JPS60210569A - Composition for ceramics - 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 The present invention relates to an easily sinterable ceramic composition containing a specific compound.

Conventionally, as a composition for ceramics, a composition consisting of a ceramic material and a sintering aid has been used. The composition is mixed with a molding binder if necessary, then molded into a desired shape, degreased, and sintered without degreasing to produce a ceramic product. Here, the sintering aid is added to facilitate sintering, and it is desirable to form a powder mixture that is as finely dispersed as possible, and is generally pulverized by a ball mill.

However, due to the mixing of powders, there is a limit to dispersibility.
If the amount added is increased until a sufficient sintering effect is obtained, the high temperature strength of the ceramic product will decrease.

In view of the above problem, the present inventors focused on the fact that polysilsesquioxane becomes liquid with or without the addition of a solvent, and as a result of intensive research, they found that It was discovered that a composition consisting of the following exhibits easy sinterability, and the present invention was achieved.

That is, the present invention relates to a ceramic composition comprising a ceramic material and polysilsesquioxane.

The composition for ceramics of the present invention is easily sinterable and has great utility value in the production of ceramics.

The ceramic material in the present invention is one or more of alumina, zirconia, zircon, mullite, cordierite, forsterite, steatite, silicon carbide, silicon nitride, and sialon. In addition, sintering aids such as magnesia, magnesium carbonate, calcia, calcium carbonate, ittria, beryllia, sericia, magnesium oxide, chromium oxide, clay, etc. can be used in combination as long as they do not impair the purpose of the present invention. be.

The polysilsesquioxane used in the present invention is RISi
(OR2)3, [R1 in the formula is a hydrocarbon group such as an alkyl group, an aryl group, an alkenyl group, an alkynyl group,
R2 is an alkyl group or an aryl group, and R1 and R2 have 1 to 20 carbon atoms. ], or synthesized by condensation polymerization using R15icIa as a raw material monomer, and has the general formula (R
It is expressed as tSIOi, θn. Examples of these compounds include polymethylsilsesquioxane and polyphenylsilsesquioxane.

Furthermore, even if polysilsesquioxane has a structure other than a ladder structure in which unreacted S1-0R2 groups remain, there is no problem in the present invention and the polysilsesquioxane is applicable. can do.

The molecular weight of the polysilsesquioxane used in the present invention is not particularly limited, but from the viewpoint of workability, the molecular weight is 400-100.
A range of 0000 is preferred.

In the present invention, polysilsesquioxane is used as a solvent solution, if necessary. Suitable solvents include alcohols, ketones, esters, aromatics, halogens, etc., such as isopropyl alcohol,
Examples include benzene, acetone and toluene.

The composition of the invention preferably consists of 0.1 to 3.0 parts by weight of polysilsesquioxane per 100 parts by weight of ceramic material. If the proportion of polysilsesquioxane is too small, no sintering effect will be obtained, and if it is too large, the high temperature strength will decrease.

The method of mixing the ceramic material and the polysilsesquioxane is not particularly limited, but from the purpose of the present invention, it is preferable to add and mix the polysilsesquioxane in the form of a liquid such as a solvent solution.

The composition is molded into a desired shape by a molding method such as casting, extrusion, pressing, or injection, with the solvent removed or with the solvent still contained, and a known molding binder added if necessary. When using a binder for
After degreasing at a temperature range of 0°C, the product is sintered at a temperature of 800 to 1800°C in an atmosphere suitable for ceramic materials to produce a ceramic product.

As described above, the composition for ceramics of the present invention is easily sinterable, and is therefore suitable for mechanical parts such as pulp, nozzles, shafts, cutting tools, high-temperature jigs, heat exchangers, stud bottles, skid buttons, and high-temperature It is used for a variety of purposes, including as a shrine, heat-resistant coating agent, and heat-resistant adhesive.

Examples will be described below. All percentages and parts in the examples are by weight.

Examples 1 and 2 Relative viscosity (1% benzene liquid) obtained by condensing 100 parts of low soda alumina LS-42 (manufactured by Sumitomo Chemical Co., Ltd., alumina powder) and methyltriethoxysilane by salt ethanol reaction
1 part or 5 parts of polymethylsilsesquioxane with ηrel=3 and 80 parts of isopropyl alcohol were mixed in a ball mill, dried at 50°C, and then heated at 200°C for 30 minutes.
The mixture was heated for 1 minute to obtain a powder of the composition.

100 parts of this powder, 10 parts of CMC 2% aqueous solution, solid content 3
10 parts of 0% wax emulsion and 70 parts of water were added to form a slurry, and the slurry was granulated using a spray dryer. A rod-shaped molded product of 5 x 5 x 40 mm was obtained by press molding, heated from room temperature to 500°C at a temperature increase rate of 5°C/hour, and sintered at 1550'c for 2 hours. As shown in Table 1, it can be seen that the composition of the present invention has easy sinterability and excellent high-temperature strength.

Comparative Example 1 Sintered crystals were obtained in the same manner as in Example 1 except that 1 part of polymethylsilsesquioxane in Example 1 was replaced with 1 part of silica powder as shown in Table 1. The results are shown in Table 1.

Table 1 Example 3 Relative viscosity (3%) obtained by hydrolyzing 100 parts of DENKSi3N4 powder 5N-73 (silicon nitride manufactured by Denki Kagaku Co., Ltd.), 1 part of ittria, and phenyltrichlorosilane, and then dehydrating it at high concentration and high temperature. Benzene liquid) 1 part of polyphenylsilsesquioxane with ηre1=3 and 80 parts of toluene were mixed in a ball mill and then dried at 80°C to obtain a powder of the composition.

Thereafter, in the same manner as in Example 1, 5 rod-shaped molded products of 5M and 40m were obtained, heated from room temperature to 700°C at a temperature increase rate of 5°C/hour, and then sintered at 1700°C for 1 hour in a nitrogen atmosphere. Table 2
These results show that the composition of the present invention exhibits easy sinterability.

Comparative Examples 3 to 4 Sintered crystals were obtained in the same manner as in Example 1 except that polydimethylsiloxane and silica powder having the same weight of molecules [5000] were used instead of the polyphenylsilsesquioxane in Example 2.

Table 2 Agent Patent Attorney Katsutoshi Takahashi Procedural Amendment (Voluntary) May 2, 1980 Director General of the Patent Office Kazuo Wakasugi 2 Title of Invention Ceramic Composition 3 Comparison with the case of the person making the amendment Related Patent applicant: 35-58 Sakashita, Itabashi-ku, Tokyo 174 (28
B) Dainippon Ink & Chemicals Co., Ltd. Representative: Shigeru Kuni Mura 4, Agent Address: 103 3-7-20 Nihonbashi, Chuo-ku, Tokyo Dainippon Ink & Chemicals Co., Ltd. Detailed description of the invention in the specification 6. Contents of the amendment (1) "Degrease, j" in line 13 of page 1 of the specification is corrected to "degrease, or J."

(2) Page 3, line 4 of the same I am corrected.

(3) The column for density in Table 2 on page 7 is corrected as follows.

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Claims (1)

[Claims] A composition for ceramics comprising a ceramic material and polysilsesquioxane.