Method of making .alpha. type silicon nitride powder

DETAILED DESCRIPTION Accordingly, one object of the present invention is to provide a method of manufacturing high quality .
alpha.
silicon nitride in high yield.
Another object of the invention is to provide a high quality .
alpha.
silicon nitride.
Still another object of the invention is to provide a high quality .
alpha.
Si.
sub.
3 N.
sub.
4 powder which is suitable for use as refractory material in high temperature and high stress environments.
Briefly, these objects and other objects of the present invention as hereinafter will become more readily apparent can be attained in a method for preparing .
alpha.
silicon nitride powder by (a) mixing silica powder, carbon powder and metallic silicon powder; (b) heating said mixture in a non-oxidizing atmosphere containing nitrogen such that reduction and nitridization reactions occur which produce silicon nitride; and (c) heating said silicon nitride in an oxidizing atmosphere to effect decarbonization of said silicon nitride.