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

Abstract

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−1K−1 at 1200 °C, ~25% lower than that of 8 wt% yttria partially stabilized zirconia (8YSZ). Gd2Hf2O7 ceramics also present large thermal expansion coefficients, which decrease from 12.0 × 10−6 K−1 to 11.3 × 10−6 K−1 (300–1200 °C). Besides, the hot corrosion behaviors of Gd2Hf2O7 ceramics exposed to V2O5 and Na2SO4 + V2O5 salts at temperatures of 900–1200 °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.