Study of Electroless-Deposited Zn on the Surface of Mg-Li Alloy

Abstract

The Mg-Li alloy stands as the lightest metallic structural material known to date, finding a wide range of applications. However, its development has been hindered by its susceptibility to oxidation and corrosion. In this study, we aimed to address this issue by employing electroless deposition to form a protective zinc layer on the surface of a magnesium–lithium alloy. The optimization of the zinc layer was achieved through varying parameters such as the zinc dipping time (1~10 min), temperature (20~70 °C), and zinc content (20~200 g/L). Surface characterization was performed using scanning electron microscopy (SEM) and X-ray diffraction, while electrochemical tests and scratch tests were conducted to evaluate corrosion resistance and coating adhesion. The results demonstrated the successful formation of a uniform and dense pure zinc layer on the surface of the Mg-Li alloy when the zinc-dipping time was set at 5 min, the temperature was at 30 °C, and the zinc content was at 50 g/L. Under these conditions, the corrosion potential of the Mg-Li alloy experienced the greatest positive shift, reaching as high as −1.38 V. Additionally, the corrosion current was minimized, measuring at 2.78 × 10−6 A/cm2. Furthermore, the maximum arc tolerance radius was observed. Consequently, the electroless deposition of zinc onto Mg-Li alloys significantly improves their corrosion resistance and bonding, opening up new prospects for the application of zinc-plated Mg-Li alloys.

Characterization and Corrosion Behavior of Zinc Coatings for Two Anti-Corrosive Protections: A Detailed Study

“…This resulted in the formation of corrosion products in various forms, with a higher proportion being represented by prismatic crystals (Figure 28). The  phase in the corrosion process, due to the difference in corrosion potential, acts as an anode at the interface between the  and ζ phases, while the ζ-FeZn13 phase acts as a cathode, forming a galvanic corrosion couple [41][42][43] (Figure 29). During corrosion, the Zn phase preferentially corrodes, while the ζ-FeZn13 phase, the cathode, remains Deep ellipsoid, shallow ellipsoid, groove, and saddle forms are the four types of corrosion pits on the surface of steel wires [30].…”

“…The η phase in the corrosion process, due to the difference in corrosion potential, acts as an anode at the interface between the η and ζ phases, while the ζ-FeZn13 phase acts as a cathode, forming a galvanic corrosion couple [41][42][43] (Figure 29). During corrosion, the Zn phase preferentially corrodes, while the ζ-FeZn13 phase, the cathode, remains unchanged.…”

The Synergistic Effect of Trace Ag and Hot Extruding on the Microstructure and Properties of a Biodegradable Mg-Zn-Sr-Ag Alloy

“…Surface technologies of coating, electroless deposition, physical vapor deposition, etc. have been used to delay the degradation process of the magnesium alloy [17,18]. Nevertheless, if the inherent corrosion resistance of the magnesium alloy is insufficient, the alloy would still be corroded rapidly when the protective layer of the alloy is damaged.…”