Modeling and Analysis of Aluminium Corrosion Using Electrochemical Impedance Spectroscopy (EIS)

Aluminium is widely used in many industries like automotive, aerospace and construction because of its low weight, good mechanical strength and resistance to corrosion. This resistance comes mainly from a passive oxide layer that forms on its surface. However, when aluminium is exposed to harsh environments, especially those containing chloride ions in marine environments, this layer can break down and lead to localized corrosion, such as pitting. This study examined aluminum profiles at different processing stages, including homogenization and aging, anodizing and pre-anodizing followed by The corrosion behavior of the samples was studied using two electrochemical methods. Potentiodynamic polarization was used to measure corrosion rate and current density, while Electrochemical Impedance Spectroscopy (EIS) helped to understand how the protective layers behave and how corrosion progresses. The tests were carried out in a 3.5% NaCl solution at room temperature. The EIS results were analyzed using equivalent circuit models to better understand the electrochemical processes. Overall, the study shows how surface treatment affects corrosion resistance and highlights the advantages of EIS in studying corrosion behavior in a more reliable and repeatable way.