| 摘要 |
PURPOSE:To produce high-alpha type silicon nitride powder having a high specific surface area without a need for the post-treatment requiring much labor such as a special pulverizing step or wet purifying treatment by using relatively inexpensive metallic silicon. CONSTITUTION:This method for producing silicon nitride is to nitride a raw material to be nitrided, containing metallic silicon powder and having a thickness (d) in an atmosphere containing nitrogen and/or ammonia under the following conditions (1) to (4): (1) the oxygen content in an area ranging from the surface of the raw material to be nitrided to a depth of [(d)/10] is <2wt.% up to 30% nitriding ratio; (2) the rate of reaction is <=4%/hr; (3) the rate of reaction at 10-90% nitriding ratio is >=0.5%/hr and (4) the increment in the rate of reaction at <50% nitriding ratio <=0.6%/hr<2>. |
