Fabrication of Mullite Powders by a Novel Processing

A novel and general processing (heterogeneous nucleation and growth processing) was used to prepare composite coating particles with homogeneous component distribution. Composite coating particles consisting of α‐Al 2 O 3 cores with an outer amorphous silica layer were prepared by this processing using an ethanol suspension containing ammonia, tetraethylorthosilicate and α‐Al 2 O 3 . Fine mullite powders ( d 50 = 0.73 μm) were fabricated by calcinating these particles at 1500 °C for 2 h.