JPH02301173A - Piezoelectric porcelain composition - Google Patents

Abstract

PURPOSE:To obtain a piezoelectric porcelain composition of a high electrostriction effect by application of voltage and low hysteresis by adding specific quantities of NiO and/or Bi2O3 as auxiliary constituents to a specific basic composition. CONSTITUTION:0.02-0.5wt.% of NiO and/or Bi2O3 are added as auxiliary constituents to a basic composition satisfying formula I. PbO, NiO, Nb2O5, MnCO3, Sb2O3, ZrO2, TiO2, and the specified auxiliary constituents selected as starting materials are mixed in a ball mill and baked temporarily. Powder which is obtained by re-pulverization and to which a proper quantity of organic binder is added is shaped by pressurization and baked.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a piezoelectric ceramic composition, and in particular, by applying a voltage,
The present invention relates to a piezoelectric ceramic composition suitable for voltage-driven piezoelectric displacement elements that require large mechanical displacement and high-precision position control.

[Prior Art] In recent years, a new type of drive source that replaces the electromagnetic type uses the electrostrictive effect of piezoelectric ceramics to convert electrical energy into mechanical energy. 2. Description of the Related Art Voltage-driven piezoelectric displacement elements (hereinafter referred to as displacement elements) have been put into practical use in a variety of fields, such as minute position control devices. As this type of displacement element, for example, as shown in FIG. 2, a bimorph structure is known in which piezoelectric ceramic plates 2 and 2' having electrodes sandwiched between them are bonded to a metal elastic plate 1. ing.

When a DC or AC voltage is applied to this displacement element, a mechanical displacement dS occurs due to an electrostrictive effect (in this case, a piezoelectric transverse effect).
r or dS2 occurs. This mechanical displacement depends on the application and the mechanism used when it is mounted.

Generally, it is desirable that the displacement element be as large as possible in terms of its function, and it is further desirable that the voltage-displacement hysteresis be as small as possible in terms of highly accurate position control or quality as a device. For example, with respect to one mechanical displacement, piezoelectric ceramic compositions having a greater electrostrictive effect are considered advantageous.

[Problems to be Solved by the Invention] Conventionally, piezoelectric ceramic compositions of this type include Pb (NipsN b 2.
) 03 P b Z r O3P b T i O
There are three-component systems such as 3rd grade. However, with conventional compositions, although mechanical displacement occurs to some extent,
Due to the large voltage-displacement hysteresis, its use as a displacement element was limited to an extremely narrow range. Therefore, a piezoelectric ceramic material that provides a larger mechanical displacement and has a smaller voltage-displacement hysteresis has been desired in order to be suitable for a wide range of uses as a displacement element.

Therefore, one technical object of the present invention is to sufficiently meet such demands, and the electrostriction effect due to voltage application is large and the hysteresis is small.

As a result, the object of the present invention is to provide a piezoelectric ceramic composition that can be used in a wide range of applications as a displacement element.

[Means to solve the problem] The piezoelectric ceramic composition of the present invention is.

General formula P b [(N i r, a Nb2.3 )
A(Mn, n 5b23)a (Sbl□Nbl□
) (Z r □ T i E ] 03 (However, A+B+C+D+E-1) 0.300≦A≦0.550.

0.001≦B≦0.020.

0.002≦C≦0.050.

0.090≦D≦0.290.

0.290≦E≦0.407.

N　i　O as a subcomponent for the basic composition that satisfies the following.

At least one species selected from Bi2O3 is added in an amount of 0.02 to 0.
It is characterized by containing 5% by weight.

In the present invention, 0.300>A, A>0.5
50.

B>0.020, C>0.050, 0.09
0>D, D>0.290, 0.290>
In the basic composition consisting of E, E > 0.407 and in the composition containing more than 0.5% by weight of at least one selected from the subcomponents NiO and Bi2O3, the electrostrain amount 1 mechanical displacement decreases, and therefore , 1'' is not preferable for use as a displacement element.

In compositions containing less than 0.02% by weight of at least one selected from 0.002>C and subcomponents NiO, Bi2O, no significant improvement effect on electrostrain amount 9 mechanical displacement was observed,
Furthermore, in the basic composition, when 0.00t>B, a significant improvement effect on hysteresis was not observed, so it was excluded from the scope of the present invention.

[Example] Hereinafter, examples of the present invention will be described in detail while comparing with reference examples.

Chemically high purity PbO, NiO, Nb as starting materials
2O,,MnC0,,5b20. , Z r02 , T
i02 and predetermined subcomponents were selected and accurately weighed to give the compositions shown in Tables 1 to 3. next.

These raw materials are mixed in a ball mill and then dried.

Temporary firing was performed at 850°C. Next, an appropriate amount of a binder was added to the powder obtained by pulverization using a ball mill, and the mixture was granulated, followed by pressure molding at a pressure of 1 ton/cj.

It was baked at a temperature of 1200-1250°C for several hours.

After cutting and polishing the blued sintered body into the specified shape.

