Thermal analysis was used to study the trapping and transport of H. The dislocations acted as trapping sites for H, and the H trap activation energy at these appeared to be lower than the activation energy for the bulk diffusion of H. It was suggested that both H-trapping at grain boundaries, and short-circuit diffusion through grain boundaries, occurred. The trap binding energy at grain boundaries was estimated to be 20.5kJ/mol. The diffusivity of H could be described by:

D (m2/s) = 7.5 x 10-7 exp[-39.1(kJ/mol)/RT]

The Trapping and Transport Phenomena of Hydrogen in Nickel. S.M.Lee, J.Y.Lee: Metallurgical Transactions A, 1986, 17[2], 181-7