Fabrication and characterization of nanoporous copper through chemical dealloying of cold-rolled and annealed Mn–Cu alloy

This study investigated the effects of the manufacturing process on the microstructure of nanoporous copper (NPC) produced using cold-rolled Mn–30 at.% Cu and Mn–40 at.% Cu precursor sheets. NPC was prepared by chemically dealloying these precursor sheets in a 4% HCl aqueous solution. The initial Mn–Cu alloys were homogenous solid solutions with good cold-rolling workability. After dealloying, Mn–30 at.% Cu and Mn–40 at.% Cu precursors formed nanoporous structures with ligament size of 122 ± 5 nm and 97 ± 4 nm, respectively. In addition, the annealing conditions of the precursors were strongly related to the formation of a bi-continuous nanoporous structure. This was attributed to the lower diffusivity of Mn atoms at 550 ℃ than that at 750 ℃, which resulted in the slower rearrangement of Cu atoms during the dealloying process. Additionally, NPC sheets derived from annealed Mn–30 at.% Cu precursors at different annealing temperatures under the same dealloying condition exhibited ligament sizes of 223 ± 9 nm and 149 ± 4 nm. These results indicate that the change in the annealing temperature of the precursor significantly refined the nanoporous structure.