Comparison of hot corrosion resistance of Sm2Zr2O7 and (Sm0.5Sc0.5)2Zr2O7 ceramics in Na2SO4+V2O5 molten salt

Sm2Zr2O7 and (Sm0.5Sc0.5)2Zr2O7 ceramics were fabricated by a chemical co-precipitation and calcination method, and their hot corrosion behaviors in Na2SO4+V2O5 molten salt were investigated. Hot corrosion tests were carried at 700 °C, 800 °C and 900 °C for 4 h, and corroded surfaces were investigated using X-ray diffractometer and scanning electron microscopy. The corrosion products of Sm2Zr2O7 ceramics were composed of SmVO4 and monoclinic-ZrO2, while those of (Sm0.5Sc0.5)2Zr2O7 ceramic consisted of SmVO4 and Zr5Sc2O13. Considering the fact that Zr5Sc2O13 is more desirable than monoclinic-ZrO2 for thermal barrier coating applications, (Sm0.5Sc0.5)2Zr2O7 showed better corrosion resistance to Na2SO4+V2O5 salt than Sm2Zr2O7. The hot corrosion mechanisms of Sm2Zr2O7 and (Sm0.5Sc0.5)2Zr2O7 in Na2SO4+ V2O5 salt were discussed in detail.