WO2020066739A1 - Laminated piezoelectric element - Google Patents

Abstract

Provided is a laminated piezoelectric element which includes a plurality of ceramic piezoelectric layers, inner electrodes that are formed between the ceramic piezoelectric layers, and an outer electrode that is electrically connected to the inner electrodes, wherein the laminated piezoelectric element is characterized in that the ceramic piezoelectric layers are represented by the compositional formula, {Ba1-xCaxO}mTiO2+αRe2O3+βMgO+γMnO [provided that Re2O3 is at least one selected from the group consisting of Y2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Yb2O3, and La2O3, and α, β, and γ represent molar ratios and satisfy relational expressions (1) to (5)], the ceramic piezoelectric layers comprise 0.2 to 0.8 parts by weight of SiO2 as a secondary component relative to 100 parts by weight of a primary component in the {Ba1-xCaxO}TiO2 raw material used for the ceramic piezoelectric layers, the ceramic piezoelectric layers have remnant polarizations in a specific direction, and the inner electrodes comprise nickel, nickel alloy, copper, or copper alloy.

Description

Piezoelectric multilayer device

The present invention relates to a piezoelectric laminated device.

2. Description of the Related Art In recent years, demand for piezoelectric laminated elements such as piezoelectric actuators capable of obtaining a large displacement amount even with a small voltage has been increasing.

Conventionally, Pb-containing PZT-based piezoelectric ceramics have been used as piezoelectric ceramics because of their high piezoelectric properties. However, in recent years, with increasing environmental awareness, Pb-free piezoelectric ceramics have been required. BaTiO ₃ -based piezoelectric ceramics used for multilayer capacitors are known as Pb-free piezoelectric ceramics.

Since BaTiO ₃ -based piezoelectric ceramics have significantly lower piezoelectric characteristics than PZT-based piezoelectric ceramics, they need to have a laminated structure for use in piezoelectric actuators.
2. Description of the Related Art Conventionally, many multilayer capacitors in which internal electrodes and BaTiO ₃ are co-sintered have been disclosed (Patent Document 1). However, its potential as a piezoelectric actuator has not been studied because of its low piezoelectric properties.

JP 2000-58378 A

In order to use the element as a piezoelectric actuator, it is necessary to perform a polarization process of applying a constant high electric field for a fixed time and evaluate the piezoelectric characteristics. When a device was prototyped and polarized to evaluate the piezoelectric characteristics, it was found that the piezoelectric characteristics were so low that the piezoelectric characteristics could not be measured. Further, it has been found that since the dielectric constant is extremely high as compared with the piezoelectric characteristics, the load on the driver is high, and it cannot be used as a piezoelectric actuator.

In addition, a noble metal such as Ag or Pd may be used for the internal electrode. However, it is preferable to use a base metal such as Ni because the cost of raw materials can be significantly reduced. In order to use a base metal such as Ni, it is necessary to perform co-sintering with a base metal such as Ni by firing in a reducing atmosphere in which the base metal such as Ni is not oxidized in the firing step.
Therefore, when a base metal such as Ni is used as the internal electrode, the composition of the piezoelectric ceramic is required to be a composition that can be fired in a reducing atmosphere.

An object of the present invention is to solve these problems and to provide a highly reliable piezoelectric laminated element which has high piezoelectric characteristics, can be co-sintered with a base metal such as Ni, and is highly reliable.

