Evaluation of surface interaction of plant root extract components on mild steel surface in HCl medium: Electrochemical, and surface characterization approaches

Mild steel materials are extensively used in various industrial operations in acidic conditions, but it susceptible to corrosion and lose its service life. Decalepis hamiltonii root extract (DHRE) containing several phytochemicals are readily interact on mild steel surface and prevent it from corrosion. The weight loss method, potentiodynamic polarization and electrochemical impedance spectroscopy revealed that, DHRE inhibited maximum 97.19%, 97.35%, and 96.73%, respectively for corrosion of MS in 1 M HCl. Activation energy in the absence of the inhibitor was found to 80.89 kJ/mol, which increased to 140.55 kJ/mol with 200 ppm of DHRE concentration, indicating a higher energy requirement to undergo corrosion Scanning electron microscopy images of MS surface in presence of DHRE constituents, serving as a safeguard for MS corrosion. Atomic force microscopic images shows the corroded MS surface roughness in presence of DHRE reduced from 1048 nm to 682 nm. The variation of MS surface hydrophilic character was evaluated by contact angle measurements. [Display omitted] •Mild steel materials are extensively used in various industrial operations in acidic conditions, but it susceptible to corrosion and lose its service life.•Decalepis hamiltonii root extract protects mild steel from corrosion by 98.89% in acidic condition and acts as eco-friendly.•Chemical and Electrochemical measurements showed the significant corrosion protection ability of the extract in acid condition.•Surface characterization techniques supported the formation of a strong protective layer over the material surface and control the corrosion to a greater extent.