Electrodes are applied at a temperature of 60 to 100°C in a silicone well.
DC electric field 35-50 kV/crn under the conditions of 3
The voltage was applied for 0 minutes and a polarization process was performed to piezoelectrically activate the voltage. Next, after determining the various piezoelectric constants using a prescribed measurement method, further polishing and processing were performed to confirm the substantial effect, and two types of rectangular piezoelectric elements were created, namely: ■ length 10 m
m, width 2ms, thickness 1mm.

(2) A length of 35 mm, a width of 10 mm, and a thickness of 0.15+a- was obtained. Of these two types of piezoelectric elements, the piezoelectric element with the shape ■ has a polarization direction of 500 mm in the same direction as the polarization direction. A DC voltage of V was applied, and the amount of electrical strain (shrinkage strain) generated at that time was measured and evaluated as a Δg/g value (Δg: shrinkage amount 1 g−element length).

On the other hand, regarding the piezoelectric element of shape 2, it was further sandwiched between two sides of a metal elastic plate to produce a bimorph type displacement element as shown in FIG. 2, and its mechanical displacement and hysteresis were investigated. 1. Mechanical displacement is determined by the displacement dsju generated at the tip with one end fixed and the other end free when a DC voltage of 30V is applied, as shown in Figure 1, while hysteresis is determined by the displacement dsju at a voltage of 30V. It was calculated from the residual displacement dSo generated when the voltage was returned to O using a linear equation.

Hysteresis” (d So / d 530) X1
00 [%] Examples of the results are shown in Tables 1 to 3. In Tables 1 to 3, sample numbers marked with * correspond to piezoelectric ceramic compositions of the present invention.

As is clear from Tables 1 to 3, the samples made of the piezoelectric ceramic composition of the present invention had both a larger electrostriction amount and a larger mechanical displacement than the reference examples of each composition group, and It is clear that the voltage-displacement hysteresis is extremely small, making it suitable as a displacement element.

2. In the present invention, N i O is a subcomponent.

Even if Bi2O is added at the same time, the total added content is 0.02 ~
A similar effect can be obtained within the range of 0.5% by weight.

[Effect of the invention] In this way, ``the present invention provides Pb [(N i > 3Nb
2. i)A (Mn+, Sb2.-t)B
(Sb+・2Nbl 2 )(ZrDTia) Os is the basic composition.

Set each of A, B, C, D, and E to an appropriate range.

It contains one of NiO and Bi2O3 as a subcomponent in an appropriate range, and in particular, P b (Mn +3S b2.1) 03 in the basic composition,
Due to the interaction with the P b (S b +2N b +2) 03 component and the subcomponents, it is possible to achieve a larger electrostriction amount 9 mechanical displacement and low hysteresis that could not be achieved with conventional compositions. Furthermore, the piezoelectric ceramic composition of the present invention can be expected to be applied to the following uses.

(1) Since large mechanical displacement is generated and piezoelectric displacement hysteresis is small, it can be widely applied to new fields of displacement elements that require highly accurate position control.

(2) Since it generates a large mechanical displacement, it can be made smaller, lighter, and driven at a lower voltage, and can be applied to the field of displacement elements that meet the energy saving era.

(3) Application to displacement elements requiring large mechanical displacement at relatively low voltage is possible.

(4) It can be applied to displacement elements that require large mechanical displacements by adopting a one-sided drive method (applying only a DC voltage in the same direction as the polarization direction of the piezoelectric element). In this case, the magnitude of the applied voltage can be freely selected depending on the application.

(5) Since it has a relatively high piezoelectric constant (for example, piezoelectric d constant), it can be applied to various piezoelectric products that require a high piezoelectric constant.

1. In the embodiments of the present invention, the electrical strain amount 1 mechanical displacement and voltage-displacement hysteresis associated with the piezoelectric transverse effect were explained with particular reference to a bimorph type piezoelectric displacement element, but piezoelectric vertical displacement elements using the same composition were explained. The effectiveness has also been investigated and its improvement effect has been confirmed.

Therefore, it is fully possible to apply the present invention to, for example, a laminated piezoelectric displacement element.

As detailed above, the piezoelectric ceramic composition of the present invention is suitable for displacement elements that can be used in a wide range of applications, and is of great industrial value.

[Brief explanation of drawings]

FIG. 1 is a graph showing a measurement standard in an embodiment of the present invention, and FIG. 2 is a diagram showing an example of a conventional bimorph type piezoelectric displacement element. In the figure, 1... metal elastic plate, 2.2'... piezoelectric ceramic plate. Figure 1 Figure 2

Claims (1)

[Claims] 1. General formula Pb[(Ni_1_/_3Nb_2_/_3
)_A(Mn_1_/_3Sb_2_/_3)_B(S
b_1_/_2Nb_1_/_2)_CZr_DTi_
E] O_3 (A+B+C+D+E=1) 0.300≦A≦0.550, 0.001≦B≦0.020, 0.002≦C≦0.050, 0.090≦D≦0. 290, 0.290≦E≦0.407, NiO, Bi_ as subcomponents for the basic composition satisfying
0.02 to 0.5 of at least one type selected from 2O_3
A piezoelectric ceramic composition characterized in that it contains an additive amount by weight%.