Influence of Rare Earth Additive on Preparation and Corrosion Resistance of Ni-Fe Alloy Coating postprint

Abstract: The Ni-Fe alloy coating with Ce was electroplated on the 20# steel by adjusting the concentration of CeCl3 in plating solution with the rare earth cerium salt CeCl3 as the additive. The relevant microstructure and corrosion behavior in 3.5%NaCl solution of coatings were studied by means of SEM, EDS and XRD, as well as electrochemical polarization curve and impedance spectroscopy. The results indicate that rare earth additive in acidic bath is extremely favor of the generation of sol Ce(OH)3, but restrains the generation of (FeOH) and Fe(OH)2 etc. With cathodic adsorptive characteristics the adsorption of Ce(OH)3 would compete with the adsorption of (FeOH). The former is preferentially absorpt on the surface of material, which restrains the generation of Fe. On the other hand, the addition of CeCl3 improves the current efficiency greatly, so as to increase the deposition rate. When concentration of CeCl3 is 3 g/L, the coating with better quality and better corrosion resistance would be obtained with the content of Fe controlled to about 16%.