Effects of carbon source on microstructural evolution and sintering behavior of porous silicon nitride ceramics

Porous β-Si3N4 ceramics were fabricated by carbothermal reaction between silica and carbon. The influences of carbon source on microstructure and the sintering behavior of the samples obtained via different sintering processes were studied. The results showed that phase composition and microstructure varied with carbon source. The resultant porous β-Si3N4 ceramics with nanometer carbon had finer microstructure, more uniform pore structure, lower weight loss and linear shrinkage, and higher flexural strength than those using micrometer carbon.