Development of textured mullite by templated grain growth

Highly textured mullite was obtained by enhancing anisotropic grain growth by TiO2 doping and by templating grain growth on oriented acicular mullite seed particles in a mullite precursor. Upon heating, the mullite precursor crystallized and densified to an equiaxed microstructure of 1-2 mu m mullit e grains at which time the mullite seed particles grew rapidly in the lengt h direction (c-axis) to produce a highly textured microstructure. By changi ng the seed (template) particle concentration, a range of oriented microstr uctures and anisotropic grains could be produced.