PURPOSE: To obtain silicon nitride powder of high purity consisting essentially of granular crystals and giving a sintered body with superior thermal and mechanical characteristics by working a silane compound contg. nitrogen into powder having a specified bulk density or above and by heating and thermally decomposing the powder.
CONSTITUTION: A silane compound contg. nitrogen such as silicon diimide obtd. by reacting silicon halide with ammonia or a decomposed product of the diimide is worked into a molded body or powder having ≥0.1g/cm3 bulk density with regard to contained silicon by press molding spray granulation. The silane compound is then heated and thermally decomposed to manufacture silicon nitride. At this time, the temp. rising speed in the temp. range of 1,350W1,550°C is preferably controlled to ≥15°C/min. Thus, the formation of needlelike crystals and prismatic crystals which deteriorate remarkably properties as a powdered starting material for sintering and the formation of β type silicon nitride are prevented, and α type silicon nitride powder consisting essentially of granular crystals is obtd.
KASAI KIYOSHI
TSUKIDATE TAKAAKI
| JP56149614Y | ||||
| JPS52130300A | 1977-11-01 | |||
| JPS54124898A | 1979-09-28 |