Effect of CeO ₂ -Y ₂ O ₃ sintering aids on the microstructure and properties of corundum-based composite ceramics

Reducing the preparation cost of alumina ceramics has received significant attention, as alumina is one of the most widely used structural ceramics. In this study, corundum-based composite ceramics with a white corundum-to-zircon powder mass ratio of 7:3 were selected as the matrix. CeO2 and Y2O3 doped corundum-based composite ceramics were prepared via pressureless sintering. The total content of CeO2-Y2O3 was set at 10 wt% to study the effects of different temperatures and CeO2-Y2O3 ratios on the properties of the corundum-based composite ceramics. Physical phase and microstructural analyses of the corundum-based composite ceramics were performed using X-ray diffraction and scanning electron microscopy, respectively. The results showed that the sintering temperature of the corundum-based composite ceramics could be effectively reduced by using a solid solution of CeO2 and Y2O3. The best sintering temperature was 1400°C, and the best composition was 5 wt% CeO2-5 wt% Y2O3. The physical properties of the corundum-based composite ceramics prepared under these technological conditions include a flexural strength of 386.2 MPa, hardness of 13.5 GPa, density of 3.9128 g/cm3, linear shrinkage of 16.31% and an apparent porosity of 0.62%.