DE102004015853A1 - Piezoelectric material for producing stacked piezoelectric components e.g. for fuel injectors in vehicles, comprises a mixed oxide of lead, zirconium, titanium, yttrium, niobium, manganese and other metals - Google Patents

Abstract

Piezoelectric material (I) comprises a mixed oxide of lead, zirconium, titanium, yttrium, niobium, manganese and other metals is new. Piezoelectric material of formula (I) is new: (Pb 1 - xMa x) 1 + d(Zr 1 - yTi y) 1 - p - q(Y 1 / 2Nb 1 / 2) p(Mn 1 - z 1 - z 2Mb z 1Mc z 2) qO 3 + d (I) Ma : Ba, Ca and/or Sr and either Ba or Ca; Mb : Nb, Sb and/or Ta; Mc : W and/or Mo; d : -0.02 to 0.04; x : 0.01-0.2; y : 0.40-0.55; p : 0.005-0.05; q(1-z1-z2) : 0.001-0.02; (1-z1-z2)/(z1+2z2) : 0.7-1.5; z1, z2 : 0 or positive numbers, but not both 0. An independent claim is also included for producing a stacked piezoelectric component by preparing (I) with a BET surface area of 1.6-8 m 2>/g, adding an oxide of formula (II), shaping the mixture to form a film, printing the film with an electrode paste, stacking several such printed films, and calcining the product. (1-beta -gamma )PbO.beta WO 3.gamma MoO3 (II) beta +gamma : 0.005-0.27; beta , gamma : 0 or more.

Description

FIELD OF THE INVENTION

The The present invention relates to an Mn containing lead zirconate titanate based piezoelectric material and a method of manufacture of a stacked piezoelectric component, which is the piezoelectric Material used.

BACKGROUND OF THE INVENTION

A conventionally known piezoelectric material for use in a stacked piezoelectric component for actuators is a piezoelectric material based on PbZrO ₃ -PbTiO ₃ -Pb (Y _1/2 Nb _1/2 ) O ₃ . It comprises a compound having a composition in which a part of Pb is replaced by Sr and at least one element selected from Sb, Nb, W, La, Ta, Bi, Nd and Pr is added and Mn is also added.

The using the piezoelectric described above However, materials produced are stacked piezoelectric device not necessarily satisfactory in deflection, depending on the use of the actuator.

henceforth in this piezoelectric material, an acceptor element Mn added together with a donor element such as Sb, Nb and W, but an appropriate relationship is sometimes between the donor element and the acceptor element not reached and, as a result, persists with the stacked piezoelectric component a problem that the dielectric property yourself during aging extraordinarily changed and is not stabilized.

at this problem is known to when Mn becomes a piezoelectric based on lead zirconium titanate Material is added, a reduction in dielectric loss and an increase of the mechanical quality coefficient occur and this to suppress energy loss accompanying heat generation leads.

Even though the change the aging of the dielectric property by not adding Mn prevented from a piezoelectric material made of lead zirconate titanate consequently, this sacrifices the effect of suppressing the heat generation by adding Mn and is not practical.

As a result, are remedial measures to stabilize the dielectric property of the Mn-containing piezoelectric material based on lead zirconium titanate he wishes.

The The present invention is directed to solving these problems. An object of the present invention is a piezoelectric material to disposal to be placed on a stacked piezoelectric component with a big one Deflection and stabilized dielectric properties applied can be. The aim of the present invention includes a method of manufacturing a stacked piezoelectric Component using this piezoelectric material for disposal to deliver.

SUMMARY OF THE INVENTION

A first invention is a piezoelectric material represented by the chemical formula: (Pb 1-x Ma x ) 1 + d (Zr 1-y Ti y ) 1-p-q (Y 1.2 Nb 1.2 ) p (Mn 1-z1-z2 mb z1 Mc z2 ) q O 3 + d wherein
Ma means at least one or more elements selected from Ba, Ca and Sr and contains either Ba or Ca,
Mb means at least one or more elements selected from Nb, Sb, and Ta, and
Mc means at least one or more elements selected from W, and Mo means, where
-0.02 ≤ d ≤ 0.04,
0.01 ≤ x ≤ 0.20,
0.40 ≤ y ≤ 0.55,
0.005 ≤ p ≤ 0.05,
0.001 ≤ q · (1 - z1 - z2) ≤ 0.02, and
0.7 ≤ (1 - z1 - z2) / (z1 + 2z2) ≤ 1.5
(with the proviso that z1 and z2 are each 0 or a positive number and at least one of the variables z1 and z2 is not 0)

