ESTUDIO TERMODINAMICO DEL SISTEMA SiO2-NiO-Cu2O

Abstract

In this work, the evaluation of the thermodynamic properties and phase diagrams of the NiO-SiO2, Cu2O-SiO2 and SiO2- NiO-Cu2O systems is presented in which a structural model is used for the liquid phase. This thermodynamic model is based on the assumption that each metallic oxide produces the depolymerization reaction of silica network with a characteristic Gibbs free energy change. A least squares optimization program permits all available thermodynamic and phase diagram data to be optimized simultaneously for the binary systems. In this manner, data for these binary systems have been analyzed and represented with a small number of parameters. The binary structural model is extended to the ternary system assuming a random mixing of cations Cu+  and Ni2+, since the Cu2O-SiO2 and NiO-SiO2  binary systems exhibit dissimilar thermodynamic behavior, the SiO2- NiO-Cu2O ternary system is proposed as a tentative phase diagram.