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Aiming at producing high temperature structural ceramics, ultra-fine SiC powders were synthesized by the gas phase reaction of silicon tetrachloride with methane in a d.c. thermal plasma. The influence of parameters as the SiCI4 feeding rate, C/Si and H2/C molar ratios and internal pressure on the powder properties were investigated. The SiC powders were characterized by chemical analysis, Fourier transform infrared spectroscopy, X-ray diffraction and scanning electronic microscopy. The experimental set-up allows the production of I3-SiC powders at a rate of 200 g h -1 with particle size around 0.1 gm. The main impurities in the as-produced powder handled at ambient atmosphere are: oxygen (1.8-2.5%) and free carbon (3-4%). Interesting relationships were found between the SiCI4 feeding rate and the H2/C molar ratio and between the C/Si molar ratio and the internal pressure. The internal pressure plays a major role in controlling the particle size.

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