JPH07277822A - Piezoelectric element material and its production - Google Patents

Abstract

PURPOSE:To enable sintering even at a low temp. by using Pb-contg. ceramics having a specified average grain size and a specified grain size distribution and to obtain a piezoelectric element material having improved piezoelectric characteristics of piezoelectric ceramics by controlling the fine structure of the Pb-contg. ceramics. CONSTITUTION:This piezoelectric element material contains Pb-contg. ceramics having 0.5-5mum average grain size and a grain size distribution in which >=90wt.% grains are within the range of 0.5-5mum. The basic compsn. of this material is preferably represented by the general formula Pb1-xSrx(Mg1/3 Nb2/3)aTibZrcO3 (where a+b+c=1, 0.20<=a<=0.30, 0.30<=b<=0.45, 0.30<=c<=0.40 and 0.01<=x<=0.20) and 0.01-0.2wt.% Fe2O3 is preferably added to the basic compsn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to positioning of precision machinery,
The present invention relates to a piezoelectric element material such as a piezoelectric actuator for video auto tracking, a piezoelectric element such as a ceramic filter and a ceramic oscillator, a pyroelectric element such as an infrared sensor and a linear array sensor, and an electrostrictive ceramic. .

[0002]

2. Description of the Related Art Ferroelectric ceramics or piezoelectric ceramics have been conventionally used as Pb (Ti, Zr) O ₃ binary system, Pb (Mg _1/3 Nb _2/3 ) _x Ti _y ) ZrO ₃ ternary system, Pb (Zn _1/3 Nb _2/3 ) _A (Sn _1/3 Nb
_2/3 ) _B TiCZrD ₃ There is a ceramic material composed of a quaternary composition. Almost all of the constituents of these conventional ceramic materials are ceramics, and they are produced by molding a raw material or calcined powder into a predetermined shape and then firing it at a high temperature. With these conventional piezoelectric ceramics, piezoelectric ceramics with various characteristics can be produced by selecting the composition ratio of the components, and used for actuators, ceramic filters, piezoelectric buzzers, piezoelectric ignition plugs, ultrasonic transducers, etc. ing.

[0003]

In the conventional piezoelectric ceramics, the evaporation of PbO and the formation of the secondary phase are unavoidable in the production thereof, and the ceramics exhibiting the characteristics of the material system have not been sufficiently obtained. In particular, when an element that impairs sinterability, such as an alkaline earth element such as Sr, is included, a sufficiently dense sintered body cannot be obtained, and it is difficult to fully exhibit the characteristics of the material. . Therefore, it is necessary to improve the sinterability and control the fine structure in order to obtain ceramics having excellent characteristics.

In order to solve the above-mentioned conventional problems, it is an object of the present invention to provide a piezoelectric element material which can be sintered even at a low temperature and whose fine structure is controlled to improve the piezoelectric characteristics of piezoelectric ceramics, and a manufacturing method thereof. And

[0005]

In order to achieve the above object, in the piezoelectric element material of the present invention, the average crystal grain size of the ceramic is 0.5 to 5 μm, and the average grain size of the particles is 90% by weight. The Pb-based ceramics distributed in the range of 0.5 to 5 μm are included.

In the above structure, the average crystal grain size is 1 to
It is preferable that the Pb-based ceramics has a diameter of 3 μm and the particles having the average crystal grain size are distributed in the range of 75% by weight or more and 1 to 3 μm.

[0007] In the above configuration, the piezoelectric element material composition formula _{Pb 1-x Sr x (Mg} 1/3 Nb 2/3) A Ti
_B Zr _C O ₃ (where A + B + C = 1) 0.20 ≦ A ≦ 0.30 0.30 ≦ B ≦ 0.45 0.30 ≦ C ≦ 0.40 0.01 ≦ x ≦ 0. It is preferable that the main component is a basic composition satisfying 20.

