JPS60108371A - Manufacture of beta-sialon sintered body - 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 In the present invention, an aluminum alkoxide solution is added to silicon nitride powder, mixed in a ball mill, and then evaporated to dryness. The resulting powder is calcined at 100 to 400°C, and then
A method of obtaining a β-dium iron sintered body by pressure sintering at 900°C, and a method of adding aluminum alkoxide to silicon nitride powder, hydrolyzing it, and then passing it through the mouth.
Calcined at ℃ and pressure sintered at 1700-1900℃ to obtain β
- It relates to a method for manufacturing a sintered body, characterized by obtaining a sialon sintered body.

β-Sialon has excellent hardness, wear resistance, #4 oxidation resistance, and corrosion resistance against high-temperature gases and molten metals, and is expected to be put to practical use as a high-temperature mechanical material such as gas turbine parts and rolling roll materials for steel and non-ferrous metals. It is a material that

β-Sialon sintered body is generally produced by hot-pressing a mixed powder of silicon nitride and alumina or under atmospheric pressure.
Manufactured by baking and hardening at 0 to 1900°C.

After weighing a predetermined amount of silicon nitride and alumina powder, they are mixed using a ball mill. Mixing of powders using a ball mill is normally carried out for 1 to 7 days, but disadvantages include the mixing of medium from the container and ball during mixing, and the difficulty of uniformly mixing the powders even after long mixing times. There is.

Since β-sialon is a brittle material, defects in the sintered body have a fatal effect on the strength of the sintered body. Defects in the sintered body include processing scratches on the surface of the sintered body.

There are pores, unsintered parts, coarse particles, etc. in the sintered body. Among these defects, pores, unsintered parts, and coarse particles in the sintered body are often caused by non-uniform mixing of raw material powders.

Therefore, mixing of powder is an important process in the production process of β-Sialon, and various studies have been made.

In addition to ball mills, mixing of powders can be done using atomizers,
Mixing using mechanical stirring, such as a Henschel mixer, has been carried out, but good results have not been obtained. In view of this, the present inventors conducted intensive research and found that when silicon nitride was mixed with an alumina source in a liquid phase, the mixing progressed uniformly and good sintering was achieved. The inventors have discovered that the present invention can be achieved by the present invention.

5. In other words, when producing a β-sialon sintered body, a solution of aluminum alkoxide dissolved in a solvent such as benzene, tetrahydrofuran, or methanol is added to silicon nitride powder, and the silicon nitride powder and alkoxide solution are thoroughly mixed. After cooling, it was evaporated to dryness to obtain a mixed powder of silicon nitride and aluminum alkoxide.
℃, calcining to obtain a mixed powder of silicon nitride and alumina, or benzene and aluminum alkoxide to silicon nitride.

After adding the solution dissolved in a solvent such as tetrahydrofuran or methanol and mixing thoroughly, the aluminum alkoxide is hydrolyzed while heating and stirring to form aluminum hydroxide, which is dried over the mouth and calcined at 600 to 900°C. hand,
We have discovered a method for obtaining a mixed powder of silicon nitride and alumina. In both of these methods, the alumina source present in the solution is precipitated from the liquid phase as a solid phase by evaporation to dryness or hydrolysis, so after calcination, the alumina source that is present in the solution is precipitated as a solid phase. The feature is that alumina can be deposited uniformly. When the mixed powder produced in this way is hot pressed, the strength increases β
- A sialon sintered body is obtained.

As the silicon nitride powder used in this experiment, general commercially available powder can be used, but it is preferable to use one with high purity and high a content. As aluminum alkoxide,
Aluminum methoxide (AI(OCI(3)31,
Aluminum ethoxide (AI(Oll:HCH))
, aluminum isopropoxy 33 F (AIfOC) [(CH3)213) and Hifrui: = UA! l-sha! J-/14 Sai)'
(AIfOC(CI+3)3]31 etc.) can be used.Aluminum alkoxides have different solubility in solvents depending on their type, so the aluminum alkoxide must be selected depending on the composition of Sialon.

The present invention will be described in detail using examples.

Example 1 Aluminum ethoxide (AI(QC■2cH3) 3
Dissolve 1 in 500 cc of benzene (CH).

23.33 g of 6 silicon nitride (sIgu, i) is added to this rB solution and mixed for 6 hours using a ball mill. The mixed solution is spray dried. The injection conditions are as follows. Droplet speed H
20cc/min, hot air blowing temperature: 140°C, hot air volume: 13
4/min, blown air amount: 0.3rn'/min. The spray-dried powder was heated in air at 300°C for 4 hours using a siliconite furnace.
Calcined for an hour. At this stage, a white, free-flowing powder is obtained. This powder was heated to 1850°C.

Sintering was performed under a pressure of 300 kg/cwt for 1 hour.

Table 1 shows the density, X-ray composition, and bending strength at room temperature of the sintered body. 5j3N4 and α-A1203 powder were weighed to have the same composition as in Example 1, mixed in a ball mill for 3 hours, and then heated at 1850°C. , sintered under a pressure of 300 kg/ci.
A comparison with the characteristic values of co-fired viscous material is shown.

Table 1・a-Characteristics of the sintered body obtained by evaporating S13N4 and aluminum ethoxide to dryness Example 2 Aluminum ethoxide (Person 1 (OC112C[
+3) 3) 15.88 g of Hensen 5ooITh+
23.33 g of silicon nitride was added to the mixture and mixed in a ball mill for 6 hours. Transfer the mixture to a microwave oven, heat with a magnetic cooler equipped with a hot plate, and add water dropwise using a pipette while stirring. The dropping rate is 10 drops/min. Approximately 300 ml of water is added dropwise, and benzene in the mixed solution is removed while heating and stirring. mixed n
1 is further heated while stirring to form a slurry.

This slurry was passed through a press filter at 60°C.
The sample was dried in a vacuum dryer maintained at -400° C., and then calcined in air at 750° C. for 4 hours. After loosening the calcined cake in a mortar, it was sintered at 1850° C. under a pressure of 300 kg/cut for 1 hour.

Table 2 shows the density, bending strength, and X-ray composition of the sintered body.

Characteristics of the sintered body manufactured from the powder obtained by hydrolyzing the mixture of The strength exceeds the strength of the sintered body obtained from.

Patent applicant: Director of the Agency of Industrial Science and Technology Kawa 1) Designated agent Hirobe (Director of the Agency of Industrial Science and Technology) Method 3? II] Relationship with the person who takes corrective action Patent applicant 1-3-1 Kasumigaseki, Chiyoda-ku, Tokyo (114) Director of the Agency of Industrial Science and Technology Kawa 1) Hirobe Showa sq.
28th of the month

Claims (2)

[Claims] (1) A method for producing a β-sialon sintered body, characterized in that a mixture of silicon nitride and aluminum alkoxide solution is used as a starting material (2) A method for producing a β-sialon sintered body, characterized in that a sample obtained by hydrolyzing a mixture of silicon nitride and an aluminum alkoxide solution is used as a starting material.