Preparation of composite coating particles of α-Al₂O₃-SiO₂ by heterogeneous nucleation-and-growth processing

In order to solve the difficult problem of heterogeneity of different components in the procedure of ceramic preparation, heterogeneous nucleation-and-growth processing is used to prepare the homogeneous distribution powders. Composite coating particles consisting of alpha alumina cores (average particle size 0.57 μm) with an outer amorphous silica layer are prepared by the heterogeneous nucleation-and-growth processing. The amorphous silica layer on cores is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and zeta-potential measurement. Effects of silica content in composite coating particles versus concentration of tetraethylorthosilicate (TEOS), pH value, reaction time and reaction temperature are studied.