| 摘要 |
PURPOSE: To produce a silicon nitride sintered material having superior high- temperature strength and fracture toughness when compared with a conventional product by depositing crystals in a grain boundary phase. CONSTITUTION: This is a silicon nitride sintered material composed of <=20wt.% of a grain boundary phase of and a particulate phase of Si3 N4 and/or sialon in the remaining main phase. The ratio of quantity of β-Si3 N4 and/or β'-sialon based on the main phase is 0.5-1.0. The grain boundary phase contains Re2 A7 O17 (Re is an element of the group 3A and A is an element of the group 4A) as a crystal component. The objective sintered material is produced by adding thereto AO2 , Re2 O3 , etc., sintering the mixture and subsequently treating this mixture at 1050-1600 deg.C for nucleation and crystal growth. |
