Structure, thermal properties and hot corrosion behaviors of Gd2Hf2O7 as a potential thermal barrier coating material

In this work, Gd2Hf2O7 ceramics were synthesized and investigated as a potential thermal barrier coating (TBC) material. The phase composition, microstructure and associated thermal properties of Gd2Hf2O7 ceramics were characterized systematically. Results show that the thermal conductivity of Gd2Hf2O7 ceramics is 1.40 Wm(-1) K(-1 )at 1200 degrees C, similar to 25% lower than that of 8 wt% yttria partially stabilized zirconia (8YSZ). Gd(2)Hf(2)O(7 )ceramics also present large thermal expansion coefficients, which decrease from 12.0 x 10(-6) K-1 to 11.3 x 10(-6) K-1 (300-1200 degrees C). Besides, the hot corrosion behaviors of Gd(2)Hf(2)O(7 )ceramics exposed to V2O5 and Na2SO4 + V2O5 salts at temperatures of 900-1200 degrees C were discussed in great detail. We pay much attention on the corrosion process, corrosion mechanism and corrosion damage of Gd2Hf2O7 ceramics subjected to molten V2O5 and Na2SO4+ V2O5 salts at different temperatures.