The bulk diffusion of Sn in the α and γ phases of the alloys, containing 0.3 to 1.6wt%Sn, was studied. Concentration gradients were determined by using electron probe analysis, and the interdiffusion coefficients were calculated by using the Grube-Jedele method. At concentrations of up to 1.6wt%Sn, the diffusivity was independent of the concentration. The activation energies for bulk Sn diffusion were also determined. Lower values were found for the α-phase. The results could be described by:

α-Fe:     D (cm2/s) = 8.00 x 107 exp[-38.2(kcal/mol)/RT]

γ-Fe:     D (cm2/s) = 2.32 x 100 exp[-44.3(kcal/mol)/RT]

The interdiffusion coefficients decreased when Cu was present.

N.Sarafianos: Materials Science and Engineering, 1986, 80[1], 87-91