| 摘要 |
PURPOSE:To suppress the deterioration of strength and to improve creep characteristics, mechanical characteristics and oxidation resistance by sintering a compact contg. Si3N4 contg. excess oxygen, the oxide of a group IIIa element of the periodic table and SiC in a nonoxidizing atmosphere. CONSTITUTION:A compsn. contg. 92-99.5mol% Si3N4 having <=1mum average particle diameter and <=2wt.% excess oxygen content and 8-0.5mol% oxide of a group IIIa element of the periodic table is blended with 1-100 pts.wt. SiC based on 100 pts.wt. of the compsn. to obtain a mixture contg. <=0.5wt.%, in total of Al2O3, MgO and CaO as impurities. This mixture is compacted into a desired shape and sintered at <=1,900 deg.C in a nonoxidizing atmosphere to produce an Si3N4-SiC combined sintered compact contg. Si3N4 grains having <=1mum average grain diameter and 2-10 average aspect ratio, SiC grains having <=1mum average grain diameter and <=0.5wt.%, in total of the oxides of Al, Mg and Ca. |
