JPH01100052A - Dielectric porcelain composition and piezoelectric element using said composition - Google Patents

Abstract

PURPOSE:To contrive to improve energy conversion efficiency and to prevent occurrence of spurious emission in the case of use as an oscillator, by blending a ferroelectric porcelain composition containing lead oxide as a main component with a specific amount of a PbO.GeO2 glass compound having a specific composition as a subsidiary component. CONSTITUTION:The ferroelectric porcelain component comprises a ferroelectric porcelain composition containing lead oxide as a main component and 0.01-30wt.% glass compound having a general formula shown by xPbO.yGeO2 (x=1-6, y=1-3) as a subsidiary component. One or more of lead titanate- based, lead titanate zirconate-based, lead metaniobate-based and lead-containing complex perovskite-based porcelain compositions may be cited as the main components.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a ferroelectric ceramic composition, particularly a ferroelectric ceramic composition that has a large electromechanical coupling coefficient and can be sintered at a low temperature, and a piezoelectric ceramic composition using the same. Regarding elements.

(Prior art) In general, porcelain piezoelectric materials have excellent workability, mass production, and characteristics, and are therefore applied to piezoelectric elements such as filters, piezoelectric buzzers, and bimorphs. Acid-lead-based ferroelectric porcelain and lead-zirconate titanate-based ferroelectric porcelain are in practical use.

However, since these ferroelectric ceramics contain volatile Pb as a component, part of the PbO is likely to be lost from the composition during ζ firing, making it difficult to achieve reproducibility and uniformity of characteristics. Moreover, since the sintering temperature is as high as 1100°C or higher, it is not possible to obtain a composite body that is integrated with a substrate such as a metal plate, and the electromechanical coupling coefficient is large, so the filter bandwidth is not wide, making it difficult to use There was a problem of lack of stability.

For this reason, in Japanese Patent Application Laid-Open No. 58-204579, piezoelectric ceramics are made of silicate glass compounds, soda glass compounds,
Alternatively, a compound-containing piezoelectric ceramic has been proposed in which the filter bandwidth is narrowed and the stability is improved by adding 1 to 30 wt % of a lead glass compound.

(Problems to be Solved by the Invention) However, the glass compound-containing piezoelectric ceramic has a problem in that the electromechanical coupling coefficient decreases significantly due to the addition of the glass compound, resulting in a decrease in energy conversion efficiency. Furthermore, when a conventional ferroelectric ceramic composition is applied to a ceramic resonator in a spread vibration mode, there is an interlayer in which abnormal oscillations due to spurious vibrations, which are thickness longitudinal vibrations, occur.

(Means for Solving the Problems) The present invention, as a means for solving the above problems, uses a lead oxide-containing ferroelectric ceramic composition as a main component, and has a general formula: xPbO・yGeO2 (x= 1~6゜y=t~3
) The present invention provides a ferroelectric ceramic composition containing 0.01 to 30% by weight of a glass compound represented by the following formula.

Ferroelectric ceramic compositions containing lead oxide as a main component include lead titanate-based ferroelectric ceramic compositions, lead zirconate titanate-based ferroelectric ceramic compositions, and lead metaniobate-based ferroelectric ceramic compositions. Typical examples include, but are not limited to, lead-containing composite perovskite ceramic compositions.

The lead titanate-based ferroelectric ceramic composition refers to both intrinsic and modified lead titanate, and the modified lead titanate includes simple oxides of Cr1. Os, Nb*Os, Taxes, B i
t Added transition element oxides such as Os, MnO, etc.; pb sites replaced with alkaline earth metals such as Mg, Ca, Sr, Ba, etc., and rare earths such as La*Os, Nd, O, YtO3, etc. and two-component, three-component and other multi-component ceramic compositions in which a part of PbTiOs is replaced with at least one kind of composite perovskite compound represented by general formulas (1) to (VI) described below, or combinations thereof. Includes a combination.

In addition, the lead zirconate titanate-based ferroelectric ceramic composition means genuine and modified lead zirconate titanate, and the modified lead zirconate titanate includes Pb(Ti, Zr)Os, CrtOs, Nb, 05, Ta5ks, Bi.

