Effect of Y2O3 and ZnO co-doping on the densification and properties of magnesium aluminum spinel

Abstract

The effects of Y2O3 and ZnO co-doping on the densification and properties of magnesium aluminum spinel were investigated. The physical phase composition, microstructure, elemental distribution, densification, apparent porosity, particle size distribution and average corrosion depth of the specimens were investigated by XRD, SEM-EDS, Archimedes drainage method, Nano Measurer 1.2 software, and molten salt corrosion tests. The results showed that after co-doping with Y2O3 and ZnO, the cations in the sintering aids could dissolve into the spinel structure, forming solid solution ZnAl2O4, second phase Y3Al5O12 and Al2Y4O9, which inhibited the abnormal grain growth and made the grain distribution more uniform, thus promoting the densification of the samples. The best co-doping amount of Y2O3 and ZnO was 1 wt% Y2O3-3 wt.% ZnO, the relative density of the sample was 99.3%, the apparent porosity was 0.021%, and the grain size was the most uniform (6.52 μm). After the sample was placed into the aluminum electrolytic molten salt electrolyte for 1 h, and it was found that the sample doped with 1 wt% Y2O3-3 wt.% ZnO had the minimum average corrosion depth (131.9 μm) and the best corrosion resistance.