Improvement of Anticorrosion Properties of LA103Z Mg-Li Alloy Based on Fabricated Mg-Al Layered Double Hydroxide Films

Mg-Al layered double hydroxide (LDH) films were fabricated on LA103Z Mg-Li alloy substrates by an in situ hydrothermal method that involved various Al(NO3)3 concentrations. The microstructure, composition, and morphology of the Mg-Al LDH films were investigated via x-ray diffraction, energy-dispersive x-ray spectroscopy, and scanning electron microscopy, respectively. The corrosion behaviors of the LDH films were characterized using electrochemical measurements and a hydrogen evolution rate test. The results revealed that the concentration of Al(NO3)3 was a key factor in the formation of the LDH that affected the nucleation and growth process of the LDH. An appropriate increase in the Al(NO3)3 concentration promoted the growth of the LDH and thus improved the anticorrosion properties of the film. At an Al(NO3)3 concentration of 0.05 M, the LDH film was uniform and dense with optimal thickness. The results of electrochemical and corrosion tests showed that the anticorrosion properties of the bare substrate were markedly improved. The enhancement effect of the film prepared using 0.05 M Al(NO3)3 was the best. Its hydrogen evolution rate was 0.01082 mL cm−2 h−1, and its corrosion current density was 7.369 × 10−5 A/cm2.