Electrochemical Impedance Spectroscopy (EIS) Applied to Study to Aluminium Alloys Degradation in Saline Solution

摘要

The electrochemical impedance spectroscopy (EIS) has been used to evaluate the behavior of alloys immersed in marine environment. This work presents the versatility of EIS technique to identify the formation of corrosion products and the different electrochemical reactions than can be carried out on the interface metal-electrolyte when the aluminium alloys are in contact with a saline media (NaCl 0.5 M). After the time exposition, the samples were analyzed by X-Ray Diffraction (XRD), Scanning Electronic Microscopy (SEM) and EIS simulation with equivalent circuits (EEC) to propose a corrosion mechanism. The results of these observations was the possible formation of an oxide film and a diffusion process across this film. The equivalent circuit selected from the simulation of experimental results takes in consideration a process with activation and mass transport control.