Catalyst-free synthesis of β-SiC polyhedra and α-SiC nano-platelets by RF thermal plasma

• The synthesis of SiC products was a fast reaction without any catalysts.
• The contaminations of products can be significantly reduced by improving diffusion of reactants.
• It provides an opportunity to show the potential ability of reusing by-products from the silicone industry by RF thermal plasma treatment.

Based on the reuse of by-products in the silicone industry, a simple catalyst-free method has been developed for the synthesis of SiC powders in a thermal plasma system. Detailed structures of the as-prepared products were characterized. Crystals collected showed two types of morphologies, which were spheres and crystals with specific exposed facets. The spherical nanoparticles were attributed to high cooling rate of droplets. The latter ones can formed according to their crystal growth habits. As a result, the equilibrium forms of β-SiC were found to be polyhedra with regular or irregular shapes, while for α-SiC were mainly nano-platelets with (001) faces on the upper and basal planes and a few polyhedra based on platelets. By improving diffusion of reactants, the contaminations of products can be significantly reduced.