powder and / or an Li starting powder as an additive into the starting mixture such that the amount of addition per 1 mole of the isotropic one expressed by the general formula (1) Perovskite compound to the element K and / or Li is not more than 0.05 mol, and the firing step is firing for a period of not less than two hours at a temperature of not lower than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50%. A method of producing a piezoceramic of a polycrystalline material mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, and the method the steps include: mixing one or more of a Li source, a K source, a Na source, an Nb source, one Ta source and a Sb source of selected elements in a stoichiometric ratio, which produces the compound expressed by the general formula (1) to produce a starting mixture, and calcining the obtained starting mixture to produce a reactive starting powder; Forming the starting mixture into a shaped body; and firing the molded body to produce the piezoceramic, wherein the mixing step further mixes a K starting powder and / or an Li starting powder as an additive into the starting mixture such that the amount of addition per 1 mole of the isotropic one expressed by the general formula (1) Perovskite compound to the element K and / or Li is not more than 0.05 mol, and the firing step is firing for a period of not less than two hours at a temperature of not lower than 900 ° C under an atmosphere having an oxygen partial pressure 202 of not less than 50%. Method for producing a piezoceramic after Claim 6 or 7, wherein the K-starting powder and / or the Li-starting powder consist of a carbonate, a bicarbonate or a borate. A method of producing a piezoceramic of a polycrystalline material mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, and the method the following steps comprise: mixing an anisotropic powder with a starting reactive powder to produce a starting mixture, the anisotropic powder consisting of an anisotropic powder perovskite compound consisting of anisotropic powder of oriented anisotropic grains forming an oriented plane in which a crystal plane matching the lattice to the specific crystal plane A is oriented, and the reactive source powder by reaction with the anisotropic powder produces the isotropic perovskite compound expressed by the general formula (1); Forming the starting mixture into a sheet-like shaped body so that the oriented plane of each oriented anisotropic grain in the anisotropic powder is oriented approximately in a same direction; and firing the shaped body to produce the piezoceramic, wherein the reactive starting powder has a specific surface area in a range of 2 to 5 m ² / g, and the firing step comprises a temperature increasing step, a first temperature holding step, a temperature lowering step, and a second temperature holding step Temperature raising step raises the temperature to T ₁ ° C (1050 ° C <T ₁ ≤ 1150 ° C), the first temperature holding step holds the temperature T ₁ ° C for a period of t ₁ hour (t ₁ ≤ 5 hours), the temperature decreasing step Temperature of T ₁ ° C to T ₂ ° C (950 ° C ≤ T ₂ ≤ 1050 ° C) lowers, the second temperature holding step keeps the temperature T ₂ ° C for t ₂ hours (2 hours ≤ t ₂ ≤ 20 hours) and the firing step controls the firing temperature to satisfy the relationship (T ₁ -T ₂ ) / t ₂ ≦ D ₁ ≦ 200 and (T ₁ -T ₂ ) / t ₂ ≦ D ₂ ≦ 200 when the temperature increasing speed is at least between T ₂ ° C and T ₁ ° CD ₁ ° C / hour and the temperature reduction rate D ₂ ° C / hour. A method of producing a piezoceramic of a polycrystalline material mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zx Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0, 4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, and the method the following steps include: mixing one or more of a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source of selected elements in a stoichiometric ratio by the producing the compound expressed in general formula (1) to prepare a starting mixture and calcining the obtained starting mixture to produce a starting reactive powder; Forming the starting mixture into a shaped body; and firing the shaped body to produce the piezoceramic, wherein the reactive starting powder has a specific surface area in a range of 2 to 5 m ² / g, and the firing step comprises a temperature increasing step, a first temperature holding step, a temperature lowering step, and a second temperature holding step Temperature raising step raises the temperature to T ₁ ° C (1050 ° C <T ₁ ≤ 1150 ° C), the first