JP2006100853A - Piezoelectric element and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric element which has very high piezoelectric characteristics, superior vibration transmission performance between a base substance and a piezoelectric section, and has high linearity in flexure displacement with respect to electric field, and to provide a method of manufacturing the same. <P>SOLUTION: The piezoelectric element comprises the base substance formed of ceramics; the piezoelectric section formed of a piezoelectric ceramic composition which is composed mainly of PbMg<SB>1/3</SB>Nb<SB>2/3</SB>O<SB>3</SB>-PbZrO<SB>3</SB>-PbTiO<SB>3</SB>ternary-system solid solution composition, which is expressed by general formula Pb<SB>x</SB>(Mg<SB>y/3</SB>Nb<SB>2/3</SB>)<SB>a</SB>Ti<SB>b</SB>Zr<SB>c</SB>O<SB>3</SB>(in the formula (1), 0.95≤x≤1.05, 0.8≤y≤1.0, and a, b, and c are decimals in the range framed in by specific numerical values in coordinates in which a, b and c are set as axis of the coordinates), and contains NiO of 0.05 to 10.0 mass.%, wherein a particle which constitutes the piezoelectric section has an average diameter of 1 to 10 μm and the maximum diameter five times or less as large as the average diameter; and electrodes. The electrodes are electrically connected to the piezoelectric section and the piezoelectric section is fastened to the base substrate directly or via the electrode. In flexure displacement to electric field in high electric field region, the object of the present invention is attained by the piezoelectric element having high linearity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a piezoelectric element. More specifically, the piezoelectric part has extremely high piezoelectric characteristics, the actuator has a large increase rate of displacement when a large electric field is applied, and the sensor has a high resolution when a large force is applied, and a manufacturing method thereof About.

  In recent years, piezoelectric elements have been used for inkjet printer heads, speakers, microphones, and the like.

  A piezoelectric element usually includes a piezoelectric part made of a piezoelectric ceramic composition and an electrode electrically connected to the piezoelectric part on a ceramic base, and the piezoelectric ceramic composition constituting the piezoelectric part. Various improvements have been disclosed.

For _{example, Pb (Mg 1/3 Nb 2/3)} O 3 -PbTiO 3 -PbZrO 3 ternary solid solution system composition, or a piezoelectric ceramic composition obtained by substituting a part of Pb in these compositions Sr, with La, etc. A piezoelectric material having excellent piezoelectric characteristics (for example, a piezoelectric d constant) is disclosed for the piezoelectric part itself, which is the most important element for determining the piezoelectric characteristics of the piezoelectric element. It is expected that an element will be obtained.

  However, in this piezoelectric element, when the piezoelectric material composed of the piezoelectric ceramic composition described above was laminated on a ceramic substrate and then subjected to heat treatment to produce the piezoelectric element, the piezoelectric portion had low density and bending displacement was low. A problem has been pointed out that dielectric breakdown occurs at a low density or low density when a voltage is applied. This problem is particularly noticeable in the case of a piezoelectric element having a structure in which a plurality of piezoelectric parts are provided in a hierarchy and electrodes are alternately arranged between the piezoelectric parts, and negative electrodes and positive electrodes are arranged. It had been.

  Further, in the piezoelectric part made of the piezoelectric ceramic composition described above, sufficient piezoelectric characteristics are not necessarily obtained. Further, when the voltage is increased in order to increase the bending displacement, the high electric field side of 4 kV / mm or more However, there was a problem that the increase in bending displacement obtained was very small with respect to the increase in voltage.

  On the other hand, a piezoelectric material made by heat-treating the piezoelectric material made of the above-described piezoelectric ceramic composition in advance and pasting this piezoelectric portion on a ceramic substrate has been proposed (see Patent Document 3).

  In this piezoelectric element, focusing on the fact that the densification of the piezoelectric part is obstructed by the restraint of the ceramic substrate, the piezoelectric material is made by pre-heating the piezoelectric material made of the piezoelectric ceramic composition and densifying the piezoelectric part. Is an improvement.

  However, in this piezoelectric element, it is necessary to use an inorganic or organic adhesive when the piezoelectric portion is attached to the ceramic substrate. This adhesive inhibits vibration transmission between the ceramic substrate and the piezoelectric portion. Or the adhesive component penetrates into the piezoelectric part or the ceramic substrate and deteriorates these characteristics.

In addition, since this piezoelectric element does not consider the piezoelectric ceramic composition itself constituting the piezoelectric part, sufficient piezoelectric characteristics are not necessarily obtained as in the piezoelectric element described above. In the region, there was a problem that the increase in bending displacement was very small with respect to the increase in voltage.
Japanese Examined Patent Publication No. 44-17103 Japanese Patent Publication No. 45-8145 JP-A-11-29357

  The present invention has been made in view of the above problems, has extremely high piezoelectric characteristics, is excellent in vibration transmission between the substrate and the piezoelectric portion, and further bends with respect to voltage until reaching a high voltage region. An object of the present invention is to provide a piezoelectric element in which linearity of displacement is ensured and a method for manufacturing the same.

  Note that the piezoelectric element of the present invention has the above-described effects and can be suitably used for actuators, sensors, etc., particularly in a structure in which a plurality of piezoelectric portions and electrodes are alternately stacked.

The present inventors, as a result to the intensive study to solve the problems described above, the main component _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution-based composition having a specific composition, NiO When a piezoelectric ceramic composition containing a specific ratio is used as a piezoelectric material, a dense piezoelectric portion can be obtained even if heat treatment is performed after laminating the piezoelectric material on the substrate. The present invention has been completed.

That is, according to the present invention, a substrate made of ceramics, a _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition represented by the following general formula (1) as a main component, NiO Is a piezoelectric part comprising 0.05 to 10.0% by mass of a piezoelectric ceramic composition, wherein the particles constituting the piezoelectric part have an average particle size of 1 to 10 μm and a maximum particle size of the average particle size A piezoelectric part that is 5 times or less and an electrode are provided, the electrode is electrically connected to the piezoelectric part, and the piezoelectric part is fixed to the substrate directly or via the electrode. There is provided a piezoelectric element characterized by having high linearity in bending displacement with respect to.

[Chemical 1]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)

  “In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are the three coordinate axes a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425), (0.375, 0.425, 0.200) (However, a + b + c = 1.00.) ”

Further, according to the present invention, a substrate made of ceramics, represented by the following general formula (1), mainly composed of _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition, A plurality of piezoelectric parts made of a piezoelectric ceramic composition containing 0.05 to 10.0% by mass of NiO and a plurality of electrodes are provided. A plurality of piezoelectric parts are provided in a hierarchy, and a plurality of piezoelectric parts are provided between the piezoelectric parts. The negative electrode and the positive electrode are alternately arranged, and the lowermost piezoelectric portion is fixed to the substrate directly or via the electrode, and exhibits high linearity in bending displacement with respect to the electric field in a high electric field region. A piezoelectric element is provided.

[Chemical formula 2]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)

“In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are coordinate axes of the three of a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.4
75, 0.425) and (0.375, 0.425, 0.200). (It is a + b + c = 1.00.) "

  Note that, also in the piezoelectric element having this laminated structure, it is preferable that the particles constituting the piezoelectric portion have an average particle diameter of 1 to 10 μm and the maximum particle diameter is 5 times or less of the average particle diameter.