01, those added with metal oxides such as M n Ot, P
Those in which the b site is substituted with alkaline earth metals such as Mg, CB, Sr, Ba, etc. or rare earths such as I, atos, NdtOs, Y, 03, etc., and a part of Pb(Ti, Zr)Os are replaced by the following formula ( Included are three-component, four-component and other multi-component ceramic compositions substituted with at least one kind of complex perovskite compound represented by I) to (W), or a combination thereof.

Furthermore, the lead metaniobate-based ferroelectric ceramic composition means both intrinsic and modified lead metaniobate, and the modified lead metaniobate includes simple oxides such as CrtOl, Nb*Os,
Taxes, Bit's, MnOx, etc. with transition element oxides added, Mg with a part of Pb.

Alkaline earth metals such as Ca, Sr, Ba, Law's,
Two-component systems, three-component systems, and other systems in which at least one composite perovskite compound represented by general formulas (I) to (VI) described below is added to those substituted with rare earth elements such as NdtOs, Y, and 03, and lead metaniobate. Includes multi-component systems.

The lead-containing composite perovskite ceramic composition includes, in addition to lead-containing composite perovskite compounds represented by general formulas (I) to ('Vl) described below, two or more thereof, or at least one kind thereof and another composite perovskite. This includes two-component, three-component, and other multi-component ceramic compositions consisting of compounds. For example, P b(F et/3W l
/ 3) 03, one-component systems such as Pb(Fer/lNb+/1)Os, Pb(Pel7tNb+/t)C)
+-Pb (Fe, 73W l/3) 2 such as Oa
Component system, Pb(Mn+/3Nbx/3)03-P
b(F e+/tNbly1)03 Pb(Fet
/3W+/ 3)0! l, P b(Z n+/ 5Nb
ty 5)03-Pb(Fe+/lNb+/1)03-
Pb(Fe*/.

Examples include three-component composite perovskite compounds such as W+/3)03.

Typical examples of the composite perovskite compound include the general formula (1): A""(B""l/sB"!/
3) Compounds represented by 03, for example, Ba(Zr+1/5Nbti 5hos, Ba(Cd+
/3Nbt/3)03, Ba(Mg+/3Nbt/3)
03, S r(CaI25Nbt/3)Os, Pb(M
g+/3Nbt/3)03, Pb(Nit/5Nbt/
5)03,Pb(Mn+/aNt)t/5)Os,P
b(Mg+/1Tat/5)Os, Pb(Ni+/3T
at/JOs, Pb(CdI/3Nb,/,)0. ;-
Formula (It): A″″(B″l, 1B″+/1)0
Compounds represented by 3, for example, Ba(Fe+/tNb+/*)Os, BaCSc+y
tNbly *)Os, Ca(Cr+/tNbly
1) Os, Pb(Fe+/tNbly1)03, P
b(Fel/1TaI/*)03, Pb(Set/IN
b+/1)03, PbC3cl/1TaI/1)Os,
Pb(Yb+7 tNbly1)03, Pb(Yb+/
*Ta+7 *)Os, Pb(Lu+,z tNb1
7 *)03, Pb(I n+/1Ntl+/ *)O
s;-Formula (III): A″4(B2″″t/lB
""Compounds represented by l/li03, for example, Pb(Cd+/xVL/li03, Pb(Mn+72wl
/1)03,Pb(Zn+/lWl/ri03,Pb(
Mg+/lWl/l)os, Pb(Got/lWI/
*)03,Pb(Ni+/lWI/1)Os,Pb(
ML/yTe+/1)Os, Pb(Mn+/lTe+/
1) 03, Pb(Co+/*Tet/*)Os; - Formula (IV): A"(B"t/sB" I/
*) A compound represented by 03, for example, Pb(Fet/
3Wl/ 3)03;-Formula (■)' ”+(B””)
I/tB44″l/1)03, for example, Pb(Sn+/1sbt/1)Os, La(Mg+/
*Ti+/*)03%Nd(Mg+/lTi+/*)O
s; and -Formula (VI): (A"I/ *A"
Compounds represented by I/z)B'"03, for example, (Na+/lLa+/t)TiOs, (Kl/=L
a, 7 *) TiOs, (Nap/tcelyt)
TiOs, CNa17 tNd+z *) Ti03, (
Nd+/lB i+/ riTios, (Kl/ *
B1l1 t) TiOs, etc.

