ELECTROCHEMICAL CORROSION BEHAVIOUR OF DIFFERENT ANODIZING PROCESSES ON AA 2099 FOR AERONAUTICAL APPLICATIONS

Aluminum alloys present good mechanical behavior and low density, being one of the most used materials in the aeronautical industry. Development of third-generation aluminum alloys AA 2099, with a higher modulus of elasticity and resistance to corrosion, it has been possible to compete with the composite materials implemented in the different areas of the aircraft. An alternative to increase the efficiency of aluminum alloys is through an anodizing process generating an aluminum oxide layer which benefits mechanical properties and corrosion resistance of aluminum alloys. The following investigation shows the process of anodizing of a third generation alloy AA 2099 and its corrosion behavior in different media. The evaluation of the anodized alloy was performed in 3.5% NaCl and 3.5% H₂SO₄ electrolyte solutions, using electrochemical techniques: electrochemical noise (EN), electrochemical impedance spectroscopy (EIS) and cyclic potentiodynamic polarization (CPP). The results reveal a more noble behavior and a corrosion rate decrease for anodized AA 2099 compared to the non-anodized one.