The glass-like thermal conductivity in ZrO2-Dy3TaO7 ceramic for promising thermal barrier coating application

Using the solid-state reaction method, the (ZrO2)(x)-(Dy3TaO7)(1-x) (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.1) ceramics are synthesized in this work. The identification of the crystal structures indicates that the (ZrO2)(x)-(Dy3TaO7)(1-x) ceramics belong to the orthorhombic system, and the space group is C222(1) in spite of the value of x increasing to 0.1. The thermal conductivities of the (ZrO2)(x)-(Dy3TaO7)(1-x) ceramics range from 1.3 W/(m K) to 1.8 W/(m K), and this value is much lower than that of 7-8 YSZ (yttria-stabilized zirconia). Besides, the (ZrO2)(x)-(Dy3TaO7)(1-x) ceramics possess the glass-like thermal conductivity caused by intrinsic oxygen vacancies existing in the lattice of Dy3TaO7. Moreover, the results of thermal expansion rates demonstrate that the (ZrO2)(x)-(Dy3TaO7)(1-x) ceramics possess excellent high temperature phase stability, and the thermal expansion coefficients [(9.7-11) x 10(-6) K-1] are comparable to that of 7-8 YSZ. Published by AIP Publishing.