Deposition of nickel films on polycrystalline copper alloy with various current densities from watts solution

Abstract

The coating of nickel (Ni) or Ni-alloy is one of the important metals for engineering applications. These materials have properties such as good corrosion resistance, ferromagnetic, good heat conduction. A few decades, numerous researches on electrodeposition of Ni from Watts's electrolyte solution have been reported. Therefore, in this research, Ni coated on polycrystalline copper (Cu) alloy substrates were prepared with various current density 3 mA/cm², 10 mA/cm², and 25 mA/cm² in watts solution to view more details about the effect of current density on the structure, morphology, and corrosion resistance of these films. The crystal structure, electrochemical behavior, and surface morphology were analyzed using X-Ray Diffraction (XRD), Potentiostat, and Scanning Electron Microscope (SEM) respectively. The difference in current densities affects crystallography parameters, electrochemical behaviors, and surface morphology of Ni layers. There are three major peaks exhibits as (111), (002), and (022) with cubic FCC crystal system and Fm-3m space group. The crystallite size of Ni film increases as the current density rise higher value. The highest corrosion rate is seen on the Ni-25 sample, and it is probably due to larger crystallite size and smaller polarization resistance. Increasing the current density has a significant influence on the reduction peak of Ni layers. As the current density increase, the peaks decrease. All the Ni layers display active-passive-transpassive behavior in 3.5% NaCl. All the Ni film produced shows electrochemically irreversible because the distance between oxidation and reduction peaks is more than 57 mV.