A piezoelectric multilayer element according to the present invention is a piezoelectric multilayer element including a plurality of piezoelectric ceramic layers, an internal electrode formed between the piezoelectric ceramic layers, and an external electrode electrically connected to the internal electrode. hand,
The piezoelectric ceramic layer is represented by the following composition formula,
{Ba _1-x Ca _x O} _m TiO ₂ + αRe ₂ O ₃ + βMgO + γMnO
[However, _Re 2 _{O 3 is} in the _{Y 2 O 3, Gd 2 O} 3, Tb 2 O 3, Dy 2 O 3, Ho 2 O 3, Er 2 O 3, Yb 2 O 3 and _La 2 _{O 3} And α, β, and γ represent molar ratios and satisfy the following relational expressions (1) to (5).
0.0010 ≦ α ≦ (−65.32m + 67.70) / 100 (1)
0.0004 ≦ β ≦ (−28.74m + 29.79) / 100 (2)
0.0002 ≦ γ ≦ (−13.06 m + 13.54) / 100
[When m ≦ 1.006]
0.0002 ≦ γ ≦ 0.004 [when m> 1.006] (3)
0.995 ≦ m ≦ 1.011 (4)
0.01 ≦ x ≦ 0.25 (5)]
In addition, based on 100 parts by weight of the main component in the {Ba _1-x Ca _x O} TiO ₂ raw material used for the piezoelectric ceramic layer, 0.2 parts by weight or more and 0.8 parts by weight of SiO ₂ as an auxiliary component is used. Parts or less
The piezoelectric ceramic layer has remanent polarization in a certain direction,
The internal electrode is made of nickel, a nickel alloy, copper or a copper alloy.

Further, another aspect of the piezoelectric laminated element of the present invention includes a plurality of piezoelectric ceramic layers, an internal electrode formed between the piezoelectric ceramic layers, and an external electrode electrically connected to the internal electrode. A piezoelectric laminated element,
Oxidation in which the piezoelectric ceramic layer contains Ba, Ca, Ti, Mg, Mn and Re (Re is at least one selected from Y, Gd, Tb, Dy, Ho, Er, Yb and La). With respect to 100 parts by weight of the main component including the substance, 0.2% by weight or more and 0.8% by weight or less of SiO ₂ as an auxiliary component is contained,
In the oxide as the main component, the total content of Ba and Ca is mmol, the content of Re is α mol, the content of Mg is β mol, and the content of Mn is 1 mol with respect to 1 mol of Ti contained in the oxide. Is γ mol, the following relational expressions (1) to (5) are satisfied,
0.0010 ≦ α ≦ (−65.32m + 67.70) / 100 (1)
0.0004 ≦ β ≦ (−28.74m + 29.79) / 100 (2)
0.0002 ≦ γ ≦ (−13.06 m + 13.54) / 100
[When m ≦ 1.006]
0.0002 ≦ γ ≦ 0.004 [when m> 1.006] (3)
0.995 ≦ m ≦ 1.011 (4)
0.01 ≦ x ≦ 0.25 (5)
In addition, the piezoelectric ceramic layer has remanent polarization in a certain direction,
The internal electrode is made of nickel, a nickel alloy, copper or a copper alloy.

According to the present invention, it is possible to provide a highly reliable piezoelectric laminate element suitable for a piezoelectric actuator, which has high piezoelectric characteristics, can be co-sintered with a base metal such as Ni, and has high reliability.

FIG. 1 is a cross-sectional view schematically illustrating an example of the configuration of the piezoelectric multilayer device of the present invention. FIG. 2 is a cross-sectional view schematically showing another example of the configuration of the piezoelectric multilayer device of the present invention.

Hereinafter, the piezoelectric laminated device of the present invention will be described.
However, the present invention is not limited to the following configuration, and can be appropriately modified and applied without changing the gist of the present invention. It should be noted that a combination of two or more of the individual desirable configurations described below is also the present invention.

In the piezoelectric laminated device of the present invention, the ratio of the A site (Ba, Ca amount) / B site (Ti amount) is determined for the ceramic, which is the main component of the piezoelectric ceramic layer, using (Ba, Ca) TiO ₃ as a base composition. It is set within a certain range. Further, the amount of the additive to be added to the mother composition is set within a certain range. Further, in order to secure reliability in firing in a reducing atmosphere, the additive amount of SiO ₂ as an auxiliary component is set within a certain range.
By satisfying these requirements, it is possible to satisfy high piezoelectric characteristics and low relative dielectric constant required for a piezoelectric laminated element such as a piezoelectric actuator.

