Elaboration of Nanoporous Copper via Chemical Composition Design of Amorphous Precursor Alloys

Abstract

Au-group (Ag, Au) and Pt-group (Ni, Pd, Pt) metals have lower surface diffusion coeffi - cients than Cu and are defined as LSD. The chemical composition has been designed based on the differences in diffusion coefficients, and the micro-alloying of 1 at % LSD met - als with the Ti 60 Cu 40 amorphous precursor alloy results in the formation of bi-continuous nanoporous copper (NPC) with finer nanoporous structure. LSD-stabilized NPCs have the smallest characteristic pore sizes of 7 nm and 6 nm after dealloying amorphous Ti 60 Cu 39 Pd 1 and Ti 60 Cu 39 Pt 1 precursor alloys, while NPC had a pore size of 39 nm after dealloying the amorphous Ti 60 Cu 40 alloy. The refining factor increases approximately from 3.7 for Ti 60 Cu 39 Ag 1 to 1780 for Ti 60 Cu 39 Pt 1 precursors due to the dramatic decrease in the surface diffusivity during both preferential dissolution and rearrangement of Cu adatoms. The elaboration efficiencies of Ti 60 Cu 40 alloy with addition of 1 at.% Pt-group elements are higher than those of Au-group elements. The homogeneous distribution of LSD elements in both the precursors and final stabilized NPCs played a key role in restriction of the long-distance diffusion of Cu adatoms. LSD-stabilized NPCs are able to have an ultrafine nanoporosity with a pore size almost one order smaller than that from LSD-free alloys. alloys heterogeneous in microstructure