temperature holding step raises the temperature T ₁ ° C for a Duration of t ₁ hour (t ₁ ≤ 5 hours), the temperature decreasing step lowers the temperature from T ₁ ° C to T ₂ ° C (950 ° C ≤ T ₂ ≤ 1050 ° C), the second temperature holding step lowers the temperature T ₂ ° C holds for t ₂ hours (2 hours ≦ t ₂ ≦ 20 hours), and the firing step controls the firing temperature to give the relationship (T ₁ -T ₂ ) / t ₂ ≦ D ₁ ≦ 200 and (T ₁ -T ₂ ) / t ₂ ≦ D ₂ ≦ 200 is satisfied when the temperature raising rate is at least between T ₂ ° C and T ₁ ° CD ₁ ° C / hour and the temperature lowering rate D is ₂ ° C / hour. Method for producing a piezoceramic after Claim 6 or 9, wherein the reactive starting powder of a calcined Powder by mixing at least one of a Li source, a K source, a Na source, a Nb source, a Ta source and an Sb source of selected element and then calcining the selected elements is achieved, with each source mixed in a stoichiometric ratio is made from the reactive starting powder, which is from the calcined Powder, and the anisotropic powder by the general Formula (1). Method for producing a piezoceramic after Claim 6 or 9, wherein the molding step to the starting mixture to forms the sheet-like shaped body, which has a thickness in one Range of 30 microns to 200 microns has. A method of manufacturing a multilayer piezoelectric element in which piezoceramic layers and electrode-forming layers are alternately stacked, the piezoceramic layer consisting of a polycrystalline material of a crystal-oriented ceramic mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, a specific one Crystal layer A is oriented in crystal grains forming the polycrystalline material, the electrode formation layer has an electrode portion forming internal electrodes containing a conductive metal, and the method comprises the steps of: mixing an anisotropic powder with a reactive starting powder to form a starting mixture the anisotropic powder consisting of an anisotropic powder consisting of a perovskite compound, the anisotropic powder consisting of oriented anisotropic grains forming an oriented plane in which a crystal plane matching the lattice to the specific crystal plane A is oriented, and the reactive starting powder by reaction with the anisotropic powder produces the isotropic perovskite compound expressed by the general formula (1); Forming the starting mixture into a sheet-like shaped body so that the oriented plane of each oriented anisotropic grain in the anisotropic powder is oriented approximately in a same direction; Printing an electrode material containing the conductive metal on the sheet-like molded body, which forms the electrode part after a subsequent firing step; Laminating a plurality of the sheet-like molded bodies after completion of the printing step; and firing the laminated body to produce the multi-layered piezoelectric element composed of the alternately stacked piezoceramic layers and electrode forming layers, the mixing step further mixing a starting K powder and / or Li starting powder as an additive in the starting mixture such that the addition amount per 1 mol of the isotropic perovskite compound expressed by the general formula (1) based on the element K and / or Li is not more than 0.05 mol, and the firing step does not fire for a period of not less than two hours at a temperature of less than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50%. A method of manufacturing a multilayer piezoelectric element in which piezoceramic layers and electrode-forming layers are alternately stacked, the piezoceramic layer consisting of a polycrystalline material of a crystal-oriented ceramic mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, and the method the steps include: mixing one or more of a Li source, a K source, a Na source, an Nb source, one Ta source and a Sb source of selected elements in a stoichiometric ratio, which produces the compound expressed by the general formula (1) to produce a starting mixture, and calcining the starting mixture to produce a reactive starting powder; Forming the starting reactive powder into a sheet-like shaped body; Printing an electrode material containing the conductive metal, which forms the electrode part after a subsequent firing step; Laminating a plurality of the sheet-like molded bodies after completion of the printing step; and firing the laminated body to produce the multi-layered piezoelectric element composed of the alternately stacked piezoceramic layers and electrode forming layers, the mixing step further mixing a starting K