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°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°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.