THERMODYNAMIC ASSESSMENT OF THE SILVER-OXYGEN SYSTEM

An assessment of the silver-oxygen system has been made, and a consist ent set of thermodynamic parameters has been optimized. The calculated thermodynamic properties and phase relations are in good agreement wi th the experimental data, Ag2O is the only phase that is commonly foun d within the system, In air, it decomposes to silver and oxygen gas at 420 K, There is a eutectic between silver and Ag2O at a temperature o f 804 K, an oxygen partial pressure (P-O2) of 526 bar (5.26 x 10(7) Pa ), and an oxygen mole fraction in the liquid phase of 0.25, Uncertaint ies remain on the Ag2O liquidus for P-O2 > 10(8) Pa, An ionic two-subl attice model has been used to describe the liquid phase. This work is part of a study of interactions between compounds from the bismuth-str ontium-calcium-copper-oxygen system and silver.