JPH01199482A - Piezoelectric porcelain composition - Google Patents

Abstract

PURPOSE:To obtain a porcelain composition excellent in a piezoelectric property and a mechanical strength by a method wherein [Pb(Mg1/3Nb2/3) O3]x[PbTiO3]y[PbZrO3]z as a primary component of the porcelain composition is specified in value of x, y, and z, and specified amounts of Sb2O3, MnO2, and NiO as a secondary component are contained in the porcelain composition. CONSTITUTION:A porcelain composition is formed of Pb(Mg1/3Nb2/3)O3-PbTiO3- PbZrO3 as a primary component and Sb2O3, MnO2, and NiO as a secondary component, where if the primary component is represented by [Pb(Mg1/3Nb2/3) O3]x[PbTiO3]y[PbZrO3]z, x, y, and z are so set as to satisfy inequalities, 0.10<=x<=0.60, 0.30<=y<=0.60, and 0.10<=z<=0.60 (x+y+z=1), and 0.1-15% Sb2O3, 0.1-15% MnO2, and 0.01-15% NiO by mole of the primary component respectively are contained in the porcelain composition as a secondary component. Or, 0.01-15% by mole of Pb contained in the primary component is substituted with one or more kinds of elements selected from Ca, Sr, and Ba, and one or more elements 0.01-15% by mole of the primary component selected from SnO2, Bi2O2, ZnO, SiO2, La2O3, Y2O3, CeO2, and CoO are contained as the secondary component.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a piezoelectric ceramic composition, and more specifically, the piezoelectric ceramic composition can be used for filters, microphones, speakers, vibrometers, powerful ultrasonic vibrators, and the like. The present invention relates to a piezoelectric ceramic composition that has excellent piezoelectric properties and high mechanical strength.

[Prior Art] Conventionally, piezoelectric ceramics include barium titanate or lead zirconate titanate porcelain.

Various additives have been added to these materials to improve their physical and electrical properties. moreover.

Pb (Mg1za Nb2/3)Oa-Pb
By simultaneously containing MnO2 and NiO in a piezoelectric ceramic composition consisting of a three-component system of TiO3-PbZr03, the mechanical quality factor Qm can be significantly increased by 1 without decreasing the electromechanical coupling coefficient kp of radial vibration ( It is known that it can be done (for example, H, Ouchi et a
l: J, Am, Ceram, Soc,, 49
(19661577).

However, with conventional piezoelectric ceramic compositions, it has not been possible to obtain large kp, Qm, and dielectric constant ε/ε0 at the same time, and it cannot be said that the mechanical strength is sufficiently large. Improvement was desired.

[Problem 1 to be solved by the invention The present invention solves the following problems: P b (Mglz3Nb2/3) O
In a conventional piezoelectric ceramic composition consisting of a three-component system of a - P b T i O3 - P b Z r O3, let's solve the drawbacks of insufficient kp, Qm, εX3/εOi3 and mechanical strength obtained at the same time. 6 [Means for Solving Problems 1] In order to solve the drawbacks of the above-mentioned prior art, the present invention has the following features:
The invention of [Pb(Mg1/a Nb2/
3 ) 03 ] x −[PbT 1Oaly (
PbZr03) Limit the x, y, and z values of z, and add 5b2o3 as a subcomponent in a limited amount to the main component.
In addition to the first invention, the second invention contains pb in the main component by Ca, MnO2, and NiO.
Substituting with a limited amount of at least one of Ba and Sr (hereinafter referred to as Ca, etc.), and further containing 5n02. as a subcomponent. Bi2O3, ZnO, 5i02゜La2O3
, Y2O3, CeO2, CoO (hereinafter referred to as 5n02, etc.) in a limited amount.

[Action J The main component of the present invention is

[P b (Mg1/a N b2z3) Oa )
When expressed as x[PbTiOal y[PbZrO31z, the range of the main component composition is 0, lO≦X≦0.60 0.30≦y≦0.600
．． The value is limited to 10≦2≦0.60 (x+y+z=1). The reason for this is that outside the above main component composition range, both kp and ε33ε0 decrease significantly. This main component composition range is shown in FIG.

If 5b2o3 is contained within this main component composition range in an amount of O, 1-15 moβ relative to the main component, εX3/εoi5 and mechanical strength can be increased without lowering kP. When the content of Sb, 20a is less than 0.1 mo 12% of the main component, the effect is insufficient, and when it exceeds 15 mo 1%, the kp decreases significantly, 5b2
It is not clear why o3 has greater mechanical strength, but 5
This seems to be because b2o3 enters the grain boundaries.

M n 02 to the main component, 1 to 15 m o 1
When the content is 2%, Qm and mechanical strength can be increased. MnO2 content is 0.1 m o 12
If the amount is less than 15 mog%, the effect will be insufficient, and if it exceeds 15 mog%, the Qm will again drop significantly.

When NiO is contained in an amount of 0.01-15 moff% based on the main component, Qm can be further increased without reducing kpj5 and ε33ε0.

When the Nio content is 0.01 mon%, the effect is insufficient, and when it exceeds 15 moR%, the Qm decreases again.

If 0.01-15moff% of Pb in the main component is replaced with a small amount of Ca etc., εゑ3/ε0 increases greatly, but if the amount of substitution is less than O, O1moβ%, the effect is insufficient. , 15moI exceeds 2%, the kp decreases significantly.

