Mechanistic Investigation of the Corrosion Inhibition Performance of Ficus sur Leaf Extract on Mild Steel in 1 M HCl: Insights from Electrochemical and Thermodynamic Analyses

Abstract

: This study used gravimetric and electrochemical methods to assess how well Ficus sur leaf extract inhibited corrosion on mild steel in a 1 M HCl solution. Potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and open circuit potential (OCP) investigations were used to examine the inhibition mechanism while weight loss measurements were carried out at various inhibitor doses and temperatures. The findings demonstrated that while inhibition efficiency rose to a maximum of 80% using the gravimetric approach, corrosion rate reduced with increasing inhibitor concentration.The formation of a highly protective surface film was confirmed by electrochemical studies, which showed significantly higher efficiencies of 98.7% (PDP) and 98.6% (EIS) at 0.60 g/L. PDP results showed that Ficus sur functions as a mixed-type inhibitor by suppressing both anodic and cathodic reactions; adsorption of the inhibitor followed the Langmuir adsorption isotherm, with negative Gibbs free energy values indicating spontaneous physisorption. Overall, Ficus sur showed great potential as an environmentally friendly corrosion in chloride media.