Effect of TiO ₂ on melting and crystallisation properties of CaF ₂ (50%)-CaO-Al ₂ O ₃ -MgO(3%)-ZrO ₂ (4%) electroslag

This study investigates the effect of highly fluorinated electroslag with TiO 2 content of 0%, 3%, 6% and 9% on the melting process, crystallisation kinetics and crystalline product structure by using STA, XRD and SEM-EDS techniques. The results demonstrated a gradual decrease in the melting temperature, heat of fusion and first crystallisation temperature of the slag as the TiO 2 content increased. The main precipitation phases in the slag are Ca 12 Al 14 O 32 F 2 , CaF 2 , CaZrO 3 , CaTiO 3 , (Ca, Zr, Ti)O 2 and MgO. The larger the ratio of TiO 2 :ZrO 2 , the higher the precipitation rate of multi-faceted CaTiO 3 . The precipitation of dendritic CaZrO 3 was also gradually suppressed. Crystallisation kinetic analysis revealed that the slag exhibited the highest activation energy for crystallisation at a TiO 2 content of 6%. These findings have a positive impact on determining the TiO 2 content in the electroslag and enhancing the surface quality of the ingot.