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 312), 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.

M.Kano, N.Kagawa, S.Koike, K.Furuya, T.Suzuki: Acta Metallurgica, 1988, 36[6], 1553-62

Table 315

Diffusivity of 16O in V

 

Temperature (K)

D (m2/s)

624

9.35 x 10-17

580

1.20 x 10-17

529

1.23 x 10-18

496

2.18 x 10-19