MODELS FOR HYDROGEN PERMEATION IN METALS

Hydrogen transport in metals is affected by processes occurring in the bulk, the surface/bulk, and gas/surface interfaces. Several models have been proposed to explain the permeation process. Here the development of the various models is discussed and the similarities and differences among them are highlighted. By considering the limiting case of high pressure, it is shown that the dissociative chemisorption model of Wang [Proc. Cambridge Philos. Soc. 32, 657 (1936)] is sufficient to explain the observed experimental results.