Tsuyoshi Hamaguchi

Thermophysical properties of BaZrO3 and BaCeO3

Abstract Polycrystalline perovskite type oxides, BaZrO 3 and BaCeO 3 , have been prepared by mixing the appropriate amounts of ZrO 2 , CeO 2 , and BaCO 3 followed by reacting at 1273 K and sintering at 1773 K. The thermophysical properties, viz. the thermal expansion coefficient, melting point, elastic moduli, Debye temperature, and Vickers hardness, of BaZrO 3 and BaCeO 3 have been measured. The harmonic and dilatational terms of the heat capacity have been evaluated by using the values of the thermal expansion coefficient, compressibility, and Debye temperature measured in the present study, The relationships between several properties of BaZrO 3 and BaCeO 3 show the typical characteristics of the perovskite type oxides.

Heat capacities and thermal conductivities of perovskite type BaZrO3 and BaCeO3

Abstract Polycrystalline perovskite type oxides, BaZrO3 and BaCeO3, have been prepared by mixing the appropriate amounts of ZrO2, CeO2, and BaCO3 followed by reacting at 1273 K and sintering at 1773 K. The thermal conductivities of BaZrO3 and BaCeO3 have been evaluated from the heat capacity, thermal diffusivity, and density. The heat capacity has been measured by using a differential scanning calorimeter (DSC) in a high purity argon atmosphere. In the temperature range from room temperature to about 1400 K, the thermal diffusivity has been measured by a laser flash method in vacuum. The thermal conductivities of both BaZrO3 and BaCeO3 decrease with increasing temperature, showing phonon conduction characteristics. The thermal conductivity at room temperature of BaZrO3 is 5.2 Wm−1K−1, which is about 3 times larger than that of BaCeO3.