A comparative study and optimization of corrosion resistance of Mg–Al layered double hydroxides films at different hydrothermal temperatures on LA103Z Mg–Li alloy

Abstract

AbstractIn this study, to improve the corrosion protection system of Mg–Li alloy, Magnesia–alumina Layered double hydroxide (Mg–Al LDH) films were prepared on the LA103Z magnesium–lithium (Mg–Li) alloy by the in situ hydrothermal method. Subsequently, the microstructure of the Mg–Al LDH films was characterized by scanning electron microscope, X‐ray spectrometer, X‐ray diffraction, Fourier‐transform infrared spectroscopy, and the effect of different hydrothermal temperatures on the growth of the film was studied. Electrochemical impedance spectroscopy (EIS) and hydrogen evolution test were used to study the corrosion behavior of the films, revealing the anticorrosion mechanism of the films. The results show that the LDH film is in the form of a sheet‐like structure that crosses vertically on the LA103Z substrate. With the increase of the hydrothermal temperature, the size of the Mg–Al LDH sheet increases, and the distribution is denser. Electrochemical tests showed that the coated samples had significantly improved impedance modulus (|Z|) and charge transfer resistance (Rt) compared to bare samples. The potentiodynamic polarization curves demonstrated that the Mg–Al LDH film can effectively improve the corrosion resistance of the LA103Z magnesium alloy substrate.