A second invention is a piezoelectric material represented by the chemical formula: (Pb 1-x Ma x ) 1 + d (Zr 1-y Ti y ) 1-p-q (Y 1.2 Nb 1.2 ) p (Mn 1-z2 W z2 ) q O 3 + d wherein
Ma means at least one or more elements selected from Ba, Ca, and Sr and contains Ba, where
-0.02 ≤ d ≤ 0.04,
0.01 ≤ x ≤ 0.20,
0.40 ≤ y ≤ 0.55,
0.25 ≤ z2 ≤ 0.40,
0.005 ≤ p <0.05, and
0.001 ≤ q · (1 - z2) ≤ 0.02

The Effects in the operation of the first and second inventions will be described.

In the case of materials according to conventional Techniques is the element to replace a part of Pb in the piezoelectric material only Sr with almost the same ion radius like Pb and the perovskite crystal lattice will not be satisfactory distorted. By knowing this point in the piezoelectric Material of the present invention is at least either Ba with a larger ion radius than Pb or Ca with an ion radius smaller than Pb than the element selected to replace part of Pb. The ion radius is more special of Pb with 12-fold coordination 1.49 Å and Ba, Ca and Sr have one Ion radius with 12-fold coordination of 1.61 Å, 1.34 Å and 1.44 Å.

Accordingly, in the piezoelectric material of the first and second inventions a bigger distortion than in conventional Materials introduced into the perovskite crystal lattice and therefore occurs a larger piezoelectric Effect.

by virtue of which may be when a stacked piezoelectric component is made of the material of the first and second inventions is made, the manufactured component have a large deflection.

In the materials according to conventional Techniques establish a sufficient relationship between the donor element and does not necessarily reach the acceptor element and the due to insufficient balance of the valence of these elements Oxygen defect affected the change disadvantageous to the aging of the dielectric property. By taking note this point is in the piezoelectric material of the present Invention the relationship of the donor element Sb, Nb or Mo to the acceptor element Mn in one appropriate range. With this appropriate ratio the amount of oxygen defect generated in the crystal lattice reduced in the piezoelectric material and the change in Aging of the dielectric property can be suppressed.

A third invention is a method of manufacturing a stacked piezoelectric device obtained by alternately stacking a piezoelectric layer and an inner electrode layer, comprising:
Production of the piezoelectric material according to inventions 1 or 2 in order to have a specific BET surface area of 1.6 to 8 m ² / g, and for this purpose addition of an auxiliary oxide which is represented by the chemical formula: (1 - β - γ ) PbO · βWO ₃ · γMoO ₃ (where 0.005 ≤ β + γ ≤ 0.27, with the proviso that β ≥ 0 and γ ≥ 0) to produce a mixture
Shaping the mixture to produce a green sheet and providing a printed layer on the green sheet comprising a paste containing an electrode material for the inner electrode layer,
Stacking a large number of unfired film webs with the printed layer provided on them to get an unbaked, stacked body and burning the unbaked, stacked body.

The made by the manufacturing method of the third invention stacked piezoelectric component has a piezoelectric Layer that is the piezoelectric material of the first or second Invention includes and consequently a big one Deflection and small change while the aging of the dielectric property.

As well contains the piezoelectric layer contains the auxiliary oxide described above and the presence of this auxiliary oxide affects the sintered state of the piezoelectric material of the first or second invention as the base material of the piezoelectric layer, so that the unfired one stacked bodies low temperature can be sintered.

henceforth in the third invention, the specific surface area of the piezoelectric material in the range described above controlled, whereby the auxiliary oxide uniformly in the environment of the piezoelectric Material can be distributed and during the burning the liquid phase forms. As a result, the unbaked stacked body can contribute a lower temperature will be sintered while the performance of the piezoelectric material of the first or second invention is maintained.

There Sintering can be realized at a low temperature a cheaper one Electrode material (e.g. Cu, Ag or Ag-Pg alloy with a Pd content of 10% or less) for uses the inner electrode layer and reduces material costs become.

