Coatings based on self-assembled molecules (SAMs) for corrosion protection of aircraft aluminum alloys have been studied to evaluate their potentialities as replacements to yellow chromate conversion coatings (CCC), due to the toxicity of these leading to environmental problems. In this work, the influence of alkane diphosphonates self-assembling molecules on the corrosion resistance of the AA7475-T761 cladded with AA7072 was investigated by electrochemical impedance spectroscopy and cathodic and anodic polarization curves, in naturally aerated 0.5 mol/L Na 2 SO 4 aqueous solution, with pH adjusted to 4. Corrosion accelerated experiments (salt spray tests) were also carried out to examine the resistance of the SAM treated samples against corrosion. The results suggested that the development of boehmite (aluminum oxide) layer with incorporation of SAM was beneficial to the corrosion resistance of the tested aluminum alloy. Samples surface treated with SAM or aluminum oxide/ SAM (without and with subsequent polyester layer) showed better corrosion resistance results than samples with CCC, indicating that this last type of coating containing hexavalent chromium could be replaced by the environmentally friendly pre-treatment corresponding to boehmite growth followed by incorporation of SAM.

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In this work, the corrosion behavior of the AA4006 alloy made by the twin roll caster process was evaluated using electrochemical impedance spectroscopy (EIS), anodic potentiodynamic polarization curves, and scanning electron microscopy (SEM). This alloy belongs to the Al–Fe–Si system and is present with higher amounts of Fe and Si than AA1050 aluminum. Electrochemical tests were performed in a sulfate solution with or without chloride ions, and two different areas of the AA4006 alloy were tested: at the surface and at the center of the sheet (half thickness). The results obtained were compared to the commercially pure AA1050 aluminum. Electrochemical tests carried out using the solution without chloride ions presented similar results; however, the addition of chloride ions resulted in localized corrosion in all samples. It was possible to compare the corrosion behavior of the studied materials analyzing these electrochemical data and the micrographs obtained by scanning electron microscopy.