Non Destructive Eis Corrosion Evaluation of Aerospace Metals

Given the situation of corrosion damage of aerospace materials, resistant materials such as aluminum alloys are employed in order to use as structural materials in aircrafts and related industries. This impact enlarged researches moves toward the evaluation of pretreated and primed in the materials with non-destructive electrochemical impedance spectroscopy (EIS) for corrosion resistance performance when exposed to corrosive solution environment. Aerospace materials should be pretreated with corrosion inhibitor prior to paint in order to prevent and reduce the corrosion. In order to evaluate the resistance of these coatings to corrosion in these materials EIS was performed. These materials were exposed in a room temperature environment having EIS cell attached to the surface containing a solution of salt. The solution simulates salt water conditions was indirect contact with the metal surface. Periodically, these systems were taken out in order to observe physical damages to the bare metal/coated surface. With the experimental data obtained by EIS and using Gamry instrumental setup, charge transfer resistance and capacitance were obtained as function of exposure time. A 3-time constant equivalent electrical circuit model was performed in order to fit frequency dispersion data using non-linear statistical least square fit (NLLSF).