As the glass compound represented by the general formula xPbO・yGeOz, which is a subcomponent, there are various compounds selected from the range of x=l to e and y=t to 3. For example, PbO—Ge
O7, Pb5Gepa+, 3PbO−GeOt, ÷←←
→→÷−6PbO−Ge0t and the like.

(Function) The present invention imparts ferroelectric behavior at a low melting point to a ferroelectric ceramic composition containing a lead oxide such as lead titanate, lead zirconate titanate, or lead metaniobate as a main component. General formula having the following properties: xPbO・yGeOz (x=1 to 6.
By adding a glass compound represented by y = 1 to 3) and producing a different phase ceramic bulk by liquid phase sintering, lead titanate-based, lead zirconate titanate-based, or lead metaniobate-based ceramic compositions are originally This makes it possible to sinter at a low temperature of 850 to 1000° C. without reducing the electromechanical coupling coefficient, thereby making it possible to perform integral sintering with a metal plate, which was previously impossible.

Further, the ferroelectric ceramic composition according to the present invention can be formed or processed by any method such as screen printing, coating, press molding, extrusion, sheet molding, hot pressing, etc. By printing the paste on the surface of a metal plate using a screen printing method and sintering it, an integrally sintered piezoelectric element can be obtained.

A compound represented by the general formula: xPbO-yGeo, which is a subcomponent, lowers the sintering temperature, but its content is reduced to 0.
The reason why the content is 0.01 to 30% by weight is that if it is less than 0.01% by weight, the effect cannot be expected much, and if it exceeds 30% by weight, the sintering temperature will be lower, but the electromechanical coupling coefficient will be significantly lowered. This is because it becomes like this. In particular, xPbO・yG
eo, the content of (x=1~6.y=1~3) as o, t-
When the amount is 0% by weight, a ferroelectric ceramic composition having a low sintering temperature and a large electromechanical coupling coefficient can be obtained. Also, set the values of x and y to x=1 to 6. The reason for setting y to 1 to 3 is that it can be melted and vitrified at low temperatures, and that when this glass compound is heat treated and left to recrystallize, it exhibits ferroelectric properties. Furthermore, the ferroelectric ceramic composition according to the present invention exhibits high flexural strength. This is thought to be because chemical bonding force is generated between the lead oxide in the main component and the lead oxide in the glass compound, increasing the mechanical strength at the grain boundaries.

Examples of the present invention will be described below.

(Example 1) PbjO, , Tie, , Zr (L, and N
Using btOs, these were PbTio, 4aZro, 5
A ferroelectric ceramic having a composition of tOs-1, Owt%NbtOs is weighed and the mixture is mixed for 20 hours. This mixture is dehydrated, dried, calcined at 850° C. for 2 hours, and then pulverized. 2 to 5% by weight of an organic binder is added to the calcined powder, and the mixture is mixed for 20 hours and granulated. After forming this into a thin plate with a thickness of 1 to 1.5 mm by press molding, this thin plate was fired at 1200°C for 2 hours to obtain ferroelectric porcelain, which was crushed and passed through a 325 mesh sieve to produce PbTlo , 4sZro, 5tC)+-1,O
A ferroelectric ceramic powder consisting of wt% NbtO5 is prepared.

Apart from this, Pb3O4 and Ge are also used as raw materials.
Using Ox, these are xPbO-yGeoz (x=1
6, y=1 to 3), and wet-mix the mixture for 16 to 20 hours. This mixture is dehydrated, dried, and calcined at 650°C for 3 hours, then placed in a high-purity aluminum crucible and melted at 875°C. This melt is poured into pure water, rapidly cooled and crushed, and then released into the general public: xP
bO・yGeos (x=1~6.