In the above construction, it is preferable that Fe ₂ O ₃ be present in the range of 0.01 to 0.2% by weight. Further, in the above structure, the composition is represented by the general formula Pb (Ni
_1/3 Nb _2/3 ) _A Ti _B Zr _C O ₃ (where A
+ B + C = 1) It is preferable that the main component is a basic composition satisfying 0.40 ≦ A ≦ 0.55 0.15 ≦ B ≦ 0.30 0.10 ≦ C ≦ 0.30.

In the above structure, Fe₂O₃To
It is preferable to exist in the range of 0.01 to 0.5% by weight.
Yes. In the above structure, the composition is represented by the general formula Pb_1-xS
r_x(Ni_1/3Nb_2/3) _ATi_BZr_CO₃Indicated by
(However, A + B + C = 1) 0.35 ≦ A ≦ 0.55 0.15 ≦ B ≦ 0.40 0.15 ≦ C ≦ 0.40 0.01 ≦ x ≦ 0.10 It is preferable to use it as a main component.

In the above structure, Fe₂O₃To
It is preferable to exist in the range of 0.01 to 0.5% by weight.
Yes. In the above structure, the general formula Pb (Ni_1/3T
a_2/3)_BTi_CZr_DO ₃It is indicated by ((A + B +
C = 1) For a piezoelectric element material whose main component is a basic composition satisfying 0.25 ≦ A ≦ 0.45 0.20 ≦ B ≦ 0.35 0.20 ≦ C ≦ 0.40
A part of Pb as an alkaline earth metal and a rare earth element
At least one metal selected from among 0.01 to
Replaced by 0.2 mol% and Fe as an accessory component₂O₃To
It is preferable that 0.01 to 0.5% by weight be present.

Further, in the above constitution, the composition is represented by the general formula P
b_1-xSr_x(Mg_1/3Nb_2/3) _A(Ni_1/3Nb
_2/3)_BTi_CZr_DO₃Or Pb_1-xSr_x(M
g_1/3Nb_2/3)_A(Ni_1/3Ta_2/3)_BTi_CZr
_DO₃Or Pb (Ni_1/3Nb_2/3)_A(Ni_1/3T
a_2/3)_BTi_CZr_DO₃It is indicated by ((A + B +
C + D = 1) 0.05 ≦ A ≦ 0.55 0.05 ≦ B ≦ 0.55 0.15 ≦ C ≦ 0.30 0.15 ≦ D ≦ 0.30 0.01 ≦ x ≦ 0.20 For piezoelectric element materials whose main component is a satisfying basic composition
As an accessory component, a small amount selected from oxides of rare earth elements.
0.01 to 0.5% by weight at least, and Fe₂O
₃Is preferably added in an amount of 0.05 to 0.5% by weight.
Good

Next, the method of manufacturing the piezoelectric element material of the present invention is as follows.
Pre-sintering raw material powder is a fine powder having an average particle size of 0.4 μm or less and a particle size distribution of the powder containing 7% by weight or more of particles having a size twice or more the average particle size. Used as a body, the raw material powder before sintering is sintered so that the average crystal grain size of the ceramic is 0.5 to 5 μm, and the average grain size is 9 or more.
The piezoelectric element material contains Pb-based ceramics distributed in the range of 0% by weight or more and 0.5 to 5 μm.

In the above structure, the volume of the powder medium liquid is 4 times or less of the true volume of the powder, the dispersant is added and the powder is crushed, and the fine boulders of 0.6 mm or less are used. It is preferable.

[0014]

According to the structure of the piezoelectric element material of the present invention, the average crystal grain size of the ceramic is 0.5 to 5 μm, and the particles of the average grain size are 90% by weight or more and 0.5 to 5 μm.
By including Pb-based ceramics distributed between
It is possible to obtain a piezoelectric ceramic in which the piezoelectric characteristics of the piezoelectric ceramic, for example, the absolute value of the piezoelectric constant d ₃₁ is large, and other piezoelectric constants d ₃₃ and d ₁₅ are also large.

