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Molecular inhibitors added to the corrosive medium attacking metallic materials are a well-established way of combating corrosion. The inhibitive action proceeds via adsorption of the inhibitor on the surface to be protected. Aromatic building blocks in the inhibitor play a major role in its protective action, and further details like substituents, heteroatoms, and molecular geometry contribute. An overview focused on aromatic inhibitors is provided, aiming at the identification of particularly promising inhibitors and their mode of action. Directions for further research and development are pointed out in the conclusion. [ABSTRACT FROM AUTHOR]

Significant concerns with corrosion might occur in terms of assurance, the natural world, and financial damage. One key piece of innovation toward preventing metallic corrosion includes the application of corrosion inhibitors. The polymer inhibitions of corrosion constitute the most promising areas for advancing of new corrosion inhibitors because they have more excellent adherence locations, higher temperature rebellion, versatility, viscosity, and superior filming capacity than smaller molecule corrosion inhibitors. The present review examines the development of natural and synthetic polymers for anti-corrosion agents. Such polymeric anti-corrosion agents work very well at inhibiting corrosion and do not need a high molecular weight. At this point, we examine the published literature on polymeric corrosion inhibitors and discuss how to improve them for use in the industry. [ABSTRACT FROM AUTHOR]

Two compound derived from fused Pyrazolo-Triazolo-Pyrimidine (C1 and C2), have inhibitory action against corrosion of Zinc in 1 M HNO3 examined experimentally by electrochemical tests and theoretically by density functional theory (DFT). The findings demonstrate that zinc corrodes in acidic conditions with greater corrosion resistance than C1 and C2. Concentration and corrosion inhibition directly relate to one another. The two Pyrazolopyrimidine-derived compounds had optimum inhibition efficiency of 92.06 and 79.36% for C1 and C2, respectively, at 700 ppm. In accordance to the polarization curves, the antagonists feature a mixed but primarily anodic inhibitor and a Langmuir process. DFT computations validated the compounds apparent antagonistic response. SEM also show the development of a barrier on the zinc surface. In conclusion, these two antagonists, C1 and C2, are successful in avoiding zinc dissolution in HNO3. [ABSTRACT FROM AUTHOR]

Environmentally friendly corrosion inhibitors have gained popularity in recent years due to growing environmental concerns caused by the widespread usage of traditional toxic corrosion inhibitors. These environmentally friendly inhibitors are made from renewable sources, providing both high inhibition efficacy and little to no environmental impact. The aim of the study was to synthesize a novel organic ionic liquid derived from triazole thione and investigate its toxicity and ability to inhibit copper corrosion in a 3% NaCl solution. The inhibitory power of tris(2-hydroxyethyl) ammonium 3-phenyl-5-sulfido-1,5-dihydro-1,2,4-triazol-4-ide (LIPTS) was exploited using electrochemical methods, against the corrosion of copper in a 3% NaCl solution. This study was conducted using stationary techniques, namely polarization and transient curves, particularly electrochemical impedance diagrams. The results obtained showed that this compound has an LD50 greater than 4000 mg/Kg, which confirms its ecological nature. Stationary polarization measurements revealed that the product tested as copper corrosion inhibitor acted at low concentrations in the corrosive medium. Its effect was expressed by a displacement of the potential in the anodic direction and a significant decrease in the current density, with the appearance of a plateau of low current density attributed to the formation of a thin film on the metallic surface of the copper. The electrochemical impedance measurements confirm the previous results by revealing the appearance of a low-capacity high-frequency loop corresponding to the presence of a protective film of inhibitor. The inhibitory efficiency is about 98%, indicating the protective effect of this product against copper corrosion in a 3% NaCl solution. [ABSTRACT FROM AUTHOR]

Two environmentally friendly inhibitors of imidazolium-based ionic liquids namely 3-benzyl-1-hexadecyl-1H-imidazol-3-ium chloride (IL-H), and 3-(4-chlorobenzyl)-1-hexadecyl-1H-imidazol-3-ium chloride (IL-Cl) were manufactured and their chemical structures were confirmed by spectra tools (FT-IR, and 1H NMR). The utilizing of these two new ionic liquids as green corrosion inhibitors for low carbon steel (LCS) in 1.0 M HCl under altered experimental conditions. Mass loss (ML), potentiodynamic polarization (PP), AC impedance spectroscopy (EIS) and surface morphology are take place in this study. The protection performance found to increase with increasing ionic liquid dose and temperature, reaching 92.9% and 95.1% for IL-H and IL-Cl at 120 ppm, respectively. Based on the PP records, the investigated ionic liquids behave as mixed-type inhibitors, influencing both anodic and cathodic responses. The inhibitory activity from these explored ionic liquids was stimulated by their adsorption on the effective surfaces of the steel surface in accordance with the Langmuir adsorption isotherm. The Density Functional Theory (DFT) method is used to analyze the relationship between quantum chemical calculations and the protection efficiency of ionic liquids. [ABSTRACT FROM AUTHOR]

