Porous Si3N4/SiC Ceramics Prepared via Nitridation of Si Powder with SiC Addition

Porous Si3N4/SiC ceramics with high porosity were prepared via nitridation of Si powder, using SiC as the second phase and Y2O3 as sintering additive. With increasing SiC addition, porous Si3N4/SiC ceramics showed high porosity, low flexural strength, and decreased grain size. However, the sample with 20wt% SiC addition showed highest flexural strength and lowest porosity. Porous Si3N4/SiC ceramics with a porosity of 36-45% and a flexural strength of 107-46MPa were obtained. The linear shrinkage of all porous Si3N4/SiC ceramics is below 0.42%. This study reveals that the nitridation route is a promising way to prepare porous Si3N4/SiC ceramics with favorable flexural strength, high porosity, and low linear shrinkage.