FIG. 1 is a cross-sectional view schematically illustrating an example of the configuration of the piezoelectric multilayer device of the present invention.
Hereinafter, the configuration of the piezoelectric multilayer device of the present invention will be described with reference to FIG.
The piezoelectric multilayer device 1 shown in FIG. The laminate 10 has a structure in which piezoelectric ceramic layers 20a, 20b, 20c, 20d, 20e, and 20f and internal electrodes 22a, 21a, 22b, 21b, and 22c are alternately laminated.

The laminated body 10 has a rectangular parallelepiped shape or a substantially rectangular parallelepiped shape, and has a length perpendicular to the laminating direction with the first main surface 11 and the second main surface 12 facing in the laminating direction (vertical direction in FIG. 1). The first end face 13 and the second end face 14 facing each other in the direction (the left-right direction in FIG. 1) and the first side face facing the width direction (the front-back direction in FIG. 1) orthogonal to the laminating direction and the length direction. And a second side surface (not shown in FIG. 1).

The internal electrodes 22a, 21a, 22b, 21b, and 22c are made of nickel, a nickel alloy, copper, or a copper alloy, and are co-sintered with the piezoelectric ceramic layers 20a, 20b, 20c, 20d, 20e, and 20f.
The internal electrode is preferably made of nickel or a nickel alloy.

The piezoelectric multilayer device 1 shown in FIG. 1 further includes an external electrode 31 provided on the first end face 13 of the multilayer body 10 and an external electrode 32 provided on the second end face 14 of the multilayer body 10. I have. The external electrodes 31 and 32 are preferably made of a conductive material such as a Ni—Cr alloy (nichrome) or Ag.
Further, there may be electrodes on the front and back of the laminate to increase the number of driving layers. FIG. 2 shows the piezoelectric multilayer element 2 in which electrodes (external electrodes 31) are provided on both sides of the multilayer body.

The piezoelectric ceramic layers 20a, 20b, 20c, 20d, 20e and 20f are mainly composed of a ceramic having (Ba, Ca) TiO ₃ as a mother composition.
Ceramic as the main component is
{Ba _1-x Ca _x O} _m TiO ₂ + αRe ₂ O ₃ + βMgO + γMnO
[However, _Re 2 _{O 3 is} in the _{Y 2 O 3, Gd 2 O} 3, Tb 2 O 3, Dy 2 O 3, Ho 2 O 3, Er 2 O 3, Yb 2 O 3 and _La 2 _{O 3} And α, β, and γ represent molar ratios and satisfy the following relational expressions (1) to (5).
0.0010 ≦ α ≦ (−65.32m + 67.70) / 100 (1)
0.0004 ≦ β ≦ (−28.74m + 29.79) / 100 (2)
0.0002 ≦ γ ≦ (−13.06 m + 13.54) / 100
[When m ≦ 1.006]
0.0002 ≦ γ ≦ 0.004 [when m> 1.006] (3)
0.995 ≦ m ≦ 1.011 (4)
0.01 ≦ x ≦ 0.25 (5)]

In the present specification, the “main component” means a component having the largest abundance ratio (mol%), and desirably a component having an abundance ratio exceeding 50 mol%.

Formulas (1), (2), and (3) determine the contents of Re, Mg, and Mn, which are additives other than (Ba, Ca) TiO ₃ , contained in the ceramic as the main component.
When α, β, and γ satisfy 0.0010 ≦ α, 0.0004 ≦ β, and 0.0002 ≦ γ, respectively, the polarization failure rate decreases.
α, β, and γ are respectively α ≦ (−65.32 m + 67.70) / 100, β ≦ (−28.74 m + 29.79) / 100, and γ ≦ (−13.06 m + 13.54) / 100 [m ≦ 1. 006] or γ ≦ 0.004 [m> 1.006], the grain growth is facilitated, and the piezoelectric characteristics are exhibited.

