Calorimetric study and thermodynamic assessment of the SrO–Ga2O3 system

Abstract

Abstract Enthalpies of formations of Sr4Ga2O7, SrGa2O4, and SrGa12O19 are measured for the first time using high-temperature oxide-melt drop-solution calorimetry. A self-consistent thermodynamic dataset for the SrO – Ga2O3 system is derived by means of the CALPHAD method based on these data, literature phase diagram information, and recent structural studies. In total seven compounds, Sr4Ga2O7, Sr10Ga6O19, Sr3Ga2O6, Sr3Ga4O9, SrGa2O4, SrGa4O7, and SrGa12O19 are included. Their enthalpy of formation as well as the enthalpy of mixing of the liquid is strongly exothermic. The systematic variation of thermodynamic properties with composition is discussed in terms of the structural relationships between strontium gallates and the possible formation of associates in the liquid phase.