Preparation of high alpha-type silicon nitride powder

摘要

Silicon nitride powder is prepared by nitriding metallic silicon powder in a nitriding gas atmosphere at a temperature of 1, 000° C.- 1,500° C. Midway the nitriding step, the nitrided product is heat treated in an inert non-oxidizing gas atmosphere or vacuum at a temperature higher than the nitriding temperature, but lower than 1,600. degree. C. The product is nitrided again, obtaining high &agr; -content silicon nitride powder.