The diffusion behaviors of hydrogen, deuterium and tritium in bulk niobium was investigated using first-principles methods. The diffusion energy barrier with quantum-correction was calculated to be 0.12eV; in good agreement with the experimental value of ∼0.106eV. According to the diffusion theory of Wert and Zener, the diffusion pre-exponential factors of H, D and T were 7.74 x 10-8, 5.47 x 10-8 and 4.48 x 10-8m2/s, respectively. These results were also in quantitative agreement with experimental values.

Diffusion Behaviors of Hydrogen Isotopes in Niobium from First-Principles. W.Lu, A.Gao, Y.Liu, Z.Dai: Science China: Physics, Mechanics and Astronomy, 2012, 55[12], 2378-82

[268] Nb: D, H, T Diffusion

The isotope effect for the diffusion of H, D and T in body-centered cubic Nb was measured by using the Gorsky effect. It was found that the data could be represented by Arrhenius relationships at temperatures ranging from 190 to 310K (table 89). The DH/DD ratio was much larger than the classical value of √2, and exhibited a strong temperature-dependence. The DD/DT ratio was slightly larger than √(3/2) and was relatively temperature-independent.

The Isotope Effect for the Diffusion of Hydrogen in Niobium. G.Matusiewicz, H.K.Birnbaum: Journal of Physics F, 1977, 7[11], 2285-9

Table 89

Isotope Effect for H Diffusion in Nb