The gas permeation method, and quadrupole mass spectrometry, were used to monitor the super-diffusion of H under the influence of a stress which was applied to polycrystalline V specimens with electroplated Pd films. It was found that the effective diffusion coefficients (table 181), measured under an applied stress of more than 18MPa at a temperature of 404 or 426K, increased steeply to values which were 6 to 10 times higher than those under no applied stress. It was also noted that the H solubility decreased by a factor of about 1/3. It was suggested that super-diffusion involved the hopping motion of 4T-type H atoms.
Superdiffusion of Hydrogen in Vanadium Measured by the Permeation Method. M.Kano, N.Kagawa, S.Koike, K.Furuya, T.Suzuki: Acta Metallurgica, 1988, 36[6], 1553-62
Table 180
Activation Energies for H Diffusion in V-Ni Hydrides
Hydride | Temperature (K) | E (kJ/mol) |
VH0.77 | 180-420 | 18 |
VH0.77 | 240-420 | 20 |
VH0.77 | 120-240 | 7 |
V0.95Ni0.05H0.73 | 200-400 | 18 |
V0.95Ni0.05H0.73 | 140-200 | 10 |
V0.95Ni0.05H0.73 | 250-400 | 18 |
V0.95Ni0.05H0.73 | 120-250 | 3 |
V0.90Ni0.10H0.65 | 230-400 | 17 |
V0.90Ni0.10H0.65 | 140-230 | 10 |
V0.90Ni0.10H0.65 | 220-400 | 16 |
V0.90Ni0.10H0.65 | 120-220 | 3 |