Evaluation of Tannins as Potential Green Corrosion Inhibitors of Aluminium Alloy Used in Aeronautical Industry

Abstract

In this work some organic natural products were studied, namely tannic acid, gallic acid, mimosa tannin and chestnut tannin, as potential green corrosion inhibitors of the aluminium alloy AA2024-T3. The anodizing treatment was performed in a solution of the referred organic compounds in diluted sulfuric acid. The electrochemical impedance spectroscopy and the potentiodynamic polarization were performed to assess sealing quality and corrosion protection granted by the anodic films. To understand the green inhibitors; interaction with the metal surface, FTIR spectra of anodizing and anodizing and sealed samples of AA2023-T3 were recorded, and the shifts in the position of the major bands confirmed that the green inhibitor interacts with the metal surface. Images of the morphology of the coatings were provided by Scanning Electron Microscopy. From the results obtained through the various techniques that were used to carry out this study it is possible to conclude that the formed anodic films can be a good contribution for the prevention of corrosion in the aluminium alloy AA2024-T3.