【摘要】 采用包混工艺将酚醛树脂和硅粉制备成粉体先驱体,然后经碳化和煅烧,制备出球形度好、粒径分布窄且均匀的亚微米碳化硅粉体,其平均粒径约为0.1μm。亚微米碳化硅粉体的生成过程为硅–酚醛树脂核壳粉体先驱体经过800℃碳化处理生成硅–碳核壳粉料;在1500℃烧结,液态硅与碳壳内层反应生成碳化硅层;在热应力和液态硅的冲击下碳化硅壳破碎,形成的亚微米碳化硅颗粒进入液态硅中,通过碳化硅生成、破碎的不断循环,新的碳化硅层不断向碳层推进直至完全生成亚微米碳化硅球形粉体。更多还原

【Abstract】 A spherical submicron silicon carbide powder was prepared by carbonizing and calcining the precursor powder fabricated by coating phenolic resin on the surface of silicon powder through a coat mixing process. The obtained spherical silicon carbide pow-der has a narrow and uniform size distribution, and a mean particle size of about 0.1 μm. The formation mechanism of the submicron silicon carbide powder was investigated by analyzing the microstructure transformation. The formation process of submicron silicon carbide is as follows: (1) Silicon–carbon core–shell powder is obtained by carbonizing the precursor powder. (2) A silicon carbide shell is formed by the reaction of liquid silicon and carbon shell inner layer during sintering at 1500 ℃. (3) The silicon carbide shell is fragmented into powder under the effect of thermal stress and the attack of liquid silicon. (4) The continued repetition of the above two steps results in the formation of new layers of silicon carbide until submicron silicon carbide powder is finally formed.更多还原