The diffusion of H was studied by measuring H evolution from pre-charged Ni specimens during annealing. The results for spherical and cylindrical specimens obeyed:

sphere:     D (cm2/s) = 6.5 x 10-3 exp[-0.400(eV)/kT]

cylinder:     D (cm2/s) = 5.4 x 10-3 exp[-0.395(eV)/kT]

for temperatures of between 206 and 606C and between 200 and 650C, respectively.

P.Combette, P.Azou: Mem. Sci. Rev. Met., 1970, 67[1], 17-33