Fe Solubility in the Zn-Rich Corner of the Zn-Al-Fe System for Use in Continuous Galvanizing and Galvannealing

The concentration of Al and Fe in molten zinc saturated with delta (∼Fe2Zn10Al) or eta (∼Fe2Al5Zn) intermetallic precipitates has been measured by melt equilibration for temperatures in the range of 450 °C to 480 °C. This information has generated a thermodynamic model for the phase equilibrium in the zinc-rich corner of the Zn-Al-Fe system for the range of compositions and temperatures of commercial interest in continuous galvanizing and galvannealing. The model is constrained by the reported activities of Al in the molten zinc phase and permits small compositional variance of the intermetallic solids. The resultant isothermal phase diagrams are compared with the work of others.