辐照和碳化对SiC空心微球的影响

Effects of irradiation and carbonization on Si-C hollow microspheres

以聚碳硅烷（PCS）为原料，通过炉内成球技术制备SiC空心陶瓷微球，讨论辐照交联和高温碳化对SiC陶瓷微球化学成分、成键结构和表面特性的影响。结果表明，PCS在热处理过程中的失重率约为35％，其分解温度在400~800℃之间。微球经电子束辐照后会生成以Si-C-Si和Si-O-Si骨架结构为主的三维网络交联结构。碳化过程使Si—CH3键，Si—H键和C—H键断裂，生成以Si—C为主的无定形态SiC。辐照的均化作用使高温热处理碳化的微球能够维持完好的球壳结构，且具有更好的表面粗糙度和平整性。

SiC ceramic materials are well-known for its excellent thermo-mechanical properties, and its advantages compared with hollow glass microspheres make it one of the candidates for ICF target application. SiC ceramic microspheres were fabricated by drop-tower technique by using polycarbosilane （PCS） as raw material. The reaction mechanism of precursor pyrolysis and the effects of irradiation and carbonization on the SiC hollow microspheres were investigated. The results show that the ceramic yield at 850 ℃ is 65 ℃ and the temperature at which the PCS begins to decompose is from 400 ℃ to 800 ℃. Bridge structure of Si-- C--Si or Si--O--Si was formed in the irradiated products, and in the process of pyrolysis, Si--H bonds, C H bonds and Si-- CH3 groups were partly broken down, the structure of Si--C--Si was formed. In addition, the influence of irradiation is to main- tain the spheres frame during carbonization at high temperature and to increase the surface finish quality and evenness of hollow SiC ceramic microspheres.