How can be described above according to the present Invention a piezoelectric material applicable to a stacked one piezoelectric component with a large deflection and stabilized dielectric property, and a method for producing a stacked piezoelectric component by using the piezoelectric Material available be put.

BRIEF DESCRIPTION OF THE DRAWINGS

1 10 is a perspective view of the stacked piezoelectric device in Example 1.

2 10 is a top view of the piezoelectric layer of the stacked piezoelectric device in Example 1.

3 12 is a perspective developed view showing the stacked state of piezoelectric layers in Example 1.

DETAILED DESCRIPTION

In According to the first invention, the sintering temperature can be increased if d <-0.02, whereas the deflection performance may decrease if d> 0.04.

If x <0.01 can the deflection performance decreases, whereas the Curie temperature of the piezoelectric material can decrease (about 200 ° C or less), if x> 0.20, to narrow the range of usable temperature, and that piezoelectric material may have poor applicability.

If y is <0.40 or y> 0.55, it can Decrease deflection performance.

If p <0.005 or p> 0.05, can decrease the deflection performance.

henceforth can increase the sintering temperature be if p> 0.05 is.

If q · (1 - z1 - z2) <0.001, can the effect of increasing performance (reduction dielectric loss and increase in mechanical quality coefficient), attainable by the addition of Mn, difficult to obtain, or if q · (1 - z1 - z2)> 0.02, it can Decrease deflection performance.

If (1 - z1 - z2) / (z1 + 2 · z2) <0.7, the deflection performance may decrease, or if (1 - z1 - z2) / (z1 + 2 · z2)> 1.5, the dielectric property can change significantly during aging.

In the chemical formula of the piezoelectric material of the first invention, the term "Pb _1-x Ma _x " means that Pb is replaced by the element "Ma" in the crystal lattice (perovskite structure) of the piezoelectric material. When a plurality of elements are selected for Ma, x represents a total molar portion of the plurality of elements.

For example, when Ma includes Ba, Sr, and Ca, "Pb _1-x Ba _l Sr _m Ca _n " and 1 + m + n = x. The same applies in the case of selecting a plurality of elements for other terms chemical formula.

Ma is at least one or more elements selected from Ba, Ca and Sr and contains either Ba or Ca, and thus is the group of elements selected for Ma can, Ba alone, Ca alone, Ba and Ca, Ba and Sr, Ca and Sr or Ba, Ca and Sr. If Sr alone for the element Ma is used, the effect of the present Invention cannot be obtained.

In In the second invention, if z2 <0.25, the dielectric property may change while aging extraordinarily change, or if z2> 0.4 the deflection performance can decrease.

If 1 · (1 - z2) <0.001, can the effect of increasing performance (reducing the dielectric loss and increase the mechanical quality coefficient), attainable by the addition of Mn, difficult to obtain, or if q · (1 - z2)> 0.02, it can Decrease deflection performance. Other parameters are the same as in the first invention.

The added amount α of the auxiliary oxide represented by the chemical formula: (1 - β - γ) PbO · βWO ₃ · γMoO ₃ (where 0.005 ≤ β + γ ≤ 0.27, with the proviso that β ≥ 0 and γ ≥ 0) is preferably 0.05 to 5% by weight (external%) per 100% by weight of the piezoelectric material.

The Auxiliary oxide can be a composite oxide in which Pb oxide, W oxide and / or Mo oxide are mixed to the chemical described above Fulfill formula and as a solid solution or a mixture of Pb oxide, W oxide and / or Mo oxide are present which are mixed to the one described above chemical formula to meet or it can be one obtained by partial solids solution of this mixture Be oxide because even if Pb oxide, W oxide and / or Mo oxide in remain behind the auxiliary oxide, the solid solution these oxides progress in the process of sintering and the Function as an auxiliary oxide is secured.

If the auxiliary oxide defined above is used, the temperature for baking the piezoelectric material of the first or second Invention lowered and a stacked piezoelectric component using a less expensive electrode material (e.g. Cu, Ag, Ag-Pd alloy with a Pd content of 10% or less) getting produced. Hence, one can be for low cost manufacturing of a stacked piezoelectric component suitable material be preserved.

If β + γ <0.005 or β + γ> 0.27, the Effect of lowering the baking temperature cannot be obtained.

If α <0.05% by weight, cannot get the effect of lowering the sintering temperature be, or if α> 5 wt .-%, can the deflection performance will be reduced because a not auxiliary oxide contributing to the deflection in the piezoelectric Material rises.

