The refinement of the nanoporous copper by adding third elements

Fine nanoporous copper was fabricated from the amorphous Ti-Cu alloys with a minoraddition of silver in 10 mM HF solutions. The pore sizes decreased from 100 nm to 12 nm with theincrease of the Ag contents in comparison of Ti₆₀Cu₄0 ribbons free of Ag. With increasing of thedealloying time, the sizes of the nanopores and ligaments increased for the nanostrucutres onTi₆₀Cu₃₈Ag₂ ribbons since the segregation of the Ag phase which triggered the galvanic dissolutionof the adjacent Cu matrix in form of micro-couplings to further coarsen the nanoporous Cu. On thecontrary, the trace formation of the Ag phase on the Ti₆₀Cu₃₉Ag₁ ribbons had a weak ability tomotivate the galvanic dissolution, indicating by the constant pore sizes and slight decrease in theligament sizes with the increase in the dealloying time. The refinement of the nanoporous structureswas ascribed to the drastic decrease in the surface diffusivity. The decrease in the surface diffusivitydue to the involvement of Ag with a lower surface diffusivity in comparison of Cu was more thanone order of magnitude. The involvement of Ag adatoms restricted the diffusion of Cu adatoms inthe interface regions in the inward and outward directions.