Effect of different anion intercalations on the corrosion resistance of layered double hydroxides on the surface of LA43M

Abstract

Layered double hydroxides (LDH) are widely used in the field of Mg alloy surface protection due to their interlayer anion exchangeable and physical barrier. To explore the effect of corrosion inhibitor modification on the growth and corrosion resistance of LDH coating, MgAl‐NO3−‐LDH precursor film was obtained on the surface of LA43M alloy by in situ growth method, and then MgAl‐V2O74−‐LDH, MgAl−Cl−‐LDH and MgAl‐ASP‐LDH were prepared by the ion exchange method. The morphology, composition, and corrosion resistance of the LDH film with different anion intercalation were studied systematically by scanning electron microscope, energy disperse spectroscopy, X‐ray diffractometer, Fourier‐transform infrared spectroscopy, and electrochemical tests. The results show that the modified LDH nanosheets are larger in size and uniformly tightly bonded to the substrate, and the thickness of the film is increased. Electrochemical tests and hydrogen precipitation experiments demonstrated that all four LDH films provided protection to the substrate, and the corrosion resistance of the V2O74−, Cl− and ASP‐containing films modified by corrosion inhibitors was improved compared with that of the precursor films, among which the MgAl‐V2O74−‐LDH had the best corrosion resistance.