沉积温度对碳芯SiC 纤维微观结构的影响

以沥青基碳单丝为基体,一甲基三氯硅烷为碳化硅前驱体,使用通电加热的冷壁CVD工艺,温度在1 473～1 773 K,制备了碳芯SiC纤维.采用扫描电子显微镜和拉曼光谱对纤维的表面形貌及结构进行了表征,研究了沉积温度对其结构的影响.结果表明,SiC涂层为β-SiC晶型.沉积温度的升高引起了沉积速率的增加以及SiC涂层晶粒尺寸的长大.同时,导致碳芯中心区域发生结构重排,引起了该区域取向度的提高以及晶粒尺寸的减小.

Effects of Deposition Temperature on Microstructure ofSilicon Carbide Filaments With Carbon Core

By using pitch based carbon filaments as the substrate in cold wall chemical vapor deposition
process, silicon carbide filaments were prepared from methyltrichlorosilane and hydrogen system. The effect of deposi tion temperature (from 1 473 K to 1 773 K) on microstructure of as prepared fibers was investigated by scanning elec tron microscopy and Raman spectrascopy. The results shows that the main crystalline phase of coating is SiC. The increase in deposition temperature leads to the increase of deposition rate and the enlargement of grain size of SiC coat ing. Meanwhile, as the deposited temperature increases, the microstructure rearrangement of the central region of car bon core results in the decrease of grain size and better orientation.