Development of alpha-beta SiAlON ceramics from different Si3N4 starting powders

Abstract

alpha-beta SiAlON ceramics were produced from different starting Si3N4 powders including beta-Si3N4 and alpha-Si3N4 powders and mixtures of these powders. Gas pressure sintering was used for sintering. After sintering, resultant fracture toughness values were correlated with microstructure and starting powders. By optimizing chemistry and process parameters; alpha-beta SiAlON ceramics with reasonable fracture toughness can be produced from rather coarse beta-Si3N4 powder. This could improve the economic viability of SiAlON ceramics since beta-Si3N4 powders are less costly.