Silicon nitride-silicon carbide nancocomposites fabricated by electric-field-assisted sintering

Starting with Si-C-N(-O) amorphous powders, and using the electric field assisted sintering (EFAS) technique, silicon nitride/silicon carbide nanocomposites were fabricated with yttria as an additive. It was found that the material could be sintered in a relatively short time (10 min at 1600degreesC) to satisfactory densities (2.96-3.09 g/cm(3)) using 1-8 wt% yttria. With decreasing yttria content, the ratio of SiC to Si3N4 increased, whereas the grain size decreased from similar to150 nm to as small as 38 nm. This offers an attractive way to make nano-nanocomposites; of silicon nitride and silicon carbide.