Effect of the self-induced strain on the hydrogen permeation through Al

The similarity between the observed unusual hydrogen permeation through Al membranes at application of cathodic polarization in alkaline solutions and the hydrogen transport through the Pd membrane at application of increased hydrogen pressure (Lewis effect) has been found. The data of electrochemical measurements of hydrogen permeation through Al have been analyzed and rationalized from the point of view of the involved hydrogen transport due to the gradient of concentration and the gradient of strain introduced at application of cathodic polarization. The possible origins of surface stress and strain produced in Al at cathodic polarization have been discussed and the implication of the effect in determination of hydrogen diffusion coefficient in Al and in the hydrogen-induced degradation of Al have been shown.