Ce/LDHs coating modified by GO applied on AZ31 alloys corrosion protection

Abstract

Layered double hydroxides (LDHs) exhibit anion exchange properties and adjustable characteristics, which make them suitable for applications in the field of anticorrosion. However, the smooth growth pattern of a single LDHs nanosheet limits its effectiveness in blocking corrosive media. Graphene oxide (GO) has a large specific surface area and numerous oxygen-containing functional groups on its surface, which can form strong interactions with polar molecules. This inhibits the migration of small ions, such as Cl⁻. In this work, Ce was incorporated into a micro-arc oxidation (MAO) coating on the AZ31 alloy by immersion in a cerium salt solution, and GO was incorporated using a hydrothermal solution to prepare layered double hydroxide composite coating (Ce/LDHs-G). The significance of charge transfer resistance (R_ct) mainly reflects the charge transfer process at the electrode/electrolyte interface. The R_ct of Ce/LDHs-G increased by one order of magnitude compared to MAO coating. The corrosion current density (i_corr) of Ce/LDHs-G coating was 3.73 × 10⁻⁸ A cm⁻², lower than that of MAO coating (1.56 × 10⁻⁶ A cm⁻²). Additionally, the cumulative hydrogen evolution over 336 h was lower, indicating that Ce/LDHs-G coating provides effective corrosion protection for the AZ31 alloy.