Phase equilibria study and thermodynamic description of the BaO-CaO-Al₂O₃ system

A combined experimental investigation and thermodynamic assessment was performed for the BaO-CaO-Al₂O₃ system. By using a high-temperature equilibration/quenching technique and scanning electron microscopy, electron probe microanalysis, and X-ray powder diffraction analysis, the phase equilibria at 1500°C and phase stability of BaCa₂Al₈O₁₅ phase were determined. An extensive literature survey was conducted for the experimental and thermodynamic modeling data of the BaO-CaO-Al₂O₃ system. According to the literature data and the present measurements, a thermodynamic assessment was made in order to obtain a set of self-consistent thermodynamic parameters to describe the BaO-CaO-Al₂O₃ system. Based on the thermodynamic parameters acquired in this work, isothermal sections at 1100°C, 1250°C, 1400°C, 1475°C, and 1500°C and the BaO·Al₂O₃-CaO·Al₂O₃ and BaO·6Al₂O₃-CaO·6Al₂O₃ joints were calculated and compared with the available experimental data.