Further, according to the present invention, a substrate made of ceramics, represented by the following general formula (1), mainly composed of _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition, A piezoelectric part comprising a piezoelectric ceramic composition containing 0.05 to 10.0% by mass of NiO, and a piezoelectric part in which particles mainly composed of NiO are present inside or on the surface and inside the piezoelectric ceramic composition, an electrode, The electrode is electrically connected to the piezoelectric part, and the piezoelectric part is fixed to the substrate directly or via the electrode, and has high linearity in bending displacement with respect to the electric field in a high electric field region. A featured piezoelectric element is provided.

[Chemical formula 3]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)

  “In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are coordinate axes of the three of a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425), (0.375, 0.425, 0.200) (However, a + b + c = 1.00.) ”

  Also in this NiO particle presence type piezoelectric element, it is preferable that the particles constituting the piezoelectric portion have an average particle diameter of 1 to 10 μm and a maximum particle diameter of 5 times or less of the average particle diameter. Moreover, the particle | grains which have NiO as a main component may consist only of NiO, and may form solid solution of MgO.

  In the present invention, in any piezoelectric element, Ni in the piezoelectric ceramic composition is dispersed with a concentration gradient that becomes a high concentration in the thickness direction from the fixing surface with the substrate in the piezoelectric portion. It is preferable.

  In addition, 2 to 10 mol% of Pb in the piezoelectric ceramic composition is preferably substituted with at least one selected from the group consisting of Sr, Ca, and Ba, and 0.2 to 0.2 of Pb in the piezoelectric ceramic composition. 1.0 mol% is preferably substituted with La.

  Moreover, it is preferable that the thickness of a base | substrate is 3 micrometers-1 mm, and it is preferable that the thickness of a piezoelectric part is 1-300 micrometers. Further, the ratio of the thickness of the ceramic substrate to the thickness of the piezoelectric portion (substrate / piezoelectric portion) is preferably 0.1 to 30. Furthermore, the cross-sectional shape in the thickness direction of the base is preferably a so-called W shape in which concave portions are formed in the vicinity of both left and right end portions of the base and convex portions are formed in the central portion of the base portion.

According to the present invention is further illustrated by the following general formula (1), mainly composed of _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition, the NiO 0.05 to 10 A piezoelectric material composed of a piezoelectric ceramic composition containing 0.0 mass% is laminated on a ceramic substrate or an electrode formed on the substrate, and an atmosphere adjusting material having the same composition as the piezoelectric material When the amount of atmosphere adjusting material having the same composition as that of the piezoelectric material contained per volume is expressed by the amount of NiO obtained by dividing the amount of NiO in the atmosphere adjusting material by the volume in the same container, 0.03 to 0 A method of manufacturing a piezoelectric element having high linearity in bending displacement with respect to an electric field in a high electric field region, characterized by heat-treating laminated piezoelectric materials in a container containing 0.5 mg / cm ³ is provided. The

[Chemical formula 4]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)

  “In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are coordinate axes of the three of a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425), (0.375, 0.425, 0.200) (However, a + b + c = 1.00.) ”

Further, according to the present invention, shown in the following general formula (1), mainly composed of _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition, 0.05 to NiO A piezoelectric material made of a piezoelectric ceramic composition containing 10.0% by mass is laminated on a ceramic substrate or an electrode formed on the substrate, and the laminated piezoelectric material is heat-treated in an atmosphere. In the piezoelectric element manufacturing method, an atmosphere adjusting material having the same composition as that of the piezoelectric material is used per unit volume of the space in the container as a container for storing the stacked piezoelectric materials and a shelf board for placing the stacked piezoelectric materials. When the amount of the atmosphere adjusting material having the same composition as the piezoelectric material contained is expressed by the amount of NiO obtained by dividing the amount of NiO in the atmosphere adjusting material by the volume in the same container, 0.03 to 0.5 mg / cm ³ in the capacity as to be included In inner, a manufacturing method of a piezoelectric element having a high linearity in flexural displacement with respect to the electric field in the high field region which is characterized by using a material obtained by heat treatment is provided. In addition, in the following description, it may be described as an atmosphere in which 0.03 to 0.5 mg / cm ³ coexists in terms of NiO per unit volume of the space in the container. When the amount of the atmosphere adjusting material contained in is expressed by the amount of NiO obtained when the amount of NiO in the atmosphere adjusting material is divided by the volume in the same container, 0.03 to 0.5 mg / cm ^{3 is} included. It is synonymous with the inside of the container.

[Chemical formula 5]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)

  “In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are coordinate axes of the three of a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425), (0.375, 0.425, 0.200) (However, a + b + c = 1.00.) ”

  The piezoelectric element according to the present invention can be used as a dense and small dielectric element or pyroelectric element for capacitors and various sensors.

  According to the present invention, it is possible to provide a piezoelectric element that has extremely high piezoelectric characteristics, is excellent in vibration transmission between the base and the piezoelectric portion, and has high bending displacement linearity with respect to an electric field, and a method for manufacturing the same. In particular, in a piezoelectric element having a structure in which a plurality of piezoelectric portions and electrodes are alternately stacked, these effects are significant and can be suitably used as an actuator, a sensor, or the like.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

As shown in FIG. 1, the piezoelectric element of the present invention includes a base 2 made of ceramics, a piezoelectric portion 1 made of a specific piezoelectric ceramic composition, and electrodes 3 (3a, 3b), and an electrode 3 (3a, 3 b) is electrically connected to the piezoelectric part 1, and the piezoelectric part 1 is fixed to the substrate 2 directly or via the electrode 3.
Hereinafter, each component will be specifically described.

  The substrate 2 used in the present invention is made of ceramics, but from the viewpoint of heat resistance, chemical stability, and insulation, stabilized zirconium oxide, aluminum oxide, magnesium oxide, mullite, aluminum nitride, Those containing at least one selected from the group consisting of silicon nitride and glass are preferred. Among these, those containing stabilized zirconium oxide are preferable because they have high mechanical strength and excellent toughness.

  In the present invention, the thickness of the substrate 2 is preferably 3 μm to 1 mm, more preferably 5 to 500 μm, and particularly preferably 7 to 200 μm.

  If the thickness of the substrate 2 is less than 3 μm, the mechanical strength of the piezoelectric element may be weakened. If the thickness exceeds 1 mm, the stiffness of the substrate against the contraction stress of the piezoelectric portion increases when a voltage is applied to the piezoelectric element. The bending displacement of the piezoelectric element may become small.

  However, as shown in FIG. 2, the base body 2 substantially corresponds to a portion other than the fixing surface 2a and the thin-walled portion 2c having the above-described thickness substantially corresponding to the fixing surface 2a to the piezoelectric portion 1 or the electrode 3 (3b). It is also possible to provide a thick portion 2b in which the region to be made is thicker than the thin portion 2c.

  Thereby, the bending displacement of the piezoelectric element can be increased and the mechanical strength can be increased.

  Moreover, as shown in FIG. 3, it is also possible to adopt a structure in which a plurality of such structural units are provided on a common base 2.

