Aluminum Substrate Surface Hydrotalcite-Based Hybrid Thin Films And Electrochemical Corrosion Studies

Metal corrosion, involving many areas of the national economy, has become a global problem in the industry with the rapid development of technology today. In the non-ferrous metal materials aluminum is much more widely and largely applied than others. However, due to poor corrosion resistance, aluminum is susceptible to electrochemical corrosion especially in the external environment. Therefore, the study of corrosion protection methods related to aluminum has attracted the attention of scholars. As we all know, the traditional chromium conversion coating has a very good protective effect on the protection of metal corrosion, however, Cr6+ ions produced in the course caused pollution. Inhibitor is an affordable and efficient anti-corrosion chemicals, little of which added to the medium can significantly reduce the rate of metal corrosion. Currently,studying the new technology of anti-corrosion inhibitor which do not cause damage to the ecological environment has become one hot research in this field.This paper is aimed at creating the environment friendly functional film to prevent metal corrosion. Firstly Zn-Al hydrotalcite ?ZnAl-LDH? film growed in anodized aluminum substrate, and then, the environment-friendly corrosion inhibitors N-lauroyl sarcosine anion ?LS? intercalated in the LDHs layers to prepare ZnAl-LDH-LS film, based on the adjustable nature of the inter-layer ions in LDHs. Different characterization techniques was adopted to study the morphology, composition, structure and the corrosion resistance performance of the film material. The main results are as follows:1. The ZnAl-LDH film with NO₃^- ions was growed on an anodized aluminum substrate based on the in-situ growth method. The ?001? planes ?or ab planes? of the LDH Crystals growed perpendicular to the substrate and the film was uniform and dense.2. environmentally friendly corrosion inhibitor N-lauroyl sarcosine anion ?LS? intercalated into the LDH laminates to get hybridized ZnAl-LDH-LS film. The polarization curve test results that the hybrid film of the polarization current density is as low as 10-8 mps/cm², manifest the modified LDH film has good corrosion resistance. In addition, after 21 long days of immersion the modified hydrotalcite film did not show any evidence of corrosion, and the X-ray powder diffraction ?XRD? test suggested the hybrid crystal structure of the film remained unchanged. In conclusion, the experimental results show that the ZnAl-LDH-LS hybrid films can plays an effective role on preventing the corrosion of aluminum through isolating the corrosive chlorine ions from the surface of the aluminum matrix.