Diffusion of Chromium, Manganese, and Nickel in Molten Iron

Diffusion coefficients of chromium, manganese, and nickel in molten iron were measured by the diffusion-couple method at 1550 and 1600°C in the composition range of up to about 5%.(1) Diffusion coefficients of Cr, Mn, and Ni in molten iron obtained are as follows:DCr(1550°C)=3.04(±0.37)×10−5cm2⁄sec,DCr(1600°C)=3.42(±0.40)×10−5cm2⁄sec,DMn(1550°C)=4.37(±0.36)×10−5cm2⁄sec,DMn(1600°C)=4.96(±0.61)×10−5cm2⁄sec,DNi(1550°C)=4.67(±0.45)×10−5cm2⁄sec,DNi(1600°C)=5.59(±0.34)×10−5cm2⁄sec.(2) A close correlation was found between the diffusivity Dj and the standard free energy of solution ΔFj0 for the elements dissolved in molten iron; the diffusivity Dj increases with an increase of ΔFj0.(3) Comparison of the above-mentioned finding with the previous results on the diffusion in molten carbon-saturated iron suggested the same functional relationship between the diffusivity and the standard free energy of solution, irrespective of whether carbon is contained in the solvent iron or not.