Effect of Percent and Grain Size of Second Phase on Microstructure of Mullite-Silicon Carbide Nanocomposite Fabricated via Two-step Sintering

Mullite-silicon carbide composite was fabricated via two-step sintering process to achieve high density and low grain growth. In this work, 5 and 10 wt.% nano and micro silicon carbide was used to investigate the effect of percent and grain size of reinforced phase on microstructure of desired composite. The reinforced phase suppresses the grain growth by Zener mechanism. The grain size of composite was lower by addition of nano-silicon carbide but enhancement of body density in contrast with micro silicon carbide was difficult. Notwithstanding of suppression of grain growth, it was prevented to reach high density by applying 10 wt.% silicon carbide.