Effect of Eu₂O₃ on sintering densification and corrosion resistance of magnesium aluminate spinel

The effect of the doping amount of Eu₂O₃ on the densification behaviour of magnesium aluminate spinel (MAS) and its corrosion resistance to aluminium electrolyte were studied. The relative density, phase composition, micro morphology and hardness of the sintered samples were characterised by Archimedes’ drainage method, X-ray diffractometer, scanning electron microscope and automatic micro Vickers hardness tester. Results showed that the doping of Eu₂O₃ was conducive to the densification of MgAl₂O₄. When the content of Eu₂O₃ was 3 wt.%, the relative density of MAS was the largest (99.32%), the microstructure was more compact and the hardness was the largest (2293.4 kgf/mm²). The MAS sample with 3 wt.% Eu₂O₃ had the best corrosion resistance to aluminium electrolyte, and the corrosion depth was 80.99 μm. It was speculated that the electrolyte may penetrate into the sample through the micropores, and the fluoride salt chemically reacted with MgAl₂O₄ to form Al₂O₃, NaF and MgF₂.