Vapor phase dealloying kinetics of MnZn alloys

Porous gold with three-level structural hierarchy

“…The above results demonstrate that owing to the equilibrium vapor pressure difference between pure Zn and Ag-Au alloy, Zn in the (Ag 95 Au 5 )Zn was selectively evaporated and the remaining Ag and Au atoms diffused and rearranged to form the microporous structure ( Lu et al., 2018 ). Notably, the average ligament size of the 1 st hierarchy level is smaller than the length scale of pores, which could be associated with the diffusion-limited transport kinetics ( Lu et al., 2021 ). Afterward, a moderate potential of 0.65 V (vs. Ag/AgCl) was applied on the MP-Ag 95 Au 5 alloy to partially dissolve Ag during the 1 st ECD in 1 mol L −1 HClO 4 , leading to an absolute black appearance of the as-dealloyed sample ( Figure 2 D).…”

How Can We Efficiently Fabricate Nanostructured Materials with Unprecedented Properties?

“…Prior work in the field suggested that the bicontinuous structure of nanoporous gold was the sole morphology available to dealloyed materials, regardless of starting alloy composition. This new, wider palette of accessible morphologies has been observed in both liquid metal and vapor phase dealloying systems , and was attributed to a much faster dissolution rate (1–2 orders of magnitude higher than electrochemical dealloying) in comparison to surface diffusion.…”

“…To-date, dealloying has been carried out in aqueous liquids, molten metals, and molten salts. ,,,, Beyond the apparent novelty, these new solvents relax the constraint of synthesizing only noble nanoporous metals. Consequently, dealloying has been extended to a number of more common alloy systems, including: refractories (V, Nb, Mo, Ta, W), steels, Ti-base alloys, Ni-base superalloys, and semiconductors such as Si. , Furthermore, gas-phase reactions, selective evaporation, and diffusion couples have recently extended dealloying to nonliquid solvents. ,− Although the dissolution media and environment have changed, the common thread between all of these examples is that a nanoscale pattern emerges from two competing processes: roughening by selective removal, and smoothing driven by interfacial diffusion …”

“…Three key research areas to realize true nanoscale control via self-organization processes: (bottom) extension of these tools to any material class; , (left) manipulating kinetic and thermodynamic factors during self-organization to control the resulting nanoscale morphology; , (right) sequential self-organization and post processing protocols to develop multiscale nanocomposites. , Images adapted with permission from refs (Copyright 2014 American Chemical Society), (Copyright 2021 Elsevier), (Copyright 2021 The American Association for the Advancement of Science), (Copyright 2016 John Wiley and Sons), and (Copyright 2021 John Wiley and Sons).…”

Bicontinuous Nanoporous Metals with Self-Organized Functionalities

“…It in principle resists dissolution by passivation, but it also exposes sites otherwise inaccessible to the dissolution medium scriptC . The kinetics become more complicated in LMD because the diffusing scriptB atoms can also be sparingly soluble in scriptC , whose strong influence on the porous structure has been recently discussed by Lai et al In VPD, the temperature can be high enough to invoke diffusion in the bulk solid, much like the dealloying of Mg and Li alloys, giving rise to new structures and intermediate phases not covered yet by the dealloying theory . RID further challenges the mechanism, as the interface between the growing metallic scriptB and the compound scriptA q scriptB bears little coherency.…”