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