For the main component in which pb is replaced with Ca etc., Sb, 20a is O, 1 to 15 moR% as a subcomponent, MnO2 is O, l to l 5 mo I; 2%,
NiO was added to 0. Ol-15m o 12% and further 5
When n02 etc. contain O, Ol-15m o Q% gold,
kp, Qm, ε stone, /ε0 are all large, and tO
A piezoelectric ceramic composition with high W strength is obtained.

If the content of 5b2o3 is less than 0.1 m oβ%, ε3
3/ε0 and mechanical strength increase effect is insufficient, 15
When moR% is exceeded, kp decreases significantly, and M n O2
If the content of NiO is less than 0-1 m o 12, the effect of increasing Qm and mechanical strength is insufficient, and if it exceeds 15 m0β%, the decrease in Qm becomes significant again, and the content of NiO is less than 0.
If the Qm increase is less than 0.01 moff%, the effect of increasing Qm is insufficient;
When it exceeds 5m0β%, the decrease in Qm becomes significant again, and 5m0β% is exceeded.
If the content of n02 etc. is less than O, O1moβ%, εX3/
The effect of increasing ε0 is insufficient, and when l exceeds 5moβ%, kp decreases significantly. In addition, εX3/ due to 5n02 etc.
It is thought that the increase in εo occurs due to the synergistic effect of 5n02 etc. and 5b2o3.

The composition of the present application contains PbO, MgO, Nb2O5°Ti
02, ZrO2, Sb203, MnO2.

As raw materials for containing NiO, CaO, etc. and 5n02, etc., in addition to oxides, hydroxides, peroxides, nitrates, carbonates, etc. which become oxides when heated can also be used.

〔Example] The present invention will be explained below based on examples.

The compositions should be as shown in Table 1.

PbO, MgO, Nb205. TiO2, ZrO2, S
b203, MnO2, N i O, CaCO3, 5n
02 was weighed down.

The mixing conditions were as follows: A zirconia ball was used as a mixing ball in a plastic pot, and the mixture was mixed 24 hours a day in a ball mill. After drying the material made into a slurry by this mixing, it was pressure-molded at a pressure of 500 kg/crn' and
It was calcined at ℃ for 2 hours.

The calcined product was placed in the pot again, and subjected to 7-pole pulverization and mixing under the same conditions as above, followed by drying to obtain a raw material phase.

Polyvinyl alcohol (
After adding 1 to 2% of PVA) and granulating it,
Pressure molding was carried out at a pressure of 1.5 t/crn' using a mold of 1.0 m. The molded product was main fired at 1200 to 1300°C for 2 hours to produce a piezoelectric ceramic composition.

This piezoelectric ceramic composition was polished to a thickness of 1 mm, silver electrodes were provided on both sides, and the composition was polarized in silicone oil at a temperature of 100° C. with a DC electric field of 3 to 4 kv/mm to prepare a sample for piezoelectricity measurement. In addition, for the measurement of bending strength, porcelain fired under the above conditions was cut and polished into a cross section of 3 x 4 mm.

Composition, density, kp, Qm, ε'r of main component and subcomponent
3/εo:! 3 and bending strength are shown in Table 1. kp,
Qm and ε13/ε0 are average values of 5 samples.1 Bending strength is an average value of 10 samples.

Instead of using Ca alone, Sr and Ba are also used to reduce the main component p.
b is replaced and instead of using 5n02 alone as a subcomponent, Bi2O3, ZnO, 5i02゜La2O3, Y2O3
, CeO2, Coo were also used, but almost the same results as in Table 1 were obtained. According to the present invention, kp, Qm and εS3/ε
A piezoelectric ceramic composition having a high value of 0 and a high mechanical strength was obtained.

Table 1-1-b Note) This mark indicates Comparative Example Table 1-2-b Note) This mark indicates Comparative Example Table 1-3-b Note) * indicates Comparative Example [Effect of the invention 1 The piezoelectric ceramic composition has -kp, Qml and εX3/
Since both ε0 are large, larger mechanical vibrations can be obtained and the loss of mechanical energy is smaller compared to conventional piezoelectric ceramic compositions. Furthermore, since it has high mechanical strength, it does not cause cracking, chipping, chipping, etc. during processing such as cutting and polishing, and is useful for applications such as refilters, microphones, speakers, and vibrometer 1 powerful ultrasonic vibrators.

[Brief explanation of the drawing]

FIG. 1 is a triangular diagram showing the composition range of the main components in the present invention.

Claims (1)

[Claims] 1 The main component is Pb (Mg_1_/_3Nb_2_/_3
)O_3-PbTiO_3-PbZrO_3, which is [Pb(Mg_1_/_3Nb_2_/_3)O_3]
When expressed as x[PbTiO_3]y[PbZrO_3]z, x, y, and z are each 0.10≦x≦0.600.30≦y≦0.600.1
It has a value of 0≦z≦0.60 (x+y+z=1), and contains 0.1 to 15 mol% of Sb_2O_3 and 0.1 to 15 mol% of MnO_2 with respect to the main component as subcomponents.
and 0.01 to 15 mol% of NiO. 2 0.01 to 15 mol% of Pb in the main component is Ca,
It is substituted with at least one of Sr and Ba, and further contains SnO_2, Bi_2O_3, ZnO, SiO_2, L as a subcomponent.
At least one of a_2O_3, Y_2O_3, CeO_2, and CoO is added to the main component by 0.01 to 15 m
The piezoelectric ceramic composition according to claim 1, containing ol%.