As well The third invention is a method of manufacturing a stacked one piezoelectric component, which is one using the piezoelectric Material of the first or second invention and admixing the above described auxiliary oxide has formed piezoelectric layer.

Furthermore, in the third invention, the piezoelectric material is adjusted to have a predetermined surface. If the BET specific surface area is less than 1.6 m ² / g, the sintering temperature of the piezoelectric material may be increased, or if it exceeds 8 m ² / g, the solids solution of the auxiliary oxide in the piezoelectric material progresses excessively and the deflection performance can be reduced.

Other objects which relate to the piezoelectric component and auxiliary oxide are same as that of the first and second inventions above have been described.

The specific BET surface area means a specific surface area measured by the BET method.

The measurement methods a specific surface includes adsorbing a molecule with a known area occupied by adsorption on the surface of a Material at the temperature of liquid nitrogen and then Determination of the specific surface area of the sample from the adsorbed Amount one. In particular, the process of physical adsorption of an inert gas at a low temperature and a low Moisture called BET process.

In The manufacturing method of the third invention uses a piezoelectric Material having the composition of Invention 1 or Invention 2 available beforehand and a separately produced auxiliary oxide with the mixed composition described above.

The Treatment to adjust the BET specific surface area of the piezoelectric material in the range described above can be in the state of piezoelectric material alone or after admixing the Auxiliary oxide performed become.

special the raw materials are weighed to obtain a predetermined composition ratio result, the starting materials are calcined, the calcined body is ground to have a predetermined BET specific surface area and then the auxiliary oxide is added to obtain a mixture.

alternative the starting materials are calcined, the auxiliary oxide is added and then the mixture is ground.

The fine powder of the piezoelectric material obtained by calcining and grinding of the raw materials obtained has against that Auxiliary oxide a higher Reactivity. To consequently the solids solution of the auxiliary oxide into the piezoelectric material as good as possible to suppress, it can also be possible be that Piezoelectric material ground and pre-baked at 400 to 700 ° C and the resulting powder with an auxiliary oxide, a solvent, mixed with a binder, a plasticizer and a dispersant and is then brought into shape.

In the manufacturing process of a stacked piezoelectric component The present invention sets the predetermined specific BET surface area preferably by grinding the piezoelectric material with the help a ball mill, a medium-stirring Mill or the like to a fine particle size.

at the shape of the mixture that the piezoelectric material and which comprises auxiliary oxide, becomes a slip by adding a binder and the like the mixture is made, and the slurry can be an unfired Film web by a generally known doctor blade method (doctor blade). After that, it becomes an electrode material containing paste printed on the green sheet to make a printed layer available to deliver.

A desired Number of unfired film webs, on each of which the printed one Layer available is stacked and pressure bonded to make an unbaked making stacked bodies and this unburned stacked body is released, baked and, after providing a side electrode or the like to achieve electrical conduction of the inner electrode layer, subjected to a polarization treatment, whereby a stacked piezoelectric component can be obtained.

The The procedure described here is a well known manufacturing process of a stacked piezoelectric component. In the case of manufacturing a piezoelectric component by other methods, the third invention can also be applied.

Incidentally, the inner electrode layer may be formed to have a complete electrode structure (an area almost equal to the piezoelectric layer), unlike the partial electrode structure shown in Example 1 (the area of the cross section at right angles to the stacked layer direction is smaller than the piezoelectric layer), which will be described later.

The stacked piezoelectric device manufactured as above has a piezoelectric layer that consists of one in the dielectric Property composed of stabilized piezoelectric material is. Due to the dielectric property, the transition property the deflection is less scattered, and consequently the stroke rate of the piezoelectric layer when a voltage is applied, that is, the Number of strokes of the actuator when used as a piezoelectric Actuator, almost constant.

Under Use of such a piezoelectric actuator as one Control source of an injector for fuel injection in an internal combustion engine such as an automobile engine can scatter reduced in the amount of fuel injected and the Combustion state can be controlled more precisely. In this point are the piezoelectric materials of the first and second inventions as a material for building a piezoelectric layer of a piezoelectric actuator used as a control source of the injector works for fuel injection, suitable. That through the third Stacked piezoelectric device manufactured according to the invention is also as a control source of the injector for fuel injection suitable.

