Mild steel corrosion inhibition by some heteroatom organic compounds in acetic acid medium

Four heteroatom organic compounds (HAC) such as L-methionine (Meth), L-Cysteine (Syst), Phenyl MercaptoTetrazol (PMT) and Glutamic acid (GA) were evaluated as corrosion inhibitors for mild steel in 1M acetic acid (AcA) solution. The technique used are potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), UV-Vis spectroscopy analysisand scanning electron microscopy (SEM). As a comparative study results, the corrosion inhibitor rankings were: Meth ˂ Cyst ˂ PMT ˂ GA. Furthermore, the GA was the best inhibitors against mild steel corrosion and provided an inhibition efficiency of 74% at 10-4M. For this reason, we have besides studied the GA concentration and immersion time on the performance delivered by GA. In this way, it is affirmed that the inhibition efficiency was well improved with the GA concentration increasing. In addition, the GA is a good corrosion inhibitor even with long durations.

In-situ construction of grass-like hybrid architecture responsible for extraordinary corrosion performance: Experimental and theoretical approach

Despite the engineering potential by the co-existence of inorganic and organic substances to protect vulnerable metallic materials from corrosive environments, both their interaction and in-situ formation mechanism to induce the nature-inspired composite remained less understood. The present work used three distinctive mercapto-benzazole (MB) compounds working as corrosion inhibitors, such as 2-mercaptobenzoxazole (MBO), 2-mercaptobenzothiazole (MBT), and 2-mercaptobenzimidazole (MBI) in a bid to understand how the geometrical structure arising from O, S, and N atoms affected the interaction toward inorganic layer. MB compounds that were used here to control the corrosion kinetics would be interacted readily with the pre-existing MgO layer fabricated by plasma electrolysis. This phenomenon triggered the nucleation of the root network since MB compounds were seen to be adsorbed actively on the defective surface through the active sites in MB compound. Then, the molecule with twin donor atoms adjacent to the mercapto-sites affected the facile growth of the grass-like structures with ‘uniform’ distribution via molecular self-assembly, which showed better corrosion performance than those with having dissimilar donor atoms with the inhibition efficiency (η) of 97% approximately. The formation mechanism underlying nucleation and growth behavior of MB molecule was discussed concerning the theoretical calculation of density functional theory

Electrochemical and theoretical analysis of a novel spirocyclopropane derivative for corrosion inhibition of mild steel in acidic medium

The adsorption behavior and corrosion inhibition mechanism of 1-benzoyl-2-(4-methoxyphenyl)-6,6-dimethyl-5,7-dioxaspiro[2.5]octane-4,8-dione (Pt-5) on the Fe surface, in HCl medium, have been studied using both experimental and theoretical approaches. The effectiveness of corrosion inhibition has been evaluated by the use of electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and weight loss methods.It was found that Pt-5 has a maximum inhibition efficiency of 92.85% at a concentration of 5×10-3 M, and it is clear from data obtained using Pt-5 corrosion test results that the inhibition efficiency increases with increasing inhibitor concentration. The inhibitor's adsorption process follows the Langmuir isotherm while the thermodynamic parameters underwent discussion. This inhibitor can be adsorbed onto surfaces by physical and chemical means.The inhibitory efficiencies obtained from the experimental techniques agreed well with the calculated quantum chemical parameters based on DFT / B3LYB / 6-31G (d, p) and MD simulation results

Development of Natural Plant Extracts as Sustainable Inhibitors for Efficient Protection of Mild Steel: Experimental and First-Principles Multi-Level Computational Methods

In the present work, we present the superior corrosion inhibition properties of three plant-based products, Fraxinus excelsior (FEAE), Zingiber zerumbet (ZZAE), and Isatis tinctoria (ITAE), that efficiently inhibit the corrosion of mild steel in phosphoric acid. The anti-corrosion and adsorption characteristics were assessed using a combination of experimental and computational approaches. Weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy methods were used to evaluate the inhibitive performance of the inhibitors on the metal surface. Then, both DFT/DFTB calculations and molecular dynamic simulations were further adopted to investigate the interaction between organic inhibitor molecules and the metal surface. The protective layers assembled using the active constituents, such as carbonyl and hydroxyl groups, of the three plant-based products offer high electrochemical stability at high temperatures and robust protection against aggressive acidic solutions. All electrochemical measurements showed that the inhibition performance of extracts increased by increasing their concentration and improved in the following order: FEAE > ZZAE > ITAE. Further, these extracts worked as mixed-type inhibitors to block the anodic and cathodic active sites on the mild steel surface. Multi-level computational approaches revealed that FEAE is the most adsorbed inhibitor owing to its ability to provide electron lone pairs for electrophilic reactions. The experimental and theoretical results showed good agreement. These results indicate the possibility of replacing conventional compounds with natural substituted organic products in the fabrication of hybrid materials with effective anti-corrosion performance