【摘要】 对不同生坯进行硅化处理后得到的反应烧结碳化硅的显微组织进行了研究.结果表明:选用αSiC+C粉的混合物作为生坯,SiC相的体积分数随生坯中wC的增加而增加,但过大的wC将使硅化后的试样出现残碳;选用碳毡作为生坯,反应烧结碳化硅的显微组织特点是C/Si反应生成的碳化硅颗粒均匀细小,并呈线状分布在游离硅中;浸渍过树脂的碳毡硅化处理后的显微组织特点是反应生成的碳化硅颗粒粗大且呈不均匀分布.X射线衍射结果也表明,反应烧结碳化硅陶瓷由游离Si、αSiC、βSiC组成,试样中不同晶型碳化硅的出现与C/Si反应的放热过程有关更多还原

【Abstract】 The microstructure of reaction bonded silicon carbide (RBSC) is examined. The experimental results show that the content of SiC in RBSC increases with carbon content while α SiC is chosen as a filler. However, the residual carbon would appear in specimens when the carbon content exceeds 30% by weight. Using carbon felt, the reaction formed SiC particles are small and uniform in size and distribution. However, when carbon felt is impregnated with phenol resin, the reaction formed SiC is nonuniform in size and distribution. X ray diffraction shows that the fabricated RBSC is composed of α SiC, β SiC, and free Si. The polytype of SiC is related to the reaction heat during sintering.更多还原