In the above, the average crystal grain size is 1 to 3 μm.
According to a preferred configuration in which the particles having the average crystal grain size include Pb-based ceramics distributed in the range of 75% by weight or more and 1 to 3 μm, the ceramics having dense pores existing in the grain boundary portion In the case of, the number becomes sufficiently small depending on the crystal grain size, or the number thereof decreases significantly, and the characteristics of the material can be sufficiently exhibited.

In the above, the piezoelectric element material composition is
General formula Pb_1-xSr_x(Mg_1/3Nb _2/3)_ATi_BZr
_CO₃(Where A + B + C = 1) 0.20 ≦ A ≦ 0.30 0.30 ≦ B ≦ 0.45 0.30 ≦ C ≦ 0.40 0.01 ≦ x ≦ 0.20 A preferred composition in which the composition is the main component
According to Morpho Topic Phase Boundary
The composition is similar, and the relative permittivity ε_r, And electromechanical coupling coefficient
k_pAnd k₃₁Is large, and the piezoelectric constant d₃₁Large absolute value of
The material can be obtained.

In the above, 0.01% Fe ₂ O ₃ is added.
According to the preferable constitution that it exists in the range of up to 0.2% by weight, it is possible to obtain a dense ceramic having a finer crystal grain size and a material having a large absolute value of the piezoelectric constant as the firing temperature decreases. You can

In the above structure, the composition is represented by the general formula Pb
(Ni_1/3Nb_2/3)_ATi_BZr _CO₃Indicated by
(However, A + B + C = 1) 0.40≤A≤0.55 0.15≤B≤0.30 0.10≤C≤0.30
According to Morpho Topic Phase Boundary
The composition is similar, and the relative permittivity ε_r, And electromechanical coupling coefficient
k_pAnd k₃₁Is large, and the piezoelectric constant d₃₁Large absolute value of
The material can be obtained.

Further, in the above, 0.01% Fe ₂ O ₃ is added.
According to the preferable constitution that it exists in the range of 0.5 wt%, it is possible to obtain a fine ceramic having a finer crystal grain size and a dense ceramic, and to obtain a material having a large absolute value of the piezoelectric constant. You can

In the above structure, the composition is represented by the general formula Pb
_1-x Sr _x (Ni _1/3 Nb _2/3 ) _A Ti _B Zr _C O ₃ (where A + B + C = 1) 0.35 ≦ A ≦ 0.55 0.15 ≦ B ≦ 0.40 According to a preferable structure in which the main component is a basic composition satisfying 0.15 ≦ C ≦ 0.40 0.01 ≦ x ≦ 0.10, the Curie point is lowered and the value of relative dielectric constant is increased, and The composition is close to the morphotopic phase boundary, and a material having a large absolute value of the piezoelectric constant d ₃₁ can be obtained.

In the above, 0.01% Fe ₂ O ₃ is added.
According to the preferable constitution that it exists in the range of 0.5 wt%, it is possible to obtain a fine ceramic having a finer crystal grain size and a dense ceramic, and to obtain a material having a large absolute value of the piezoelectric constant. You can

In the above, the general formula Pb (Ni_1/3
Ta_2/3)_BTi_CZr_DO₃It is indicated by ((A + B
+ C = 1) For a piezoelectric element material whose main component is a basic composition satisfying 0.25 ≦ A ≦ 0.45 0.20 ≦ B ≦ 0.35 0.20 ≦ C ≦ 0.40
A part of Pb as an alkaline earth metal and a rare earth element
At least one metal selected from among 0.01 to
Replaced by 0.2 mol% and Fe as an accessory component₂O₃To
Preferred composition of 0.01 to 0.5% by weight
According to Morphotopic Phase Boundary
And the relative permittivity ε_r, And the electromechanical coupling coefficient k
_pAnd k ₃₁Is large, and the piezoelectric constant d₃₁Material with a large absolute value of
You can get a fee.

