JPS6131353A - Manufacture of piezoelectric ceramic - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to the production of piezoelectric ceramics which prevents sintering of molded bodies in contact with each other and improves the quality of the sintered bodies when the piezoelectric ceramics are sintered. It is about the method.

Conventional Structures and Problems With the rapid development of LSIs in recent years, electronic components have become lighter, thinner, and smaller. Piezoelectric ceramics, whose basic operating principle is free vibration, are no exception and are becoming thinner.

There is a demand for chipping, and the forming method for this has changed from dry pressing to sheet forming methods centered on doctor blade or vacuum extrusion. This sheet forming method is suitable for obtaining the required final porcelain thickness with high accuracy without cutting, and relatively thin products such as piezoelectric buzzer filters and ultrasonic microphones are efficiently produced.

The important point in this sheet forming method is up to the next punching hole sintering process. In order to sinter efficiently, Zr02 powder 3 for preventing adhesion is applied to a punched compact 2 punched from a green sheet 1 using a sieve 4 as shown in FIG. After that, they are stacked as shown in Fig. 1C, and in order to reduce the "reaction" during sintering, they are heated in a firing furnace with a suitable load applied to the load setter 5 as shown in Fig. 1D. Sinter.

At this time, what influences the quality of the porcelain is the ease with which the stacked compacts (sintered compacts) are peeled off after sintering, and the surface roughness of the porcelain. Since ceramics have the disadvantage of being brittle, these two items determine the yield and quality of electrode coating or bonding in subsequent processing.
It is no exaggeration to say that the success of introducing this sheet forming method depends on the quality of sintering.

The ZrO2 powder 3, which is intended to prevent the conventional punched compact 2 from sticking during sintering, is
In order to minimize rO2-piezoelectric ceramic adhesion, relatively rough commercial products are used. The particle size is widely distributed from 1 to 8 μm, and as shown in Figure 2, these particles dig into the porcelain surface during sintering, resulting in a porcelain surface roughness of 2 to 8 μm.
3 μm vs. 10-16 μm vs. 1
The roughness was 0 to 15 μm. Moreover, when the stacked sintered bodies are peeled off, they are strongly stuck together, which causes microcracks or cracks, which is a major cause of quality fluctuations.

OBJECTS OF THE INVENTION The present invention eliminates the problems of the conventional examples described above, and aims to obtain a piezoelectric ceramic having excellent peelability and surface roughness.

Structure of the Invention In order to achieve the above object, the present invention uses ZrO2 powder to prevent reaction and sticking of the sintered bodies to each other when piezoelectric ceramic green sheets cut into a desired shape are stacked and sintered. It is characterized by using particles that contain 80 wt% or more of classified particles of 10 to 50 pm and are heat-treated at 1000 to 1400°C. By this method, they are distributed more uniformly on the compact, and the Zr on the surface of the sintered compact is reduced. The penetration of O2 particles is reduced and uniformity is achieved, and furthermore, the reaction and sticking with the piezoelectric ceramic fired at the same temperature is significantly reduced, making it possible to create a sintered body that is easy to peel off.

Description of examples An embodiment of the present invention will be described below with reference to the drawings.

Commercially available Zr02 powder was classified with an aqueous solution and further 8o.

Heat treatment was performed at a temperature of ~1500°C for 1 hour. This Zr
○2 Punched out from green sheet 1 using powder 2 7
Z r The O2 powder 3 is uniformly distributed on the punched compact 2 as shown in FIG. After peeling off the sintered body, the adhering ZrO2 powder was lightly removed using paper, and the data shown below was obtained.

Margin below The releasability was evaluated on a 6-level sensory test.

(1; Peelability is poor and cracks appear on the fired sandalwood body (defective)
, 6; can be peeled off very smoothly (good), 3 is fair) Effects of the Invention As shown in the above data, the present invention provides a piezoelectric ceramic with very good peelability and surface roughness compared to conventional methods. It is of great industrial value.

[Brief explanation of the drawing]

Figures 1a to d are process diagrams showing the process from applying a release agent to a molded body until it is transferred to a firing process, and Figure 2 is a model diagram showing the distribution state in a conventional method. 1...Green sheet, 2...Punched molded body, 3...ZrO2 powder. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (1)

[Claims] 10 to 50 as ZrO_2 powder used to prevent the sintered bodies from reacting and sticking to each other when piezoelectric ceramic green sheets cut into the desired shape are stacked and sintered.
Contains 80 wt% or more of a particle size of μm and 1000 to 1
A method for producing piezoelectric ceramics, characterized in that piezoelectric ceramics are heat-treated at 400°C.