Nickel-stabilized nanoporous copper fabricated from ternary TiCuNi amorphous alloys

摘要

Minor additive nickel (1 at%) to Ti-Cu amorphous alloy helped to form the finer nanoporous copper (NPC). The pore size of open-cell nanoporous fee Cu was confirmed to be 71 nm for Ti_(60)Cu_(40) alloy and 23 nm for Ti_(60)Cu_(39)Ni_1 alloy after immersion of 43.2 ks in 0.03 M HF solution at 298 K. The pore size increased with immersion time in a form of the power law function with an exponent of 0.26. The estimated surface diffusivity decreased by about two orders of magnitude from 2.5 × 10~(18) to 2.7 × 10~(50) m~2s~(-1)by adding 1 at% Ni to Ti_(60)Cu_(40) ribbons. The activation energy of surface diffusion of Cu atoms was estimated to be 68 kJ mol ~(-1). The refinement of nanoporous Cu was resulted from the additive Ni with one-order lower surface diffusivity than Cu. Ni adatoms acted as a barrier for the diffusion and rearrangement of Cu adatoms, as a result, the smaller nanopores formed on Ti-Cu-Ni amorphous alloy.