0.0010 ≦ α ≦ (−65.32m + 67.70) / 100, 0.0004 ≦ β ≦ (−28.74m + 29.79) / 100, 0.0002 ≦ γ ≦ of the above formulas (1) to (3). In a region that satisfies (−13.06m + 13.54) / 100 [when m ≦ 1.006] or 0.0002 ≦ γ ≦ 0.004 [when m> 1.006], the content of the ceramic as the main component is With respect to the value of m, it is preferable that m ≦ 1.011 because the d value (piezoelectric constant) increases.
0.0010 ≦ α ≦ (−65.32m + 67.70) / 100, 0.0004 ≦ β ≦ (−28.74m + 29.79) / 100, 0.0002 ≦ γ ≦ (-13.06m + 13.54) / 100 [when m ≦ 1.006] or 0.0002 ≦ γ ≦ 0.004 [when m> 1.006], the value of m in the ceramic as a main component is 0.995. When ≦ m, the polarization failure rate is reduced, which is preferable.
From the above, by satisfying the expressions (1), (2), (3) and (4) together, the polarization failure rate is low and the d value is high, so that the performance required for the piezoelectric multilayer element is satisfied. Can be.
Further, in the formula (5), when x is 0.01 ≦ x ≦ 0.25, the same effect can be exerted.

Further, the piezoelectric ceramic layer contains SiO ₂ as an auxiliary component in an amount of 0.2 to 0.8 parts by weight based on 100 parts by weight of the main component.
When the added amount of SiO ₂ as a subcomponent is 0.2 parts by weight or more, firing in a reducing atmosphere can be suitably performed.
When the added amount of SiO ₂ as an auxiliary component is 0.8 parts by weight or less, piezoelectric characteristics can be exhibited.

As other subcomponents, an oxide of Li ₂ O— (Si, Ti) O ₂ —MO (where MO is at least one selected from Al ₂ O ₃ and ZrO ₂ ), An oxide of a SiO ₂ —TiO ₂ —XO system (XO is at least one selected from BaO, CaO, SrO, MgO, ZnO and MnO) may be included.

In the piezoelectric laminated device of the present invention, the average grain diameter of the ceramic contained in the piezoelectric ceramic layer is preferably 0.6 μm or more and 3.7 μm or less.
It is preferable to grow the ceramic particles so that the average grain diameter is in the above range for use as a piezoelectric laminated element.
The grain diameter of the ceramic can be determined by observing the ceramic contained in the piezoelectric ceramic layer with a scanning electron microscope and using an intercept method.

In the piezoelectric laminated element of the present invention, it is preferable that the average thickness of one piezoelectric ceramic layer is 5 μm or more and 60 μm or less.
Unlike the ceramic layer used for the multilayer capacitor, it is preferable that the thickness of the ceramic layer be within a certain range as described above for use in the piezoelectric multilayer element.

In the piezoelectric laminated device of the present invention, it is preferable that the residual polarization value of the piezoelectric ceramic layer is 3.0 μC / cm ² or more. When the remanent polarization value is 3.0 μC / cm ² or more, it can be preferably used as a piezoelectric multilayer device.
The remanent polarization value can be obtained with a ferroelectric tester.

