Preparation of SrAl2O4 from an oxide mixture via a high-energy ball milling

The effect of high-energy ball milling and subsequent annealing on a mixture of Al2O3 and SrCO3 has been investigated. DTA results show that the decomposition temperature of SrCO3 obviously decreases with the increase of ball milling time duration. X-ray diffraction (XRD) measurement indicates that an amorphous phase is produced and no SrAl2O4 crystallized from the amorphous phase during a high-energy ball milling process after milling for 30 h. Significant crystallization of SrAl2O4 from the amorphous state milled for 30 h is observed after annealing at 900-1000 °C, while a trace of Sr3Al2O6 exists at this temperature. Single phase SrAl2O4 can be achieved for the sample milled for 30 h at 1180 °C, which is at least 150 °C lower than that used in the traditional solid-state method. No significant grain growth is observed when the milled powders were annealed at temperature below 1000 °C. SrAl2O4 ceramics with an average grain size of about 2.5 μm are obtained after annealing at 1180 °C from the as-milled powders.