| abstract |
A silicon nitride based sintered compact which comprises β-sialon represented by Si6-zAlzOzN8-z, where z representing the amount of each element forming a solid solution is 0.1 to 1, as a main phase, a grain boundary phase and Fe silicide particles, wherein the above grain boundary phase contains RE (III Group element of the Periodic Table)-Al-Si-O and the component percentage for Al, Si and Re in terms of Al2O3, SiO2 and RE2O3 is 5 to 50 mass % of Al2O3, 5 to 20 mass % of SiO2 and the balanced amount of RE2O3, and wherein the sintered compact contains said grain boundary phase in a rage of 20 vol % or less relative to 100 vol % thereof and the above Fe silicide particles in an amount of 0.02 to 3 mass % in terms of Fe relative to 100 mass % thereof. The above silicon nitride based sintered compact exhibits high resistance to thermal shock, and thus can be suitably used for a member for a molten metal, a member for hot working, a member for excavation and the like. |