SiC-nanoparticle-reinforced Si₃N₄ matrix composites

Hot-pressed nanosized SiC-particle (SiC_p)-reinforced Si₃N₄ composites have been studied with respect to their microstructures, room temperature mechanical properties and thermal shock resistance. The experimental results indicate that the flexural strength, fracture toughness and thermal shock resistance are all increased by the addition of 5 vol% SiC_p. Further additions of SiC_p, however, have a detrimental effect on these properties. These changes are closely related to the effects of SiC_p on the matrix grain morphology. The mechanisms of nucleation and growth of βP-Si₃N₄ grains in the presence of SiC nano-particles are discussed.