In the above, the composition is represented by the general formula Pb _1-x
Sr _x (Mg _1/3 Nb _2/3 ) _A (Ni _1/3 Nb _2/3 ) _B
Ti _C Zr _D O ₃ or Pb _1-x Sr _x (Mg _1/3 N
_{b 2/3) A (Ni} 1/3 Ta 2/3) B Ti C Zr D O 3 or _{Pb (Ni 1/3 Nb 2/3) A} (Ni 1/3 Ta 2/3)
_B Ti _C Zr _D O ₃ (where A + B + C + D =
1) 0.05 ≦ A ≦ 0.55 0.05 ≦ B ≦ 0.55 0.15 ≦ C ≦ 0.30 0.15 ≦ D ≦ 0.30 0.01 ≦ x ≦ 0.20 0.01 to 0.5% by weight of at least one selected from oxides of rare earth elements and Fe ₂ O as auxiliary components to the piezoelectric element material containing the basic composition as a main component.
According to the preferable composition in which 0.05 to 0.5 wt% of ₃ is added, a material having a large absolute value of the piezoelectric constant d ₃₁ can be obtained as in the above.

Next, according to the structure of the method for producing a piezoelectric element material of the present invention, the average particle size of the powder is 0.4 μm or less, and the particle size distribution of the powder is at least twice the average particle size. A fine powder containing 7% by weight or more of particles having a size is used as a raw material powder before sintering, and the raw material powder before sintering is sintered to have an average crystal grain size of 0.5 to 5 μm. The piezoelectric element material of the present invention can be efficiently and rationally produced by obtaining a piezoelectric element material containing Pb-based ceramics in which particles having an average particle size are distributed between 90% by weight and 0.5 to 5 μm. it can.

In the above, the volume of the powder medium liquid is 4 times or less of the true volume of the powder, and the dispersant is added to the powder, and the powder is pulverized.
Moreover, according to the preferable configuration in which the fine boulders of 0.6 mm or less are used, since the medium liquid has a high concentration and a good fluidity, it has excellent homogeneity and uses the fine boulders. In addition, the contact surface area is increased, and it is possible to finely pulverize to a particle size that is difficult with a normal pulverization time. Further, it is preferable that the average crystal grain size of the piezoelectric ceramic is 1 to 5 μm or less and that the piezoelectric ceramic has a uniform structure. The density is 97
% Or more, and it is preferable to have a structure containing few pores.

[0026]

EXAMPLES The present invention will be described more specifically with reference to the following examples.
explain. The piezoelectric ceramics used in the present invention include:
Pb as an example_1-xSr_x(Mg _1/3Nb_2/3)_ATi
_BZr_CO₃Alternatively, Pb (Ni_1/3Nb_2/3)_ATi
-B Zr_CO₃Alternatively, Pb (Ni_1/3Ta_2/3)_ATi
_BZr_CO₃(However, A + B + C = 1), or
Pb_1-xSr_{x (}Mg_1/3Nb_2/3)_A(Ni_1/3Nb
_2/3)_BTi_CZr_DO₃Or Pb_1-xSr_x(M
g_1/3Nb_2/3)_A(Ni_1/3Ta_2/3)_BTi_CZr
_DO₃Or Pb (Ni_1/3Nb_2/3)_A(Ni_1/3T
a_2/3)_BTi_CZr_DO₃(However, A + B + C + D =
As shown in 1), the sinterability of these material systems is improved, and even at low temperatures.
Piezoelectric ceramics that can be sintered and whose microstructure is controlled
To create a box and establish a manufacturing method
For the purpose of Ming. At that time, as a manufacturing method,
Although methods such as fine pulverization are taken,
In this regard, it is necessary to mix an organic solvent as a dispersant and
Rea is used, but increase the hydrogen ion concentration of the slurry.
When using raw material powder that changes
To prevent gelation of the slurry by adjusting the hydrogen ion concentration of
That is also important.

