Microwave-assisted synthesis of lanthanum conversion coating on Mg–Li alloy and its corrosion resistance

Lanthanum-based conversion coating on Mg–Li alloy has been prepared by a microwave-assisted method. X-ray diffractions (XRD) indicate that the intermetallic compounds of lanthanum are formed on Mg–Li alloy surface. Scanning electron microscopy (SEM) images show that the coating has different morphologies and special structures. The corrosion resistance was assessed by means of potentiodynamic polarization curves and electrochemical impedance spectra (EIS). The results indicate that this coating significantly reduces the corrosion rate of Mg–Li alloy in NaCl solution. A comparing experiment indicates that the coating prepared by microwave-assisted process has superior corrosion resistance to the coating obtained at room temperature.

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► The method of microwave is used to synthesize lanthanum conversion coating.
► Lanthanum conversion coating on Mg–Li alloy was studied.
► Different conditions between room temperature and microwave were compared.
► The corrosion behavior of lanthanum conversion coatings was studied.
► The corrosion mechanism of lanthanum conversion coatings was studied.