Carbothermal synthesis of β-SiC powders from silicon and SiO2-coated carbon powders

Abstract

Abstract β-SiC powders were synthesized via a direct carbothermal reaction between solid silicon and SiO2-coated carbon powders. An SiO2 layer can be coated on carbon powders by appropriately controlling the ratios of 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS). The mixture of silicon and SiO2-coated carbon was reacted at 1 500 °C for 1 h in an Ar atmosphere. The morphologies of the SiO2-coated carbon and the synthesized SiC powders were examined, and the phase evolution in the SiC powders during synthesis was analyzed. β-SiC powders with a particle size of around 200 nm were synthesized under SiO2-coating conditions of 0.2 – 0.6 mL of APTES and 0.8 – 0.4 mL of TEOS for 100 mg of carbon black powders. When no TEOS was used in the coating procedure, the β-SiC powders showed large and irregular shapes, while coating was not possible without the addition of APTES.