Equilibrium Distribution Coefficient of Phosphorus in Iron Alloys

Abstract

In this work, the equilibrium distribution coefficients of phosphorus k^P₀ in Fe-P binary and Fe-C-P ternary systems were obtained experimentally and the carbon content dependence of the equilibrium distribution of P was discussed using Distribution Interaction Coefficient. Temperature dependence of k^{P, α}₀ for α phase is given by
k^{P, α}₀=N^s_P/N^l_P=0.715-3.2O×10^-4T.
From the above equation, k^{P, α}₀ at infinite dilution of P, that is to say, at the melting point of iron, is 0.136, k^{P, γ}₀ for γ phase at high carbon concentration is about 0.09. k^{P, γ}₀ increases with the concentration of carbon and k^{P, γ}₀ at infinite dilution is 0.06. Also, the relation between k^X₀ of various elements for α phase and that for γ one was derived thermodynamically.