  The surface of the substrate 2 in the present invention is not particularly limited, and for example, a rectangle, a square, a triangle, an ellipse, a true circle, an R-attached square, an R-attached rectangle, a capsule, or a combination of these. Or the like.

  Further, the cross-sectional shape in the thickness direction of the base 2 is preferably a W shape having three inflection points in that the linearity of the bending displacement with respect to the electric field is high.

Next, the piezoelectric unit 1 used in the present invention is mainly composed of _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition represented by the following general formula (1), the NiO It consists of a piezoelectric ceramic composition containing 0.05 to 10.0% by mass.

[Chemical 6]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)

  “In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are coordinate axes of the three of a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425), (0.375, 0.425, 0.200) (However, a + b + c = 1.00.) ”

  As a result, even when directly fixed on the substrate, the piezoelectric portion can be made dense, and not only has excellent piezoelectric characteristics, but also a piezoelectric element having high linearity of bending displacement with respect to an electric field up to a high electric field region. it can.

Here, in the above general formula (1), a, b, and c are within the above-described specific range. If the value is outside this range, the bending displacement of the piezoelectric element is reduced and the bending displacement is linear with respect to the electric field. This is because it causes a decline in sex. Similarly, the content of NiO in the piezoelectric ceramic composition is 0.05 to 10.0% by mass because the NiO content is less than 0.05% by mass and the densification is insufficient. Therefore, when the NiO content exceeds 10.0% by mass, the reaction with the substrate increases, and the piezoelectric element also decreases. This is because the bending displacement and the linearity of the bending displacement with respect to the electric field are reduced.

  Therefore, in the piezoelectric ceramic composition used in the present invention, the content of NiO is more preferably 0.50 to 8.0 mass% in the piezoelectric ceramic composition, and 1.0 to 6.0 mass%. More preferably it is.

  Further, in the present invention, it is preferable that Ni in the piezoelectric ceramic composition is uniformly dispersed in the piezoelectric portion 1 constituted by the piezoelectric ceramic composition, and the thickness of the piezoelectric portion from the fixing surface to the substrate is preferable. It is more preferable to disperse in the direction with a high concentration gradient.

  Thereby, even if it is a case where the piezoelectric part 1 adheres to the ceramic base | substrate 2 directly or via an electrode, it can be set as the densified piezoelectric part 1. FIG.

  In the present invention, it is preferable that at least a part of NiO in the piezoelectric ceramic composition is present as particles mainly composed of NiO.

  In addition, in the present invention, the particles containing NiO as a main component can ensure the linearity of the bending displacement with respect to the electric field to a higher electric field region, so that the inside or the surface and the inside of the piezoelectric portion (piezoelectric ceramic composition). It is preferable that it exists in the surface of the piezoelectric portion (piezoelectric ceramic composition).

  In addition, in the present invention, the particles containing NiO as a main component can secure the linearity of bending displacement with respect to the electric field to a higher electric field region, so that the surface and / or the inside of the piezoelectric portion (piezoelectric ceramic composition) can be secured. It is preferable that it exists in the surface of the piezoelectric portion (piezoelectric ceramic composition).

  The term “unevenly distributed” as used herein literally means that it is biased on the surface or inside of the piezoelectric part (piezoelectric composition), and is present on the surface and inside of the piezoelectric ceramic composition. And those existing only on the surface are included.

  In the present invention, the particle size of the particles mainly composed of NiO is not particularly limited, but is preferably 0.1 to 2 μm. Further, the particles mainly composed of NiO may be composed of only NiO or may be formed by dissolving MgO, but those formed by dissolving MgO in terms of high linearity of bending displacement with respect to the electric field. preferable. Moreover, the particle | grains which have NiO as a main component may exist in the grain boundary of a piezoelectric ceramic composition, and may exist in the grain of a piezoelectric ceramic composition.

  Next, the piezoelectric ceramic composition according to the present invention has an average particle size of 1 to 10 μm, a maximum particle size of 5 times or less of the average particle size, an average particle size of 2 to 5 μm, and a maximum particle size of The average particle size is preferably 4 times or less, more preferably 2 to 5 μm, and the maximum particle size is more preferably 3 times or less of the average particle size.

  If the average particle size is less than 1 μm, the domain in the piezoelectric portion is not sufficiently developed, resulting in a decrease in bending displacement and a decrease in linearity of bending displacement with respect to the electric field in the high electric field region, while the average particle size is Even if it exceeds 10 μm, although the domain in the piezoelectric part is large, the domain becomes difficult to move, so that the bending displacement is eventually reduced.

  Further, when the maximum particle size exceeds 5 times the average particle size, the number of coarse particles that are difficult to move polarization increases, so that the linearity of the bending displacement with respect to the electric field is lowered and the bending displacement itself is also reduced.

The piezoelectric ceramic composition according to the present invention is composed of Sr, Ca, Ba, and La for Pb in the piezoelectric ceramic composition in order to improve the piezoelectric characteristics and improve the linearity of the bending displacement with respect to the electric field. Substitution with at least one selected from the group is preferred.

  However, if Pb in the piezoelectric ceramic composition is replaced at a high rate, the bending displacement decreases, the influence of the bending displacement on the temperature change increases, and the linearity of the bending displacement with respect to the electric field amount decreases. It is preferable to set a suitable range for each substitution element.

  Specifically, when Pb in the piezoelectric ceramic composition is replaced with at least one selected from the group consisting of Sr, Ca, and Ba, 2 to 10 mol% of Pb in the piezoelectric ceramic composition is replaced. It is preferable to replace 4 to 8 mol%. Moreover, when substituting Pb in the piezoelectric ceramic composition with La, it is preferable to replace 0.2 to 1.0 mol% of Pb in the piezoelectric ceramic composition, and to replace 0.4 to 0.9 mol%. More preferably.

  Moreover, in order to improve the bending displacement of the piezoelectric element, the piezoelectric portion 1 in the present invention preferably has a phase other than the perovskite phase at 20% by volume or less, and more preferably at 10% by volume or less.

  Moreover, the piezoelectric part 1 preferably has a porosity of 10% by volume or less in order to ensure a desired bending displacement and mechanical strength and to improve the linearity of the bending displacement with respect to the electric field in the high electric field region. More preferably, it is 5 volume% or less.

  Furthermore, the piezoelectric part 1 in the present invention preferably has a thickness of 1 to 300 μm, more preferably 3 to 100 μm, and particularly preferably 5 to 30 μm.

  When the thickness of the piezoelectric portion 1 is less than 1 μm, densification tends to be insufficient even in the piezoelectric portion made of the specific piezoelectric ceramic composition described above. On the other hand, if the thickness of the piezoelectric portion exceeds 300 μm, the stress on the base becomes relatively excessive, so that a thicker ceramic base is required to prevent the base from being destroyed, and eventually it becomes difficult to cope with downsizing. .

  Further, in the present invention, the ratio of the thickness of the ceramic substrate 2 to the thickness of the piezoelectric portion 1 (substrate / piezoelectric portion) is 0. 0 in view of ensuring the mechanical strength of the piezoelectric element and a desired bending displacement. 1 to 30 is preferable, 0.3 to 10 is more preferable, and 0.5 to 5 is particularly preferable.

