Magnesium aluminate (MgAl2O4) spinel produced via self-heat-sustained (SHS) technique

Usage of a new but simple and reactive technique employing metallic aluminum as one of the reactants to produce very high phase-purity magnesium aluminate powder under rather mild experimental conditions is described. Low temperature melting of aluminum and subsequent exothermic reaction between molten aluminum and magnesia appeared to have led to the powder with a very high fraction of the spinel phase with small particle size and narrow particle size distribution. This powder upon sintering for 4h at 1600°C led to compacts with density as high as ∼ 92% with benign microstructural features. The beneficial effect of slightly off-stoichiometry (∼9 wt. %) in compositions on either side of magnesium aluminate in the starting powders has been discussed.