INTERFACIAL-TENSION BETWEEN MOLTEN IRON AND CAO-SIO2 BASED FLUXES

Flux-metal interfacial tension has been examined by X-ray photography of a metal drop melted in a molten flux. The experiments were carried out at 1 580 degrees C using a zirconia crucible with low solubility i n the fluxes. The systems used in the investigation were as follows: M etal phase: Fe-O alloy, oxygen content in the alloys varied from 0.002 to 0.070 mass%. Flux phase: Ternary system: CaO-SiO2-M-x(F,O)(y), whe re M-x(F,O)(y) represents NaF, CaF2, Al2O3, Na2O, MgO, Li2O or ZrO2 an d concentrations varied from 2 to 40 mass%. Multicomponent system: CaO -SiO2-Al2O3-Fe2O3-Na2O-NaF-CaF2-MgO-Li2O-ZrO2. The interfacial tension was observed to increase with increasing NaF, CaF2, Na2O, MgO or Li2O contents, while only minor changes in the values were observed with v arying Al2O3 or ZrO2 contents in CaO-SiO2 or CaO-SiO2-Al2O3 systems. T he interfacial tensions between flux and molten iron decreased with in creasing oxygen activity in iron, gamma = gamma(0)-0.324In(1+116a(0)).