Tuning cardanol concentration for optimized self-assembled monolayers to inhibit corrosion on galvanized iron sheets

Abstract

This study investigated the influence of cardanol concentration on the formation of self-assembled monolayers (SAMs) for corrosion inhibition on galvanized iron sheets in a 1 M H 2 SO 4 environment. Cardanol, extracted from cashew nut shell liquid (CNSL), was characterized using Fourier-transform infrared spectroscopy (FTIR) and evaluated for its corrosion inhibition efficiency via potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Results demonstrated that cardanol effectively forms protective SAMs, with inhibition efficiency ranging from 33.54 % to 90.28 %, peaking at 900 mg/L. Electrochemical analyses revealed a significant reduction in corrosion current density (from 1858.20 µA/cm 2 to 180.59 µA/cm 2 ) and an increase in charge transfer resistance (from 14.468 Ω cm 2 to 151.49 Ω cm 2 ) with higher cardanol concentrations. The study highlights cardanol’s potential as an eco-friendly corrosion inhibitor, attributing its efficacy to the formation of a dense, hydrophobic barrier on the metal surface. These findings offer sustainable solutions for corrosion mitigation in industrial applications.