SiC/Si₃N₄複合材の機械的特性に及ぼす出発原料の影響

抄録

Mechanical properties of SiC-particle/Si₃N₄ composites produced from two types of starting powders were investigated. Composites fabricated from the Si₃N₄ powder prepared by nitridation of Si showed a 40% increase in bending strength resulting from greater fracture toughness. In contrast, composites made from Si₃N₄ powder obtained by thermal decomposition of Si(NH)₂ exhibited increase in only bending strength. The latter composites contained SiC particles, which inhibited grain growth of β-Si₃N₄. These differences are attributed to the effect of carbon and oxygen in the starting powders on the sinterability of β-Si₃N₄. The SiC additive and impurities in the starting powders are responsible for the difference in the sintering behavior of β-Si₃N₄, and thereby resulting in different mechanical properties.