Alumina‐Silica Phase Diagram in the Mollite Region

Abstract

The alumina‐silica phase relations of samples annealed in oxygen and quenched were studied by optical microscopy, image analysis, X‐ray diffraction, and the electron microprobe. The solid solution boundaries of mullite changed with increasing temperature and joined at 1890°C and a composition of 77.15 wt% alumina. The melting point of mullite was 189°C with a peritectic between 76.5 and 77.0 wi% alumina.