A vacuum hot-extraction method was used to monitor the out-diffusion of H from cylindrical specimens which had been pre-charged with H. At temperatures ranging from 570 to 630C, the results could be described by:

D (cm2/s) = 2.0 x 10-2 exp[-12.0(kcal/g-atom)/RT]

S.Matsuo, T.Hirata: Transactions of the National Research Institute for Metallurgy, 1969, 11[2], 88-92