powder and / or Li starting powder as an additive in the starting mixture such that the addition amount per 1 mol of the isotropic perovskite compound expressed by the general formula (1) based on the element K and / or Li is not more than 0.05 mol, and the firing step does not fire for a period of not less than two hours at a temperature of less than 900 ° C under an atmosphere having an oxygen partial pressure P ₀₂ of not less than 50%. Method for producing a multilayer piezoelectric element according to claim 13 or 14, wherein the K starting powder and / or the Li-starting powder of a carbonate, a bicarbonate or consist of a borate. A method of manufacturing a multilayer piezoelectric element in which piezoceramic layers and electrode forming layers are alternately stacked, the piezoceramic layer consisting of a polycrystalline material of a crystal oriented ceramic consisting mainly of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, a specific one Crystal layer A is oriented in crystal grains forming the polycrystalline material, the electrode formation layer has an electrode portion forming internal electrodes containing a conductive metal, and the method comprises the steps of: mixing an anisotropic powder with a reactive starting powder to form a starting mixture wherein the anisotropic powder consists of a perovskite compound consisting of anisotropic powders of oriented anisotropic grains forming an oriented plane in which a crystal plane matching the lattice to the specific crystal plane A is oriented, and the starting reactive powder a reaction with the anisotropic powder produces the isotropic perovskite compound expressed by the general formula (1); Forming the starting mixture into a sheet-like shaped body so that the oriented plane of each oriented anisotropic grain in the anisotropic powder is oriented approximately in a same direction; Printing an electrode material containing the conductive metal, which forms the electrode part after a subsequent firing step; Coating the shaped bodies after the printing step; and firing the laminated body to produce the multi-layered piezoelectric element composed of the alternately stacked piezoceramic layers and electrode forming layers, wherein the reactive starting powder has a specific surface area in a range of 2 to 5 m ² / g, and the firing step comprises a temperature increasing step, a first step Temperature holding step, a temperature decreasing step and a second temperature holding step, wherein the temperature raising step raises the temperature to T ₁ ° C (1050 ° C <T ₁ ≤ 1150 ° C), the first temperature holding step sets the temperature T ₁ ° C for a duration of t ₁ hour (t ₁ ≤ 5 hours), the temperature decreasing step lowers the temperature from T ₁ ° C to T ₂ ° C (950 ° C ≤ T ₂ ≤ 1050 ° C), the second temperature holding step lowers the temperature T ₂ ° C for t ₂ hours (2 hours ≤ t ₂ ≤ 20 hours) and holds the firing step so controls the firing temperature that it (the relationship T ₁ T ₂₎ / t ₂ ≤ D ₁ ≤ 200 and (T ₁ - T ₂₎ / t ₂ ≤ D ₂ ≤ 200 satisfied when the temperature elevation rate is at least between T ₂ ° C and T ₁ ° CD ₁ ° C / hour, and the temperature reduction rate D is ₂ ° C / hour. A method of manufacturing a multilayer piezoelectric element in which piezoceramic layers and electrode-forming layers are alternately stacked, the piezoceramic layer consisting of a polycrystalline material of a crystal-oriented ceramic mainly consisting of an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1, and the method the following steps include: mixing one or more of a Li source, a K source, a Na source, an Nb source, a Ta source, and a Sb source of selected elements in a stoichiometric ratio by the producing the compound expressed in general formula (1) to prepare a starting mixture and calcining the obtained starting mixture to produce a starting reactive powder; Forming the starting reactive powder into a sheet-like shaped body; Printing an electrode material containing the conductive metal, which forms the electrode part after a subsequent firing step; Laminating a plurality of the sheet-like molded bodies after completion of the printing step; and firing the laminated body to produce the multi-layered piezoelectric element composed of the stacked piezoceramic layers and the electrode forming layers, wherein the reactive starting powder has a specific surface area in a range of 2 to 5 m ² / g, and the firing step comprises a temperature increasing step, a first step Temperature holding step, a temperature decreasing step and a