Further, as another embodiment of the piezoelectric laminated element of the present invention, the main component ceramic constituting the piezoelectric ceramic layer can be defined as follows.
In this case, the piezoelectric multilayer element of the present invention includes a piezoelectric multilayer including a plurality of piezoelectric ceramic layers, an internal electrode formed between the piezoelectric ceramic layers, and an external electrode electrically connected to the internal electrode. An element,
Oxidation in which the piezoelectric ceramic layer contains Ba, Ca, Ti, Mg, Mn and Re (Re is at least one selected from Y, Gd, Tb, Dy, Ho, Er, Yb and La). With respect to 100 parts by weight of the main component including the substance, 0.2% by weight or more and 0.8% by weight or less of SiO ₂ as an auxiliary component is contained,
In the oxide as the main component, the total content of Ba and Ca is mmol, the content of Re is α mol, the content of Mg is β mol, and the content of Mn is 1 mol with respect to 1 mol of Ti contained in the oxide. Is γ mol, the following relational expressions (1) to (5) are satisfied,
0.0010 ≦ α ≦ (−65.32m + 67.70) / 100 (1)
0.0004 ≦ β ≦ (−28.74m + 29.79) / 100 (2)
0.0002 ≦ γ ≦ (−13.06 m + 13.54) / 100
[When m ≦ 1.006]
0.0002 ≦ γ ≦ 0.004 [when m> 1.006] (3)
0.995 ≦ m ≦ 1.011 (4)
0.01 ≦ x ≦ 0.25 (5)
In addition, the piezoelectric ceramic layer has remanent polarization in a certain direction,
The internal electrode is made of nickel, a nickel alloy, copper or a copper alloy.
The structure can be the same as that of the piezoelectric laminated element of the present invention described above, except that the definition of the main component ceramic constituting the piezoelectric ceramic layer is different.

The piezoelectric laminated device of the present invention is preferably manufactured by the following method.

First, as a ceramic raw material, a raw material powder prepared by a solid phase method in which an oxide or a carbonate is reacted at a high temperature, or a raw material powder prepared by a wet synthesis method such as an alkoxide method or a hydrothermal synthesis method is prepared. In addition, as an additive, a solution of an alkoxide, an organic metal, or the like can be used in addition to a powder of an oxide or a carbonate.

Thereafter, the prepared raw materials are weighed and mixed at a predetermined composition ratio, and then an organic binder is added to form a slurry, which is then formed into a sheet to obtain a green sheet. Next, an internal electrode made of nickel, a nickel alloy, copper or a copper alloy is formed on one surface of the green sheet. The method for forming the internal electrode may be screen printing or the like, or may be deposition or plating.

Thereafter, a required number of green sheets having internal electrodes are laminated, and the green sheets having no internal electrodes are sandwiched and pressed to obtain a laminate. Then, this laminate is fired in a reducing atmosphere at a predetermined temperature (for example, 1200 ° C. or more and 1300 ° C. or less) to obtain a ceramic laminate.

Thereafter, a pair of external electrodes is formed on both end surfaces of the ceramic laminate so as to be electrically connected to the internal electrodes. In general, the external electrode is formed by applying a metal powder paste as a material to a ceramic laminate obtained by firing and baking, but is applied before firing and is formed simultaneously with the ceramic laminate. You can also. Further, an external electrode can be formed by sputtering.

Thereafter, a predetermined polarization process is performed. As described above, a piezoelectric laminated device is obtained.

Hereinafter, examples showing the piezoelectric laminated element of the present invention more specifically will be described. Note that the present invention is not limited to only these examples.

First, TiO ₂ , BaCO ₃ and CaCO ₃ were prepared as starting materials. After mixed and pulverized, the mixture was heated at a temperature of 1000 ° C. or higher to synthesize barium calcium titanate. The particle size of the raw material was observed with a scanning electron microscope, and the average particle size was 0.5 μm. In addition, SiO ₂ powder was prepared as a subcomponent.

Next, BaCO ₃ or TiO ₂ for adjusting the (Ba, Ca) / Ti molar ratio m of barium calcium titanate and Dy ₂ O ₃ , MgO and MnO having a purity of 99% or more were prepared. These raw material powders and the above-mentioned SiO ₂ powder as a subcomponent were weighed. The amount of SiO ₂ added was set to 0.4 parts by weight based on 100 parts by weight of the main component [{Ba _0.87 Ca _0.13 O} _m TiO ₂ + αDy ₂ O ₃ + βMgO + γMnO]. . This time, Dy ₂ O ₃ was used as Re ₂ O ₃ , but Y ₂ O ₃ , Gd ₂ O ₃ , Tb ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Yb ₂ O _3, and La ₂ O ₃ The same effect can be obtained by using one selected from the above.
In the samples of each sample number, the raw material powder is weighed for each composition. Table 1 shows the compositions of the samples of each sample number.
In some samples, the amount of addition of the SiO ₂ powder as a sub-component is changed.

