A relation between relative density, alloy composition and sample shrinkage for nanoporous metal foams

Nanoporous metal foams synthesized by dealloying inherently undergo dimensional changes (shrinkage). If these changes are unaccounted for in the measurement of relative density, this can be underestimated, causing up to an order of magnitude error in weight-normalized properties. In constrained samples the shrinkage leads to build-up of tensile stress that modifies the porosity and may lead to crack formation. A relationship between shrinkage, relative density and atomic fraction is proposed and experimentally verified.