Construction of an epoxy coating with excellent protection performance on the AA 2024-T3 using ion-exchange materials loaded with eco-friendly corrosion inhibitors

Abstract

Ion-exchange materials were used in this study to boost the active/passive anti-corrosive functionality for the epoxy coating applied on the AA2024-T3. For this purpose, a zinc-aluminum layered double hydroxide conversion coating (LDH) loaded with diethyldithiocarbamate molecules was synthesized as the surface pretreatment for the AA2024-T3. Also, sodium montmorillonite was filled with Ce3+ cations and then applied on the LDH layer after being mixed with the hybrid sol-gel silane solution. The surface-modified layer was finally coated with epoxy resin. The three-layer coating system's electrochemical behavior in the absence and presence of the ion-exchange materials and the corrosion inhibitors was examined using electrochemical impedance spectroscopy (EIS), electrochemical current noise, and salt spray testing. The synthesized layers' chemical composition and surface morphology were analyzed using SEM-EDS. Results indicated that the epoxy coating active/barrier anti-corrosive performance significantly improved in the presence of ion-exchange materials loaded with the corrosion inhibitors. Based on the findings, the loading of the corrosion inhibitors into the structure of the ion-exchange material coated on the AA2024-T3 substrate leads to an enhancement in the log|Z|10mHz of the three-layer coating from 6.3 to 8.27 Ω·cm2. Additionally, the incubation of active protection performance for the three-layer coating after being loaded with the corrosion inhibitors was illustrated through the electrochemical testing and surface analysis.