As an example of the present invention, the piezoelectric ceramic powder has a composition of Pb _0.9 Sr _0.1 (Mg _1/3 N
b _2/3 ) _0.255 Ti _0.38 Zr _0.365 , and Pb (Ni
_1/3 Nb _2/3 ) _0.45 Ti _0.35 Zr _0.2 O _{3 and} other raw material powders are added to a zirconia cobblestone having a diameter of 0.6 mm with an organic dispersant and water using a medium stirring mill to obtain an average particle size of about 0. After pulverizing to 0.2 μm, it was dried and granulated. A disk-shaped molded body having a diameter of 13 mm and a thickness of about 1 mm was produced from this powder using a mold, and fired at a temperature lower than the usual firing temperature for 2 hours to produce a piezoelectric ceramic with controlled microstructure. To do.

In the following examples, ε: permittivity, ε ₀ : permittivity in vacuum, k _p : electromechanical coupling coefficient of radial vibration, d ₃₁ : piezoelectric constant in the direction perpendicular to the polarization axis. Shown respectively.

(Example 1) PbO and Sr as raw material powders
CO₃, MgO, Nb₂O_Five, TiO₂, ZrO ₂For
The composition was as shown in Table 1. Predetermined composition
Slurry by adding pure water and dispersant to the mixed powder blended in
And mixed and pulverized using a medium stirring mill. Mixed powder
While measuring the average particle size after crushing with a laser type particle size measuring device,
Each composition was 0.2 μm or less. The resulting mixture
The flour was calcined for 2 hours. Further, using a media stirring mill,
Organic dispersant along with zirconia cobblestone with a diameter of 0.6 mm
And water, and crushed to an average particle size of 0.4 μm or less.
It was For comparison examples, the average particle size was
I also crushed it. This is dried to obtain raw powder before sintering
It was Mix this powder with an organic binder, 500 μm
The powder was passed through a No. 4 sieve to be sized. This powder, using a mold
A disk-shaped molded body with a diameter of 13 mm and a thickness of about 1 mm was prepared.
This is baked in an electric furnace for 2 hours to produce piezoelectric ceramics.
It was The temperature rising / falling rate is 300 ° C./h. Then each
A vapor deposition electrode of Cr-Au was applied to both sides of the sample, and then 120
DC electric field of 3kV / mm between both electrodes in silicon oil at ℃
Was applied for 30 minutes for polarization treatment to obtain a piezoelectric element. this
The piezoelectric characteristics of the sample were measured, and from the SEM photograph
Observe the fine structure and intercept the grain size distribution
I found it by law. The measurement results are shown in (Table 1).

[0030]

[Table 1]

As is clear from (Table 1), the piezoelectric ceramics of the present invention are improved in any of the piezoelectric characteristics of No. 12 to No. 14 having the same composition. In this embodiment, by using fine powder having an average particle diameter of 0.4 μm or less, firing can be performed at a low temperature of 1200 ° C., and the characteristics of the piezoelectric ceramic are greatly improved by controlling the fine structure. In No. 12 with an average powder particle size of 0.22 μm and No. 13 with an average powder particle size of 0.63 μm, the ratio of powders having a size twice or more the average particle size is 3 wt% and 6 wt% or more, respectively. 14 and No. 15 were 8 wt% and 13 wt% respectively. That is, No. 14 and No. 15, which are comparative examples, were prepared from fine powders having a particle size distribution of powders having a size of at least twice the average particle size of 7 wt% or more. Since it was not controlled and was not pulverized at the same time, the crystal grain size was 5.1 μm, the firing temperature was high, and the characteristics were not good.

(Example 2) PbO and Sr as raw material powders
CO₃, MgO, Nb₂O_Five, TiO₂, ZrO ₂, F
e₂O₃And the composition is as shown in Table 2.
It was Pure water and a dispersant are added to the mixed powder that has been blended to the specified composition.
In addition, it is made into a slurry and mixed and pulverized using a media stirring mill.
went. The average particle size after mixing and crushing is the laser particle size measuring device.
Make sure that each composition is 0.2 μm or less.
It was The resulting mixed powder was calcined for 2 hours. Medium stirring
Using a mill, coexist with zirconia boulders with a diameter of 0.6 mm
To the above, an organic dispersant and water are added, and the average particle size is about 0.4.
It was pulverized to a size of less than μm. Raw material powder before drying and sintering
Got Mix this powder with an organic binder, 500
The particles were sized by passing through a μm sieve. Use this powder in a mold
A disk-shaped molded body with a diameter of 13 mm and a thickness of approximately 1 mm
Then, this is fired in an electric furnace for 2 hours to obtain the piezoelectric ceramics.
It was made. The temperature rising / falling rate is 300 ° C./h. Next
In addition, Cr-Au vapor deposition electrodes were applied to both sides of each sample,
After that, in silicon oil at 120 ° C, apply 3kV / mm between both electrodes.
Apply a DC electric field for 30 minutes to perform polarization to obtain a piezoelectric element.
It was The piezoelectric characteristics of this sample were measured, and the SEM
The microstructure is observed from the photograph and the grain size distribution is examined.
-Sept method was used. The measurement results are shown in (Table 2).
You

