Activity of Silicon in Liquid Iron and the Effect of Carbon on the Activity of Silicon

Abstract

The thermodynamic properties of silicon in liquid iron and iron-carbon solution have been studied by distribution experiments at 1450°C and 1540°C. The data in iron-silicon system are in good agreement with those of the previous studies above 0.2 atom fraction of silicon in liquid iron, while they showed somewhat lower values under 0.2 atom fraction of silicon. Data on heat of mixing by KÖRBER and OELSEN are applied to extend the present results to 1600°C. The interaction parameters difined as ∂ ln γ_S1/∂N_S1 were the values of 19.2 at 1450°C, 17.5 at 1540°C and 17.0 at 1600°C in the concentration range from 0.2 to 0.35 atom fraction.
Liquid iron-silicon-carbon alloys are equilibrated with iron-silicon alloy through the liquid bridge of silicon-silver alloy. The results obtained are consistent with the data by S_CHROEDER and C_HIPMAN.
Interaction parameter ε^C_S1 was 21.0 at 1450°C when the value of ε^S1_S1=19.2 was applied.