In the past few decades, great attentions have been paid to the BaO-SrO-CaO-MgO-Al2O3-SiO2 system due to its wide applications in metallurgy, glass ceramics and geochemistry. BaO-containing oxide slag (BaO-CaO-MgO-Al2O3-SiO2) is commonly applied in the removal of sulfur in steelmaking. Glass ceramics prepared based on BaO-SrO-CaO-MgO, with addition of Al2O3 and SiO2, can be used for the production of sealing materials in the solid oxide fuel cells (SOFCs). A good knowledge of the phase equilibria and thermodynamic properties contributes to improve the understanding of this multi-components system. However, high experimental temperature, complex chemical reaction and corrosive behavior, altogether hinder the further experimental investigations and technical progress.
By means of CALPHAD (CALculation of PHAse Diagram) technique, the thermodynamic database, such as MTOX oxide database used in smelting and refining , can be established, which facilitates to predict the phase equilibria, thermodynamic properties, chemical process and so on. To build a thermodynamic database with high accuracy and reliability, well-assessed binary systems play a key role when it coms to the extrapolation into higher order systems.
In the present work, the BaO-CaO, BaO-MgO, BaO-SrO, BaO-Al2O3, BaO-SiO2 and SrO-SiO2 binary systems were experimentally investigated coupled with thermodynamic assessments using Thermo-Calc. Several sets of self-consistent thermodynamic parameters capable of reproducing the experimental results were achieved. Based on the thermodynamic parameters acquired, phase diagrams and thermodynamic property diagrams were calculated and compared with the experimental data. Future work will be concentrated on the extrapolation into higher order oxides systems.
 MTOX, Release Notes for Version 8.1 of Mtox Database (2015) National Physical Laboratory, Teddington, UK.