[0033]

[Table 2]

As is clear from (Table 2),
The piezoelectric ceramics of No. 2 to No. 9 show improved piezoelectric characteristics compared to No. 1 of single composition. In this embodiment, fine powder having an adjusted average particle diameter of 0.4 μm or less is used, and Fe2 O3 is further added to obtain 120
The properties of the piezoelectric ceramics are greatly improved by being able to fire at a low temperature of 0 ° C. and controlling the fine structure.

(Example 3) PbO and Sr as raw material powders
CO₃, MgO, Nb₂O_Five, TiO₂, ZrO ₂For
The composition was as shown in Table 3. Predetermined composition
Slurry by adding pure water and dispersant to the mixed powder blended in
And mixed and pulverized using a medium stirring mill. Mixed powder
While measuring the average particle size after crushing with a laser type particle size measuring device,
Each composition was 0.2 μm or less. The resulting mixture
The flour was calcined for 2 hours. Further, using a media stirring mill,
Organic dispersant along with zirconia cobblestone with a diameter of 0.6 mm
And water, and crushed to an average particle size of 0.4 μm or less.
It was For comparison examples, the average particle size was
I also crushed it. This is dried to obtain raw powder before sintering
It was Mix this powder with an organic binder, 500 μm
The powder was passed through a No. 4 sieve to be sized. This powder, using a mold
A disk-shaped molded body with a diameter of 13 mm and a thickness of about 1 mm was prepared.
This is baked in an electric furnace for 2 hours to produce piezoelectric ceramics.
It was The temperature rising / falling rate is 300 ° C./h. Then each
A vapor deposition electrode of Cr-Au was applied to both sides of the sample, and then 120
DC electric field of 3kV / mm between both electrodes in silicon oil at ℃
Was applied for 30 minutes for polarization treatment to obtain a piezoelectric element. this
The piezoelectric characteristics of the sample were measured, and from the SEM photograph
Observe the fine structure and intercept the grain size distribution
I found it by law. The measurement results are shown in (Table 3).

[0036]

[Table 3]

As is clear from (Table 3), the piezoelectric ceramics of this example had No. 1 to No. 5 and No. 7 having the same composition.
-No. 9 and No. 19 and 20 show improvement in piezoelectric characteristics. In this example, by using a fine powder having an adjusted average particle diameter of 0.4 μm or less, which can be fired at a low temperature of 1200 ° C., the characteristics of the piezoelectric ceramic are increased by controlling the fine structure. Has improved. None of the comparative examples whose fine structure could not be controlled were not finely pulverized, the crystal grain size was 5 μm or more, the firing temperature was high, and the characteristics were not good.

