Microstructure and composition of silicon carbide films deposited on carbon fibers by chemical vapor deposition

The microstructure and the composition of CVD silicon carbide films used as fiber coatings in composite materials were investigated by photoelectron spectroscopy and transmission electron microscopy. The films with a uniform thickness of 50 nm consisted of small SiC grains with a mean diameter of 15 nm and showed a stripe contrast in bright field images. Large grains with diameters in the dimension of the film thickness were used for imaging the lattice structure by high-resolution electron microscopy. The results are discussed as a polytype of cubic lamellae of a few nanometers and intermediate random stacking sequences of hexagonal structure.