Preparation of Zn-Al-Ce-Mo LDHs Film with Enhanced Corrosion Resistance on 6061 Al Alloy Surface
摘要
Ce3+ and MoO42−-co-doped Zn-Al layered double hydroxide (Zn-Al-Ce-Mo LDH) films were synthesized on the anodized 6061 Al alloy via a combined hydrothermal and ion exchange method. The morphology, structure, composition, and corrosion resistance of the film in 3.5 wt% NaCl solution was investigated via SEM, XRD, XPS, and electrochemical measurements. The results indicate that the Zn-Al-Ce-Mo LDH film exhibits a corrosion current density of 4.53 × 10−8 A/cm2, which is approximately two and one orders of magnitude lower than those of the undoped Zn-Al LDHs and single Ce3+-doped Zn-Al-Ce LDH films, respectively. After 480 h of immersion in a 3.5 wt.% NaCl solution, the Zn-Al-Ce-Mo LDH film exhibited a corrosion resistance of 2.5 × 104 Ω cm2, which is approximately 2.5 times greater than that of the other two films. The enhanced corrosion resistance can be attributed to grain refinement and a denser microstructure induced by Ce3+ and MoO42− co-doping, as well as the ability of MoO42− to immobilize Cl−ions through ion exchange. Moreover, the original film's corrosion products can be transformed into a new Al-Ce-Mo LDH film under specific conditions, thereby achieving autonomous repair of its morphology, composition, and corrosion resistance.