Heat capacities and thermal conductivities of palladium and titanium melts and correlation between thermal diffusivity and density of states for transition metals in a liquid state

摘要

The normal spectral emissivities at 807 and 940 nm, heat capacities at constant pressure and thermal conductivities of Pd and Ti melts were measured using an electromagnetic levitation technique in a static magnetic field. The static magnetic field suppresses the surface oscillation, translational motion, and convection flow on electromagnetically levitated samples. The convections in the levitated Pd and Ti melts were suppressed sufficiently for thermal conductivity measurement by the static magnetic field. The emissivities and heat capacities of Pd and Ti melts showed no temperature dependence within the experimental temperature region. The thermal conductivity of Pd melt was constant within experimental temperature region, on the other hand, the thermal conductivity of Ti melt increased with increasing temperature. The measured emissivity and thermal conductivity were compared with values evaluated by a free electron model such as Drude model and Wiedemann-Franz law. Based on the results, the correlation between density of states (DOS) at Fermi energy and thermal diffusivities for transition metals was discussed. (C) 2020 The Author(s). Published by Elsevier B.V.