Hot isostatic pressing of α-silicon carbide ceramics

Abstract A submicron α-SiC powder was densified by hot isostatic pressing using a Vycor glass container. The effect of different additives such as B 4 C, AlN and Al 2 O 3 on densification, mechanical properties and oxidation behaviour was investigated. The results showed that the densification mechanism was attributed to liquid-phase sintering via the formation of a eutectic between SiO 2 and additive, and Al 2 O 3 was confirmed to be an effective additive for hot isostatic pressing of SiC. Hot isostatically pressed, Al 2 O 3 -doped SiC had an ultrafine-grained microstructure with grain size varying from 0·5 to 2·5 μm, and exhibited a flexural strength above 570 MPa and a fracture toughness higher than 5·17 MPa m 1 2 .