Fabrication of fine mullite powders by α-Al(OH)3–SiO2 core–shell structure precursors

In order to obtain fine mullite powders by a simple and inexpensive process, alpha aluminum hydroxide (α-Al(OH)3) was used as raw material, and heterogeneous nucleation-and-growth process was chosen for the preparation of powders. Composite coating particles consisting of α-Al(OH)3 cores with outer amorphous silica shell were prepared by heterogeneous nucleation-and-growth process in the ethanol suspension containing ammonia, tetraethylorthosilicate (TEOS) and α-Al(OH)3. Fine mullite powders (average particle size 0.67 μm) were fabricated by calcined composite coating particles at 1500 °C for 2 h.