JPH05175007A - Manufacture of semiconductor porcelain component - Google Patents

Abstract

PURPOSE:To provide a method for manufacturing a semiconductor porcelain component in which electric characteristics of a component material to be obtained by eliminating the step of handling a material in a dry state are stabilized and the number of steps is largely reduced to facilitate coping with a small quantity and many type production. CONSTITUTION:The method for manufacturing a semiconductor porcelain component comprises the steps of adding water and dispersant to material powder and mixing them to prepare slurry, simultaneously pressurizing and dehydrating the slurry and molding a molded form, drying the form and baking the dried form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor porcelain component, and more particularly to a process for obtaining a sintered body which is a component body from a raw material powder.

[0002]

2. Description of the Related Art In the manufacture of semiconductor porcelain parts, for example, barium titanate-based positive temperature coefficient thermistors, a component element body is often formed by dry-forming raw material powder and then firing it.

That is, one example thereof will be described with reference to the process chart shown in FIG. 2. First, water is added to a raw material powder containing barium titanate as a main component, and this is mixed with hard balls to form a slurry. adjust. Next, the slurry is dehydrated using a filter press or the like to form a dehydrated cake, which is then dried and coarsely crushed and then calcined. Further, water and a binder are added to the powder obtained by calcination, and these are mixed to form a slurry. Then, the slurry is granulated using a spray dryer or the like. Then, after the granulation raw material is molded by a dry press to obtain a molded body, the molded body is degreased and then fired.

The sintered body thus obtained serves as a component element body of the positive temperature coefficient thermistor, and the positive temperature coefficient thermistor can be obtained by applying electrodes to this sintered body or a sliced body of the sintered body. Will be completed.

[0005]

By the way, in the above-mentioned conventional manufacturing method, there are many steps of handling the raw material in a dry process, and there are many routes in which impurities are easily mixed. For example, in a granulation process using a spray dryer, there is direct contact between the stainless steel used for this spray dryer and the raw material, so that Fe molecules are mixed in the raw material. If impurities such as Fe molecules are included in the sintered body that is the component body, the electrical characteristics such as the resistance value of the component body will not be stable.

Further, in the conventional manufacturing method, it is usual that about 6 to 7 days are required to complete the component body due to the large number of steps, and it is difficult to cope with the production of a small amount of a wide variety of products. There was also an inconvenience.

The present invention was devised in view of such conventional inconveniences, and aims to stabilize the electrical characteristics of a component body obtained by eliminating the step of handling a raw material in a dry process and to reduce the number of steps. It is an object of the present invention to provide a method for manufacturing a semiconductor porcelain component, which can be greatly reduced to facilitate the production of a large number of products in small quantities.

[0008]

In order to achieve such an object, the method of manufacturing a semiconductor ceramic component according to the present invention is
A step of adding water and a dispersant to the raw material powder and mixing them to prepare a slurry, a step of simultaneously performing pressurization and dehydration of this slurry to form a molded body, a step of drying the molded body, and a drying step. And a step of firing the formed body.

[0009]

According to this manufacturing method, the steps of handling the raw material in a dry manner are eliminated, so that the route of mixing impurities is reduced and at the same time,
The number of processes will be reduced to about half of the conventional one.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a semiconductor ceramic component according to the present invention will be described below with reference to the process chart of FIG. It is assumed here that the semiconductor ceramic component is a barium titanate-based positive temperature coefficient thermistor.

First, BaCO ₃ and Ti as materials
Prepare O ₂ , SrCO ₃ , Y ₂ O ₃ , MnO and SiO ₂ ,
By adjusting these and mixing them (Ba
_{0 ・ 895} Sr ₀ .1 Y ₀ .005) TiO ₃ +0.001 MnO +
After obtaining the raw material powder represented by the composition formula of 0.02SiO ₂ , 100 parts of this raw material powder was mixed with 16 parts of water and a dispersant.
Parts and 0.3 parts each and then mixed with hard balls for 24 hours to obtain a finely pulverized slurry.

Next, the obtained slurry is put into a predetermined molding die, and a molded body is molded by applying pressure using a press and simultaneously dehydrating. In this case, it is also possible to perform dehydration using a water-absorbing mold such as a plaster mold.

Further, the obtained molded body is placed in a dryer and dried at a temperature of 30 to 100 ° C. for 12 hours.

The dried molded body is placed in a firing furnace, calcined at a temperature of 1150 ° C. for 2 hours, and then main-baked at a temperature of 1350 ° C. for 1 hour without cooling. As a result, a sintered body as a component body is obtained.

The inventor of the present invention prepared, as a sample, a sintered body produced by the production method of the present invention and a conventional production method, that is, a disc-shaped sintered body having a diameter of 16 mm and a thickness of 2 mm. When the initial characteristics of each sample were investigated, the results shown in Table 1 were obtained.

[0016]

[Table 1]

That is, according to Table 1, in the sample obtained by the method of the present invention, the mixed amount of Fe molecules as impurities is reduced by one digit or more as compared with the sample obtained by the conventional method. It can be seen that the variation in resistance between the samples is significantly reduced. Further, it has been clarified that the samples manufactured by the manufacturing method of the present invention have improved withstand voltage, while the number of days required for manufacturing is reduced to one third.

By the way, the sample by the conventional manufacturing method used in this investigation was manufactured according to the conventional process described with reference to FIG. 2, and specifically, was manufactured according to the following procedure.

First, 150 parts of water is added to 100 parts of the same raw material powder as used in this embodiment, and then mixed with hard balls to obtain a slurry. Then, after dehydrating this slurry to obtain a dehydrated cake,
This was dried and crushed, and then calcined at a temperature of 1150 ° C. for 2 hours. Then, 15 parts of water and 15 parts of binder are added to 100 parts of the powder obtained by calcination.
After adding 0 part and 3 parts each and mixing to make a slurry, the slurry was granulated by spray drying to obtain a granulated raw material, which was dry-molded under a pressure of 1 t / cm ² .
Further, this molded body was degreased at a temperature of 500 ° C. for 30 minutes and then subjected to main firing at a temperature of 1350 ° C. to obtain a sintered body as a sample.

[0020]

As described above, according to the method for manufacturing a semiconductor ceramic component of the present invention, since the step of handling the raw material in a dry process is eliminated, the route of mixing impurities is reduced and the component element body is obtained. Impurities contained in the sintered body are reduced. As a result, the effect that the electrical characteristics of the component body can be stabilized can be obtained.

Further, since the number of steps is reduced to about half that of the conventional manufacturing method, the number of days required for manufacturing is greatly reduced, and it is possible to easily deal with small-quantity multi-product production.

[Brief description of drawings]

FIG. 1 is a process drawing showing a method of manufacturing a positive temperature coefficient thermistor according to an embodiment of the present invention.

FIG. 2 is a process chart showing a method of manufacturing a positive temperature coefficient thermistor according to a conventional example.

Claims (1)

[Claims] 1. A step of adding water and a dispersant to a raw material powder and mixing them to prepare a slurry, a step of simultaneously pressurizing and dehydrating this slurry to form a molded body, and drying the molded body. A method of manufacturing a semiconductor porcelain component, comprising the steps of: and a step of firing the dried molded body.