Synthesis of SiC nano-powders from liquid carbon and various silica sources

The precursors of SiC powders were fabricated from various silica and phenolic resin sources of Si and C. The silica particles were 3.7 µm to 34 nm in size, and much finer silica was obtained from a liquid tetraethoxysilane oligomer. Silica and phenolic resin mixtures were cured and carbonized to form SiC precursors, and fine SiC powders were synthesized by carbothermic reaction of the precursors at 1600–2000°C. Powders with a grain size of 10–30 nm were synthesized at 1600°C from liquid silica and C. Dispersed SiC powder in water had primary grain size of 10–30 nm. SiC yield was higher from precursors having higher C/Si ratios. The carbon dispersion on fine-grain SiO2 was important in fabricating the SiC nano-powders.