The time-lag method was used to study the vacuum desorption of H from cathodically H-charged Armco Fe specimens. From these results, permeation and diffusion data were derived. Permeation at 25 to 300C was described by:

P (cm/s) = 2.72 exp[-10.0(kcal/mol)/RT]

while diffusion was described by:

25-80C:     D (cm2/s) = 1.97 x 10-5 exp[-16.6(kcal/mol)/RT]

80-300C:     D (cm2/s) = 3.71 x 10-3 exp[-4.17(kcal/mol)/RT]

It was found that, at temperatures below 80C, H was trapped by imperfections in the metal.

V.Safonov, J.Chene, J.Galland, P.Azou, P.Bastien: Comptes Rendus, 1974, 278[7], 445-9