| 摘要 |
PURPOSE:To manufacture uniform and fine alpha-silicon nitride powder in a high yield by adding specified amounts of carbon powder, silicon nitride powder and Be or the like to silicon oxide powder and heat treating the mixture in an atmosphere contg. nitrogen. CONSTITUTION:To 1pt.wt. of silicon oxide powder are added 0.4-4pts. carbon powder, 0.01-0.1pt. silicon nitride powder and at least one kind of component selected among Be, Sr, Sn, Ge, Ti, Hf and compounds thereof as a catalyst by 0.001-0.1pt. (expressed in terms of Be, Sr, Sn, Ge, Ti and Hf). The mixture is heat treated at about 1,300-1,500 deg.C in an atmosphere contg. nitrogen to manufacture alpha-Si3N4 by reduction and nitriding. In order to remove the remaining carbon, the reaction product is heat treated at about 600-800 deg.C in an oxidizing atmosphere.
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