The migration of H was studied at 260 to 1000K by using electrochemical and gas permeation techniques. It was found that the diffusion of H in Ni was described by:

D (m2/s) = 9.2 x 10-7 exp[-41.4(kJ/mol)/RT]

The results for the alloys could also be described by straight Arrhenius plots. The activation energy for H diffusion was greatest at 70at%Cu in Ni-Cu alloys, and increased with increasing Co content in Ni-Co alloys.

Diffusion Coefficients of Hydrogen in Ni-Cu and Ni-Co Alloys. H.Hagi: Transactions of the Japan Institute of Metals, 1986, 27[4], 233-40. See also: Journal of the Japan Institute of Metals, 1983, 47[12], 1029-35