Effect of Yb2O3 Addition and Sintering Temperature on the Densification Behavior of Magnesium Aluminate Spinel Powder

The effect of Yb2O3 and sintering temperature on the densification behavior of magnesium aluminate spinel powder was studied. Results showed that Yb2O3 was beneficial to the sintering densification of MgAl2O4. When the content of Yb2O3 was 3 wt%, the relative density of magnesium aluminium spinel (MAS) was 98.54%, and the microstructure was more compact. The maximum hardness was 21.48 GPa, and the second phase Yb3Al5O12 appeared in the 3 wt% Yb2O3 samples. The mechanism of Yb2O3 in promoting the sintering densification of MAS is due to the appearance of Yb3Al5O12. When the sintering temperature is 1700 degrees C, the relative density of MAS reaches a maximum of 98.54%, the hardness also reaches a maximum value of 21.48 GPa, and the grain size is more uniform. When the temperature exceeds 1700 degrees C, the relative density and hardness of MAS decrease. The best sintering aid content and temperature synergistically worked to promote the densification and increased the hardness of MAS.