(Example 4) PbO and Sr as raw material powders
CO₃, MgO, Nb₂O_Five, TiO₂, ZrO ₂For
The composition was as shown in Table 4. Predetermined composition
Slurry by adding pure water and dispersant to the mixed powder blended in
And mixed and pulverized using a medium stirring mill. Mixed powder
While measuring the average particle size after crushing with a laser type particle size measuring device,
Each composition was 0.2 μm or less. The resulting mixture
The flour was calcined for 2 hours. Further, using a media stirring mill,
Organic dispersant along with zirconia cobblestone with a diameter of 0.6 mm
And water, and crushed to an average particle size of 0.4 μm or less.
It was For comparison examples, the average particle size was
I also crushed it. This is dried to obtain raw powder before sintering
It was Mix this powder with an organic binder, 500 μm
The powder was passed through a No. 4 sieve to be sized. This powder, using a mold
A disk-shaped molded body with a diameter of 13 mm and a thickness of about 1 mm was prepared.
This is baked in an electric furnace for 2 hours to produce piezoelectric ceramics.
It was The temperature rising / falling rate is 300 ° C./h. Then each
A vapor deposition electrode of Cr-Au was applied to both sides of the sample, and then 120
DC electric field of 3kV / mm between both electrodes in silicon oil at ℃
Was applied for 30 minutes for polarization treatment to obtain a piezoelectric element. this
The piezoelectric characteristics of the sample were measured, and from the SEM photograph
Observe the fine structure and intercept the grain size distribution
I found it by law. The measurement results are shown in (Table 4).

[0039]

[Table 4]

As is clear from (Table 4),
The piezoelectric ceramics of No.10 to No.20 show improved piezoelectric characteristics as compared with the piezoelectric ceramics of No.1 to No.10 having the same composition. In this example, by using a fine powder having an average particle size of 0.4 μm or less with an adjusted particle size distribution, it is possible to perform firing at a low temperature, and by controlling the fine structure, the characteristics of the piezoelectric ceramic are greatly improved. There is.

(Embodiment 5) PbO and Sr as raw material powders
CO₃, MgO, Nb₂O_Five, TiO₂, ZrO ₂For
The composition was as shown in Table 5. Predetermined composition
Slurry by adding pure water and dispersant to the mixed powder blended in
And mixed and pulverized using a medium stirring mill. Mixed powder
While measuring the average particle size after crushing with a laser type particle size measuring device,
Each composition was 0.2 μm or less. The resulting mixture
The flour was calcined for 2 hours. Further, using a media stirring mill,
Organic dispersant along with zirconia cobblestone with a diameter of 0.6 mm
And water, and crushed to an average particle size of 0.4 μm or less.
It was For comparison examples, the average particle size was
I also crushed it. This is dried to obtain raw powder before sintering
It was Mix this powder with an organic binder, 500 μm
The powder was passed through a No. 4 sieve to be sized. This powder, using a mold
A disk-shaped molded body with a diameter of 13 mm and a thickness of about 1 mm was prepared.
This is baked in an electric furnace for 2 hours to produce piezoelectric ceramics.
It was The temperature rising / falling rate is 300 ° C./h. Then each
A vapor deposition electrode of Cr-Au was applied to both sides of the sample, and then 120
DC electric field of 3kV / mm between both electrodes in silicon oil at ℃
Was applied for 30 minutes for polarization treatment to obtain a piezoelectric element. this
The piezoelectric characteristics of the sample were measured, and from the SEM photograph
Observe the fine structure and intercept the grain size distribution
I found it by law. The measurement results are shown in (Table 5).

[0042]

[Table 5]

From Table 5, in this example, it is possible to perform firing at a low temperature by controlling the fine structure by using a fine powder having an average particle size of 0.4 μm or less whose particle size distribution is adjusted. The characteristics are greatly improved from those of.

[0044]

As described above, in the piezoelectric ceramics of the present invention, the piezoelectric characteristics of the piezoelectric ceramics can be improved by controlling the fine structure by lowering the firing temperature by fine pulverization by a medium stirring mill.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H01L 41/22 A

Claims (12)

