CONSTITUTION OF LASER MELTED AL2O3-MGO-SIO2 CERAMICS

An investigation has been made of ceramics of the Al2O3-MgO-SiO2 syste m produced as pellets by laser melting of powder mixtures of the compo nent oxides, followed by relatively rapid solidification. The phase co nstitution and microstructural features have been investigated using X -ray diffraction, microscopy, and differential thermal analysis. Compo sitions were selected with the aim of determining the solidification s equences, including certain invariant reactions involving combinations of the silica, cordierite, mullite, protoenstatite, forsterite, and p ericlase phases. Taking account of compositional changes that occurred during melting, and the fact that glass formation interrupted the sol idification sequences, the observations were generally consistent with existing phase diagram data. (C) 1995 The Institute of Materials.