The microstructural characterization of in situ grown Si3N4 whisker-reinforced barium aluminum silicate ceramic matrix composite

The microstructure of Barium Aluminum Silicate (BAS)/Silicon Nitride in sit u whisker reinforced ceramic matrix composite was examined by X-ray diffrac tion, transmission electron microscopy, electron diffraction and energy-dis persive X-ray microanalysis. Although we cannot conclusively exclude the pr esence of orthorhombic BAS, hexagonal BAS and both alpha-Si3N4 and beta-Si3 N4 were identified in this material. The crystallization process of the gla ss phase can be taken almost to completion but a small proportion of residu al glass phase is present. Both whiskerlike and equiaxed beta-Si3N4 exist i n this material. (C) 1999 Kluwer Academic Publishers.