Comparative microhardness analysis of various thin metallic multilayer composite films

Different composite systems of electrodeposited monolayered and multilayered thin metal films of Ni and Cu on cold-rolled copper substrates were made. Thin metal layers were deposited at narrow spacing of 300 nm and 150 nm and high strength of composites was obtained. Microhardness analysis was performed on the systems of ED Ni film (sulphate “Slotonik 20” electrolyte) / ED Cu film (sulphate electrolyte), ED Ni film (sulphamate electrolyte) / ED Cu film (sulphate electrolyte) and ED Ni film (sulphamate electrolyte) / ED Ni film (“Slotonik 20” electrolyte). Characterization of mechanical properties of the composite systems was done using Vickers microhardness testing with loads ranging from 0.049 N to 1.96 N. Dependence of microhardness for different composite systems on microstructure and Ni/Cu and Ni/Ni layer thickness ratio was investigated. Composite hardness model of Korsunsky was applied to the experimental data in order to determine the absolute composite film hardness. The highest value of all the composite film hardness values was obtained for the system of multilayered Ni films from two different electrolytes, and ”Slotonik 20” and sulphamate and with sublayer thickness ratio 1∶2, respectively.