Effects of self-stress on hydrogen diffusion in Pd membranes in the coexistence of α and β phases

We analyze and compare the influence of lattice strain gradients on hydrogen absorption in tubular and planar membranes in the coexistence of alpha and beta phases. We show, by means of numerical simulations and analytical arguments, that self-stresses strongly influence the dynamics of the propagation of the beta phase within a planar membrane. Conversely, the et-p phase transition is only slightly influenced by lattice strain gradients in a tubular membrane. The occurrence of uphill-diffusion phenomena at the early stages of the permeation process is also addressed. (C) 2003 Elsevier B.V. All rights reserved.