The migration of Fe in pure Al was studied by using a tracer sectioning technique. The penetration plots were fitted by a solution to the diffusion equation for the case where the surface flux was controlled by a surface barrier. This characterized the dissolution of tracer atoms from the intermetallic phases formed in the near-surface layer and was represented by an energy which was higher than the diffusion activation energy in the bulk. The diffusivity could be described by:

D (cm2/s) = 5.3 x 101 exp[-1.90(eV)/kT]

D.L.Beke, I.Gödény, I.A.Szabo, G.Erdélyi, F.J.Kedves: Philosophical Magazine A, 1987, 55[4], 425-43

The best linear fits to the solute diffusion data ([562] to [565], [567] to [570], [573] to [577], [581] to [585], [592] to [599], [608] to [611], [623] to [626]) yield:

Au: Ln[Do] = 0.67E – 20.7 (R2 = 0.999); Co: Ln[Do] = 0.43E – 12 (R2 = 0.69);

Cu: Ln[Do] = 0.69E – 22.7 (R2 = 0.99); Fe: Ln[Do] = 0.56E – 20.5 (R2 = 0.996);

H: Ln[Do] = 0.63E – 9.45 (R2 = 0.96); Mn: Ln[Do] = 0.52E – 21.4 (R2 = 0.993);

Zn: Ln[Do] = 0.77E – 24 (R2 = 0.99)