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