Effect of Nickel Pre-plating on the Plating of Zn-Ni Alloy Coating on Stainless Steel Substrate

Abstract

Abstract. Nickel pre-plating on stainless steel parts, electroplating Zn-Ni alloy layer on the basis of pre-plating layer. In order to improve the bonding strength between the coating and substrate by the introduction of nickel to form a good bonding with the iron matrix. To explore the influence of nickel pre-plating process on the film base bonding strength of Zn-Ni/304 stainless steel. The morphologies, Rockwell hardness indentation and phase structure of the Zn-Ni alloy plating were characterized with Scanning Electron Microscopy (SEM), Metallographic microscope observation, X-ray diffraction (XRD). Corrosion resistance of the Zn-Ni alloy plating was evaluated by electrochemical polarization tests. Results show that after nickel pre-plating adhesion of the coating and stainless steel substrate improved significantly, and the corrosion resistance also improved relative to the direct plating Zn-Ni alloy coating.

Effect of Cr(III) passivation layer on surface modifications of zinc-nickel coatings in chloride solutions

“…In order to further improve the corrosion resistance of Zn-Ni coatings, different strategies can be applied such as coating thickening [11], microsctructuring [3], Ni preplating [15,28], or modification of the Zn-Ni electrodeposition baths composition [29,30,31]. It seems that the best protection was achieved by post-plating passivation treatments (conversion coatings), often containing Cr, applied on a single γ-phase [17,[32][33][34].…”