中文摘要：

以甲基三氯硅烷和乙炔为源气体，用直流电热三级化学气相沉积法制备了带有碳涂层的钨芯SiC纤维，利用扫描电子显微镜、激光抟曼光谱仪和透射电子显微镜等方法观察了纤维的微观组织结构．结果表明，所制备的SiC纤维由钨芯、W／SiC界面反应层、两层SiC和表面碳涂层组成．纤维中的SiC主要为β-SiC，而且有明显的〈111〉择优取向，沉积过程中出现的Si共沉积等缺陷，导致其晶格紊乱．拉曼光谱分析表明，乙炔裂解得到的表面碳涂层由无定型碳和石墨组成．

英文摘要：

Continuous silicon carbide （SIC） fiber with carbon coating was fabricated by three-stage chemical vapor deposition （CVD） on tungsten filament heated by direct current （DC）, using CH3SiCl3 ＋H2 as gaseous reactant for SiC sheath and C2H2 for the outmost carbon coating, respectively. Microstructure of the SiC fiber was examined by X-ray diffraction （XRD）, scanning electron microscope （SEM）, Raman spectroscope and transmission electron microscope （TEM）. The results show that the SiC fiber consists of tungsten core, a W/SiC interfacial reaction zone, two layers of SiC with total thickness of 41μm and an outermost carbon coating of about 2 μm in thick. The deposited SiC is mainly composed of β-SiC, and exhibits strong 〈111〉 fiber texture with abundant growth defects, such as co-deposit of free silicon and stacking faults, leading to the lattice imperfection of the SiC sheath. Raman spec- trum indicates that the outmost carbon coating decomposed from C2H2 involves a mixture of amorphous carbon and graphite crystallite.