Thermodynamic modeling of the MBr-BaBr2 (M=Alkali metals) systems

Abstract

The complete thermodynamic optimizations of MBr-BaBr2 (M = Li, Na, K, Rb, Cs) systems were performed based on thermodynamic principles using CALPHAD approach. In this work, the existence of BaBr2-based solid solubility was firstly evaluated according to the corresponding liquid curves in available literature by the limiting liquidus slope equation and ideal liquid curve. The liquid enthalpy of mixing for LiBr–BaBr2 binary system was calculated via empirical prediction method. The Gibbs energy of liquid molten mixtures were modeled by the substitutional solution model (SSM) and the associate solution model (ASM), while that of the double salts were processed into stoichiometric compounds based on the Neumann-Kopp technique. The thermodynamic database with a series of thermodynamic properties and phase equilibria data of investigated systems were successfully established by optimizing model parameters. The simulated results could provide theoretical guidance and technical support, as well as applying in the design for the multi-components eutectic materials by combination with the binary alkali metal bromide systems.