Characterization of Cu-Al₂O₃ and Ni-Al₂O₃ Nanocomposites Electrodeposited on Copper Substrate

In the present work, it was attempted to electrodeposit Cu-Al2O3 and Ni-Al2O3 metal matrix composite (MMC) coatings onto a copper substrate using a modified Watts bath containing dispersed nanosized Al2O3 with an average particle size of 50 nm. The prepared nanocomposite coatings were subjected to different tests to characterize their surface morphology, crystalline structure and mechanical properties. The microstructure and composition of the composite films were studied with Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) techniques. The use of nanoparticles could change the microstructure and morphology of the electrodeposits, depending on the metal matrix composites. The hardness and wear resistance tests were carried out on nanocomposite coating samples to investigate the mechanical properties. The co-deposited Al2O3 nanoparticles in the deposit increased the hardness and wear resistance, which were closely related with Al2O3 content in the nanocomposites. The hardness of the Ni-Al2O3 coating increased by about 26.3 % compared to pure copper plate due to the dispersion hardening effect. The hardness of the Cu-Al2O3 coating decreased by about 25.2 % as compared to pure copper plate due to the minimization of surface energy and the surface porosity of the coating. The wear resistance of the Ni-Al2O3 coating on the copper substrate was higher than that of Cu-Al2O3 as deduced from the lower mass loss of the former. The novelty of this project is the creation of very hard coating using a relatively low cost method.