采用激光拉曼光谱仪和扫描电子显微镜对以C2H2+H2和C2H2+C3H8+Ar为反应气体, 通过直流加热化学气相沉积工艺在SiC纤维表面制备的碳涂层的微观结构及断口形貌进行了研究。 结果表明, 两种碳涂层的拉曼光谱中1 350, 1 400～1 500和1 600 cm-1附近均观察到D, D”和G特征峰的存在。 碳涂层具有类似石墨的片层结构, 结构中微晶的排列显示出一定的无序性, 并含有少量非晶态碳。 随着沉积温度的升高, 微晶尺寸有所增加, 结构中的均匀性和有序度也得到改善。 断口观察发现, 采用C2H2+H2制备的碳涂层平整、 致密; 而由C2H2+C3H8+Ar得到的碳涂层呈曲折的层片状。 分析表明, 这主要与结构中的有序度和均匀性有关。

The microstructure and fracture morphology of carbon coatings were investigated by means of Raman spectrometer and scanning electron microscopy (SEM), which were prepared by chemical vapor deposition (CVD) on the surface of SiC fiber with C2H2+H2 and C2H2+C3H8+Ar as the reactants. The results show that the spectra of the carbon coating contain characteristic D, D” and G peaks around 1 350, 1 400～1 500 and 1 600 cm-1 respectively, indicating a disordered-graphite structure with a small amount of amorphous carbon. The size of microcrystallite increased with the increase in temperature, and the degree of order, together with the uniformity in the carbon coating was improved simultaneously. It was observed on the fracture surface that coatings prepared by C2H2+H2 are flat and dense, whereas those prepared by C2H2+C3H8+Ar exhibit a flexural lamellar structure, which should be attributed to the relatively low degree of order and the non-uniformity in the microstructure.