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Electrolytic dealloying of a solid-solution alloy is usually understood to involve a relatively large content of more-noble element in the alloy (e.g. 25%), from which starting point it is natural that dealloying will produce a connected nanoporous structure. But it has been known for a long time, since the work of H.W. Pickering, that starting alloys such as Cu-10 at.% Au can be dealloyed to produce fully connected Au-rich dealloyed layers, at least to a certain thickness. Clearly not all the Cu could have been removed during this process, and Pickering demonstrated not only that the dealloyed material retained much of its Cu, but that there was a compositional gradient, or at least a range of dealloyed compositions, within the material. In the present work we have used a 95Ag-5Au (at.%) alloy and have attempted to correlate the dealloying behaviour (ligament size in the nanoporous layer; true surface area) with Kinetic Monte Carlo simulations of the dealloying process. The results are analogous, with some areas for further quantitative development. A related behaviour in stainless steels is discussed.

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