Examples of the present invention are described below with reference to the Described drawings.

example 1

In this example, is a stacked piezoelectric device using the piezoelectric material of the present Made invention and evaluated its performance.

The piezoelectric material of this example is a piezoelectric material represented by the chemical formula: (Pb _1-x Ma _x ) _{1 + d} (Zr _1-y Ti _y ) _1-p-q - (Y _1/2 Nb _{1 / 2} ) _p (Mn _1-z1-z2 Mb _z1 Mc _z2 ) _q O _{3 + d} (where Ma is at least one or more elements selected from Ba, Ca, and Sr and contains either Ba or Ca, Mb is at least one or more Means selected from Nb, Sb, and Ta, and Mc means at least one or more elements selected from W, and Mo means, where
-0.02 ≤ d ≤ 0.04,
0.01 ≤ x ≤ 0.20,
0.40 ≤ y ≤ 0.55,
0.005 ≤ p ≤ 0.05,
0.001 ≤ q · (1 - z1 - z2) ≤ 0.02, and
0.7 ≤ (1 - z1 - z2) / (z1 + 2z2) ≤ 1.5 (with the proviso that z1 and z2 are each 0 or a positive number and at least one of the variables z1 and z2 is not 0 ).

Alternatively, the piezoelectric material of this example is a piezoelectric material represented by the chemical formula: (Pb _1-x Ma _x ) _{1 + d} (Zr _1-y Ti _y ) _1-p-q - (Y _1/2 Nb _1/2 ) _p (Mn _1-z2 W _z2 ) _q O _{3 + d} (where Ma is at least one or more elements selected from Ba, Ca, and Sr and contains Ba), wherein
-0.02 ≤ d ≤ 0.04,
0.01 ≤ x ≤ 0.20,
0.40 ≤ y ≤ 0.55,
0.25 ≤ z2 ≤ 0.40,
0.005 ≤ p ≤ 0.05, and
0.001 ≤ q · (1 - z2) ≤ 0.02.

This Example is detailed below described.

In this example, using samples 1 through 14 of the Invention and the comparative samples C1 to C3 the piezoelectric Material of the present invention by the manufacturing process stacked piezoelectric obtained by the present invention Component evaluated in terms of performance.

More specifically, Samples 1 through 14 are piezoelectric materials, which by changing the group of substituted elements Ma, Mb, and Mc and the composition ratio (x, y, z1, z2, p, q, d) in the chemical formula (Pb _1-x Ma _x ) _{1 + d} (Zr _1-y Ti _y ) _1-p-q - (Y _1/2 Nb _1/2 ) _p (Mn _1-z1-z2 Mb _z1 Mc _z2 ) _q O _{3 + d} , Comparative sample C1 has a composition outside the scope of the present invention in which (1-z1-z2) / (z1 + 2 • z2) is 0.54. Comparative sample C2 has a composition outside the scope of the present invention in which the elements Mb and Mc are not included. Comparative sample C1 has a composition outside the scope of the present invention in which (1 - z1 - z2) / (z1 + 2 * z2) is 2.

An in 1 stacked piezoelectric component shown 1 manufactured and examined its piezoelectric properties.

As in 1 to 3 was shown, the stacked piezoelectric component 1 made so that inner electrode layers 21 and 22 , working alternately as a positive electrode and a negative electrode, between piezoelectric layers 11 were introduced. As in 2 (a) shown, an inner electrode layer was provided to a reserved area 119 in the piezoelectric layer 11 to leave and, as in 1 shown to with a side face 101 to be exposed, and another inner electrode layer was provided to be with a different side surface 102 to lie freely.

On the side surfaces 101 and 102 of the piezoelectric component 1 became a side electrode 31 provided to electrical conduction between exposed end portions of the inner electrode layers 21 or 22 to enable.

The central area in the stacked layer direction of the piezoelectric component 1 is a control part 111 which is achieved by passing electricity to the inner electrode layers 21 and 22 is extended. The the control part 111 enclosing ceramic layers 12 who like in 2 shown at least one surface of each ceramic layer not with the inner electrode layer 21 or 22 is in contact, work as blind parts 112 which are not extended even if electricity is through the inner electrode layers 21 and 22 is directed.

The Method of manufacturing the piezoelectric material and the stacked piezoelectric component are specific below described.

