Low-thermal-conductivity and high-toughness CeO2-Gd2O3 co-stabilized zirconia ceramic for potential thermal barrier coating applications

Yttria partially stabilized zirconia (∼4.0 mol% Y2O3-ZrO2, 4YSZ) has been widely employed as thermal barrier coatings (TBCs) to protect the high-temperature components of gas-turbine engines. The phase stability problem existing in the conventional 4YSZ has limited it to application below 1200 °C. Here we report an excellent zirconia system co-doped with 16 mol% CeO2 and 4 mol% Gd2O3 (16Ce-4Gd) presenting nontransformable feature up to 1500 °C, in which no detrimental monoclinic (m) ZrO2 phase formed on partitioning. It also exhibits a high fracture toughness of ∼46 J m−2 and shows high sintering resistance. Besides, the thermal conductivity and thermal expansion coefficient of 16Ce-4Gd are more competent for TBCs applications as compared to the 4YSZ. The combination of properties suggests that the 16Ce-4Gd system could be of potential use as a thermal barrier coating at 1500 °C.