A glass compound having a composition represented by y=t~3) is obtained.

This glass compound is ground with a mortar and pestle to obtain a powder of 325 mesh or less. This was heated at 650°C for 3 hours to recrystallize it, and then passed through a 325 mesh sieve again to obtain xPbO-yGeot (X = 1-6, y = 1-3).
Get the powder.

The ferroelectric ceramic powder is xPbO-yGeO2 (x=1
~6. F=1 to 3) Mix the powder with the composition ratio shown in Table 1, and add 10% of an organic binder consisting of a resin and a solvent to the mixture.
A thick film paste was prepared by mixing % by weight. This thick film paste was screen printed as a circle with a diameter of 18III11 on a heat-resistant metal plate, such as a Ni-Cr metal plate, with a diameter of 20 mm and a thickness of 0.1 mm, and then baked at the temperature shown in Table 1 to a thickness of 50 μm. An integrally sintered composite was obtained.゛A silver electrode was formed on the surface of this ceramic by a baking method, and a DC voltage of 3 to 4 kv/mm was applied between the silver electrode and the metal plate at 80°C for 30 minutes to perform a polarization treatment to obtain a porcelain piezoelectric sample. .

For each sample, the relative dielectric constant (Cr) and the electromechanical coupling coefficient (Kv) of the bending vibration of the disk were measured. The result is the first
Shown in the table. Table 1 shows, as a comparative example, Pb0-BtOi.5iOe as a subcomponent in the ferroelectric ceramic powder.
Glass-based glass compound I wt% (Comparative Example 1) or NatO'BtO3'5iOt-based glass compound 5wt%
The results for a sample prepared using a thick film paste prepared by adding (Comparative Example 2) are also shown.

(Example 2) Ferroelectric ceramic powders (P b
Tio, 4sZro, s*Os-1, Owt%Nbt
Os) is blended with powder of a glass compound (5Pb0.3GeOt) in the composition ratio shown in Table 2, 2 to 3% by weight of an organic binder is added to this, mixed for 20 hours, granulated, and press molded to form 1 to 3 GeOt. A square plate of 1.5 mm x 10 nm x 20+n+n was formed, and the square plate was fired for 2 hours at the temperature shown in Table 2 to obtain a porcelain square plate. Three-point bending test method (
The bending strength was measured based on the distance between supporting points: 11 mm).

The results are also shown in Table 2.

(Example 3) Pb5O4, Ti0t, ZrO,,5nOz as raw materials
, 5btOs and M n Ot, and the calcination temperature was 9
0.05Pb in the same manner as in Example 1 except that the temperature was 00°C.
(Sn, /lsb, /1)03-0.47PbTiO1
A ferroelectric ceramic powder having a composition of -0,48PbZrOs-〇, 7 wt% MnO was prepared.

xPbc prepared in Example 1 was added to this ferroelectric ceramic powder.
lyGeo2 (x = 1 to 6. y = 1 to 3) in the proportion shown in Table 3, and 6 to 7 wt% of organic binder.
In addition, after mixing for 20 hours, it was formed into a sheet using a doctor blade method, and punched into a sheet with a diameter of IQ mm and a thickness of 0.
A 1 mm disk is formed and the disk is fired for 2 hours at the temperature shown in Table 3 to obtain a porcelain disk. Silver electrodes are baked on both sides of the obtained porcelain disk, and a voltage of 3 to 4 kV is applied at 80°C between both electrodes.
A DC voltage of /mm was applied and polarization was performed for 30 minutes to obtain a porcelain piezoelectric sample.

(Comparative Example 3.4) In Example 3, xPbO-yGeo was used as a subcomponent.
2 (X=1~6,'l=1~3) instead of
5 wt% pbo・B=03・S i O based glass compound or 0.1 wt% Nato-BtOi-S
A sample of a porcelain piezoelectric material was obtained in the same manner as in Example 3 except that an IOT glass compound was used.

For each sample, the relative dielectric constant (εr) and the electromechanical coupling coefficient (Kp) of the spreading vibration of the disk were measured. The results are shown in Table 3.