  Next, the electrode 3 in the present invention only needs to be electrically connected to the piezoelectric portion 1.

  As the electrode 3 in the present invention, for example, as shown in FIG. 4, a pair of comb-shaped electrodes 3a and 3b is formed on the piezoelectric portion 1 fixed to the base 2, and conversely, as shown in FIG. In addition, an example in which the piezoelectric portion 1 is fixed on a pair of comb-shaped electrodes 3c and 3d fixed to the base 2 can be mentioned.

  Further, as shown in FIG. 6, the piezoelectric portion 1 is fixed on a pair of comb electrodes 3c and 3d fixed to the base 2, and the surface of the piezoelectric portion to which the comb electrodes 3c and 3d are fixed The common electrode 3e may be formed on the opposite surface. Conversely, as shown in FIG. 7, the piezoelectric portion 1 is fixed on the common electrode 3e fixed to the base 2, and the common electrode 3e is fixed. A pair of comb-shaped electrodes 3c and 3d may be formed on the surface opposite to the surface of the piezoelectric portion 1 to which 3e is fixed.

  Furthermore, as shown in FIG. 8, in a stacked piezoelectric element in which a plurality of piezoelectric portions (1a to 1k) are provided in a hierarchical manner, the electrode 3 is connected between each piezoelectric portion (1a to 1k), and the negative electrode 3f. It is preferable to arrange the positive electrodes 3g alternately.

At this time, the electrode width is preferably 60 to 90%, more preferably 70 to 80% of the piezoelectric portion width.
If the electrode width is less than 60% of the piezoelectric part width, the piezoelectric part area to which the electric field is applied is small, so the bending displacement is small. If the electrode width exceeds 90% of the piezoelectric part width, the electrode needs to be aligned accurately. If the alignment accuracy is poor, it may cause a short circuit between the electrodes or a dielectric breakdown.

  In the electrode 3 in the present invention, the material is not particularly limited, and examples thereof include at least one selected from the group consisting of platinum, palladium, rhodium, gold, silver, and alloys thereof. From the viewpoint of high heat resistance when heat-treating the piezoelectric part, platinum or an alloy containing platinum as a main component is preferable. However, a glass component may be further added to facilitate the formation of the electrode during the heat treatment described below. In the case of the laminated piezoelectric element described above, the material of each electrode may be the same for all the electrodes, or may be different for some or all of the electrodes.

  The electrode 3 in the present invention has a thickness of preferably 15 μm or less and more preferably 5 μm or less because the electrode 3 acts as a relaxation layer when the thickness is large and the bending displacement tends to be small.

  Next, the piezoelectric element of the present invention is characterized in that the piezoelectric portion 1 is fixed to the base body 2 directly or via the electrode described above.

  As a result, a decrease in vibration transmission between the ceramic substrate 2 and the piezoelectric portion 1 due to the presence of an adhesive or the like, and a deterioration in piezoelectric properties due to a deterioration in the properties of the piezoelectric portion 1 or the ceramic substrate 2 due to penetration of an adhesive component, etc. can do.

  Here, “adhesion” means tight integration of the piezoelectric part directly or via an electrode with a solid phase reaction between the ceramic base and the piezoelectric part or electrode without using any organic or inorganic adhesive. It means to do.

  In the laminated piezoelectric element shown in FIG. 8, the lowermost piezoelectric portion 1a may be fixed to the base 2 directly or via the electrode 3g.

  Further, in the piezoelectric element of the present invention, the ratio of the capacitance after polarization to the capacitance before polarization is preferably 120% or more, and more preferably 125% or more in terms of a movable polarization structure.

Next, the manufacturing method of the piezoelectric element of this invention is demonstrated.
In the production method of the present invention, first, a piezoelectric material made of a specific piezoelectric ceramic composition is laminated on a base made of ceramics or an electrode formed on the base.

  The substrate used in the present invention is a condition that is usually performed after a molded body having a desired shape is produced by a conventional method such as press working or extrusion using a raw material corresponding to the ceramic described in the piezoelectric element of the present invention. Can be produced by firing.

  The piezoelectric material used in the present invention is composed of the piezoelectric ceramic composition described in the piezoelectric element of the present invention, and can be prepared as follows.

That is, first, a simple substance composed of each element of Pb, Ba, Ca, Sr, La, Mg, Nb, Zr, and Ti, and oxides of these elements (for example, PbO, Pb ₃ O ₄ , La ₂ O ₃ , MgO) , Nb ₂
O ₅ , TiO ₂ , ZrO ₂ ), carbonates of these elements (for example, BaCO ₃ , SrCO ₃ , MgCO ₃ , CaCO ₃ ), or compounds containing a plurality of these elements (for example, MgNb ₂ O), etc. , Pb, Ba, Ca, Sr, La, Mg, Nb, Zr, and Ti are mixed so that the content of each element becomes a desired ratio shown in the general formula (1) described above. The raw material which becomes the main component of the composition is prepared. In this case, the obtained raw material has an average particle size of preferably 1 μm or less, more preferably 0.5 μm or less, from the viewpoint of easy uniform mixing.

  Next, NiO is added to the raw material which is the main component of the piezoelectric ceramic composition so as to contain 0.05 to 10.0% by mass in the entire composition, and this mixed raw material is calcined at 750 to 1300 ° C. Thus, a piezoelectric ceramic composition is obtained. The piezoelectric ceramic composition after calcination preferably has a ratio of the intensity of the strongest diffraction line of the pyrochlore phase and the intensity of the strongest diffraction line of the perovskite phase in the diffraction intensity by the X-ray diffractometer of 5% or less. More preferably, it is 2% or less.

  Next, the obtained piezoelectric ceramic composition is pulverized into a piezoelectric material powder having a desired particle diameter by using a general pulverizer such as a ball mill, an attritor, or a bead mill. At this time, the average particle size of the piezoelectric material powder is preferably 0.1 to 1.0 μm, and more preferably 0.3 to 0.7 μm. The maximum particle size of the piezoelectric material powder is preferably 3.0 μm or less, and more preferably 2.0 μm or less. By setting it as such a particle size, it can be set as the desired three-component solid solution composition whose average particle diameter is 1-10 micrometers and whose maximum particle diameter is 5 times or less of an average particle diameter by the heat processing mentioned later. .

  The powder particle size may be adjusted by heat-treating the piezoelectric material powder obtained by pulverization at 400 to 750 ° C. In this case, finer particles are preferable because they are integrated with other particles to form a powder having a uniform particle diameter, and a piezoelectric part having a uniform particle diameter can be obtained. The piezoelectric material may be prepared by, for example, an alkoxide method or a coprecipitation method.

  In the present invention, examples of the method for laminating the obtained piezoelectric material include screen printing, spraying, dipping, and the like. Of these, the screen printing method is preferred because it can be easily and continuously laminated with a highly accurate shape and thickness.

  Further, when the piezoelectric portion is directly fixed on the base, a piezoelectric material may be laminated directly on the base. When the piezoelectric portion is fixed on the base via an electrode, the electrode is first formed on the base. And a piezoelectric material may be laminated on the electrode.

