The recovery of excess dissolved H was studied by using a modified Schultz H-quenching method. Two recovery stages in the electrical resistance were found. The lower-temperature stage was presumed to arise from trapping and/or clustering of H atoms within the specimens. The higher-temperature stage was due to the escape of H from the specimens. This stage was closely studied by means of isothermal annealing over a wide temperature range, using various specimen sizes. All of the results could be fitted to a generalized curve. The diffusivity of H in Ni was described by:
D (cm2/s) = 1.90 x 10-3 exp[-8890/RT]
K.Yamakawa, F.E.Fujita: Japanese Journal of Applied Physics, 1977, 16[10], 1747-52
Table 94
Diffusivity of H in Ni
Temperature (C) | D (m2/s) |
23 | 4.00 x 10-14 |
22 | 3.03 x 10-14 |
20 | 2.63 x 10-14 |
8 | 1.78 x 10-14 |
0 | 1.45 x 10-14 |