Effect of α-Alumina as a Seed in Alumina/Silicon Carbide Composites
Intra-type structure of ceramic matrix composites (CMCs) can improve the mechanical properties of ceramic materials. In this work, we used γ-alumina as a matrix including nano-pore for fabricating alumina/silicon carbide composites using pressure-less sintering and pulse electric current sintering (PECS) techniques. We added α-alumina as a seed in order to improve densification of this commercially available γ-alumina. The mixture was sintered from 1250 to 1450 by pressure-less sintering and PECS techniques. Densification of the specimen sintered by pressure-less sintering is very difficult and bulk density of the specimen sintered at 1450 showed lower than 3.0 g/cc. In the case of the PECS technique, the density was improved to 3.8 g/cc in seed added specimen sintered at 1450. Maximum Vickers hardness and maximum fracture strength were obtained 17 GPa and 500 MPa for the seed added specimens sintered at 1450, respectively.
T. Ohji, T. Sekino and K. Niihara
S. M. Choi et al., "Effect of α-Alumina as a Seed in Alumina/Silicon Carbide Composites", Key Engineering Materials, Vols. 317-318, pp. 115-118, 2006