Precipitation and sintering behaviour of non-stoichiometric MgAl2O4 solid solution powder prepared by combustion synthesis

In this work, non-stoichiometric MgAl2O4 spinel solid solution powders with excess magnesia or alumina were synthesized by combustion synthesis, and their precipitation and sintering behaviour were investigated. The dissolution of MgO or Al2O4 in the lattice of spinel formed interstitial or vacancy solid solutions, respectively. During annealing, the powders with different solid solubility exhibited various precipitation and phase transition behaviour. After hot-press sintering with the as-prepared powders, there were many spheres with 100 nm evenly precipitated in the MgAl2O4 ceramic matrix, which improved mechanical performance. This work can not only provide comprehensive information about the precipitation of magnesia-and alumina-rich MgAl2O4 spinel solid solutions during annealing or sintering, but also offer an easy and convenient way for the industrial preparation of nanocomposite MgAl2O4 ceramics.