Nickel-stabilized nanoporous copper fabricated from ternary TiCuNi amorphous alloys

Abstract

Minor additive nickel (1at%) to Ti–Cu amorphous alloy helped to form the finer nanoporous copper (NPC). The pore size of open-cell nanoporous fcc Cu was confirmed to be 71nm for Ti60Cu40 alloy and 23nm for Ti60Cu39Ni1 alloy after immersion of 43.2ks in 0.03M HF solution at 298K. 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 2.7×10−20m2s−1by adding 1 at% Ni to Ti60Cu40 ribbons. The activation energy of surface diffusion of Cu atoms was estimated to be 68kJmol−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.