Effect of scandia content on the hot corrosion behavior of Sc2O3 and Y2O3 co-doped ZrO2 in Na2SO4 + V2O5 molten salts at 1000 °C

The effect of Sc 2 O 3 content on the hot corrosion behavior of x mol.% Sc 2 O 3 -1.5 mol.% Y 2 O 3 co-doped ZrO 2 ceramics (ScYSZ) in Na 2 SO 4 + V 2 O 5 (50/50 wt.%) molten salts at 1000 °C was investigated. The experiments revealed that the hot corrosion resistance and phase stability of the ScYSZ ceramics increase with the Sc 2 O 3 content as results of the enhanced strength of rare earth-oxygen bond and the increased prohibition effect on the vanadate penetration due to the small ionic radius of Sc 3+ and the weak reactivity of Sc 2 O 3 with vanadates. The hot corrosion mechanism was also discussed.