Parameters variation on Ni-Co-W coating electroplating to evaluate improvements in morphology and corrosion resistance

The Ni-Co-W alloys combine metal properties and provide anti-corrosive characteristics. In this study, the ternary alloy Ni-Co-W was deposited using factorial design to study its corrosion responses by varying current density (100-500 A/m(2)), temperature (333.15-353.15 K) and rotation (13-16 rpm). The experiments were characterised with a scanning electron microscope, an energy-dispersive X-ray and X-ray diffraction. Corrosion tests were performed using NaCl 0.1 mol L-1 as an electrolyte to progress the electrochemical impedance spectroscopy and Tafel extrapolation. The parameter variation caused some modifications in surface morphology and crystallography; however, Ni-Co-W alloy composition remained similar in all experiments. The alloy structure was demonstrated to be conducive to slight modifications in some electroplating conditions, resulting in corrosion tests improvements and cracks absence for specifics parameters. Structure and morphology variation created a coating which favoured an association between the higher current efficiency (74.12%) and the best corrosion resistance (I-corr = 0.00840 A/m(2)).