Phase equilibria of CaO-Al2O3-Ti2O3 system at 1500 °C and 1600 °C in C/CO equilibrium atmosphere

Abstract

The phase diagram of CaO-Al₂O₃-Ti₂O₃ system has significant implications for the metallurgical slag design of Al-Ti alloy steel. In this work, the high-temperature equilibrium experiments were conducted at 1500 °C and 1600 °C in C/CO equilibrium atmosphere, respectively. The types and compositions of the equilibrium phases were determined by Electron Probe Micro Analysis (EPMA) and X-ray diffraction (XRD). The isothermal section of CaO-Al₂O₃-Ti₂O₃ system in the low w(TiO_x) region at 1500 °C was constructed for the first time, in which there are 6 three-phase fields, 7 two-phase fields, and a liquid phase field. The isothermal section of CaO-Al₂O₃-Ti₂O₃ system in the low w(TiO_x) region at 1600 °C was constructed and revised, including 3 three-phase fields, 6 two-phase fields, and a liquid phase field. Additionally, under the current experimental condition, the reasons for the formation of TiC in the high w(TiO_x) region of this slag system were analyzed, further discussing the effect of carbon on the phase equilibria of CaO-Al₂O₃-Ti₂O₃ system.