(Example 4) Ferroelectric ceramic powder (0,0,5Pb
(Sn+/!sb1/y)Os-〇, 47PbTiO3
Using 0゜48PbZrO*-0.7wt%Mn0J and the powder of the glass compound (5Pb0.3GeO7) prepared in Example 1, a porcelain square plate was obtained in the same manner as in Example 2, and its bending strength was measured. . The results are shown in Table 4 along with the blending ratio of the main component and the glass compound and the firing temperature.

(Example 5) Pb30. , TiO*, ZrO2, M n
0.05 Pb(Mr++/5Nbt/3)03-0 in the same manner as in Example 3 using Ot and NbzOs.
．． A ferroelectric ceramic powder having a composition of 45PbTi0+-0,50PbZrOi was prepared.

Examples of this ferroelectric porcelain powder! XPbO prepared with
yGeOt (x = I ~ 6. y = 1 ~ 3) was blended in the proportions shown in Table 5, 2 ~ 3 wt% of organic binder was added and mixed for 20 hours, then granulated and press molded to a diameter of 1
5 thickness! An open disk is formed and the disk is fired for 2 hours at the temperature shown in Table 5 to obtain a porcelain disk. Silver electrodes were baked on both sides of the obtained porcelain disk, and a temperature of 3 to 3
A DC voltage of 4 kv/mm was applied and polarization was performed for 30 minutes to obtain a porcelain piezoelectric sample.

(Comparative Example 5.6) In the composition of Example 5, xP b was added as a subcomponent.

・Instead of yGeOt (x=1~6.y=1~3),
pb.

・B, 03・5iOt type glass vitrification addition amount 0, 1
A sample of a porcelain piezoelectric material was obtained in the same manner as in Example 5, except that Na*O'BtOs (115 wt%) or Na*O'BtOs (115 wt%) was used.

For each sample, the results of the measured relative dielectric constant (εr) and electromechanical coupling coefficient (Kp) of the spreading vibration of the disk are
Shown in the table.

(Example 6) Ferroelectric ceramic powder (0,05Pb(
Mn, /3Nb, /3)03-0.45 PbT iO
. The results are shown in Table 6 along with the blending ratio of the main component and the glass compound and the firing temperature.

(Example 7) Pb30. , Tie, , Lat, s, and M n Ot were used, and Pbo, esLao, +aTiO
s-0゜7wt%MnO! A ferroelectric ceramic powder with the composition was prepared.

This ferroelectric ceramic powder was coated with the XPbO prepared in Example I.
yGeOt (x = 1 to 6. y = 1 to 3) was blended in the proportion shown in Table 7, and 4 to 5 wt% of an organic binder was added.
After kneading for 0 hours, extrusion molding was performed to obtain a green sheet, which was punched to form a disk with a diameter of 10 mm and a thickness of 0.51 mm, and the disk was fired at the temperature shown in Table 7 for 2 hours. A porcelain disc was obtained. Silver electrodes were baked on both sides of each porcelain disk, and a DC voltage of 3 to 4 kv/mm was applied between the two electrodes at 80° C. to conduct polarization treatment for 30 minutes to prepare a porcelain piezoelectric sample.

(Comparative Example 7.8) In the composition of Example 7, xPbC1y was added as a subcomponent.
Instead of GeO7 (x=1~6.y=1~3), lψ
A sample of a porcelain piezoelectric material was obtained in the same manner as in Example 7, except that t% of pbo.B, 03.5iot glass compound or 10wt% of NatO.BtOa.5tOt glass was used.

For each sample, the measured dielectric constant (εr) and electromechanical coupling coefficient (K t) of vibration in the thickness direction of the disk! The results are shown in Table 7.

(Example 8) Ferroelectric ceramic powder (Pba, ssL) prepared in Example 7
ao, +oTio 3-0, 7 wt%Mn0
2) and the glass compound prepared in Example 1 (5Pb0.3
A porcelain square plate was obtained in the same manner as in Example 2 using powder of GeO*), and its bending strength was measured. The results are shown in Table 8 along with the blending ratio of the main component and the glass compound and the firing temperature.

