Effect of Alloying and Reinforcing Nanocomposites on the Mechanical, Tribological, and Wettability Properties of Pulse-Electrodeposited Ni Coatings.

Abstract

Research into the introduction of alloying and reinforcing nanocomposites into nickel (Ni) coatings has been motivated by the need for tribologically superior coatings that will improve energy efficiency. Using pulse electrodeposition, this work investigates the effects of adding cobalt (Co) as the alloying nanoparticle and silicon carbide (SiC), zirconium oxide (ZrO2), and aluminium oxide (Al2O3) as reinforcing nanocomposites to Ni coatings. The surface properties, mechanical strength, nanotribological behaviour, and wettability of these coatings were analysed. Surface characteristics were evaluated by the use of a Scanning Electron Microscope, revealing a grain dimension reduction of approximately ~7–43% compared to pristine Ni coatings. When alloying and reinforc-ing nanocomposites were added to Ni coatings, nanoindentation research showed that there was an increase in nanohardness of ~12% to ~69%. This resulted in an improve-ment in the tribological performance from approximately 2% to 65%.The hydrophilic nature of Ni coatings was observed with wettability analysis. This study demonstrates that nanocomposite reinforcement can be used to customise Ni coatings for applica-tions that require exceptional tribological performance. The results point to the use of Ni-Co coatings for electronics and aerospace sectors, with more improvements possi-ble with the addition of reinforcing nanoparticles.