Noncontact Laser Modulation Calorimetry for High-Purity Liquid Iron

The heat capacity and thermal conductivity of liquid iron were measured the using recently developed method of noncontact laser modulation calorimetry. An iron sample was levitated using an electromagnetic levitator. Then the convection in the levitated droplet was suppressed to measure the thermal conductivity by the application of a dc magnetic field. High-purity iron (99.9972 mass%) prepared using an ion exchange method was used for measurements. The molar heat capacity of liquid iron at constant pressure was measured to be 45.4 +/- 3.2 J.mol(-1).K-1 (1848-1992 K) in low dc magnetic fields because a semi-adiabatic condition was achieved, assisted by the remaining convection in the liquid. The apparent thermal conductivity of liquid iron decreased concomitantly with the increasing dc magnetic field. It finally converged to 39.1 +/- 2.5W.m(-1).K-1 (1794-2050 K) at 9 T or higher. The experimental uncertainties in the molar heat capacity and thermal conductivity are double the standard deviation. (C) 2011 The Japan Society of Applied Physics