Electrodeposition of Nanocrystalline Ni-Fe Alloy Coatings Based on 1-Butyl-3-Methylimidazolium-Hydrogen Sulfate Ionic Liquid

The electrodeposition of nanocrystalline Ni-Fe alloy coatings and associated nucleation/growth processes are investigated on the glassy carbon (GC) electrode in 1-butyl-3-methylimidazolium-hydrogen sulfate ([BMIM] HSO4) ionic liquid (IL). Cyclic voltammetric data suggest that the coelectrodeposition of Ni-Fe alloys is quasi-reversible. Moreover, chronoamperometry results indicate that the electrodeposition proceeds via a simultaneous nucleation and three-dimensional growth mechanism. In addition, the effects of electrodeposition potential and electrolyte temperature on the coating thickness and Fe content are also studied. The microstructure and composition of the Ni-Fe alloy coatings on Cu substrate are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS). SEM observations show that these electrodeposits present a dense and compact structure, EDS analysis indicates that the coatings are composed of Ni and Fe, XRD pattern shows the coatings are crystalline with a face-centred cubic (fcc) structure. Tafel plots reveal that the Ni-Fe alloy prepared from [BMIM] HSO4 IL presents better corrosion resistance than that of pure Ni.