The Gorsky-effect technique was used to study the diffusion of H in Nb, and the effect of N upon this process. In the case of out-gassed samples (N concentration below 0.01%), the H diffusivity could be described by the sum of 2 exponentials; one of which predominated at 0 to 300C while the other predominated at -50 to-100C:

D (cm2/s) = 5.2 x 10-4 exp[-0.125(eV)/kT] + 5 x 10-5 exp[-0.062(eV)/kT]

The presence of up to 0.55%N decreased the H diffusivity, and it was suggested that N in Nb suppressed the fast low-temperature diffusion process.

W.Muenzing, J.Völkl, H.Wipf, G.Alefeld: Scripta Metallurgica, 1974, 8[11], 1327-30