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

Abstract

AbstractThe hot corrosion behaviors of the Sc2O3–Gd2O3–Y2O3 co‐doped ZrO2 (SGYSZ) ceramics in Na2SO4 + V2O5 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% Na2SO4 + 50 wt% V2O5 molten salts at 1000°C. It is attributed to the doping of small Sc3+, 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 Gd3+ and Y3+ from the SGYSZ. The significant synergistic effects of Sc3+, Gd3+, and Y3+ 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 (RE2O3). More Gd3+ in SGYSZ can promote the forming and coarsening of the GdVO4 during mineralization, which can also decrease the loss of Y3+ from the SGYSZ. The corrosion mechanism is discussed in detail.