PbO, SrCO ₃ , BaCO ₃ , CaCO ₃ , ZrO ₂ , TiO ₂ , Y ₂ O ₃ , Nb ₂ O ₅ , Sb ₂ O ₃ , WO ₃ and MoO ₃ were used as starting materials containing each constituent atom of the piezoelectric material , and weighed to give a desired composition shown in Table 1, namely so that the ratio of the respective constituent atoms in the starting materials became the same as the ratio of respective constituent atoms in the target composition.

The weighed starting materials were wet mixed, dried and calcined at 800 ° C for 5 hours and the calcined body was wet milled with a medium stirring mill to add a milled material with a BET specific surface area of 2.5 to 3 m ² / g receive. Then, a solvent, a binder, a plasticizer and a dispersant were added thereto and mixed in a ball mill to obtain a slip.

Out this slip was a green sheet with a thickness of 100 μm molded using a squeegee device. On this unfired one Foil sheet was an electrically conductive paste that was a silver / palladium (7/3 by weight) contained extensive electrode material, printed, around a printed layer for to provide the inner electrode layer.

As in 3 21, unfired film sheets, each with the printed layer provided thereon, were stacked, an unfired film sheet without a printed layer for the inner electrode layer was placed on top and bottom, these film sheets were heat-bonded to produce an unfired stacked body.

The unfired stacked bodies was then debindered in an electric oven and baked at 850 ° C to 1100 ° C and the entire surface polished to obtain a 7 × 7 × 1.8 mm stacked sintered body.

henceforth was a pair of side electrodes to achieve electrical conduction to any other inner electrode layer on the side surfaces of the stacked sintered body printed, and then the stacked sintered body was added 130 ° C in an applied electric field of 2 kV / mm for 30 minutes of polarization subjected and then left at room temperature for 48 hours.

On In this way, a stacked piezoelectric device was obtained.

The Measurement of the performance of the stacked piezoelectric The component is described below.

The Impedance-frequency properties of the stacked piezoelectric obtained The component was measured with an impedance analyzer and the difference between the resonance frequency (fr) and the anti-resonance frequency (fa) for the fundamental vibration were determined. The baking temperature, at saturation starts, is shown in Table 2.

Then were the deflection and change in aging of the electrostatic capacity each stacked piezoelectric device that is in the above baked temperature was examined.

at A voltage of 150 V was applied to the measurement of the deflection stacked piezoelectric component applied while a load of 500N was imposed and the deflection of the stacked piezoelectric component was measured with a laser deflection measuring device. The measurement was made performed at two points and an average of the two points was taken as the deflection of the Component used. The deflection was measured at room temperature and the measurement was done after driving the stacked piezoelectric component before for about Had been aged for 20 minutes.

When measuring the change in the aging of the electrostatic capacity, the stacked piezoelectric device was polarized and then left to stand at room temperature for 48 hours, and then the electrostatic capacity Q1 at 1 kHz was measured with an LCR meter. The electrostatic capacity Q2 was expired 1 Measured again for a week and the rate of change between Q1 and Q2 determined by calculation.

The Measurement results are shown in Table 2. As the results show was in the using the piezoelectric material present invention (samples 1 to 14) manufactured stacked piezoelectric component increases the deflection and at the same time the change the aging of the electrostatic capacity is reduced, as with comparative samples Cl to C3 compared. Therefore, the improvement became clear is called, the dielectric property has been stabilized.

In the piezoelectric material (samples 1 to 14) of this example, at least Ba with an ion radius larger than Pb or Ca with a smaller ion radius than Pb is selected as the element for replacing a part of Pb in the perovskite crystal lattice constituting the piezoelectric material ( see table 1). A large distortion is introduced into the perovskite crystal lattice, which constitutes the piezoelectric material, and there is a greater piezoelectric effect. Consequently, a large displacement can be obtained when an in 1 to 3 Stacked piezoelectric component shown is made of the piezoelectric material of samples 1 to 14 in this example (see Table 2).

henceforth the ratio of. in the piezoelectric material of samples 1 to 14 Donor elements Sb, Nb, W or Mo to the acceptor element Mn on one appropriate range, thereby reducing the amount of in the crystal lattice oxygen defect caused in the piezoelectric material decreased and the change the aging of the dielectric property can be suppressed can.

