Preparation of nanosized silicon carbide powders by chemical vapor deposition at low temperatures

Liquid carbosilane was synthesized and analyzed by infrared (IR) and H-NMR (nuclear magnetic resonance) spectroscopy. Silicon carbide (SiC) powders were prepared by chemical vapor deposition (CVD) at 850°C and 900°C from liquid carbosilanes. The product powders were characterized by IR spectroscopy, X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Results show that liquid carbosilane synthesized was the mixture of several oligomers that had a Si-C backbone. The powders prepared at 850°C contain some organic segments, and those prepared at 900°C are pure nanosized SiC powders, which are partly crystallized, the size of which is about 50–70 nm.