Thermal properties of zirconium hydride

Zirconium hydride specimens with hydrogen contents of 1.45–1.70 H/Zr were fabricated directly from zirconium metal in a modified UHV Sieverts apparatus. All the zirconium hydride fabricated in the present study were found from X-ray diffraction analysis to be CaF2-type δ-ZrH2−x. At temperatures of 350–700 K, the heat capacity of the zirconium hydride was measured using an enthalpy method by means of a differential scanning calorimeter (DSC), and the experimental results were consistent with the values estimated from the sound velocities and the thermal expansion coefficient. In the temperature range of 300–700 K, the thermal diffusivity of the zirconium hydride was examined by a laser flash method. The thermal diffusivity decreased with increasing temperature and was not markedly influenced by the hydrogen content. The thermal conductivity of the zirconium hydride was calculated from thermal diffusivity and heat capacity and found to have slightly lower thermal conductivity than pure zirconium metal.