The residual activity technique was used to study the self-diffusion of 59Fe in several Fe-Mo alloys. In the paramagnetic region, T > TC, where TC was the Curie point, the temperature dependence of D obeyed Arrhenius equations,

0.54wt%:     D (cm2/s) = 1.55 x 101 exp[-263(kJ/mol)/RT]

1.06wt%:     D (cm2/s) = 2.36 x 101 exp[-257(kJ/mol)/RT]

1.50wt%:     D (cm2/s) = 2.85 x 101 exp[-266(kJ/mol)/RT]

2.50wt%:     D (cm2/s) = 4.77 x 101 exp[-264(kJ/mol)/RT]

and the frequency-factor and activation energy for self-diffusion were independent of the alloy composition. A marked effect of ferromagnetic ordering upon the temperature dependence of D was observed at T < TC, where log[D] was not proportional to 1/T.

J.Ruzicková, B.Million: Kovove Materialy, 1977, 15[2], 140-5