Hot corrosion behavior of YSZ/ZrW2O8 composites exposed to V2O5 at 700 °C and 850 °C in air

Abstract The hot corrosion behavior of YSZ/ZrW2O8 composites as a promising thermal barrier coating system exposed to V2O5 at 700°C and 850°C was investigated in order to better understand the influence of the incorporated ZrW2O8 with isotropic negative thermal expansion performance on the corrosion resistance. Results indicate that the ZrW2O8 incorporation could retard the degradation of YSZ from V2O5 attack and the corrosion process is significantly related to the inclusion content and the temperature. The corrosion resistance could be determined by the incorporation content, while the reaction products are only temperature dependent. At 700°C, ZrV2O7, YVO4 and m-ZrO2 were the main corrosion products, while ZrW2O8 recrystallized under the acidic environment provided by V2O5. At 850°C, ZrW2O8 decomposed and only WO3, YVO4 and m-ZrO2 could be detected as final corrosion products. The corrosion mechanisms of YSZ/ZrW2O8 composites at 700°C and 850°C were discussed based on the phase diagrams and Lewis acid-base rule as well as the volume compensation of the positive and negative expansion ceramics.