Crystal–Liquid Interfacial Free Energy of Supercooled Liquid Fe Using a Containerless Technique

We report a crystal–liquid interfacial free energy of a supercooled liquid Fe, which is estimated from the classical homogeneous nucleation theory, using a containerless technique, electrostatic levitation (ESL). Thermophysical properties on the supercooled and the stable Fe liquids that are prerequisite for the estimation of interfacial free energy are measured by the ESL, for the first time. A hypercooling limit, which is one of the important parameters to determine the interfacial free energy, is obtained with 357 °C. Specific heat (C p ) and total hemispherical emissivity (εT) are 45.1 ± 3 J/mol·K and 0.314 at melting temperature, respectively. The C p of the supercooled liquid Fe shows weak temperature dependence, confirmed by a calculated cooling curve. Densities of the stable, the supercooled liquid, and the crystal phases of Fe are successfully measured in a wide temperature range from 650 to 1600 °C. Finally, the crystal–liquid interfacial free energy of Fe is estimated with the measured thermophysical parameters. The value is about 0.22 ± 0.01 J/m2, which is consistent with a molecular dynamic simulation result.