  Examples of the method for forming the electrode include screen printing, spraying, dipping, and the like. Among these, the screen printing method is preferable from the viewpoint of bonding properties with the ceramic substrate and the piezoelectric portion.

  Further, the formed electrode can be integrated with the base and / or the piezoelectric portion by heat treatment at about 1000 to 1400 ° C. At this time, the heat treatment may be performed at the time when the electrode is formed before the piezoelectric material is laminated, or may be collectively performed by a heat treatment performed after the piezoelectric material described below is laminated.

  Next, in the manufacturing method of the present invention, a piezoelectric material laminated on a substrate or an electrode is heat-treated in a sealed atmosphere in the presence of a specific amount of an atmosphere control material having the same composition as the piezoelectric material.

  Thereby, volatilization of each piezoelectric material component such as Pb and Ni can be prevented, and a piezoelectric portion containing each component in a desired ratio can be obtained. Further, by this heat treatment, the piezoelectric portion can be fixed to the substrate directly or via an electrode.

In the present invention, the atmosphere adjusting material is preferably allowed to coexist with 0.03-0.50 mg / cm ^{3 in} terms of NiO amount per unit volume of space in the container in the atmosphere, and 0.07-0.40 mg / cm ^3. More preferably, it is made to coexist, and it is still more preferable that 0.10 to 0.30 mg / cm < ³ > coexist.

When the NiO equivalent amount per unit volume of space in the container in the atmosphere is less than 0.03 mg / cm ^3, it is difficult to obtain a piezoelectric part containing a desired amount of Ni, and therefore the bending displacement of the electric field when a high electric field is applied It tends to be a piezoelectric element with low linearity. On the other hand, if the amount of NiO per unit volume of the container space exceeds 0.50 mg / cm ³ , particles containing NiO as a main component are excessively present and become a starting point of dielectric breakdown, and hence dielectric breakdown is likely to occur. .

  Note that by making the NiO content of the coexisting atmosphere control material the same as that of the piezoelectric ceramic composition constituting the piezoelectric material, NiO can be uniformly dispersed in the piezoelectric portion, and the piezoelectric ceramic constituting the piezoelectric material. By making the concentration higher than that of the composition, NiO can be dispersed in the piezoelectric portion with a concentration gradient that becomes higher in the thickness direction from the contact surface with the ceramic substrate. Moreover, the magnitude | size of a concentration gradient can also be adjusted by adjusting the NiO content rate of the composition to coexist.

  In the present invention, during the heat treatment, as a container for storing a laminate of piezoelectric materials and a shelf to be placed, heat treatment (hereinafter referred to as an atmosphere adjustment material having the same composition as the piezoelectric material) It is also preferable to use what is simply referred to as “pretreatment”.

  Thereby, a piezoelectric part containing a desired amount of NiO can be obtained with certainty, and a piezoelectric element having high linearity of bending displacement with respect to the electric field can be obtained up to the high electric field region.

  In addition, in the present invention, it is particularly preferable to heat-treat the piezoelectric material using the container and the shelf plate that have been subjected to the pretreatment, in addition to the coexistence of the specific amount of the atmosphere adjusting material.

  By such heat treatment, a piezoelectric part in which particles mainly composed of NiO are present on the surface and / or inside of the porcelain composition is obtained, and a piezoelectric element having a higher linearity of bending displacement with respect to the electric field up to the high electric field region is obtained. be able to.

  In order to make the particles mainly composed of NiO unevenly distributed, heat treatment is performed in the same manner as in the case where NiO is present in the piezoelectric portion with a concentration gradient under the condition that the particles can be formed. Just do it.

  In the present invention, the material of the container and the shelf is preferably a material mainly composed of magnesium oxide, aluminum oxide, zirconium oxide, mullite, or spinel.

  Further, the pretreatment is preferably performed within a temperature range of ± 100 ° C. with respect to the temperature at which the piezoelectric material laminated on the substrate or the like is heat-treated in order to fully exhibit the effect of the pretreatment. .

  Further, in order to ensure that particles mainly composed of NiO are present on the surface and / or inside of the porcelain composition, the pretreatment is preferably performed a plurality of times, and more preferably at least three times.

  However, it is also preferable to perform the heat treatment of the piezoelectric material a plurality of times after performing the pretreatment once, and conversely, it is also preferable to perform the heat treatment of the piezoelectric material once after performing the pretreatment a plurality of times. Moreover, it is also preferable to perform the heat treatment of the piezoelectric material a plurality of times after performing the pretreatment a plurality of times.

In this invention, 1000-1400 degreeC is preferable and the heat processing temperature of a piezoelectric material has more preferable 1100-1350 degreeC.
If the temperature is lower than 1000 ° C., the ceramic substrate and the piezoelectric portion may not be firmly fixed, or the piezoelectric portion may not be dense enough. If the temperature exceeds 1400 ° C., Pb and Ni in the piezoelectric material Since the amount of volatilization increases, it is difficult to obtain a piezoelectric portion having a desired composition.

The maximum temperature holding time during the heat treatment is preferably 10 minutes or longer and 10 hours or shorter, and more preferably 1 hour or longer and 4 hours or shorter.
If the maximum temperature holding time is less than 10 minutes, densification and grain growth of the piezoelectric ceramic composition are liable to be insufficient, and desired characteristics may not be obtained. Even if the control is performed, the total amount of volatilized Pb and Ni increases, and the problem that the characteristics are deteriorated and the dielectric breakdown increases is likely to occur.

  In the present invention, the heat treatment may be performed before the electrode is formed, or may be performed collectively after the electrode is formed. Similarly, in a laminated piezoelectric element, each electrode and each piezoelectric part may be heat-treated each time they are formed, or may be heat-treated after all of them are formed, or heat-treated after some of them are formed. You may repeat what you do.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
In addition, evaluation about an Example and a comparative example was performed as follows.

(Evaluation methods)
(1) Bending displacement Bending displacement generated when a voltage was applied so that the electric field was 3 kV / mm between the upper and lower electrodes was measured with a laser displacement measuring machine.

(2) Linearity of bending displacement with respect to electric field Bending displacement that occurred when voltage was applied so that the electric field was 4 kV / mm between the upper and lower electrodes, and occurred when voltage was applied so that it was 2 kV / mm The displacement was measured and the ratio was determined and evaluated. The higher the linearity, the closer to 200%.

(3) Average particle diameter and maximum particle diameter The surface of the three-component solid solution composition constituting the piezoelectric portion was measured by microscopic inspection with a scanning electron microscope. Specifically, a straight line is drawn on an arbitrary observation image, the grain boundary distance across the straight line is taken as the particle size, the particle size for 100 ternary solid solution compositions is measured, and the average particle size and maximum particle size are measured. Asked.

(4) Porosity The surface of the piezoelectric part of each piezoelectric element obtained in each example and each comparative example, and the range of 50 μm in length and breadth are examined with a scanning electron microscope, and the pores in the piezoelectric part occupy three views. Each area ratio was determined, and the average value was defined as the porosity.

(5) Dielectric breakdown rate When a voltage was applied between the electrodes so that the electric field was 4 kV / mm, the ratio of the number of piezoelectric elements with dielectric breakdown in the total number of piezoelectric elements was evaluated as the dielectric breakdown rate.

