Fabrication, thermal treatment and microstructure development in SiC-AIN-Al₂OC ceramics

Abstract

Samples containing equimolar amounts of SiC, AIN and Al₂OC were fabricated by hot pressing a mixture of SiC, AIN, Al₂O₃ and Al₄C₃. The predominant constituent in the hot pressed material was of 2H crystal type. The samples were subsequently annealed at a temperature up to 2050‡ C for up to 153 h in an atmosphere of nitrogen. Samples made with IbigawaΒ-SiC exhibited formation of needle-type precipitates. Carbon deficient specimens contained substantial amounts of Al₃O₃N. Principal characterization techniques employed consisted of optical microscopy, electron microscopy, X-ray diffraction and chemical analysis.