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 μm mullite grains at which time the mullite seed particles grew rapidly in the length direction (c-axis) to produce a highly textured microstructure. By changing the seed (template) particle concentration, a range of oriented microstructures and anisotropic grains could be produced.