High temperature mechanical and thermal properties of CaxBa1-xZrO3 solid solutions

Abstract

The excellent high temperature phase stability enables the perovskite BaZrO3 to be a promising candidate for thermal barrier coatings (TBCs). Further improvement of its thermo-physical properties is necessary to fulfill the increasing requirements for TBCs. In this work, CaxBa1-xZrO3 (x = 0.05, 0.10, 0.15, 0.20, 0.25) solid solutions are fabricated and the influence of the Ca2+ content on their mechanical/thermal properties is studied. They have moderate mechanical properties and their residual Young's moduli at 1473 K are around 80% of the values at room temperature. Compared with BaZrO3, CaxBa1-xZrO3 solid solutions have decreased thermal conductivities which are comparable to those of YSZ and other potential TBCs materials. Among these solid solutions, Ca0.25Ba0.75ZrO3 exhibits the lowest thermal conductivity that is in the range from 2.06 W⋅m-1⋅K-1 to 2.52 W⋅m-1⋅K-1. Meanwhile, CaxBa1-xZrO3 solid solutions have higher thermal expansion coefficients than that of BaZrO3. These good high temperature mechanical and thermal properties reveal their promising applications as high temperature structural ceramics including TBCs.