In this modest work, a local biopolymer (CHA), biodegradable, non-toxic, and soluble in acidic media, was extracted from the plant Artemisia herba-alba located in the eastern region of Morocco, and characterized by FT-IR, in order to valorize it as a corrosion inhibitor of mild steel in 1 M HCl medium. The electrochemical tests show that the extract is an excellent corrosion protective agent, reaching a maximum value of 96.17% at the concentration of 800 mg/L in the inhibitor. The potentiodynamic polarization (PDP) curves indicate the mixed behavior of the extract, to reduce the current density from 3.445 mA/cm2 to 0.104 mA/cm2 in the presence of 800 mg/L in the inhibitor. The biopolymer CHA of the extract of Artemisia herba-alba undergoes the Langmuir adsorption isotherm, whose adsorption energy is −20.75 kJ/mol, which is attributed to the presence of electrostatic and covalent bonds. In addition, the visualization of the metal surface by a scanning electron microscope (SEM) indicates the formation of a protective layer formed by the extracts of Artemisia herba-alba, which confirms the protective characteristic of the extract used. Theoretical investigations by DFT, MD, and MC confirm previous experimental results. [ABSTRACT FROM AUTHOR]

This review article outlines the set of observations and findings from some previous publications that addressed the different techniques used for understanding and evaluating metallic corrosion and its retardation by using different inhibitors. The main emphasis is on the different electrochemical characterization techniques and surface analysis methods used for studying corrosion inhibition. A brief about polarization, electrochemical noise, electrochemical frequency modulation, impedance study for electrochemical characterization techniques and contact angle, scanning electrochemical microscopy, atomic force microscopy, and scanning electron microscopy methods, x-ray photoelectron spectroscopy, etc. are included for a better understanding of corrosion inhibition phenomenon. The literature suggests that corrosion of metals and alloys is effectively controlled by the use of inhibitors having heteroatoms such as nitrogen, oxygen, or sulfur. In this article, the papers from the last sixteen years i.e., from 1996 to 2021 are considered to get an insight into current methods for retarding corrosion. General introduction, mechanisms of corrosion along with factors affecting corrosion has also been described in the present article. Data collected in this review will be advantageous for researchers to get an idea about the basics and the recent techniques used in corrosion study. [ABSTRACT FROM AUTHOR]

Divalent Mn, Ni, Zn, and trivalent La complexes of H3L ligand [N',2-bis((Z)-2-oxoindolin-3-ylidene)hydrazine-1 carbohydrazide] were synthesized and characterized via diverse spectroscopic methods (FT-IR, NMR, electronic, PXRD, and GC-MS), molar conductance and magnetic susceptibility measurements. The different ways of binding for the H3L ligand with metal ions were inferred, as the H3L ligand acted in mono-negative N2O tridentate, mono-negative N2O3 pentadentate, bi-negative N2O3 pentadentate, and tri-negative N2O3 pentadentate manners in coordination to Mn2+, Zn2+, La3+, and Ni2+ metal ions, respectively. DFT modeling was performed using the DMOL3/material studio software, and some of the experimental outcomes were interpreted and authenticated. Electrochemical performance of Mn2+ ions in the existence and absence of H3L ligand was considered via cyclic voltammetry. The corrosion effectiveness of the H3L ligand (inhibitor) to aluminum metal was evaluated, and the molecular dynamic (MD) simulations for adsorption of the H3L inhibitor on Al surface were performed via FORCITE quench code. The isolated compounds were inspected for their antimicrobial (against C. albicans fungi, G+ bacteria S. aureus and B. subtilis, and G− bacteria P. aeruginosa and E. coli), cytotoxic, and antioxidant (ABTS, and SOD) activities. A molecular docking study was performed to give the favorable binding sites for the ligand to E. coli, and S. aureus proteins. [ABSTRACT FROM AUTHOR]

The inhibitive effect of a novel Schiff base can be evaluated by electrochemical measurements at the temperature range of 300–330 K. The inhibition efficiency of the inhibitor increases with increasing its concentration but decreases with increasing temperature. The polarisation measurement reveals that the inhibitor acts as a mixed type inhibitor. The inhibitive action of the inhibitor is attributed to the adsorption of inhibitor onto the steel surfaces, and it obeys the Langmuir adsorption isotherm model. [ABSTRACT FROM AUTHOR]