Evaluation of Sealing Process on the Surface Properties of Nanoporous Aluminum Oxide Layers Electrochemically Growth on 1050 Aluminum Alloy Surface

Thanks to its low density, aluminum and its alloys are extensively used in the transport and construction industries. The improving of aluminum and its alloys corrosion resistance is an extensively studied topic. Different methods are applied to improve the corrosion resistance of aluminum and its alloy: painting, waxing, zinc-chromate priming, conversion coatings and also anodic oxidation. The anodic oxidation is the most used method to fabricate nanoporous aluminum oxide layers, with controlled thickness and pores diameters, on aluminum and its alloys surfaces. The aim of this work is to evaluate the influence of the sealing process of the nanoporous aluminum oxide layers obtained by anodic oxidation on 1050 aluminum alloy surface. Scanning electron microscopy (SEM) was used to observe the morphological structure of untreated and modified surfaces. Corrosion behavior of oxidized 1050 aluminum alloy, sealed oxide layer and untreated 1050 aluminum alloy were investigated using electrochemical methods such as open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD). The experimental results show that the anodic oxidation process improve the corrosion resistance of 1050 aluminum substrate and the sealing process improve even more the anticorrosive properties. (paper)