Adsorption and corrosion-inhibiting effect of 2-(2-{[2-(4-Pyridylcarbonyl)hydrazono]methyl}phenoxy)acetic acid on mild steel surface in seawater

The corrosion inhibition property of a Hydrazone derivative, namely 2-(2-{[2-(4-Pyridylcabonyl)hydrazono]methyl}phenoxy)acetic acid (PMA) for mild steel surface corrosion in synthetic seawater medium was analyzed by weight loss, electrochemical techniques (potentiodynamic polarization and electrochemical impedance), the experimental results suggest that PMA is a good corrosion inhibitor and the inhibition efficiency increased with the increase of PMA concentration, while the adsorption followed the Langmuir isotherm. X-ray photoelectron spectroscopy, scanning electron microscopy, theoretical calculation of electronic density, molecular electrostatic potential and molecular dynamics were carried out to establish mechanism of corrosion inhibition for mild steel with PMA in synthetic seawater medium. The inhibition action of the compound was assumed to occur via adsorption on the steel surface through the active centres in the molecule. The results indicated that the corrosion inhibition is due to the formation of a chemisorbed film on the steel surface.