Thermodynamic calculation of phase equilibria in the Al-Fe-Zn-O system

Abstract

The thermodynamics of the phase equilibria in the Al-Fe-Zn-O quaternary system was studied using the calculation of phase diagrams method to understand the oxidation behavior of the Zn bath surface during galvanizing process. The thermodynamic parameters for the Gibbs energies of the different constituent phases in the binary and ternary systems relevant to this quaternary system were taken mainly from previous studies. In this study, the thermodynamic assessment of the Al2O3-ZnO system was carried out based on the available experimental data, and some modifications to the thermodynamic model and/or parameters for the Fe-Zn-O ternary system were made to maintain consistency with the thermodynamic descriptions of other binary and ternary systems, making up the Al-Fe-Zn-O quaternary system adopted in this study. The calculated results on the ternary and quaternary systems generally agreed with the available experimental results on phase equilibria. The set of thermodynamic parameters enabled us to calculate the phase equilibria in the Al-Fe-Zn-O quaternary system over the entire composition and temperature ranges.