(Left below) As is clear from the results in Tables 1 to 8, the ferroelectric porcelain composition according to the present invention has a sintering temperature of 100 to 400°C lower than that of ferroelectric porcelain that does not contain subcomponents. has a freezing temperature, and
The Kp and dielectric constant are approximately the same. Also,
The ferroelectric ceramic composition according to the present invention includes xPbO-yGe
As the content of Ot (x = 1 to 6. y = 1 to 3) increases, the electromechanical coupling coefficient and dielectric constant gradually decrease,
The degree of this is significantly smaller than when a P bo -B to s·S iO-based glass or a NatO'BtO3'S r O-based glass is contained.

(Example 9) Using the same raw materials and method as in Example 5, 0. lPb(Mn
, /3Nb, /3)0. -0, 52PbTiO,
A ferroelectric porcelain powder having a composition of -0,38P bZ ro was prepared.

Examples of this ferroelectric porcelain powder! XPb0− prepared with
yGeOt (x = 5. y = 3) was blended in the proportions shown in Table 9, 2 to 3 wt% of an organic binder was added, mixed for 20 hours and granulated, and then press-molded to form a square plate. This was baked for 2 hours at the temperature shown in Table 9, and the size of each side was 51+1ff.
A square porcelain plate with a thickness of 0.5 mm was obtained.

Silver electrodes were baked on both sides of this porcelain square plate, and a DC voltage of 3 to 4 kv/+n+n was applied between both electrodes at 80°C.
Polarization treatment was performed for 0 minutes to obtain an oscillator (resonator) polarized in the vertical direction within the plane.

The oscillators were each connected to the oscillation circuit shown in FIG. 1, and oscillated at an oscillation frequency of 455 KHz. In the figure, 1 is an oscillator,
IC+ is an inverting amplifier, R1 is a resistor, CL, CLt are capacitors. When the oscillation circuit was operated 100 times, Table 9 shows the number of times abnormal oscillation occurred from the oscillation frequency of 455 KHz to 4.5 MHz.

(Left below) Table 9 No. Composition (wt%) Firing temperature Abnormal oscillation main component Glass ('C) Number of times (times) 57*1
00 0 1200 7059* 100
0 1100 8061* 100 0 1
000 9063* 100 0 900
100 As is clear from the results in Table 9, no abnormal oscillation was observed in the oscillator using the ferroelectric ceramic composition of the present invention;
In the comparative example that does not contain eO,), as shown in Figure 2, spurious thickness longitudinal vibration occurs and the frequency is 4.5 MHz.
Abnormal oscillation was observed in the vicinity.

This is a glass compound XPb0 added to ferroelectric porcelain.
This is considered to be because -yGeo2 not only increases the strength of grain boundaries, but also reduces spurious vibrations of thickness longitudinal vibrations without adversely affecting main vibrations when used as an oscillator. Therefore, the ferroelectric ceramic composition according to the present invention is advantageous in damping vibrations higher than the fundamental oscillation frequency. Incidentally, such an effect was observed not only in oscillators that utilize spread vibration, but also in ferroelectric ceramic compositions used as materials for oscillators and the like that utilize edge vibration.

(Example 10) In the same manner as in Example 3, 0,70 P b(F e+/
*NbI/z)03-0.30 Pb(Fet/*W+
/3) A ferroelectric ceramic powder having a composition of C)+ was prepared.

The XPb0- prepared in Example 1 was added to this ferroelectric ceramic powder.
yGeO! (x = 5. y = 3) in the proportions shown in Table 1O, 2 to 3 wt% of an organic binder was added, mixed for 20 hours, granulated, and then press-molded to form a disk. was baked for 2 hours at the temperature shown in Table 10 to obtain a diameter of 10 am.
A porcelain disk with a thickness of 1.0 mm was obtained.

A capacitor was obtained by baking silver electrodes on both sides of this porcelain disk, and its dielectric constant was measured. The results are shown in Table 10. Note that the measurement results for the bending strength of these samples are also shown in the same table.

