Microstructure and properties of hot isostatically pressed SiC ceramics with an Al2O3 addition

Abstract Dense Al 2 O 3 -doped SiC ceramics with an average grain size of 1.2 μm were obtained by hot isostatic pressing. The microstructure has been analyzed by TEM, EDX, EELS, SAD and SEM. The results show that the non-crystalline secondary phase, an alumino-silicate glass, is predominantly located at triple grain junctions in Al 2 O 3 -doped SiC ceramics. The influence of the glassy phase on sintering behaviour, high-temperature strength and oxidation resistance is investigated and discussed.