Mechanistic study of polyaspartic acid (PASP) as eco-friendly corrosion inhibitor on mild steel in 3% NaCl aerated solution

Corrosion inhibition mechanism of Polyaspartic acid (PASP) as eco-friendly polymer on mild steel in aerated 3% NaCl solution was investigated utilizing electrochemical, thermodynamic, microscopic and computational chemistry techniques. Electrochemical results confirm moderate inhibition efficiency of PASP reaching 61% at 2.0 g/L by forming an adsorption layer on metal surface. Zinc ion addition enhanced the efficiency to 97% at 0.5 g/L of PASP through a synergistic effect mechanism. Scanning electronic microscopy (SEM) and Atomic force microscopy (AFM) micrographs revealed the morphology of adsorption layer indicates anodic inhibition mechanism of PASP. Quantum calculation and Monte Carlo simulation provided molecular level insights into the adsorption mechanism of PASP on steel surface which were consistent to the experimental findings. (C) 2017 Elsevier B.V. All rights reserved.