JPS6186476A - Manufacture of porous 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] Object of the Invention (Industrial Application Field) The present invention relates to a manufacturing method for manufacturing a porous ceramic using an organic material having a two-dimensional or three-dimensional network structure. It is.

(Conventional technology) Traditionally, porous ceramics are used for filtration shrines and two ventilation plates.

It is used for various purposes such as air diffusers and catalyst carriers.

As a manufacturing method thereof, there is a method disclosed in Japanese Patent Publication No. 57-21507.

This conventional method consists of: 1. A conventional polyurethane foam, which has no affinity for ceramic slurries and in which a cell membrane is present, is immersed in a solution of an alkaline hydroxide substance.

■ Apply ceramic slurry to polyurethane foam by dipping.

■ When polyurethane foam is immersed in an alkali hydroxide solution and ceramic slurry is attached by dipping, excess ceramic slurry is removed by centrifugation.
It is removed using a pressure air blowing method, a vacuum suction method, etc. to form continuous pores.

■ Polyurethane foam to which ceramic slurry is attached by def-tubing is dried and then fired.

Porous ceramics are manufactured by sequentially performing the following four steps.

However, the above conventional method has the following problems.

(1) Above all, this method uses a centrifugal separation method to remove excess ceramic slurry attached by dipping to form continuous pores, so the number of pores is 20 to 30 per inch. As described above, if the pores are connected with a diameter of around 1 mm or less, excess ceramic slurry etc. cannot be removed uniformly, and pores with a pore diameter of 1 mmΦ or less cannot be formed.

(2) In order to decompose and remove only the internal skeleton, leaving behind the ceramic slurry attached to each skeleton of the polyurethane foam, in addition to the continuous pores inside the structure, there are gaps corresponding to the skeleton of the polyurethane foam. formed and not robust in strength.

Therefore, today, the methods for creating continuous pores with a pore diameter of 1 mmΦ to 100 μΦ in ceramics are mainly based on organic materials (starch, bulbs, sawdust, cellulose fibers, carbon powder, etc.). , ) is homogeneously dispersed in the ceramic raw material in advance during raw material preparation or before press molding, and then the above organic substances are thermally or oxidatively decomposed and disappeared during the firing process using a molding method such as pottery molding or press molding. A method has been adopted in which pores are formed in the sintered body.

However, even if organic materials are dispersed homogeneously, it is difficult to homogeneously disperse organic materials because the specific gravity is greatly different from that of Hiramic, and the formation of open pores is largely due to chance. Not only is it difficult to reproduce porous ceramics, but the reality is that high strength cannot be obtained due to the presence of closed pores.

(Problems to be Solved by the Invention) The problems to be solved by the present invention are particularly
~11IIlΦ continuous pores without relying on chance,
The goal is to make it reproducible.

(Means for solving problems) The technical measures taken by the present invention are as follows.

(a) An organic material having a two-dimensional or three-dimensional network structure is embedded in a cast molded body.

(b) Demoulding (u The oxidizing acid is fired in a non-oxidizing atmosphere.

(Operation) The operation of the technical means of the present invention is that organic substances (two-dimensional or three-dimensional network structure) are contained in the cast molded body cast in the six-sided mold.
is buried, demolded, dried and fired to decompose and remove the organic substances.

(Example) The present invention embeds a blood substance having a two-dimensional or three-dimensional network structure in a cast molded body, and after demolding, it is oxidizable or non-oxidizable.
It is fired in an i-forming atmosphere.

The first step is a step of embedding a zero-like substance having a two-dimensional or three-dimensional network structure into a cast molded body.

(The geometrical object Y1 is formed by forming a thin organic wire such as a thin sponge wire or a thin plastic wire to have a two-dimensional or three-dimensional network structure; b), so it is cut into a desired three-dimensional shape.

The organic substance is formed by braiding organic thin wires having a wire diameter of 100 μm to 1 mm in diameter from several to several dozen pieces per inch.

Cast molded bodies are alumina, zirconia, silicon carbide, silicon nitride, sialon, and cordierite.

The main component is a desired ceramic powder such as Sw
The slurry is cast into the V, and the organic substance is embedded in the molded body.

At this time, it is possible to bury an organic material having a size that covers the entire area within the 6-shaped mold, but - C1 material of a desired size and shape that fits in a desired location such as a corner may be buried. , this may be buried. This selection is made depending on the intended use.

The second step is to decompose and remove organic substances by baking in an oxidizing or non-oxidizing atmosphere after demolding and drying.

This step refers to a general firing step, and this raw material is fired in a firing furnace at a desired temperature, such as 1600° C. in the case of alumina, for several hours to form a porous sintered body. At this time, internal organic substances are decomposed and removed to form continuous pores.

(Invention glue J Song) The present invention is based on the following: An organic material having a two-dimensional or three-dimensional network structure as shown in "L" is embedded in a cast molded body, and after demolding, an oxidizing or non-oxidizing PL atmosphere is used. Since the precipitate 71 is decomposed and removed by firing in the ceramic, it provides an epoch-making manufacturing method that can reproducibly form continuous pores with a diameter of 100 μm to 1' mm in the ceramic without relying on chance. obtain.

In addition, all organic substances are decomposed and removed within the ceramic, and all the communicating pores thus formed can be used as ventilation holes. Therefore, it is possible to achieve the same amount of ventilation with a small porosity, so it also has high strength as a structure.

Further, according to the manufacturing method of the present invention, it is possible to provide a desired porous portion at a desired location of the dense ceramic structure.

Therefore, the intended purpose can be achieved.

Proceedings 11 December 4, 1989 1. Indication of the case 1989 Patent Application No. 209439 2. Name of the invention Method for producing porous hiramik 3. Person making the amendment Case related to the patent application Person name (name>
(AO8) Totokiki Co., Ltd. 4, Agent Address: Mei III, 5-14-7 Hakusan, Bunkyo-ku, Tokyo
page 3, lines 18 to 19 [, organic substances (
Starch...powder, )", [, molar substances (starch, pulp, sawdust, cellulose fiber), carbon powder,)"
Correct to.

Claims (1)

[Claims] It is characterized by embedding an organic material having a two-dimensional or three-dimensional network structure in a cast molded body, and decomposing and removing the organic material by firing in an oxidizing or non-oxidizing atmosphere after demolding. A method for producing porous ceramics.