REVIEW-Graphical Displays of the Thermodynamics of High-Temperature Gas-Solid Reactions and Their Application to Oxidation of Metals and Evaporation of Oxides

The construction and utility of volatility diagrams – isothermal plots showing the partial pressures of two gaseous species in equilibrium with the several condensed phases possible in a system—are demonstrated for simple oxides with reference to the Mg‐0, A1‐0, and Si‐0 systems and compared with Ellingham‐type representations of these same data. Both types of diagrams are useful for providing a condensed format for a great deal of thermodynamic information. Their use is illustrated by analyzing the oxidation of Mg, Al, and Si and the volatilization of MgO, A12O3, and SiO2 in both neutral and reducing gases.