Thermal Conductivities of Fe-Ni Melts Measured by Non-contact Laser Modulation Calorimetry

A combination of an electromagnetic levitation technique with a static magnetic field and laser modulation calorimetry was used to measure the thermal conductivity of Fe-Ni melts between 1673 K and 1904 K, including the supercooled temperature region. The static magnetic field suppressed convection, translational motion, and surface oscillation of the levitated droplet to reduce the experimental uncertainty in the measurements. High-purity Fe (99.9985 mass pct) and Ni (99.9960 mass pct) were used for the sample of the measurements. For all melt compositions, the thermal conductivity had a positive temperature dependence, except for a sample with a 0.4 mole fraction of Fe. The measured thermal conductivity values of Fe-Ni were larger than those evaluated from the electric conductivity assuming the Wiedemann–Franz law for all composition ranges. It implies that atomic thermal vibration contributes to the thermal conductivity.