Preparation, microstructure and sliding-wear characteristics of brush plated copper–nickel multilayer films

Cu/Ni multilayer films with sublayer thickness (h) ranging from 10 to 1000 nm were prepared on ANSI 1045 steel by brush plating of periodically changing layers of Cu and Ni. The microstructure, composition, microhardness and sliding wear properties against standard SiC ball under unlubricated condition were examined. It was found that the brush plated multilayer films are highly dense and free from porosity. A decrease in h results in smaller grain size and lower coefficient of friction. Both microhardness and wear resistance reach the maximum value when h = 20 nm. Although found with lower hardness compared with brush plated Ni monolayer coating, multilayer films with h ranging from 20 to 80 nm showed improved wear resistance. The increase in the wear resistance was attributed to the combined effect of strengthening of the layer structure and the lubricating of Cu.