Critical Evaluation and Thermodynamic Modeling of the Li-Se and Na-Se Binary Systems Using Combined CALPHAD and First-Principles Calculations Method

Abstract

This work presents a complete review of the literature on and a critical evaluation and thermodynamic optimization of the Li-Se and Na-Se binary systems. The modified quasi-chemical model in the pair approximation (MQMPA) was employed to describe the liquid solution exhibiting a high degree of short-range ordering behavior of atoms. The thermodynamic properties of the compounds Li2Se (cF12_Fm3¯m), Na2Se (cF12_Fm3¯m), NaSe (hP8_P63/mmc), and NaSe2 (tI48_I4¯2d) were also calculated by using first-principles density functional theory (DFT) calculations to assist the thermodynamic description of these two binary systems. All the available and reliable experimental data are reproduced within experimental error limits. Moreover, the phase equilibria of these two systems at low total pressure were analyzed by using the developed thermodynamic model.

Keywords

• CALPHAD
• Li-Se system
• Na-Se system
• DFT
• phase equilibria