An efficient Yb2O3 additive for improved densification and corrosion resistance of MgAl2O4 spinel

The effect of Yb2O3 on the densification and corrosion resistance of MgAl2O4 spinel was studied. The phase structure, microscopic morphology and indentation diagonal length of the samples were analysed by using an Xray diffractometer, scanning electron microscope and digital micro-hardness tester. Results showed that the apparent porosity and relative density of the sintered samples with 2 wt% Yb2O3 are 0% and 99.6%, respectively. The average grain size of MASY(2) was the smallest, which was 17.51 mu m. The second phase (Al5Yb3O12) was generated when Yb2O3 was added to the MgAl2O4 spinel. Appropriate addition of Yb2O3 can refine the crystal grains, and Al5Yb3O12 was mainly located at the grain boundary, thereby improving the densification of MAS ceramics. In addition, the hardness of the MASY(2) sample was the largest, which was 1460 HV. The corrosion depth of the MASY(2) sample was the smallest (71.59 mu m). The most appropriate amount of Yb2O3 was 2 wt%.