| 摘要 |
PURPOSE:To obtain composite material of beta-type silicon nitride whiskers having arbitrary porosity by providing a coating layer of metal and/or ceramics on the surface of a molded body of beta-type silicon nitride whiskers by a CVD method. CONSTITUTION:The porous composite material of beta-type silicon nitride whiskers having 0.15-1.1g/cm<3> density, >=25kg/cm<2> flexural strength, >=45kg/cm<2> hardness and >=30kg/cm<2> compression strength is obtained by forming the coating layer of metal and/or ceramics (selected from among Ta, W, Mo, SiC, TiC, BN, TiN and TiB2) on a molded body wherein the molded body not less than 90% is made of beta-type silicon nitride whiskers (whiskers not less than 80wt.% have 0.1-5mum diameter and 2-100mum length) and the whiskers are brought into contact with each other and fixed at one or more positions per one piece of the whiskers by a CVD method. The porosity of this composite material can be regulated to 0-90% by changing the feeding rate, feeding time and pressure of reactive gas in the CVD reaction. |
