Effect of Sc2O3 addition on densification and microstructure of different spinelized magnesium aluminate spinels

The densification and microstructure of different spinelized magnesium aluminate spinels (MAS) were studied adding Sc2O3 as additive. Sintered products were then characterized in terms of densification, phase analysis, quantitative elemental analysis and microstructure. The results show that Sc2O3 is found to be beneficial for the densification of MAS. Sc2O3 has a more significant effect on the densification of partially spinelized MAS batch than that of fully spinelized MAS batch. At the sintering temperature of 1650 °C, the bulk density of sintered products of partially spinelized powders increases by 0.243 g/cm3 as the Sc2O3 content increases from 0 to 4% (mass fraction) and that of fully spinelized powder increases by 0.14 g/cm3. Compared with the sintered samples prepared from the fully spinelized powder, the sintered samples using the partially spinelized powders as raw materials have more compact microstructures.