Migration in foils was measured at 0 to 100C by using an electrochemical time-lag method (table 88). 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 87

Parameters for D and H Diffusion in Nb

 

Isotope

Temperature (K)

Do (cm2/s)

E (eV)

D

120-600

5.4 x 10-4

0.129

H

120-300

9.0 x 10-5

0.068

H

300-600

5.0 x 10-4

0.106