Migration in foils was measured at 0 to 100C by using an electrochemical time-lag method (table 90). A modified strain model indicated that the tetrahedral sites in body-centered cubic lattices had to be assumed to be stable positions for dissolved H. Elementary jumps, from one tetrahedral site to the next, passed directly through a tetrahedral plane. This model described qualitatively the experimental results, with respect to the order of the activation energies for H diffusion in these metals.
N.Boes, H.Züchner: Zeitschrift für Naturforschung A, 1976, 31[7], 760-8
Table 90
Parameters for H and D Diffusion in Nb at 0 to 100C
Isotope | Do (cm2/s) | E (kcal/g-atom) | D25C (cm2/s) |
H | 3.6 x 10-4 | 2.5 | 5.2 x 10-6 |
D | 5.0 x 10-4 | 2.8 | 4.5 x 10-6 |