Corrosion inhibition for alloy 304L (UNS S30403) in H2SO4 1M solution by Centrosema pubescens leaves extract

• Main Authors: Okiemute Dickson Ofuyekpone, Ochuko Goodluck Utu, Basil O. Onyekpe
• Format: Article
• Language: English
• Published: Elsevier 2021-03-01
• Series: Applied Surface Science Advances
• Subjects: Centrosema pubescens; Austenitic stainless steel; Corrosion inhibition; 1.0M H2SO4 solution; Scanning electron microscopy
• Online Access: http://www.sciencedirect.com/science/article/pii/S2666523921000076

The inhibitive potency of Centrosema pubescens leaves extract, a bio-extract, on corrosion of UNS S30403 in H2SO4 1M solution has been investigated using weight loss technique and polarization measurements at 303 K and 333 K, and were complemented with scanning electron microscopy surface characterization coupled with energy-dispersive x-ray spectroscopy (EDS) and X-ray Diffraction analysis (XRD). Judging from the results, it is found that the leaves extract of Centrosema pubescens served as a potent inhibitor against the acid induced corrosion of alloy 304L. Kinetic study results show that the inhibited species possessed longer service life. The inhibition efficiency of this bio-extract is dictated by the extract concentration and temperature. Inhibitive effect was afforded by adsorption of the extracts’ active ingredients which was found to align with Langmuir adsorption isotherm. The extract acted as a mixed-type inhibitor, and its inhibition mechanism is deduced from the temperature dependence of the inhibition efficiency and was further substantiated by the values of the calculated activation parameters. Surface characterization shows improved surface features in the presence of the extract.