It was shown that depth profiles with plateaux, which were sometimes detected when H was diffused, could be explained by including terms (in the diffusion equation) which described the various manners in which H could interact with impurity atoms. It was suggested that such plateau-type profiles could result from a loss of system stability, due to local interactions, and from diffusional exchange between neighboring volumes due to the appearance of long-range correlations. It was found that the behavior of the system depended upon the dimensionally of the random walk via which the H diffused. Changes in temperature and impurity concentration altered the parameters of the random walk, and thus changed the nature of the diffusion process.

J.W.Corbett, I.V.Verner: Materials Science Forum, 1992, 83-87, 57-62