Synergistic effect of pH and oxalate concentration on corrosion of aluminium alloy 2024-T3

摘要

This work aims at obtaining comprehensive information on the corrosion behaviour of AA2024-T3 in oxalic acid solutions under different concentrations (0.007-0.2 M) and pH (2-6). Various tests to characterise the corrosion behaviour are performed, including weight loss and electrochemical tests. Coupon surfaces are examined using infinite-focus microscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy. Corrosion rates, anodic and cathodic reaction kinetics are detailed to provide a fundamental understanding of the electrochemical behaviour of AA2024-T3 as a function of pH and oxalate concentration. The synergistic effect of pH and oxalate concentration on corrosion of AA2024-T3 is evaluated for both AA2024-T3 matrix and main intermetallics (i.e. Al-Cu-Mg and Al-Cu-Fe-Mn) and the electrochemical behaviour of each constituent element in AA2024-T3 is systematically studied.