Correlation between microstructure and corrosion behavior of two Al–Fe–Si alloys

Abstract

In this work, the corrosion behavior of the AA4006 alloy made by the twin roll caster process was evaluated using electrochemical impedance spectroscopy (EIS), anodic potentiodynamic polarization curves, and scanning electron microscopy (SEM). This alloy belongs to the Al–Fe–Si system and is present with higher amounts of Fe and Si than AA1050 aluminum. Electrochemical tests were performed in a sulfate solution with or without chloride ions, and two different areas of the AA4006 alloy were tested: at the surface and at the center of the sheet (half thickness). The results obtained were compared to the commercially pure AA1050 aluminum. Electrochemical tests carried out using the solution without chloride ions presented similar results; however, the addition of chloride ions resulted in localized corrosion in all samples. It was possible to compare the corrosion behavior of the studied materials analyzing these electrochemical data and the micrographs obtained by scanning electron microscopy.