How described above can be according to this For example, a piezoelectric material applicable to a stacked one piezoelectric component with a large deflection and stabilized dielectric property, and a method for producing a stacked piezoelectric component using the piezoelectric Material available be put.

Table 2

Example 2

In this example, a stacked piezoelectric component, the one made of a piezoelectric material, to which an auxiliary oxide added, has formed piezoelectric layer, evaluated together with comparative examples.

PbO, WO ₃ and MoO ₃ were used as starting materials of the auxiliary oxide and weighed to give a desired composition shown in Table 3, so that the ratio of the respective constituent atoms in the starting materials became the same as the ratio of respective constituent atoms in the target composition.

The weighed starting materials were mixed dry and then calcined in air at 500 ° C. for 2 hours, whereby a partial reaction of PbO, WO ₃ and / or MoO _{3 was} caused to obtain a calcined powder of the auxiliary oxide. The resulting calcined powder was wet milled and then dried to obtain an auxiliary powder having a BET specific surface area of 1.5 to 2 m ² / g, and this auxiliary powder was used in Samples 15 to 19.

MoO _{3 was} not contained in the auxiliary oxide of comparative sample C4 and the amount of WO ₃ was small. Therefore, this is not an auxiliary oxide that falls within the scope of the invention.

Sample 1 from Table 1 was used for the piezoelectric material. The raw materials were mixed to give the composition of Sample 1 and calcined at 800 ° C for 5 hours, and the calcined body was wet-milled with a medium stirring mill to obtain a piezoelectric material, the milled material having a BET specific surface area of 2.7 m ² / g.

Then the auxiliary oxide produced above became this piezoelectric Material added to a mixing ratio shown in Table 3 and further a solvent, a binder, a Plasticizer and a dispersant added and mixed in a ball mill. This slurry obtained became an unfired film web with a thickness of 100 μm molded using a squeegee device. After that, a Stacked piezoelectric component manufactured and evaluated in the same way as in Example 1, and the results are shown in Table 3.

How As can be seen from Table 3, the baking temperature was around Lowered 100 ° C when the added amount α of the auxiliary oxide to 0.05 to 5% by weight (external%) was set per 100% by weight of the piezoelectric material. The material of comparative sample C had no effect on the lowering of the Baking temperature.

This evaluation makes it clear that an effect on the lowering of the baking temperature can be obtained if an auxiliary oxide, which is represented by the chemical formula: (1 - β - γ) PbO · βWO ₃ · γMoO ₃ (0.005 ≤ β + γ ≤ 0.27 with the proviso that β ≥ 0 and γ ≥ 0 is added in an amount of 0.05 to 5% by weight (external%) per 100% by weight of the piezoelectric material.

Table 3

Example 3

In This example shows the performance of the stacked piezoelectric Component according to the difference in the specific BET surface area of the piezoelectric material evaluated.

Sample 1 from Table 1 is used for the piezoelectric material. The raw materials were mixed to give the composition shown in Table 1, and calcined at 800 ° C for 5 hours to obtain a calcined powder. This calcined powder was wet ground by changing the grinding conditions such as the grinder, the grinding medium size and the grinding time, and the resulting ground material with a BET specific surface area of 1.5 to 12 m ² / g became piezoelectric materials of the samples 20 to 23 manufactured.

The Piezoelectric materials of the comparative samples C5 and C6 were also manufactured, the composition being the same, but the specific BET surface area was small or big.

To each of these samples and comparative samples, sample 15 from Table 3 was added in an amount of 0.5% by weight as the auxiliary oxide, and further a solvent, a binder, a plasticizer and a dispersant were added and mixed in a ball mill. An unbaked sheet of film with a thickness of 100 μm was formed from the slip obtained using a doctor blade device. There After, a stacked piezoelectric device was manufactured and evaluated in the same manner as in Example 1, and the results are shown in Table 4.

As is clear from Table 4, sintering can be realized at a low temperature while maintaining the properties of the piezoelectric material when the specific surface area of the piezoelectric material is set to 1.6 to 8 m ² / g.

In In this example, an auxiliary oxide becomes the ground material of the Piezoelectric material is added, but the auxiliary oxide can as well to the piezoelectric material obtained by calcining the raw materials was obtained, added and together with the piezoelectric Material to be ground.

