| 摘要 |
PURPOSE:To cheaply produce high purity alpha-type silicon nitride with good sintering property capable of giving moldings of a complex shape while saving heat evergy by nitriding mixed powder of metallic silicon and a Ca cpd. at a temp. below the m.p. of metallic silicon. CONSTITUTION:To metallic silicon of a purity above 95% and a grain size below 150 mesh is added 0.2-1% as CaO of a calcium cpd. as a nitriding accelerator. This powder mixt. or its pellets, briquettes, etc. are charged into a nitriding furnace and nitrided at below the m.p. (1400 deg.C) of metallic silicon and above 1100 deg.C with nitrogen or NH3-contg. gas introduced, forming alpha-type silicon nitride. Thus, silicon nitride can be obtd. contg. more than 90% of alpha-type silicon nitride. |
