Natural Products for Material Protection: An Interesting and Efficacious Anticorrosive Property of Dry Arecanut Seed Extract at Electrode (Aluminum)–Electrolyte (Hydrochloric Acid) Interface

Abstract

The inhibitory propensity of dry arecanut seed (DAS) extract was tested on aluminum metal in 0.5 M HCl media through weight loss, electrochemical, and probe techniques. Weight loss studies exhibited the anticorrosive effect of DAS extract constituents on the aluminum metal surface, protection efficiency, increased with an increase in the DAS extract concentration and subdued as the contact time lengthened. Inhibitive effect was afforded by adsorption of the DAS extract components which was approximated by proper Langmuir isotherm fit. The activation energy of aluminum corrosion and other thermodynamic functions were determined to corroborate the experimental findings and provide adequate insight into the aluminum corrosion inhibition mechanism. Inhibitive modality of the most potent inhibitor (DAS extract) was interpreted in detail through potentiodynamic polarization technique (Tafel plot). The impedance spectroscopy approach may well be able to foretell the formation of a persistent passive layer at the aluminum–acid interface that impedes the access of corrosive ions to the surface of aluminum. Surface analysis rationalized via atomic force microscopy technique manifested the absence of corrosion products and topographic modifications on the aluminum surface. The amorphous/crystalline nature of the inhibitor (DAS extract constituents) molecules adsorbed onto the aluminum surface was indicated by powder X-ray diffraction technique. Protection efficiency values obtained by all techniques were complied with each other.