Influence of saccharin on the structure and corrosion resistance of electrodeposited CuNi multilayers

The influence of saccharin, a brightener, on the structure of CuNi multilayers, electrodeposited from a single bath on a polycrystalline copper substrate, has been studied by transmission electron microscopy and atomic force microscopy. It is shown that CuNi multilayers do not present a columnar-growth morphology when saccharin is present in the electrolyte. The consequence of this is a much smaller surface roughness and thus a bright surface aspect. The presence of saccharin improves the corrosion resistance of the CuNi multilayers in a 3% NaCl solution. This work also demonstrates that electrodeposition has a capacity to produce CuNi multilayers with modulation distances as small as 2.5 nm.