| 摘要 |
PURPOSE:To obtain a silicon nitride having a high alpha conversion rate and a low content of oxygen by nitriding a raw material consisting of a mixture of a metallic silicon powder contg. trace oxygen and a silicon nitride powder in a specified ratio and with the bulk density specified. CONSTITUTION:A raw material contg. 100 pts.wt. of metallic silicon powder contg. 0.2-0.5wt.% oxygen and 30-100 pts.wt. of silicon nitride powder and having <=1g/cm<3> bulk density is prepared. The raw material is nitrided to obtain a silicon nitride having >=90% alpha conversion rate, >=25m<2>/g specific surface and <=1.4g/cm<3> bulk density, and the silicon nitride is pulverized to obtain silicon nitride powder. |
