Effect of additives on the sintering of MgAl2O4

• The additions of SiO2, CaCO3 and TiO2 to the stoichiometric spinel are found to improve the densification of spinel.
• TiO2 is the most effective in densification.
• TiO2 formed the secondary phase in the grain boundary region and grain interior through the reaction with spinel phase.

The effect of additives on the densification of stoichiometric spinel was investigated. SiO2, CaCO3 and TiO2 are used as additives to spinel composition in the range of 1–4 wt%. Densification behavior is investigated by dilatometry measurement and the sintered body is characterized in terms of microstructure, phase formation and change in lattice parameter. In case of SiO2 and CaCO3 additions, the densification was significantly enhanced with the additives by forming glassy phases in grain boundary region. The addition of TiO2 resulted in the formation of secondary phase at grain boundaries and inside grains along with enhanced densification.