Example 1
A thin ZrO ₂ substrate stabilized with Y ₂ O ₃ (thickness: 1.6 × 1.1 m)
m, thickness: 10 μm, the cross-sectional shape in the thickness direction is rectangular (the surface to which the piezoelectric part or electrode is fixed is flat) on a rectangular bottom electrode (dimensions: 1.2 × 0.8 mm, thickness: 3 μm) was formed by screen printing and integrated with the substrate by heat treatment at 1300 ° C. for 2 hours.

On top of that, 98.5% by mass of Pb _1.00 (Mg _1/3 Nb _2/3 ) _0.20 Ti _0.43 Zr _0.37 O ₃ having an average particle size of 0.49 μm and a maximum particle size of 1.8 μm, and 1.5% by mass of NiO A piezoelectric material (dimensions: 1.3 × 0.9 mm, thickness: 13 μm) made of a piezoelectric ceramic composition containing the above was laminated by a screen printing method.

Next, an atmosphere control material having the same composition as the piezoelectric material is coexisted in a 0.15 mg / cm ³ container in terms of NiO per unit volume of the container space, and the piezoelectric material is laminated on the substrate on which the electrodes are formed. Was heat-treated at 1275 ° C. for 2 hours. The thickness of the piezoelectric part after the heat treatment was 10 μm.
At the time of heat treatment, an atmosphere adjusting material having the same composition as that of the piezoelectric material is previously coexisted in a 0.15 mg / cm ³ container with a NiO amount per unit volume of the container space, and the container and the shelf board to be used are heat treated ( Hereinafter, it may be referred to as “preliminary treatment.”) Was performed once to familiarize with the atmosphere, and was stored and placed on the container and the shelf board.

  Next, an upper electrode made of gold (dimensions: 1.2 × 0.8 mm, thickness: 0.5 μm) was formed on the piezoelectric portion by a screen printing method, followed by heat treatment to manufacture a piezoelectric element.

(Comparative Example 1)
Pb _1.00 (Mg _1/3 Nb _2/3 ) _0.20 Ti _0.43 Zr _0.37 O ₃ 98.5% by mass and NiO 1.5% by mass with an average particle size of 0.62 μm and a maximum particle size of 5.5 μm A piezoelectric element was manufactured in the same manner as in Example 1 except that a piezoelectric material made of a piezoelectric ceramic composition containing

(Evaluation)
The piezoelectric element of Example 1 has an average particle diameter of 3.0 μm and a maximum particle diameter of 8.7 μm, and a ratio of a bending displacement of 4 kV / mm to a bending displacement of an electric field of 2 kV / mm (hereinafter referred to as “4/2 bending”). The displacement ratio is sometimes referred to as 170%, and the linearity of the bending displacement with respect to the electric field was high. Also, the bending displacement itself was as large as 2.23 μm.

  On the other hand, in the piezoelectric element of Comparative Example 1, the 4/2 bending displacement ratio was 146%, the linearity of the bending displacement with respect to the electric field was low, and the bending displacement itself was as small as 1.75 μm. The results are summarized in Table 1.

(Example 2)
A negative electrode, a piezoelectric material, a positive electrode, a piezoelectric material, and a negative electrode are stacked in this order on the base, and the negative and positive electrodes are alternately sandwiched between the two piezoelectric sections. As for the layered piezoelectric element fixed to the base via an electrode, and the thickness when the piezoelectric material is laminated is half that of Example 1, and the thickness of each piezoelectric part is 5 μm. (Overall, 1 as in Example 1.
A piezoelectric element was manufactured in the same manner as in Example 1 except that the thickness was 0 μm.

(Evaluation)
In the piezoelectric element of Example 2 in which the thickness of each piezoelectric part is half and the number of layers is 2, the 4/2 bending displacement ratio is 165%, and the linearity of the bending potential with respect to the electric field is lower than that of the piezoelectric element of Example 1. However, the bending displacement was larger than 2.45 μm. The results are summarized in Table 2.

(Reference Examples 1-3)
In Example 1, a piezoelectric ceramic composition containing 98.5% by mass of Pb _1.00 (Mg _1/3 Nb _2/3 ) _0.20 Ti _0.43 Zr _0.37 O ₃ and 1.5% by mass of NiO as a piezoelectric material. The obtained piezoelectric ceramic compositions obtained by mixing 97% by volume, 93% by volume, and 85% by volume with 3% by volume, 7% by volume, and 15% by volume of latex having a particle diameter of 8 to 12 μm, respectively. A piezoelectric element was manufactured in the same manner as in Example 1 except that it was used as a piezoelectric material.

(Evaluation)
In the piezoelectric element of Reference Example 3 (15% by volume of latex mixed in the piezoelectric material), the porosity was 22%. At that time, the 4/2 bending displacement ratio was 138%, and the bending displacement itself was 1.66 μm. Similarly, in the piezoelectric element of Reference Example 2 (7% by volume of latex in the piezoelectric material), the porosity is 12%, the 4/2 bending displacement ratio at that time is 154%, and the bending displacement itself is 1 It was .98 μm. In the piezoelectric element of Reference Example 1 (3% by volume of latex in the piezoelectric material), the porosity was 6%, the 4/2 bending displacement ratio at that time was 162%, and the bending displacement itself was 2. It was 10 μm. From the above, it was confirmed that as the porosity decreases, the linearity of the bending displacement with respect to the electric field increases and the bending displacement itself increases. The results are summarized in Table 3.

(Example 3 and Comparative Examples 2 and 3)
As shown in Table 4, a piezoelectric material was obtained in the same manner as in Example 1 except that a piezoelectric material containing 1.5 mass%, 0.03 mass%, or 15.0 mass% of NiO in the piezoelectric ceramic composition was used. A device was manufactured.

(Evaluation)
In the piezoelectric element of Example 3 having a NiO content of 1.5% by mass, the 4/2 bending displacement ratio was 170%, and the linearity of the bending displacement with respect to the electric field was as high as that of the piezoelectric element of Example 1. Further, the bending displacement itself was 2.23 μm, which was as large as the piezoelectric element of Example 1.

On the other hand, in the piezoelectric element of Comparative Example 2 having a small NiO content of 0.03% by mass in the piezoelectric material, the 4/2 bending displacement ratio was 144%, and the linearity of the bending displacement with respect to the electric field was low. Further, the bending displacement itself was as small as 1.88 μm.
Further, in the piezoelectric element of Comparative Example 3 having a large NiO content of 15.0 mass% in the piezoelectric material, the 4/2 bending displacement ratio is 127%, and the linearity of the bending displacement with respect to the electric field is further lower, and the bending displacement itself. Was 1.45 μm, the smallest. The results are summarized in Table 4.

(Examples 4 to 6)
Examples 4 to 6 are piezoelectric ceramic compositions containing 98.5% by weight of Pb _1.00 (Mg _{0.97 / 3} Nb _2/3 ) _0.20 Ti _0.43 Zr _0.37 O ₃ and 1.5% by weight of NiO as piezoelectric materials. A piezoelectric element was manufactured in the same manner as in Example 1 except that the layers were laminated and heat treatment and pretreatment were performed as shown in Table 5.

