Investigation of Dolichandra unguis-cati leaves extract as a corrosion inhibitor for mild steel in acid medium

Abstract

Electroactive compounds extracted by the leaves of Dolichandra unguis-cati (DUCLE) have been utilized for corrosion studies on mild steel in HCl solution. Mass-loss, Potentiodynamic Polarization, and Electrochemical impedance measurements were applied in the evaluation. The DUCLE forms a light coating on the surface of the metal, which helps in controlling the corrosion. The percentage inhibition performance, cathodic Tafel slopes, anodic Tafel slopes, and corrosion current density were evaluated. The maximum %ηW observed was 93.61 in 1 ​M HCl at 0.76 (g/L) concentration of DUCLE inhibitor after 3 ​h of immersion at 300 ±1K. DUCLE functions as a mix type inhibitor and, DUCLE adsorption on the mild steel fits the Langmuir isotherm. The inhibitor potential for mild steel was acquired by various concentrations of inhibitor. Thermodynamic specifications disclose the corrosion inhibition process was spontaneous and exothermic. The values of ΔGadso lie between −31.585 and −32.45 ​kJ mol−1for 1 ​M HCl. FT-IR, AFM, SEM, and contact angle techniques were used to characterize the DUCLE inhibitor's relationship on the surface of mild steel.