Abstract
Surface tension of molten iron was measured under reducing gas atmosphere of Ar–He–5 vol % H2 by an oscillating droplet method using electromagnetic levitation. The temperature dependence of surface tension did not exhibit a linear relationship but revealed a peculiar kink at around 1810 K, due to competition between the temperature dependence of oxygen partial pressure and that of the oxygen adsorption equilibrium constant. We successfully derived the surface tension of molten iron as functions of both oxygen partial pressure and temperature. Furthermore, the standard enthalpy and entropy for oxygen adsorption reaction on molten iron were also estimated.