INFLUENCES OF SELF-INDUCED STRESS ON PERMEATION FLUX AND SPACE-TIME VARIATION OF CONCENTRATION DURING DIFFUSION OF HYDROGEN IN A PALLADIUM ALLOY

The nature of hydrogen diffusion in a tubular membrane of a Pd81Pt19 a lloy is discussed. The effect of self-induced stress on (a) the space- time variation of hydrogen concentration and (b) the diffusion flux in the steady state are presented. The experimental results are explaine d qualitatively assuming that the concentration profile at steady stat e is non-linear. The activation energy and the pre-exponential factor of the Arrhenius relation for the diffusion coefficient are estimated for hydrogen diffusion in a Pd81Pt19 alloy membrane containing no hydr ogen prior to the diffusion process. Estimated values are in good agre ement with published experimental results.