Oxygen solubility in Fe–Zr–O liquid

Abstract The solubility of oxygen in the liquid iron of the Fe–Zr–O system was explored thermodynamically using the ionic model for the liquid phase. The predicted oxygen solubility level is about one order of magnitude lower than the experimental data, and the calculated oxygen solubility minimum is at a much higher zirconium content than the experimentally measured value. This implies that the measured oxygen–zirconium interaction is much stronger than predicted from the thermodynamic modeling. By comparing with the calculations and experimental data of similar Fe–M–O (M = strong deoxidizers of Fe) systems, it is concluded that the experimental solubility values may have a systematic error, and the predicted oxygen solubility in the liquid iron of the Fe–M–O system from the thermodynamic modeling is probably more reliable. Due to the very low oxygen solubility in the Fe–M–O liquid, the binary M–O liquid parameters do not have a significant effect on the oxygen solubility in the liquid iron of the Fe–M–O ternary system. Thus, at low M contents, even without complete M–O thermodynamic descriptions, the oxygen solubilities in the liquid iron of the Fe–M–O systems can be systematically predicted with the thermodynamic descriptions of Fe–O, Fe–M, and the M oxides, which are readily available in the literature or in thermodynamic databases such as SSOL and SSUB.