Document Type : Research Paper
The effect of vanillin on the corrosion behavior of AA6061 Al alloy in 3.5% NaCl solution was
investigated using potentiodynamic polarization and electrochemical noise (EN) techniques. Vanillin
offers interesting possibilities for corrosion inhibition due to its nontoxicity and high solubility in
aqueous media. The best inhibition effect at 200 ppm vanillin was a marked characteristic of the
inhibitor. Potentiodynamic polarization measurements indicated that the inhibitor is of mixed type.
According to calculated amount of noise charges by using the standard deviation of partial signal
(SDPS) at the particular interval of frequency it is possible to obtain the inhibition efficiency of an
inhibitor. The inhibition efficiency values obtained from EN method show a reasonable agreement
with those obtained from potentiodynamic polarization measurements. According to the quantum
chemical calculations it can be deduced that the number of intermolecular hydrogen bonds is
increased by increase in concentration of vanillin. This verifies the decrease in the inhibition
efficiency of vanillin at high concentrations.