Superior green corrosion protection of mild steel in acidic medium using Tilia platyphyllos extract: electrochemical and surface studies

Abstract

This study introduces an eco-friendly corrosion protection method for mild steel in 0.5 M HCl using Tilia platyphyllos extract (TPE). The extract’s inhibition properties were assessed through advanced techniques. Spectroscopy methods (GC–MS, FT-IR, UV–Visible) identified functional groups enabling adsorption and film formation on steel. Electrochemical impedance spectroscopy (EIS) showed TPE achieved 97.05 % inhibition efficiency at 400 ppm, outperforming many green inhibitors in acidic conditions. Potentiodynamic polarization tests indicated a significant drop in corrosion current density from 577.67 µA/cm2 (no TPE) to 12.03 µA/cm2 (400 ppm TPE), reflecting reduced anodic and cathodic reactions, confirming TPE’s mixed-type inhibition. Adsorption studies aligned with the Langmuir model, indicating strong monolayer adsorption. Surface analyses (SEM/EDS, Raman, XPS, and CA) revealed that 400 ppm TPE formed a protective hydrophobic film, minimizing steel damage from HCl. These findings highlight Tilia platyphyllos extract as a sustainable, cost-effective corrosion inhibitor for industrial use.