Phase equilibria of the Na₂O-TiO₂-SiO₂ system between 900 and 1600°C in air

The Na₂O-SiO₂-TiO₂ system is important for the glass, ceramic, and metallurgical industries. Its features provide information on the composition and melting temperature to be utilized during the production of glass and ceramic and during the processing of TiO₂-bearing material in the metallurgical industry. The liquidus temperatures between 900 and 1600°C in the ternary system at saturation of solid SiO₂, TiO_2, Na₂Ti₆O₁₃, Na₂SiTiO₅, and Na₂Ti₃O₇ were measured using the equilibration-quenching energy-dispersive X-ray spectroscopy/Electron Probe Microanalyzer technique. A wide range of liquidus compositions were obtained with Na₂O between 0 and 41.7 mol% in the SiO₂- and TiO₂-rich regions. The present study provides liquidus data at 1500 and 1600°C for the first time. Liquidus temperatures at various double saturations were also obtained in the present investigation to determine univariant lines in the phase diagram. The present experimental data were compared with previous investigations and computed phase diagrams. The data obtained in the present investigation can be employed to optimize the thermodynamic properties and phase diagrams of the Na₂O-SiO₂-TiO₂ system.