A zinc dipping technique for Mg–16Li–5Al–0.5RE alloy at room temperature

Abstract In order to obtain a high quality protective plating coating on Mg–16Li–5Al–0.5RE alloy, a zinc dipping technique at room temperature was investigated. The zinc dipping technique included two immersion processes, the primary immersion process and the secondary immersion process. Primary zinc transition layers (PZTLs) and secondary zinc transition layers (SZTLs) were obtained after the primary and secondary immersion processes, respectively. The polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X‐ray diffraction (XRD) were employed to characterize PZTLs and SZTLs. The results indicated that immersion time had obvious effects on PZTLs and SZTLs, the optimum primary immersion time and secondary immersion time were 5 min and 30 s, respectively. Then nickel‐plating coating deposited on the SZTL of Mg–16Li–5Al–0.5RE alloy was investigated via EDS, SEM, polarization curves, and EIS. The results demonstrated that the nickel‐plating coating obviously improved corrosion resistance of Mg–16Li–5Al–0.5RE alloy and had good adherence property with the alloy because of the presence of zinc transition layer on the alloy.