Formation of Mg–Al–Ti/MgO composite via reduction of TiO2

This paper investigates the possibility of reduction of TiO₂ through the mechanical alloying of Mg and TiO₂ powders. Elemental Mg and Al powders were first mixed with TiO₂ according to the nominal composition of Mg5wt.%–Al17.15wt.%–TiO₂. The powder mixture was mechanically milled in a planetary ball mill for different durations. Two types of DSC curves have been observed. The unmilled powders showed no reaction when heated to about 500 °C, while an exothermic reaction in the mechanically milled powders was observed at about 390 °C. Further investigation of the heat treatment of the mechanically milled powders showed the complete disappearance of TiO₂ and the formation of MgAl₂O₄ after annealing at 400 °C, implying that reduction of TiO₂ has occurred via the mechanical activation and annealing processes.