ABSTRACT
In the aeronautical industry, 2024 aluminum alloys are widely used due to their excellent mechanical resistance and low specific mass. However, pitting formation is usual for these metal surfaces in certain corrosive environments, requiring treatment methods to protect them. Polypyrrole is a conductive polymer that has been studied for the protection of oxidizable metals against corrosion, as a viable alternative to toxic compounds. In this context, this study aims to investigate the performance of polypyrrole bilayers, electrodeposited in aqueous medium to protect 2024 aluminum alloy against corrosion. Potentiodynamic polarization curves, in corrosive chloride medium, indicated that the corrosion potential values were shifted towards the more positive values for the aluminum surfaces coated with polypyrrole films in relation to the surface of the metal just polished, indicating anodic protection. Furthermore, the Tafel curves indicated that the anodic current densities were lower for the polypyrrole bilayer electrodeposited in phosphoric acid and dodecylbenzenesulfonic acid, respectively. The morphology of the surfaces was investigated by Scanning Electron Microscopy and indicated that the bilayers were compact and homogeneous and that they were not damaged even after three days of immersion in chloride medium, indicating that the polymeric film can protect the metal against corrosion.
Keywords:
2024 aluminum alloy; Polypyrrole bilayer; Electrodeposition
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