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.