| 摘要 |
PURPOSE:To improve the toughness of a molded article composed mainly of SiC by baking the article under specific condition. CONSTITUTION:The objective composite sintered ceramic material is composed mainly of Si3N4 at the surface layer and SiC and Si3N4 at the core part and has a compositional gradient continuously increasing the SiC/(SiC+Si3N4) ratio from the surface layer toward the core part. It can be produced by mixing (A) SiC powder having an average particle diameter of 0.1-2mum with (B) <=10wt.% of carbon powder or a substance capable of forming carbon by baking, e.g. a phenolic resin, coal tar pitch or a boron-containing compound and (C) a binder, forming the mixture, calcining at 200-800 deg.C and baking the calcined article in an atmosphere capable of forming Si3N4 and carbon by the reaction of SiC and nitrogen. |
