Electrochemical development and characterisation of nanostructured Ni-Fe alloy coatings for corrosion protection

Nanostructured Ni-Fe alloy coatings were developed galvanostatically using a new low-concentration bath. The composition and operating parameters of the bath were optimised by taking the benefit of the conventional Hull cell method. Ni-Fe alloy coatings were developed at different current densities (2.0 to 5.0 A dm-2), keeping pH = 2.5. The corrosion behaviour of electrodeposited alloy coatings was evaluated in 3.5% NaCl solution, using Electrochemical Impedance Spectroscopy (EIS) and potentiodynamic polarisation methods. Ni-Fe alloy coating, deposited at 2.0 A dm-2 exhibited a lesser corrosion rate (14.71 x 10-2 mm y-1) than those at higher current densities. The lowest corrosion rate was attributed to its least crystallite size (10.4 nm), evidenced by an X-Ray Diffraction (XRD) study. The corrosion performance of Ni-Fe alloy coatings was discussed in the light of their surface morphology and composition, evidenced by SEM and Energy-Dispersive X-ray spectroscopy (EDS) analysis, respectively. On a d & eacute;velopp & eacute; de mani & egrave;re galvanostatique des rev & ecirc;tements en alliage Ni-Fe en utilisant un nouveau bain & agrave; faible concentration. On a optimis & eacute; la composition et les param & egrave;tres de fonctionnement du bain en profitant de la m & eacute;thode conventionnelle de la cellule de Hull. On a d & eacute;velopp & eacute; des rev & ecirc;tements en alliage Ni-Fe & agrave; diff & eacute;rentes densit & eacute;s de courant (2.0 & agrave; 5.0 A dm-2), en maintenant le pH = 2.5. On a & eacute;valu & eacute; dans une solution de NaCl & agrave; 3.5% le comportement & agrave; la corrosion des rev & ecirc;tements de l'alliage & eacute;lectrod & eacute;pos & eacute;s, en utilisant les m & eacute;thodes de spectroscopie d'imp & eacute;dance & eacute;lectrochimique (EIS) et de polarisation potentiodynamique. Il s'est av & eacute;r & eacute; que le rev & ecirc;tement en alliage Ni-Fe d & eacute;pos & eacute; & agrave; 2.0 A dm-2 pr & eacute;sentait le taux de corrosion le plus faible (14.71 x 10-2 mm an-1), compar & eacute; & agrave; ceux pr & eacute;sentant des densit & eacute;s de courant plus & eacute;lev & eacute;es. Le taux de corrosion le plus faible & eacute;tait attribu & eacute; & agrave; la plus petite taille de cristallite (10.4 nm), mise en & eacute;vidence par une & eacute;tude de diffraction des rayons X (DRX). On a discut & eacute; de la performance & agrave; la corrosion des rev & ecirc;tements en alliage Ni-Fe & agrave; la lumi & egrave;re de leur morphologie et de leur composition de surface, mises en & eacute;vidence respectivement par analyse de microscopie & eacute;lectronique & agrave; balayage (MEB) et de spectroscopie de rayons X & agrave; dispersion d'& eacute;nergie (EDS).