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 situ whisker reinforced ceramic matrix composite was examined by X-ray diffraction, transmission electron microscopy, electron diffraction and energy-dispersive X-ray microanalysis. Although we cannot conclusively exclude the presence of orthorhombic BAS, hexagonal BAS and both α-Si3N4 and β-Si3N4 were identified in this material. The crystallization process of the glass phase can be taken almost to completion but a small proportion of residual glass phase is present. Both whiskerlike and equiaxed β-Si3N4 exist in this material.