Effect of β-Si3N4 seeds on densification and fracture toughness of silicon nitride

Abstract Composite materials based on Si 3 N 4 were synthesized by introducing previously prepared β-Si 3 N 4 seeds into a mixture of α-Si 3 N 4 and 10 wt% of sintering additive. The densification process during pressureless sintering was studied in the presence of CeO 2 additive, which is less frequently used as sintering aid to Si 3 N 4 . The effect of seed concentration and sintering time on the densification and fracture toughness was followed. The results showed that the addition of seeds retarded densification. On the other hand, fracture toughness passes through maximum at the content of 3 wt% seeds.