Coupled experimental phase diagram study and thermodynamic optimization of the Na2O–B2O3–Fe2O3 system in air

Coupled key phase diagram experiment and thermodynamic optimization of the Na2O–B2O3–Fe2O3 system were carried out. Liquidus in the Na2O–B2O3–Fe2O3 system in air was experimentally determined at 1173, 1273, 1373, and 1473 K using a classical quenching method followed by Electron Probe Micro-Analyzer (EPMA) and X-Ray Diffraction (XRD) phase analysis. Based on the new phase diagram data and available literature data, the thermodynamic optimizations of binary B2O3–Fe2O3 system and ternary Na2O–B2O3–Fe2O3 (Na2O < 50 mol%) system in air were carried out. All the reliable experimental phase diagram data were reproduced within an experimental error limit. Thermodynamic properties and phase diagrams of the ternary Na2O–B2O3–Fe2O3 (Na2O < 50 mol %) in air were predicted from the thermodynamic models with optimized model parameters.