| 摘要 |
PURPOSE:To manufacture a silicon nitride sintered compact having high density and high strength by applying reduction treatment to the surface silica layer of powdered silicon nitride and subjecting the above powder to compacting and then to sintering. CONSTITUTION:Powdered silicon nitride is subjected to heating treatment in NH3 gas at about 800-1,600 deg.C, by which the surface silica layer of the above powdered silicon nitride is subjected to reduction treatment to undergo surface modification. Further, at the time of heating, gaseous mixture of NH3 and hydrocarbon (CmHn) can be used instead of NH3 gas. Subsequently, the above powdered silicon nitride is compacted into a green compact, which is subjected to sintering treatment. By this method, the silicon nitride sintered compact having high strength and high density can be obtained. |
