Establishing Aluminum-Oxygen (Al-O) Equilibria in Liquid Iron at 1873 K: An Experimental Study and Thermodynamic Analysis

Aluminum-oxygen equilibria for varying concentration of aluminum (0.0008–23.35 wt pct) content have been established at 1873 K. The experiments were carried out in an inert (high-purity argon) atmosphere by melting pure electrolytic iron with master alloy of Fe-Al in an alumina crucible and equilibrating the Fe-Al-O melt at 1873 K for two hours. A two-stage heating method in an inert gas fusion absorptiometry and scanning electron microscopy-automated inclusion analysis (SEM-AIA) have been employed to estimate the insoluble oxygen content in the samples. Aluminum-oxygen equilibria have been established separately for the total and dissolved oxygen contents. Thermodynamic analysis has been carried out using higher order interaction parameters, namely, Wagner interaction parameter formalism (WIPF) truncated at 2nd order, Darken’s quadratic formalism, and the Cubic formalism. Among these formalisms, the experimental analysis has been found to be in good agreement with thermodynamic analysis based on Cubic formalism.