(Y0.05La0.95)2(Zr0.7Ce0.3)2O7 ceramics as a thermal barrier coating material for high-temperature applications

Oxide ceramics with stable phase structure, good thermophysical properties and high sintering-resistance above 1473 K have very important applications in thermal barrier coatings (TBCs). The (Y0.05La0.95)(2)(Zr0.7Ce0.3)(2)O-7 (YLZC) ceramics were synthesized by solid state reaction at 1673 K for 24 h in air. The phase stability, thermophysical properties and sintering-resistance behavior of YLZC ceramics were investigated in detail. The YLZC ceramics consist of mixture structures of pyrochlore and fluorite, and no new phase appears after long-term annealing. Thermal expansion coefficient of YLZC is about 10.58 x 10(-6) K-1, which is larger than that of La2Zr2O7 (LZ) (9.18 x 10(-6) K-1) and similar to that of La-2(Zr0.7Ce0.3)(2)O-7 (LZC) (10.53 x 10(-6) K-1). The thermal conductivities of the YLZC ceramics first decrease gradually with the increase of temperature below 1273 K and then increase slightly above 1273 K. The minimum value of similar to 0.86 W m(-1) K-1 is gained at 1273 K. The volume shrinkages of LZC and YLZC are basically identical, only a bit of improvement in sintering-resistance is observed at 1873 K. (C) 2013 Elsevier B.V. All rights reserved.