| 摘要 |
PROBLEM TO BE SOLVED: To prevent a segregation of components and ununiform dispersion and to improve sinterability by heat-treating a powdery mixture of silicon powder with carbonaceous powder and a sintering aid in an atmosphere contg. gaseous nitrogen. SOLUTION: A powdery mixture of 81.2-97.6wt.% silicon powder having 0.2-20μm average particle diameter with 2.4-18.8wt.% carbonaceous powder having <=20μm average particle diameter and 5-20wt.% sintering aid is heat- treated at 1,000-1,450 deg.C in an atmosphere contg. gaseous nitrogen under >=1kgf/ cm<2> pressure to cause the nitriding and carbonization reactions of silicon and the heat-treated mixture is pulverized to obtain the objective crystalline silicon nitride-silicon carbide composite powder having 7-40m<2> /g specific surface area. An org. or inorg. binder is added to the composite powder and compacted. The resultant compact is fired at 1,600-2,200 deg.C for 1-5hr in a nonoxidizing atmosphere under 10kgf/cm<2> pressure to obtain the objective combined sintered compact in which the weight ratio between silicon carbide and silicon nitride is 5:95 to 50:50. |
