Hot corrosion behaviors of Sc2O3–Gd2O3–Y2O3 co-doped ZrO2 in Na2SO4 + V2O5 molten salts at 1000°C

The hot corrosion behaviors of the Sc 2 O 3 –Gd 2 O 3 –Y 2 O 3 co-doped ZrO 2 (SGYSZ) ceramics in Na 2 SO 4 + V 2 O 5 molten salts at high temperature were investigated in this work. The results show that the SGYSZ exhibits good hot corrosion resistance to the 50 wt% Na 2 SO 4 + 50 wt% V 2 O 5 molten salts at 1000°C. It is attributed to the doping of small Sc 3+ , which can decrease the M–O bonding length and increase the binding energy, and then reduce the dissolution and loss of the stabilizer as rare-earth cations Gd 3+ and Y 3+ from the SGYSZ. The significant synergistic effects of Sc 3+ , Gd 3+ , and Y 3+ are beneficial to enhance the phase stability and corrosion resistance of the zirconate ceramic due to the different ionic radius and basicity of rare-earth oxides (RE 2 O 3 ). More Gd 3+ in SGYSZ can promote the forming and coarsening of the GdVO 4 during mineralization, which can also decrease the loss of Y 3+ from the SGYSZ. The corrosion mechanism is discussed in detail.