Then, an organic solvent such as a polyvinyl butyral-based binder and ethanol was added to the weighed material, and the mixture was wet-mixed with a ball mill to prepare a ceramic slurry. This ceramic slurry was formed into a sheet by a doctor blade method to obtain a rectangular green sheet having a thickness of 30.0 μm. Next, a conductive paste mainly composed of Ni was printed on the ceramic green sheet to form a conductive paste layer for forming internal electrodes.

Thereafter, a plurality of ceramic green sheets on which the conductive paste layers were formed were stacked such that the side from which the conductive paste layers were drawn out staggered to obtain a laminate. The laminate is heated to a temperature of 300 ° C. in an air atmosphere to burn the binder, and then, from a H ₂ —N ₂ —H ₂ O gas having an oxygen partial pressure of 10 ⁻⁹ to 10 ⁻¹² MPa. It was fired at a temperature of 1200 ° C. or more and 1300 ° C. or less for 2 hours in a reducing atmosphere to obtain a ceramic sintered body.

After sintering, in order to form front and back and side electrodes on the sintered body, only the connection surface is diced, and after exposing the electrodes, a conductive film mainly composed of Ag is formed by sputtering, and The bottoms were each electrically connected to one side.

The external dimensions of the piezoelectric laminated element thus obtained are width: 3.0 mm, length: 13.0 mm, thickness: 0.3 mm, and the thickness of the piezoelectric ceramic layer interposed between the internal electrodes is 25 μm. Met. The total number of effective piezoelectric ceramic layers was 11, and the area of the counter electrode per layer was 39 × 10 ⁻⁶ m ² .

Polarization was performed with a DC voltage of 2 kV / mm in the obtained piezoelectric laminated element. In the polarization step, the polarization current value of each sample became 40 μA or more, which was regarded as polarization failure, and the occurrence rate of polarization failure (polarization failure rate (%)) for a plurality of samples was determined at n = 10. .

Next, with respect to the surface of the obtained piezoelectric laminated element, the grain diameter of the ceramic contained in the piezoelectric ceramic layer was observed with a scanning electron microscope, and determined by an intercept method. In all samples within the scope of the present invention, the grain growth progressed, and the particle diameter became 0.6 μm or more and 3.7 μm or less.

Further, the electrical characteristics of these piezoelectric laminated elements were measured. The remanent polarization Pr was obtained from a hysteresis loop at ± 2 kV / mm and a frequency of 1 kHz using a ferroelectric tester. Capacitance C, the frequency 1 kHz, measured at the voltage 0.5V, was calculated from the obtained electrostatic capacitance C relative permittivity epsilon ^T _33. Electromechanical coupling factor k ₃₁ in the length direction, using an impedance analyzer, resonant - was determined by antiresonance method. The density ρ was determined by the Archimedes method. The piezoelectric d ₃₁ constant was calculated from the previously obtained relative dielectric constant ε ^T ₃₃ , electromechanical coupling coefficient k ₃₁ , and density ρ.
These results are summarized in Table 1.

Samples 10 to 29 within the scope of the present invention had a polarization failure rate of 0%. Further, the residual polarization Pr, the dielectric constant epsilon ^T _33, the value of the electromechanical coupling coefficient _{k 31, d 31} constant has been a preferred value.
Many of the samples out of the range of the present invention had a high polarization failure rate. Samples 4 and 5 had a polarization failure rate of 0%, but could not measure the residual polarization Pr, the electromechanical coupling coefficient k ₃₁ , and the d ₃₁ constant.

