Synthesis of magnesium aluminate spinel nano-powders by co-precipitation method

Abstract

Magnesium aluminate spinel nano-powders were synthesised by the wet chemical co-precipitation method. First, the gel-like precursors were obtained by dropping ammonia into the mixed solution of magnesium chloride hexahydrate and aluminium chloride hexahydrate with different Mg2+/Al3+ molar ratios and concentrations. After drying, the precursors were calcined at 700°C, 800°C, 900°C, 1000°C and 1100°C for 1.5 hours, respectively. Finally, the obtained samples were characterised by X-ray diffraction, thermal gravimetric and differential thermal analysis and scanning electron microscopy. It was revealed that the pure phase of MgAl2O4 started to form when the calcination temperature exceeded 700°C, and MgAl2O4 spinel with the smallest average crystallite size could be obtained when the calcination temperature reached 900°C.