| 摘要 |
PURPOSE:To obtain an Si3N4-SiC combined sintered body having high density, dense fine structure, and improved strength, fracture toughness, and oxidation resistance, by sintering a mixture consisting of specified spherical amorphous powder with a sintering aid in a nonoxidizing atmosphere under pressure. CONSTITUTION:Fine powder obtd. by a gaseous phase reaction of an organosilicon compd.(e.g. hexamethyl disilazane) contg. no halogen in nonoxidizing atmosphere contg. NH3, is heat-treated in nonoxidizing gaseous atmosphere at 1,000-1,400 deg.C, and spherical amorphous powder having <=1mum average particle size and consisting of Si, C, N and O of 10.5-24.0wt.% C content is obtd. The amorphous powder is mixed with 1-15wt.% sintering aid(e.g. MgO), and sintered under pressure at 1,750-1,850 deg.C for 0.5-3hr under 200-400kg/cm<2> in nonoxidizing gas atmosphere, and sintering particle consists of primarily beta-Si3N4 and 35-80wt.% beta-SiC. Thus, an Si3N4-SiC sintered body having <=1mum particle size of uniformly dispersed Si3N4 particles and SiC particles, and having dense and fine structure, is obtd. |
