Fabrication of Fine Mullite Powders by Heterogeneous Nucleation and Growth Processing

Heterogeneous nucleation and growth was used to prepare composite particles with homogeneous component distribu tion. Composite particles consisting of 9α-Al₂O₃ cores with an outer amorphous homogeneous silica layer were prepared by heterogeneous nucleation and growth processing using an ethanol suspension containing ammonia, tetraethylorthosili cate, and α-Al₂O₃. Fine mullite powders of average particle size 0.53 μm were fabricated by calcinating the composite particles at 1500°C for 2 h.