second temperature holding step, wherein the temperature raising step raises the temperature to T ₁ ° C (1050 ° C <T ₁ ≤ 1150 ° C), the first temperature holding step sets the temperature T ₁ ° C for a duration of t ₁ hour (t ₁ ≤ 5 hours), the temperature decreasing step lowers the temperature from T ₁ ° C to T ₂ ° C (950 ° C ≤ T ₂ ≤ 1050 ° C), the second temperature holding step lowers the temperature T ₂ ° C for t ₂ hours (2 hours ≤ t ₂ ≤ 20 hours) and the firing step controls the firing temperature to determine the relationship (T ₁ -T ₂ ) / t ₂ ≦ D ₁ ≦ 200 and (T ₁ - T ₂ ) / t ₂ ≦ D ₂ ≦ 200 is satisfied when the temperature raising rate is at least between T ₂ ° C and T ₁ ° CD ₁ ° C / hour and the temperature lowering rate D ₂ ° C / hour. Method for producing a piezoceramic after Claim 13 or 16, wherein the reactive starting powder of a Calcined powder is made by mixing at least one from a Li source, a K source, a Na source, a Nb source, a Ta source and a Sb source selected element and then calcining the selected elements is achieved, wherein each source in a stoichiometric ratio is mixed to from the reactive starting powder, which is from the calcined powder, and the anisotropic powder through to generate the general formula (1) expressed compound. Method for producing a multilayer piezoelectric element according to claim 13 or 16, wherein the molding step is the starting mixture formed into the sheet-like shaped body having a thickness in a range of 30 microns to 200 microns. Method for producing a multilayer piezoelectric element according to claim 14 or 17, wherein the forming step is the reactive starting powder formed into the sheet-like shaped body having a thickness in a range of 30 microns to 200 microns. Method for producing a multilayer piezoelectric element according to one of claims 13 to 20, wherein the conductive Metal is an AgPd alloy. Method for producing a crystal-oriented Ceramics made of a polycrystalline material, mainly consists of an isotropic perovskite compound in which a {100} crystal plane in crystal grains forming the polycrystalline material, oriented, the method comprising the following steps: first Prepare an anisotropic powder of oriented anisotropic Grains in which the {100} crystal plane is oriented; second Prepare a reactive starting powder to get through a reaction with the anisotropic powder to produce the isotropic perovskite compound; Mix of the anisotropic powder with the reactive starting powder to Produce starting mixture; Forms the starting mixture to a sheet-like shaped body, so that the oriented Plane of each oriented anisotropic grain in the anisotropic powder oriented in approximately the same direction; and Burn of the shaped body to the crystal-oriented ceramics too generate, where the second preparatory step is the reactive one Used starting powder, which has a half-width of a pseudo-cubic {002} plane in a range of 0.4 ° to 0.8 °. The method for producing a crystal oriented ceramic according to claim 22, wherein the mixing step mixes the anisotropic powder with the starting reactive powder in a stoichiometric ratio producing an isotropic perovskite compound expressed by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) where 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1. The method for producing a crystal oriented ceramic according to claim 22 or 23, wherein the powder is an isotropic perovskite compound expressed by the general formula (4): {Li _p (K _1-q Na _q ) _1-p } _c (Nb _1-rs Ta _r Sb _s ) O ₃ (4) where 0≤p≤1, 0≤q≤1, 0≤r≤1,0≤≤≤1,0,95≤c≤1.05. Method for producing a crystal-oriented The ceramic of any one of claims 22, 23 and 24, wherein the second preparation step from a mixing preparation step and a calcination step, the mixing preparation step Mixing sources to produce a reactive starting mixture, and the calcination step calcines the reactive starting mixture, to produce the reactive starting powder. Method for producing a crystal-oriented Ceramics according to claim 25, wherein as starting sources one or more from a Li source, a K source, a Na source, a Nb source, a Ta source and a Sb source of selected elements be used. Method for producing a crystal-oriented The ceramic according to claim 25 or 26, wherein as the output source Oxide powder, a mixed oxide powder, a hydroxide powder, an alkoxide or a salt is used. Method for producing a crystal-oriented Ceramic according to one of claims 25, 26 and 27, wherein the Calcination step, the reactive starting mixture at a temperature of not more than 700 ° C calcined. Method for producing