Migration in foils was measured at 0 to 100C by using an electrochemical time-lag method (table 258). 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.
N.Boes, H.Züchner: Zeitschrift für Naturforschung A, 1976, 31[7], 760-8
Table 259
Parameters for H and D Diffusion in Ta
Isotope | Temperature (K) | Do (cm2/s) | E (kJ/mol) |
H | 160-230 | 9.7 x 10-4 | 20.3 |
H | 110-160 | 9.2 x 10-6 | 14.1 |
H | 87-110 | 1.4 x 10-8 | 8.1 |
D | 118-210 | 2.8 x 10-4 | 20.2 |
D | 78-118 | 1.1 x 10-7 | 12.7 |