(Evaluation)
Example in which the atmosphere control material was heat-treated in the same atmosphere using a container and a shelf board that had been pretreated three times in the amount of NiO per unit volume of the space in the container in the presence of 0.15 mg / cm ^3. 4, the 4/2 bending displacement ratio was 174%, and the linearity of the bending displacement with respect to the electric field was very high, and the bending displacement itself was very large, 2.25 μm.
Further, when the dispersion state of NiO in the piezoelectric part was confirmed by EPMA analysis, it was found that particles mainly containing NiO were present on the surface of the piezoelectric part and inside the piezoelectric part. In addition, it was confirmed that MgO is also present in the particles mainly composed of NiO.

On the other hand, the atmosphere control material is used as a unit of space in the container by using a container and a shelf plate that have been subjected to a pretreatment once in the amount of NiO per unit volume of the space in the container in the amount of 0.15 mg / cm ^3. In the piezoelectric element of Example 5 in which 0.10 mg / cm ³ of NiO per volume was present and heat-treated, the 4/2 bending displacement ratio was 171%, which was higher than the piezoelectric element of Example 4 with respect to the electric field. The linearity of the bending displacement was low, and the bending displacement itself was 2.17 μm, which was smaller than the piezoelectric element of Example 4.
Further, when the dispersion state of NiO in the piezoelectric part was confirmed by EPMA analysis, particles containing NiO as the main component were not present on the surface of the piezoelectric part, but particles containing NiO as the main component were present inside the piezoelectric part. Existence was recognized.

Furthermore, in Example 6 in which the atmosphere control material was subjected to heat treatment in the presence of 0.10 mg / cm ³ of NiO amount per unit volume of space in the container without performing pretreatment, the 4/2 bending displacement ratio was The bending displacement with respect to the electric field was further low at 159%, and the bending displacement itself was further reduced to 1.98 μm.
Further, when the dispersion state of NiO in the piezoelectric portion was confirmed by EPMA analysis, the presence of particles containing NiO as a main component was not observed on either the surface of the piezoelectric portion or inside the piezoelectric portion. The results are summarized in Table 5.

(Examples 7 to 10)
In Example 1, a piezoelectric element was manufactured in the same manner as in Example 1 except that the piezoelectric material having the composition shown in Table 6 was used.

(Evaluation)
When the 4/2 bending displacement ratio was determined for the obtained piezoelectric element, the linearity of the bending displacement with respect to a relatively high electric field of 158% or more was recognized in any of the piezoelectric elements of Examples 7 to 10.

  However, the piezoelectric element of Example 8 using a piezoelectric material having a composition in which 5.0 mol% of Pb is replaced with Sr, and the example using a piezoelectric material having a composition in which 10.0 mol% of Pb is replaced with Ba In the piezoelectric element 9, the 4/2 bending displacement ratio is 168% and 166%, respectively, which is a straight line of bending displacement with respect to the electric field as compared with the piezoelectric element of Example 7 using a piezoelectric material having a composition that does not replace Pb at all. The nature was high. Further, the bending displacement itself was 2.38 μm and 2.34 μm, respectively, which were larger than the piezoelectric element of Example 7.

  On the other hand, in the piezoelectric element of Example 10 using a piezoelectric material having a composition in which 7.5 mol% of Pb is substituted with Sr and 7.5 mol% with Ca (15 mol% in total), the 4/2 bending displacement ratio is 158. %, And the linearity of the bending displacement with respect to the electric field was lower than that of the piezoelectric element of Example 7 using a piezoelectric material having a composition in which Pb was not substituted at all. Also, the bending displacement itself was 2.11 μm, which was smaller than that of the piezoelectric element of Example 7. The results are summarized in Table 6.

(Examples 11 to 13)
A piezoelectric element was manufactured in the same manner as in Example 1 except that the piezoelectric material having the composition shown in Table 7 was used.

(Evaluation)
In any of the piezoelectric elements of Examples 11 to 13, the 4/2 bending displacement ratio was 159 or more, and the linearity of the bending displacement with respect to a relatively high electric field was recognized.

  However, in the piezoelectric element of Example 12 using the piezoelectric material in which 0.8 mol% of Pb is replaced with La, the piezoelectric material in which a 4/2 bending displacement ratio is 167% and a part of Pb is not replaced with La The linearity of the bending displacement with respect to the electric field was higher than that of the piezoelectric element of Example 11 using Further, the bending displacement itself was 2.36 μm, which was larger than that of the piezoelectric element of Example 11.

  On the other hand, in the piezoelectric element of Example 13 using a piezoelectric material in which 1.5 mol% of Pb was replaced with La, the 4/2 bending displacement ratio was 159%, which is a bending displacement with respect to the electric field as compared with the piezoelectric element of Example 11. The linearity of was low. Also, the bending displacement itself was 2.06 μm, which was smaller than the piezoelectric element of Example 11. The results are summarized in Table 7.

(Comparative Examples 4 and 5)
As shown in Table 8, the atmosphere control material, in terms of NiO per volume space unit containers each, 0.750 mg / cm ^3, it was subjected to heat treatment coexist in 0.015 mg / cm ³ in the atmosphere, A piezoelectric element was manufactured in the same manner as in Example 1 except that the preliminary treatment was not performed.

(Evaluation)
In the piezoelectric element of Comparative Example 4 in which the atmosphere control material was heat-treated in the NiO equivalent amount per unit volume of the container internal space at 0.750 mg / cm ³ , the 4/2 bending displacement ratio was relatively 162%. Although high bending displacement linearity was observed, the dielectric breakdown rate of the piezoelectric element was 17%, which was larger than that of the piezoelectric element of Example 1.

In addition, in the piezoelectric element of Comparative Example 5 in which the atmosphere control material was heat-treated in an amount equivalent to NiO per unit volume in the container space of 0.015 mg / cm ³ , the 4/2 bending displacement ratio was 139%. The linearity of the bending displacement with respect to the electric field was lower than that of the piezoelectric element of Example 1. The results are summarized in Table 8.

(Example 14)
A piezoelectric element was manufactured in the same manner as in Example 1 except that a substrate having a W-shaped cross-sectional shape in the thickness direction was used.

(Evaluation)
In Example 14 using a substrate having a W-shaped cross-sectional shape in the thickness direction, the 4/2 bending displacement ratio was 177%, and the cross-sectional shape in the thickness direction was rectangular (the surface to which the piezoelectric portion or the electrode is fixed is flat). Compared with Example 1 using this substrate, the linearity of the bending potential with respect to the electric field was high. Further, the bending displacement itself was 2.48 μm, which was larger than that of the piezoelectric element of Example 1. The results are summarized in Table 9.

