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Piezoelectric composition and piezoelectric element

A technology of piezoelectric elements and compositions, applied in electrical elements, piezoelectric/electrostrictive/magnetostrictive devices, material selection for piezoelectric devices or electrostrictive devices, etc., can solve crystal anisotropy Large, impractical, productivity problems, etc., to achieve the effect of a wide range of practical temperature

Active Publication Date: 2016-03-09
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, BT its Curie point (T c ) is at a low level of 120°C, and since the piezoelectricity disappears above this temperature, it is not practical in consideration of applications such as bonding by soldering or automotive applications.
In addition, bismuth layered ferroelectrics usually have a high T above 400 °C c And it is excellent in thermal stability, but because the crystal anisotropy is large, it is possible to obtain an excellent d that is comparable to lead-based piezoelectric compositions by a common ceramic process. 33 it is hard
If you plan to get an excellent d 33 In this case, it is necessary to orient the spontaneous polarization during firing by hot pressing or hot forging, so there is a problem in terms of productivity.

Method used

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  • Piezoelectric composition and piezoelectric element
  • Piezoelectric composition and piezoelectric element
  • Piezoelectric composition and piezoelectric element

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1~ Embodiment 9

[0087] Bismuth oxide (Bi 2 o 3 ), sodium carbonate (Na 2 CO 3 ), titanium oxide (TiO 2 ), barium carbonate (BaCO 3 ), hafnium oxide (HfO 2 ) and calcium carbonate (CaCO 3 )powder. After the weighed starting materials were mixed by a ball mill for 16 hours, the mixed powder obtained by drying at a temperature of 120°C was subjected to compression molding, and pre-fired at a temperature of 800°C for 2 hours to obtain a pre-calcined powder. Burnt body. Next, the calcined body was pulverized by a ball mill for 16 hours to obtain a pulverized powder.

[0088] A binder is added to the pulverized powder obtained by the above procedure and granulated. Next, the obtained granulated powder was press-molded by applying a load of 3.2 MPa with a press-molding machine, and a flat-shaped compact was obtained. The flat molded body thus obtained was heat-treated at a temperature of 700°C, and further fired at a temperature of 1180°C to obtain a sintered body. In addition, the obtain...

Embodiment 10~15

[0100] As Examples 10 to 15, except that x, y, and z are set to x=0.85; y=0.10; z=0.05 for the piezoelectric composition represented by the above-mentioned formula (2) and further to become A piezoelectric composition was produced under the same conditions as in Example 1 above, except that the blending ratio of the starting materials was changed as d, e, and f were shown in Table 1. In addition, for Examples 10 to 15, d was also measured in the same manner. 33 and T c . The measurement results are shown in Table 1.

[0101]As can be understood from Table 1, the ranges of 0.90≤d≤1.10; 0.90≤e≤1.10; and 0.90≤f≤1.10 are good. Therefore, the piezoelectric composition according to the present embodiment is characterized in that the sinterability is improved because it is less affected by the secondary phase due to the difference in the stoichiometric composition ratio.

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Abstract

The present invention aims to provide a piezoelectric composition which is free of lead based compounds and is represented by the following formula (1), (Bi<0.5x>Na<0.5x>Ba<0.7y+z>Ca<0.3y>) (Ti<x+y+0.8z>Hf<0.2z>) O<3> (1), wherein, x, y, z and a in formula (1) meets the following conditions, 0.70<=x<=0.90, 0.02<=y<=0.28, 0.02<=z<=0.28, 0.90<=a<=1.10 and x+y+z=1.

Description

technical field [0001] The present invention relates to piezoelectric compositions and piezoelectric elements widely used in the fields of inkjet heads, piezoelectric actuators, and thin film sensors. Background technique [0002] A piezoelectric element using a piezoelectric composition is a piezoelectric element that has the effect of deforming by applying an electric field from the outside and generating charges on the surface by receiving stress from the outside. It has been widely used in various fields in recent years. widely used. For example, a piezoelectric element using a lead-based piezoelectric composition such as lead zirconate titanate deforms in proportion to the applied voltage and the displacement is 1×10 -10 The order of m / V, so it is excellent in small position adjustment, and can also be used for fine adjustment of optical system. [0003] Piezoelectric compositions can also be used as sensors for reading minute forces or deformations because they gener...

Claims

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Application Information

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IPC IPC(8): H01L41/18H01L41/083
CPCH10N30/50H10N30/853H10N30/85
Inventor 加藤浩辉
Owner TDK CORPARATION
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