Journal of Materials Science, Vol.29, No.4, 934-938, 1994
Pressureless Sintering of Beta-SiC with Al2O3 Additions
Beta-SiC was pressureless sintered to 98% theoretical density using Al2O3 as a liquid-phase forming additive. The reaction between SiC and Al2O3 which results in gaseous products, was inhibited by using a pressurized CO gas or , alternatively, a sealed crucible. The densification behaviour and microstructural development of this material are described. The microstructure consists of fine elongated alpha-SiC grains (maximum length almost-equal-to 10 mum and width 2-3 mum) in a matrix of fine equi-axed grains (2-3 mum) and plate-like grains (2-5 mum). The densification behaviour, composition and phases in the sintered product were studied as a function of the sintering parameters and the initial composition. Typically, 50% of the beta-phase was transformed to the alpha-phase.
Keywords:SILICON CARBIDE