Corrosion Behavior of Ni-Fe-Mo Deposits Obtained under Different Electrodeposition Conditions

Ternary Ni-Fe-Mo coatings have been proposed for anti-corrosion applications to replace chromium coating. To analyze the effects of deposition current and duration six different Ni-Fe-Mo films have been electrodeposited on copper foils. Their morphologies, structures, and chemical compositions of the films have been characterized. Potentiodynamic polarization is applied on each coating and electrochemical impedance spectroscopy is applied to discuss their corrosion resistances. Ni-Fe-Mo film that is produced at the lowest current density (5 mA.cm(-2)) for 5 min. exhibits a more positive corrosion potential and higher charge transfer resistance. To shed some lights on aging mechanism, the film has been aged for 70 days. The enhanced protective properties of the film is attributed to its fine, crack free morphology with high Mo content. The existences of Fe2O3, MoO2, MoO3, and NiO in the passive layer substantiate the improved barrier protection ability of the film.