SiC繊維へのCVD-C, SiCコーティング層の組成と微構造

抄録

Nicalon-SiC fibers were coated with C, SiC at 1200°C and 1300°C by chemical vapor deposition to improve the thermal stability of the fibers and to modify fiber-matrix interface. A coating layer having thickness of 0.1-25μm was obtained by controlling the CVD conditions. According to the AES and SEM analyses, a carbon rich layer (0.1-0.5μm) was deposited on the fiber surface initially. Nuclei of silicon carbide were formed on the surface of the carbon rich layer and finally whiskers or domed grains of silicon carbide were grown. The deposition rates of the carbon rich layer and silicon carbide layer were about 0.02μm/min and 0.65μm/min, respectively. It was observed by XRD and TEM that domed grains, which were the mixtures of β-SiC and small amount of α-SiC, consisted of subgrains and contained stacking faults in high density.