Preparation of hierarchical porous metals by two-step liquid metal dealloying

A hierarchical porous metal has been prepared by two-step liquid metal dealloying using an alloy precursor containing two soluble components and two metal baths. After the first dealloying step, one of the soluble components is dissolved and a coarse porous structure is formed. After a shorter dealloying step in another melt, the other soluble component is dissolved and a fine porous structure is formed within the previously formed coarse ligaments. The resultant porous metal presents a hierarchical morphology with a bimodal pore distribution, resulting in a higher porosity and surface-area-to-volume ratio than what can be formed by one-step dealloying methods. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.