Table 1 Theta No. Composition (wt%) Firing temperature Relative permittivity Main component of bending strength Glass ('C) (k
g/amsu65* 100 0 1000 27
500 160067* 100 0 950
22500 110069* 100 0
800 10000 500 (Example 11) 0.16 Pb(Zn, /3Nb
, Mu) o3-048Pb(Pe, 8Nb+/1)03-
A ferroelectric ceramic powder having a composition of 0.36 Pb(Pet/'+W+/3)0 was prepared.

The XPb0- prepared in Example 1 was added to this ferroelectric ceramic powder.
yGeo, (z = 5, y = 3) in the proportions shown in Table 11, and a diameter of 10 m was prepared in the same manner as in Example 10.
A porcelain disk with a m1 thickness of 1.0 curves was obtained. A capacitor was obtained by baking silver electrodes on both sides of this porcelain disk, and its dielectric constant was measured. The results are shown in Table 11 together with the measurement results for the bending strength of those samples.

11 Table number -11fj2 (wt%σ - Firing temperature Relative dielectric constant
Main component of bending strength Glass ℃) (k
g/cm 71* 100 0 850 14
000 150073* 100 0 700
7000 700 As is clear from the results in Tables 1θ and 11, the dielectric constant and bending strength of composite perovskite capacitor materials containing lead oxide can be improved by adding xPbO・yGeot. can be done.

(Effect) As is clear from the above explanation, according to the present invention, 85
Ferroelectric ceramics can be sintered at a low temperature of 0 to 1000° C. and have a large electromechanical coupling coefficient and a large dielectric constant, so piezoelectric elements with high energy conversion efficiency can be manufactured. In addition, since the sintering temperature is low, it is possible to integrally sinter the metal plate, which not only makes it possible to manufacture electrostrictive elements such as integrally sintered buzzers and bimorphs, but also eliminates the need to adjust the PbO atmosphere during firing. Excellent effects such as slightly extending the life of the kiln and saving energy can be obtained. Furthermore, the flexural strength does not decrease, and when used in an oscillator, it is possible to prevent the generation of spurious waves.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an oscillation circuit including a ceramic oscillator, and FIG. 2 is a diagram showing the spread vibration, which is the main vibration, and the thickness longitudinal vibration, which is the spurious vibration, in the oscillation circuit of FIG. 1. 1 ~ ceramic oscillator, IC, ~ inverting amplifier, R1 ~ resistor, CL + , CL * ~ capacitor.

Claims (4)

[Claims] (1) The main component is a ferroelectric ceramic composition containing lead oxide,
General formula: xPbO・yGeO_2 (x=1
~6, y=1~3) at 0.01
A ferroelectric ceramic composition containing up to 30% by weight. (2) The lead oxide-containing ferroelectric ceramic composition as the main component is a lead titanate-based ceramic composition, a lead zirconate titanate-based ceramic composition, a lead metaniobate-based ceramic composition, and a lead-containing composite perovskite. The ferroelectric ceramic composition according to any one of claims 1 to 5, which is at least one selected from the group consisting of ferroelectric ceramic compositions. (3) Consisting of a ferroelectric ceramic plate and at least one electrode formed on its surface, the ferroelectric ceramic plate has a lead oxide-containing ferroelectric ceramic composition as a main component, and a ferroelectric ceramic composition containing lead oxide as a subcomponent. Formula: xPbO・yGeO_2 (x=1~6, y=
A piezoelectric element comprising a ferroelectric ceramic composition containing 0.01 to 30% by weight of a glass compound represented by 1 to 3). (4) Consisting of a metal substrate and a ferroelectric ceramic layer integrally laminated and sintered on the substrate, the ferroelectric ceramic layer mainly containing a ferroelectric ceramic composition containing lead oxide. and the general formula: xPbO・yGeO_2 (x=1 to 6, y
A piezoelectric element characterized in that it is a ferroelectric ceramic composition containing 0.01 to 30% by weight of a glass compound represented by 1 to 3).