Feasible strategies for promoting the mechano-corrosion performance of Ni-Co based coatings: Which one is better?

NiCo based deposits have attracted tremendous research interest and have undergone unprecedented development in various industrial fields. This study provides a comparative insight into three practical approaches, i.e., controlling current density, incorporating an alloying element (phosphorus), and codeposition of Y2O3 reinforcing agent, which generally possess the potential to improve the microstructural and mechano-corrosion properties of the coatings. Vickers microhardness tester, electrochemical impedance spectroscopy (EIS), and Tafel polarization assays were used to assess the mechano-corrosion behavior of the coatings. An increase of 56% in microhardness and a decrease of 97.5% in corrosion current density are obtained for optimized nanocomposite coating compared to the alloy one. Moreover, the value of the charge transfer resistance increased ≈6 times for the nanocomposite coating. It can be noticed that the inclusion of Y2O3 nanoparticles yields the highest mechano-corrosion performance and seems to be the best strategy. The Ni-Co-Y2O3 nanocomposite coating electrodeposited under 10 A dm−2 offers the prospect of employment in the marine applications that need high mechano-corrosion performance, including shipping. [Display omitted] •Ni-Co, Ni-Co-P, and Ni-Co-Y2O3 coatings are DC-electrodeposited on copper.•The effect of codeposited P and Y2O3 on the final properties of Ni-Co is discussed.•The influence of current density on characteristics of the deposits is illustrated.•A substantial improvement in the mechano-corrosion performance of Ni-Co is achieved.•Resultant deposits possess the potential to serve in fuel cells and engine pistons.