| 摘要 |
PURPOSE:To produce a material having improved strength at high temp. and improved oxidation resistance required at the time when ceramics is applied to a heat resistant member and a wear resistant member. CONSTITUTION:Powders of yttrium oxide, hafnium oxide and silicon nitride are mixed so as to obtain a compsn. consisting of 0.1-15wt.% yttrium oxide, 0.1-15wt.% hafnium oxide and the balance silicon nitride and the resulting mixture is sintered by hot pressing at 1,600-1,850 deg.C under 20-40MPa pressure in an atmosphere of gaseous nitrogen to obtain a silicon nitride sintered compact having the above-mentioned compsn. This sintered compact contains Y2Hf2O7 crystals formed at the grain boundaries and is excellent in strength at high temp. and oxidation resistance. |
