| 摘要 |
PURPOSE:To manufacture high-purity silicon nitride in good yield by collecting a product obtained by reacting a volatile silicon compd. with a decomposable nitrogen compd. contg. no oxygen in a hot air current, on a vanishing filter material. CONSTITUTION:A vanishing filter material 7 (fibrous carbon, powdered silicon dioxide etc.) is provided in a furnace consisting of a refractory furnace wall 4, a heating element 5 and an outer wall 6. The inside of the furance is filled with an inert gas atmosphere and kept at 900-1,400 deg.C. Then a decomposable nitrogen compd. such as ammonia or hydrazine contg. no oxygen from a duct 1 and a volatile silicon compd. such as SiCl4, HSiCl3 and SiF4 from a duct 2 are introduced into the furnace in a 1.5-6 ratio of N/Si (formula weight ratio) to react with each other. The obtained powdered silicon nitride is collected on the filter material 7. (symbol 3 is a gaseous by-product discharging duct) Then the silicon nitride is taken out together with the filter material 7 which is vanished by means of calcination etc. to obtain the high-purity powdered silicon nitride.
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