The effects of temperature and different precursors in the synthesis of nano spinel in KCl molten salt

Nano-particles of MgAl2O4 were successfully synthesized at 850 °C using the molten-salt method, and the effects of processing parameters, such as the amount and type of precursor and temperature on the crystallization of MgAl2O4, were investigated. Spinel nano powders were synthesized by heating stoichiometric compositions of different MgO- and Al2O3-bearing precursors in potassium chlorides (KCl). The phase formation, morphology and purity of these powders were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray fluorescence (XRF), respectively. The results demonstrated that the formation of MgAl2O4 spinel could be initiated at 850 °C and that, after the temperature was increased to 1000 °C, the amounts of MgAl2O4 in the resultant powders increased with a concomitant decrease of MgO and Al2O3. Furthermore, the synthesized MgAl2O4 grains retained the size and morphology of the Al2O3 powders, which indicated that a template formation mechanism dominated the formation of MgAl2O4 by molten-salt synthesis.