Thermal conductivity of hafnium hydride

We prepared fine bulk samples of Hf hydrides with various hydrogen contents, viz., the H/Hf ranges from 1.62 to 1.72. It was confirmed that all the Hf hydrides prepared in the present study exhibited a cubic delta phase with the fluorite-type structure. In the temperature range from room temperature to around 650 K, we measured the heat capacity and thermal diffusivity of the samples and evaluated the thermal conductivity. We succeeded in proposing empirical equations describing the lattice parameter, heat capacity, and thermal conductivity of Hf hydrides, as a function of temperature and hydrogen content.