a crystal-oriented Ceramic according to any one of claims 25, 26, 27 and 28, wherein the Calcination step calcines the reactive starting powder, the a primary mean grain size of not has more than 2.5 microns. Method for producing the crystal-oriented Ceramic according to one of claims 25, 26, 27, 28 and 29, wherein in the forming step after completion of the forming step, a plurality the sheet-like shaped body is stacked one on the other and the firing step this consisting of the moldings Laminated body burns. Method for producing a multilayer piezoelement, in the piezoceramic layers and internal electrodes, which is a conductive Contain metal, alternately stacked, being the piezoceramic layer consists of a crystal-oriented ceramic, which consists of a polycrystalline material mainly consists of an isotropic perovskite compound in which a {100} crystal plane in crystal grains forming the polycrystalline material, oriented, and the method comprises the following steps: first Prepare an anisotropic powder of oriented anisotropic Grains in which the {100} crystal plane is oriented; second Prepare a reactive starting powder with a half width a pseudocubic {002} plane in a range of 0.4 ° to 0.8 °, by reaction with the anisotropic powder to produce the isotropic perovskite compound; Mix the anisotropic Powder with the reactive starting powder to form a starting mixture manufacture; Forming the starting mixture into a sheet-like Shaped body, so that the {100} crystal plane of each oriented anisotropic grain in the anisotropic powder approximately in oriented in the same direction; Imprinting a the conductive metal-containing electrode material after completion a subsequent firing step to the internal electrodes; stack a plurality of moldings after completion of the printing step, to produce a laminate; and Burning the Layered body, due to the reaction between the anisotropic Powder and the reactive starting powder in the moldings to produce the multilayer piezoelectric element in which the piezoceramic layers and the internal electrodes are alternately stacked. A method of manufacturing a multilayer piezoelectric element according to claim 31, wherein the mixing step mixes the anisotropic powder with the starting reactive powder in a stoichiometric ratio similar to that represented by the general formula (1): {Li _x (K _1-y Na _y ) _1-x } _a (Nb _1-zw Ta _z Sb _w ) O ₃ (1) expressed isotropic perovskite compound, wherein 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.2, x + z + w> 0, 0.95 ≦ a ≦ 1 applies. The method of manufacturing a multilayer piezoelectric element according to claim 31 or 32, wherein the powder is an isotropic perovskite compound expressed by the general formula (4): {Li _p (K _1-q Na _q ) _1-p } _c (Nb _1-rs Ta _r Sb _s ) O ₃ (4) where 0≤p≤1, 0≤q≤1, 0≤r≤1,0≤≤≤1,0,95≤c≤1.05. Method for producing a multilayer piezoelectric element according to one of claims 31, 32 and 33, wherein the second preparation step from a mixing preparation step and a calcination step, the mixing preparation step Mixing sources to produce a reactive starting mixture, and the calcination step calcines the reactive starting mixture, to produce the reactive starting powder. Method for producing a multilayer piezoelectric element according to claim 34, wherein as output sources one or more of a Li source, K source, Na source, Nb source, one Ta source and a Sb source of selected elements used become. Method for producing a multilayer piezoelectric element according to claim 34 or 35, wherein as the starting source an oxide powder, a mixed oxide powder, a hydroxide powder, an alkoxide or a salt is used. Method for producing a multilayer piezoelectric element according to any one of claims 34, 35 and 36, wherein the calcining step the reactive starting mixture at a temperature of not more Calcined as 700 ° C. Method for producing a multilayer piezoelectric element according to any one of claims 34, 35, 36 and 37, wherein the calcination step the reactive starting powder calcined, which is a primary mean grain size of not more than 2.5 microns Has. Method for producing a multilayer piezoelectric element according to one of claims 31, 32, 33, 34, 35, 36, 37 and 38, wherein in the molding step after the completion of the molding step Variety of sheet-like shaped bodies stacked and the firing step of this consisting of the moldings laminated body burning. Method for producing a multilayer piezoelectric element according to one of claims 31, 32, 33, 34, 35, 36, 37, 38 and 39, wherein the conductive metal is an AgPd alloy.