The permeation behavior under oscillating-pressure conditions was studied. It was deduced from the results that the diffusivities, at temperatures of between 500 and 1000K, could be described by:

D:     D (m2/s) = 4.28 x 10-8 exp[-6.47(kJ/mol)/RT]

H:     D (m2/s) = 4.43 x 10-8 exp[-5.31(kJ/mol)/RT]

The ratio of the diffusion coefficients of the H isotopes approached unity with increasing temperature. This behavior was different to that of face-centered cubic metals, where this ratio approached 1.41 with increasing temperature.

A.Tahara, Y.Hayashi: Journal of the Japan Institute of Metals, 1985, 49[4], 248-52

Figure 2

Diffusivity of Isotopes in Fe

(open squares: H, filled squares: D)