Cerium lactate as green corrosion inhibitor of AA2024 alloy

Abstract

This paper evaluated the inhibitory effect of Ce-chloride and Na-lactate mixture on the AA2024 aluminum alloy in 0.1 M NaCl solution. Electrochemical impedance spectroscopy (EIS) was applied for testing the general corrosion resistance, while potentiodynamic polarization measurement was applied for determining the alloy pitting corrosion resistance in NaCl and inhibitive solutions. The presence of cerium on the cathodic intermetallic particles was confirmed by scanning electron microscope/energy-dispersive X-ray spectroscopy analysis. The mixture of Ce-chloride and Na-lactate was a more effective corrosion inhibitor than Ce-chloride alone. The inhibitors mixture is a mixed-type corrosion inhibitor with a higher influence on slowing down the cathodic reaction of oxygen reduction. The adsorption of the inhibitor, the presence of cerium in different oxidation states (Ce3+ and Ce4+), and lactate anion (C–C/C–H, C–OH, C═O, and O–C═O group) were confirmed by X-ray photoelectron spectroscopy analysis. A mechanism of inhibitor adsorption on the surface of AA2024 alloy in NaCl solution was proposed.