Microwave hybrid synthesis of silicon carbide nanopowders

Nanosized silicon carbide powders were synthesised from a mixture of silica gel and carbon through both the conventional and microwave heating methods. Reaction kinetics of SiC formation were found to exhibit notable differences for the samples heated in microwave field and furnace. In the conventional method SiC nanopowders can be synthesised after 105 min heating at 1500 °C in a coke-bed using an electrical tube furnace. Electron microscopy studies of these powders showed the existence of equiaxed SiC nanopowders with an average particle size of 8.2 nm. In the microwave heating process, SiC powders formed after 60 min; the powder consisted of a mixture of SiC nanopowders (with two average particle sizes of 13.6 and 58.2 nm) and particles in the shape of long strands (with an average diameter of 330 nm).