1, 2 Piezoelectric multilayer element 10 Laminated body 11 First main surface 12 Second main surface 13 First end surface 14 Second end surface 20a, 20b, 20c, 20d, 20e, 20f Piezoelectric ceramic layers 21a, 21b, 22a, 22b, 22c Internal electrodes 31, 32 External electrodes

Claims (6)

A plurality of piezoelectric ceramic layers, an internal electrode formed between the piezoelectric ceramic layers, and a piezoelectric laminated element including an external electrode electrically connected to the internal electrode,
The piezoelectric ceramic layer is represented by the following composition formula,
{Ba _1-x Ca _x O} _m TiO ₂ + αRe ₂ O ₃ + βMgO + γMnO
[However, _Re 2 _{O 3 is} in the _{Y 2 O 3, Gd 2 O} 3, Tb 2 O 3, Dy 2 O 3, Ho 2 O 3, Er 2 O 3, Yb 2 O 3 and _La 2 _{O 3} And α, β, and γ represent molar ratios and satisfy the following relational expressions (1) to (5).
0.0010 ≦ α ≦ (−65.32m + 67.70) / 100 (1)
0.0004 ≦ β ≦ (−28.74m + 29.79) / 100 (2)
0.0002 ≦ γ ≦ (−13.06 m + 13.54) / 100
[When m ≦ 1.006]
0.0002 ≦ γ ≦ 0.004 [when m> 1.006] (3)
0.995 ≦ m ≦ 1.011 (4)
0.01 ≦ x ≦ 0.25 (5)]
In addition, based on 100 parts by weight of the main component in the {Ba _1-x Ca _x O} TiO ₂ raw material used for the piezoelectric ceramic layer, 0.2 parts by weight or more of 0.8 parts by weight of SiO ₂ as a subcomponent is used. Parts or less
The piezoelectric ceramic layer has remanent polarization in a certain direction,
The internal electrode is made of nickel, a nickel alloy, copper, or a copper alloy. The piezoelectric multilayer device according to claim 1, wherein the average grain diameter of the ceramic contained in the piezoelectric ceramic layer is 0.6 µm or more and 3.7 µm or less. The piezoelectric multilayer device according to claim 1, wherein an average thickness of each of the piezoelectric ceramic layers is 5 μm or more and 60 μm or less. The piezoelectric multilayer device according to claim 1, wherein the internal electrode is made of nickel or a nickel alloy. 5. The piezoelectric multilayer device according to claim 1, wherein a residual polarization value of the piezoelectric ceramic layer is 3.0 μC / cm ² or more. A plurality of piezoelectric ceramic layers, an internal electrode formed between the piezoelectric ceramic layers, and a piezoelectric laminated element including an external electrode electrically connected to the internal electrode,
Oxidation in which the piezoelectric ceramic layer contains Ba, Ca, Ti, Mg, Mn and Re (Re is at least one selected from Y, Gd, Tb, Dy, Ho, Er, Yb and La). With respect to 100 parts by weight of the main component including the substance, 0.2% by weight or more and 0.8% by weight or less of SiO ₂ as an auxiliary component is contained,
The oxide as the main component is such that the total content of Ba and Ca is mmol, the content of Re is α mol, the content of Mg is β mol, and the content of Mn is 1 mol of Ti contained in the oxide. Is γ mol, the following relational expressions (1) to (5) are satisfied,
0.0010 ≦ α ≦ (−65.32m + 67.70) / 100 (1)
0.0004 ≦ β ≦ (−28.74m + 29.79) / 100 (2)
0.0002 ≦ γ ≦ (−13.06 m + 13.54) / 100
[When m ≦ 1.006]
0.0002 ≦ γ ≦ 0.004 [when m> 1.006] (3)
0.995 ≦ m ≦ 1.011 (4)
0.01 ≦ x ≦ 0.25 (5)
And the piezoelectric ceramic layer has a remanent polarization in a certain direction,
The internal electrode is made of nickel, a nickel alloy, copper, or a copper alloy.

Images