Permeation and resistivity methods were used to study the effect of cold-working tensile stresses upon H diffusion in zone-melted Fe. The room-temperature diffusivity was found to decrease steadily with the degree of deformation, according to:

D (cm2/s) = 8.1 - 12.5e

where e = (L-Lo)/Lo was less than 0.20, Lo was the initial specimen length and L was the length after elongation. The results quantitatively confirmed the hypothesis that H was trapped by dislocations.

M.Cornet, S.Talbot-Besnard: Corrosion Traitements, Protection, Finition, 1972, 20[8], 523-7

Figure 6

Diffusivity of H in Fe-Co

(a: 0at%Co, b: 0.41at%Co c: 0.88at%Co d: 2.83at%Co e: 4.79at%Co)