Study on the effect of vanillin on the corrosion inhibition of aluminum alloy

The effect of vanillin on the corrosion inhibition of aluminum (Al) alloy in seawater was studied by potentiodynamic polarization (PP), linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) techniques. The surface morphology after its exposure to seawater with and without vanillin was examined by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). All the studied parameters showed good inhibitive characteristics against the corrosion of Al alloy in the tested solution, and their performance was observed to increase with the inhibitor concentration. Polarization data indicated that the studied inhibitor is a mixed-type inhibitor. Linear polarization and EIS studies showed that there were significant increases in the overall resistance after the addition of vanillin. The adsorption of inhibitor on Al alloy was found to obey the Langmuir adsorption isotherm. The analysis of SEM and EDS confirmed the formation of precipitates of vanillin on the metal surface, which reduced the overall corrosion reaction.