[Claims] 1. The average crystal grain size of ceramics is 0.5 to
A piezoelectric element material containing Pb-based ceramics having a particle size of 5 μm and having an average particle size of 90% by weight or more and distributed in a range of 0.5 to 5 μm. 2. The piezoelectric element according to claim 1, wherein the average crystal grain size is 1 to 3 μm, and the particles having the average crystal grain size include Pb-based ceramics distributed between 75% by weight and 1 to 3 μm. material. 3. The piezoelectric element material composition is represented by the general formula Pb _1-x Sr.
indicated by _{x (Mg 1/3 Nb 2/3) A} Ti B Zr C O 3,
(However, A + B + C = 1) 0.20 ≦ A ≦ 0.30 0.30 ≦ B ≦ 0.45 0.30 ≦ C ≦ 0.40 0.01 ≦ x ≦ 0.20 as a main component The piezoelectric element material according to claim 1 or 2. 4. The piezoelectric element material according to claim ₃ , wherein Fe ₂ O ₃ is present in the range of 0.01 to 0.2% by weight. 5. The composition has the general formula Pb (Ni _1/3 Nb _2/3 ).
_A basic composition represented by _A Ti _B Zr _C O ₃ (where A + B + C = 1) 0.40 ≦ A ≦ 0.55 0.15 ≦ B ≦ 0.30 0.10 ≦ C ≦ 0.30 The piezoelectric element material according to claim 1, which comprises a main component. 6. The piezoelectric element material according to claim 5, wherein Fe ₂ O ₃ is present in the range of 0.01 to 0.5% by weight. 7. The composition has the general formula Pb _1-x Sr _x (Ni _1/3
Nb _2/3 ) _A Ti _B Zr _C O ₃ (provided that A + B
+ C = 1) 0.35 ≦ A ≦ 0.55 0.15 ≦ B ≦ 0.40 0.15 ≦ C ≦ 0.40 0.01 ≦ x ≦ 0.10 as a main component The piezoelectric element material according to claim 1. 8. The piezoelectric element material according to claim 5, wherein Fe ₂ O ₃ is present in the range of 0.01 to 0.5% by weight. 9. The general formula Pb (Ni _1/3 Ta _2/3 ) _B Ti
_C Zr _D O ₃ (where A + B + C = 1) 0.25 ≦ A ≦ 0.45 0.20 ≦ B ≦ 0.35 0.20 ≦ C ≦ 0.40 In the piezoelectric element material described above, a part of Pb is made of at least one metal selected from alkaline earth metals and rare earth elements in an amount of 0.01 to
The piezoelectric element material according to claim 1 or 2, which is substituted by 0.2 mol% and 0.01 to 0.5% by weight of Fe ₂ O ₃ is present as an accessory component. 10. The composition has the general formula Pb._1-xSr_x(Mg
_1/3Nb_2/3)_A(Ni _1/3Nb_2/3)_BTi_CZr_D
O₃Or Pb_1-xSr_x(Mg_1/3Nb_2/3)
_A(Ni_1/3Ta_2/3)_BTi_CZr_DO₃Or Pb
(Ni_1/3Nb_2/3) _A(Ni_1/3Ta_2/3)_BTi_C
Zr_DO₃(Where A + B + C + D = 1) 0.05 ≦ A ≦ 0.55 0.05 ≦ B ≦ 0.55 0.15 ≦ C ≦ 0.30 0.15 ≦ D ≦ 0.30 0.01 ≦ For a piezoelectric element material whose main component is a basic composition satisfying x ≦ 0.20
As an accessory component, a small amount selected from oxides of rare earth elements.
0.01 to 0.5% by weight at least, and Fe₂O
₃1. Addition of 0.05 to 0.5% by weight of
Alternatively, the piezoelectric element material described in 2. 11. A fine powder having an average particle size of 0.4 μm or less and a particle size distribution of the powder containing 7% by weight or more of particles having a size twice or more the average particle size. Used as raw material powder before sintering, the raw material powder before sintering is sintered to have an average crystal grain size of ceramics of 0.5 to 5 μm, and particles having the average grain size of 90% by weight or more and 0.5 to 5 μm. A method of manufacturing a piezoelectric element material, comprising: obtaining a piezoelectric element material containing Pb-based ceramics distributed between the layers. 12. The volume of the powder medium liquid is 4 times the true volume of the powder.
Less than twice the amount and crushed by adding a dispersant, and 0.6
The method for manufacturing a piezoelectric element material according to claim 11, wherein fine boulders having a size of not more than mm are used.