There furthermore, the fine powder of the piezoelectric obtained by grinding High reactivity has with the auxiliary oxide to the solid solution of the auxiliary oxide in the can suppress piezoelectric material as much as possible it is also possible be that Piezoelectric material ground and pre-baked at 400 to 700 ° C and the powder obtained with an auxiliary oxide, a solvent, a binder, a plasticizer and a dispersant are mixed and then molded.

Table 4

This invention relates to the provision of a piezoelectric material which can be used for a stacked piezoelectric device with a large deflection and stabilized dielectric properties. According to the invention there is provided a piezoelectric material represented by the chemical formula: (Pb 1-x Ma x ) 1 + d (Zr 1-y Ti y ) 1-p-q (Y 1.2 Nb 1.2 ) p (Mn 1-z1-z2 mb z1 Mc z2 ) q O 3 + d wherein
Ma means at least one or more elements selected from Ba, Ca and Sr and contains either Ba or Ca,
Mb means at least one or more elements selected from Nb, Sb, and Ta, and
Mc means at least one or more elements selected from W, and Mo means, where
-0.02 ≤ d ≤ 0.04,
0.01 ≤ x ≤ 0.20,
0.40 ≤ y ≤ 0.55,
0.005 ≤ p ≤ 0.05,
0.001 ≤ q · (1 - z1 - z2) ≤ 0.02, and
0.7 ≤ (1 - z1 - z2) / (z1 + 2z2) ≤ 1.5
(with the proviso that z1 and z2 are each 0 or a positive number and at least one of the variables z1 and z2 is not 0)

Claims (4)

Piezoelectric material represented by the chemical formula: (Pb 1-x Ma x ) 1 + d (Zr 1-y Ti y ) 1-p-q (Y 1.2 Nb 1.2 ) p (Mn 1-z1-z2 mb z1 Mc z2 ) q O 3 + d wherein Ma means at least one or more elements selected from Ba, Ca, and Sr and contains either Ba or Ca, Mb means at least one or more elements selected from Nb, Sb, and Ta, and Mc means at least one or more elements selected from W, and Mo means, where -0.02 ≤ d ≤ 0.04, 0.01 ≤ x ≤ 0.20, 0.40 ≤ y ≤ 0.55, 0.005 ≤ p ≤ 0.05, 0.001 ≤ q · (1 - z1 - z2) ≤ 0.02, and 0.7 ≤ (1 - z1 - z2) / (z1 + 2z2) ≤ 1.5 (with the proviso that z1 and z2 are each 0 or a positive number and at least one of the variables z1 and z2 is not 0). Piezoelectric material represented by the chemical formula: (Pb 1-x Ma x ) 1 + d (Zr 1-y Ti y ) 1-p-q (Y 1.2 Nb 1.2 ) p (Mn 1-z2 W z2 ) q O 3 + d wherein Ma denotes at least one or more elements selected from Ba, Ca, and Sr and contains Ba, where -0.02 ≤ d ≤ 0.04, 0.01 ≤ x ≤ 0.20, 0.40 ≤ y ≤ 0, 55, 0.25 ≤ z2 ≤ 0.40, 0.005 ≤ p ≤ 0.05, and 0.001 ≤ q · (1 - z2) ≤ 0.02. Piezoelectric material according to claim 1 or 2, wherein the added amount α of an auxiliary oxide represented by the chemical formula: (1 - β - γ) PbO · βWO ₃ · γMoO ₃ (where 0.005 ≤ β + γ ≤ 0.27, with the Provided that β ≥ 0 and γ ≥ 0) is 0.05 to 5% by weight (external%) per 100% by weight of the piezoelectric material. A method of manufacturing a stacked piezoelectric device obtained by alternately stacking a piezoelectric layer and an inner electrode layer, comprising: manufacturing the piezoelectric material according to claim 1 or 2 to have a BET specific surface area of 1.6 to 8 m ² / g to own, and for this purpose addition of an auxiliary oxide, which is represented by the chemical formula: (1 - β - γ) PbO · βWO ₃ · γMoO ₃ (where 0.005 ≤ β + γ ≤ 0.27, with the proviso that β ≥ 0 and γ ≥ 0) to produce a mixture, shaping the mixture to produce an unfired film web and, on the unfired film web, providing a printed layer containing a paste containing an electrode material for the inner electrode layer, stacking a multiplicity of unfired film webs printed layers provided thereon to obtain an unfired, stacked body and burning the u Burnt, stacked body.