| 摘要 |
PURPOSE:To obtain a silicon nitride-based sintered compact low in deterioration of strength from a room temperature to a high temperature, especially to 1500 deg.C and having excellent mechanical strength. CONSTITUTION:A formed body having 50-65% relative density and having a composition composed of 30-80wt.% of silicon nitride, 19.5-69.5wt.% of silicon and 0.5-20wt.% of one or more kinds of oxides of group IIIa elements in the Periodic Table is subjected to nitriding treatment by carrying out heat treatment in a nitrogen-containing atmosphere so that the content of beta-silicon nitride in total silicon nitride may become <=10wt.%, and then, this nitride is baked in a non-oxidizing atmosphere containing nitrogen. |