  As described above, according to the present invention, there is provided a piezoelectric element that has extremely high piezoelectric characteristics, excellent vibration transmission between the substrate and the piezoelectric part, and high linearity of bending displacement with respect to an electric field, and a method for manufacturing the same. Can be provided. In particular, a piezoelectric element having a structure in which a plurality of piezoelectric portions and electrodes are alternately laminated has these effects, and can be suitably used for an actuator, a sensor, and the like, so that the industrial applicability is extremely high.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows typically one Embodiment of the piezoelectric element of this invention, (A) is a top view, (B) is X-X 'sectional drawing. FIG. 5 is an explanatory view schematically showing another embodiment of the piezoelectric element of the present invention, in which (A) is a plan view and (B) is an X-X ′ cross-sectional view. FIG. 5 is an explanatory view schematically showing another embodiment of the piezoelectric element of the present invention, in which (A) is a plan view and (B) is an X-X ′ cross-sectional view. FIG. 5 is an explanatory view schematically showing another embodiment of the piezoelectric element of the present invention, in which (A) is a plan view and (B) is an X-X ′ cross-sectional view. FIG. 5 is an explanatory view schematically showing another embodiment of the piezoelectric element of the present invention, in which (A) is a plan view and (B) is an X-X ′ cross-sectional view. It is sectional drawing which shows typically other embodiment of the piezoelectric element of this invention. It is sectional drawing which shows typically other embodiment of the piezoelectric element of this invention. It is sectional drawing which shows typically other embodiment of the piezoelectric element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 (1a-1k): Piezoelectric part, 2: Base | substrate (2a: Adhering surface, 2b: Thick part, 2c: Thin part), 3: Electrode (3a: Upper electrode, 3b: Lower electrode, 3c, 3d: Comb Type electrode, common electrode: 3e, 3f: negative electrode, 3g: positive electrode).

Claims (15)

A substrate made of ceramics;
To indicate _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition represented by the following general formula (1) as a main component, containing NiO 0.05 to 10.0 wt% piezoelectric ceramic A piezoelectric part made of a composition, wherein the average particle diameter of particles constituting the piezoelectric part is 1 to 10 μm, and the maximum particle diameter is 5 times or less of the average particle diameter;
With electrodes,
The electrode is electrically connected to the piezoelectric portion;
The piezoelectric element is fixed to the substrate directly or via the electrode, and has high linearity in bending displacement with respect to an electric field in a high electric field region.
[Chemical 1]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)
“In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are coordinate axes of the three of a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425), (0.375, 0.425, 0.200) (However, a + b + c = 1.00.) ” A substrate made of ceramics;
The following general formula shown in (1), mainly composed of _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition, containing NiO 0.05 to 10.0 wt% piezoelectric A plurality of piezoelectric parts made of a porcelain composition;
A plurality of electrodes,
The plurality of piezoelectric parts are laminated between each piezoelectric part with the negative electrode and the positive electrode alternately sandwiched between them, and the lowermost piezoelectric part is fixed to the substrate directly or via the electrode, A piezoelectric element having high linearity in bending displacement with respect to an electric field in a high electric field region.
[Chemical formula 2]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)
“In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are coordinate axes of the three of a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425), (0.375, 0.425, 0.200) (However, a + b + c = 1.00.) ”   3. The piezoelectric element according to claim 2, wherein an average particle diameter of particles constituting the piezoelectric portion is 1 to 10 μm and a maximum particle diameter is 5 times or less of the average particle diameter. A substrate made of ceramics;
The following general formula shown in (1), mainly composed of _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition, containing NiO 0.05 to 10.0 wt% piezoelectric A piezoelectric part comprising a porcelain composition, and particles having NiO as a main component on the surface and / or inside of the piezoelectric ceramic composition;
With electrodes,
The electrode is electrically connected to the piezoelectric portion;
The piezoelectric element is fixed to the substrate directly or via the electrode, and has high linearity in bending displacement with respect to an electric field in a high electric field region.
[Chemical formula 3]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)
“In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are coordinate axes of the three of a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425), (0.375, 0.425, 0.200) (However, a + b + c = 1.00.) ”   5. The piezoelectric element according to claim 4, wherein the average particle diameter of particles constituting the piezoelectric portion is 1 to 10 μm and the maximum particle diameter is 5 times or less of the average particle diameter.   The piezoelectric element according to claim 4 or 5, wherein the particles mainly composed of NiO are formed by dissolving MgO as a solid solution.   The Ni in the piezoelectric ceramic composition is dispersed with a concentration gradient having a high concentration in a thickness direction from a surface of the piezoelectric portion fixed to the substrate. The piezoelectric element described in 1.   The Pb in the piezoelectric ceramic composition is substituted with at least one selected from the group consisting of Sr, Ca, and Ba in 2 to 10 mol% of the total Pb. The piezoelectric element as described.   The piezoelectric element according to any one of claims 1 to 8, wherein Pb in the piezoelectric ceramic composition is obtained by replacing 0.2 to 1.0 mol% of all Pb with La.   The piezoelectric element according to claim 1, wherein the piezoelectric portion has a thickness of 1 to 300 μm.   The thickness of the said base | substrate is 3 micrometers-1 mm, The piezoelectric element as described in any one of Claims 1-10.   12. The piezoelectric element according to claim 1, wherein a ratio of a thickness of the base body to a thickness of the piezoelectric section (a thickness of the base body / a thickness of the piezoelectric section) is 0.1 to 30. .   The piezoelectric element according to any one of claims 1 to 12, wherein a cross-sectional shape in the thickness direction of the base body is a W shape having three inflection points. The following general formula shown in (1), mainly composed of _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition, containing NiO 0.05 to 10.0 wt% piezoelectric Laminating a piezoelectric material made of a porcelain composition on a base made of ceramics or an electrode formed on the base;
The laminated piezoelectric material is heat-treated in an atmosphere in which 0.03 to 0.5 mg / cm ^{3 of} an atmosphere adjusting material having the same composition as the piezoelectric material is present in an equivalent amount of NiO per unit volume of the space in the container. A method for manufacturing a piezoelectric element having high linearity in bending displacement with respect to an electric field in a high electric field region.
[Chemical formula 4]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)
“In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are coordinate axes of the three of a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425), (0.375, 0.425, 0.200) (However, a + b + c = 1.00.) ” The following general formula shown in (1), mainly composed of _{PbMg 1/3 Nb 2/3 O 3 -PbZrO 3} -PbTiO 3 ternary solid solution system composition, containing NiO 0.05 to 10.0 wt% piezoelectric In a piezoelectric element manufacturing method in which a piezoelectric material made of a porcelain composition is laminated on a substrate made of ceramics or on an electrode formed on the substrate, and the laminated piezoelectric material is heat-treated in an atmosphere.
In the heat treatment, as a container and a shelf plate for storing and placing the laminate of the piezoelectric material, an atmosphere adjusting material having the same composition as the piezoelectric material is converted into a NiO equivalent amount per unit volume of the container internal space, A method for manufacturing a piezoelectric element having high linearity in bending displacement with respect to an electric field in a high electric field region, characterized by using a heat-treated material in an atmosphere in which 0.03 to 0.5 mg / cm ³ coexists.
[Chemical formula 5]
_{Pb x (Mg y / 3 Nb} 2/3) a Ti b Zr c O 3 ... (1)
“In formula (1), 0.95 ≦ x ≦ 1.05, 0.8 ≦ y ≦ 1.0, and a, b, and c are coordinate axes of the three of a, b, and c. In the coordinates, (a, b, c) = (0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0. 300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425), (0.375, 0.425, 0.200) (However, a + b + c = 1.00.) ”

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