The diffusion of H through Pt-coated Ti was studied electrochemically. The room-temperature diffusion coefficient at a cathodic polarization of -10mA/cm2 was equal to 3.8 x 10-12cm2/s and increased, with increasing cathodic polarization, to a limiting value of about 7.0 x 10-12cm2/s. The activation energy was equal to 6.9kcal/mol at 24 to 66C, and a cathodic polarization of -20mA/cm2. Diffusion occurred via Ti-hydride formation, and a permeation flow was observed on the anodic side of the foil only after the entire foil had been converted into Ti hydride. On the basis of this mechanism, a diffusion coefficient of 10-10cm2/s was calculated for Ti at 24C.

E.Brauer, E.Nann: Werkstoffe und Korrosion, 1974, 25[5], 309-13