Thermal and mechanical properties of perovskite-type barium hafnate

Abstract

Polycrystalline samples of the barium perovskite-type oxide, BaHfO 3 were prepared by solid-state reactions from HfO 2 and BaCO 3 powders. The thermal expansion coefficient, heat capacity, thermal diffusivity, thermal conductivity, elastic modulus, Debye temperature, and micro-Vickers hardness were measured. The crystal structure of BaHfO 3 is of the cubic perovskite type with the lattice parameter 0.4171 nm at room temperature. The sample bulk density is 91% of the theoretical density. The average linear thermal expansion coefficient is 6.93 × 10 −6 K −1 in the temperature range between 300 and 1500 K. The Young's modulus equals 194 GPa. The thermal conductivity at room temperature is 10.4 Wm −1K −1.