A fine powder of aluminum nitride having an average particle diameter of not more than 2 microns and comprising at least 94% by weight of aluminum nitride, at most 3% by weight of bound oxygen and at most 0.5% by weight as metal of metal compounds as impurities. The fine aluminum nitride powder is prepared from a fine alumina powder and a fine carbon powder as starting materials. The fine aluminum nitride powder provides a sintered body having a high purity and a high density such as at least 2.9 g/cm3. The fine aluminum nitride powder is also useful as a raw material for alpha-Sialon, beta-Sialon and AlN polytypes, as an addition aid in various ceramics.

Fine powder of aluminum nitride, composition and sintered body thereof and processes for their production

A structural ceramic material comprising single phase polycrystalline cubic aluminum oxynitride preferably with at least 97% of theoretical density which displays transparency and isotropic optical, thermal and electrical properties, an infrared cutoff at about 5.2 microns wavelength, and which shows no chemical or physical property change after heating in air (atmosphere) at 1100° C.

Process for producing polycrystalline cubic aluminum oxynitride

A one step combustion process for the synthesis of dense aluminum nitride compositions is disclosed. The process comprises igniting pure aluminum powder in a nitrogen atmosphere at a pressure of about 1000 atmospheres or higher. The process enables the production of aluminum nitride bodies to be formed directly in a mold of any desired shape.

One step process for producing dense aluminum nitride and composites thereof

Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.

Silicon nitride/silicon carbide composite powders

PURPOSE:To make it possible to continuously blank a sheetlike molded body by adding specified polyvinyl butyral resin to aluminum nitride powder. CONSTITUTION:Aluminum nitride powder having 1:1 molar ratio of aluminum: nitrogen and =80wt.% degree of butyral formation and 3,000-1,000,000 mol.wt., 0.01-10 pts.wt. one or more kinds of surfactants having 4.5-18 HLB such as carboxylated trioxyethylene tridecyl ether, <=15 pts.wt. plasticizer such as polyethylene glycol, 20-200 pts.wt. one or more kinds of org. solvents such as acetone and 0.1-10wt.% sintering aid such as calcium oxide basing on the total amt. of the aluminum nitride powder and the sintering aid. The resulting blend is molded into a sheet shape.

Aluminum nitride composition

A METHOD OF MANUFACTURING A MOULDED AND SINTERED MASS OF ALUMINUM NITRIDE COMPRISING MOULDING AN ADMIXTURE OF ALUMINUM NITRIDE POWDER, ALUMINUM OXIDE POWDER AND METALLIC ALUMINUM POWDER, NITRIDING THE MOULDED MASS IN NITROGEN OR AMMONIA GAS AT A TEMPERATURE BELOW THE MELTING POINT OF METALLIC ALUMINUM, AND SINTERING THE MASS IN NITROGEN OR INERT GAS AT TEMPERATURES RANGING FROM 1,600 TO 2,200*C.

Preparation of moulded and sintered aluminum nitride

PURPOSE:To manufacture alpha-type Si3N4 powder in a high yield by hydrolyzing a liq material prepared by adding carbon powder and Si3N4 powder or SiC powder to methyltrichlorosilane and by treating the resulting precipitate under heating in an N2 atmosphere CONSTITUTION:To methyltrichlorosilane (A) having >=99% purity fed by an amount required to form 1 part by weight of SiO2 by hydrolysis and calcination are added 01-2 parts carbon powder (B) having =99% purity and 0005-10 part crystalline Si3N4 powder and/or SiC powder (C) having =99% purity The prepared liq material is hydrolyzed, washed and dried The resulting precipitate is heated to 1,300-1,500 degC in an atmosphere contg N2 to cause reduction and nitriding reactions, or it is further treated under heating at 600-800 degC in an oxidizing atmosphere Thus, high quality alpha-type Si3N4 powder having a uniform and minute particle size and suitable for use as a heat resistant high stress material is obtd

Manufacture of alpha-type silicon nitride powder

Manufacture of high heat resistance and corrosion resistance material

PURPOSE:To prepare impalpable powder containing extremely high contents of alpha type Si3N4 at high efficiency, by executing nitrising reaction at a fixed temp to mixed powder, which uses amorphous and high purity SiO2 impalpable powder as raw material and limits added Si powder to less than 0.5mum.

Preparation of *a* type silica nitride powder

PURPOSE:To economically manufacture spherical SiC powder having a uniform and minute particle size by mixing silica powder or a compound forming silica powder in a calcining stage with carbon powder or a substance forming carbon and crystalline SiC and by calcining the mixture. CONSTITUTION:1 Part by weight as silica of silica powder or a compound forming silica powder in a calcining stage is mixed with about 0.5-4.0 parts as carbon of carbon powder or a substance forming carbon at a high temp. and about 0.01-0.2 part crystalline SiC powder. The powdered mixture is calcined in a nonoxidizing atmosphere. When carbon powder is added in excess, heating is carried out in an oxidizing atmosphere after calcination to remove residual carbon by oxidation. By this method the amount of added SiC is restricted to said low value, resulting in increased economical efficiency.

Inoue Hiroshi

Papers

Preparation of moulded and sintered aluminum nitride

Manufacture of alpha-type silicon nitride powder

Manufacture of high heat resistance and corrosion resistance material

Preparation of a type silica nitride powder

Manufacture of silicon carbide powder