Liquidus and phase equilibria in CaO−SiO₂−5%MgO−20%Al₂O₃−TiO₂ system

Abstract

The single hot thermocouple technique (SHTT) and high temperature equilibrium technique were combined to investigate the phase diagram of the CaO−SiO₂−5%MgO−20%Al₂O₃−TiO₂ system. The 1300 °C to 1500 °C liquidus lines are calculated according to the thermodynamic equations based on the pseudo-melting temperatures measured by the single hot thermocouple technique. The phase equilibria relationships are experimentally determined at 1400 °C using the high temperature equilibria technique followed by X-ray fluorescence (XRF), X-ray diffraction(XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis. The liquid phase(L), melilite solid solution phase ((C₂MS₂,C₂AS)ss), diopside phase(CMS₂) and perovskite phase (CaO·TiO₂) are found. Coupled with the liquidus lines and equilibria results, the phase diagram is constructed for the specified region of the CaO−SiO₂−5%MgO−20%Al₂O₃−TiO₂ system.

Keywords

phase diagram / liquidus / equilibrium / TiO₂ / single hot thermocouple technique (SHTT) / thermodynamics

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