The permeability time-lag method was used to determine the diffusivity of H at 496 to 946C. Previous measurements had indicated a large positive deviation from Arrhenius

behavior above 600C. No such deviation was found here. The diffusivity at 469 to 946C could be described by:

D (cm2/s) = 2.83 x 10-3 exp[-5.2(kcal/mol)/RT]

H.Katsuta, R.J.Farraro, R.B.McLellan: Acta Metallurgica, 1979, 27[7], 1111-4