The effect of saccharine on the localized electrochemical deposition of Cu-rich Cu–Ni microcolumns

High aspect ratio Cu-rich Cu–Ni microcolumns have been fabricated on brass substrates by Localized Electrochemical Deposition using a platinum microanode with an electrical bias of 7.0 V. Sulfate–citrate baths with and without the presence of saccharine as a grain-refining agent, have been used. The microcolumns are ~ 100 μm in diameter and several hundreds of micrometers in height. The addition of saccharine to the electrolytic solution resulted in the reduction of both the porosity and the surface roughness of the Cu–Ni grains in the microcolumns. The Ni/Cu atomic ratio on the top of the microcolumns was higher than that at the bottom, indicating a composition gradient along the height of the columns. Despite their relatively low Ni content (below 35 at% in all cases), the microcolumns were weakly ferromagnetic. Nanoindentation hardness and reduced Young's modulus were also measured. Larger values of both parameters were obtained in the columns grown in the presence of saccharine.

► Localized Electrochemical Deposition of Cu-rich Cu–Ni microcolumns.
► Saccharine reduces the porosity, and in turn improves the mechanical properties.
► The microcolumns exhibit an aspect ratio close to 8:1.
► The microcolumns are weakly ferromagnetic.