Corrosion inhibition of carbon steel immersed in a 1 M HCl solution using benzothiazole derivatives

Corrosion inhibition effect of 2-mercaptobenzothiazole (MBT) and 2-aminobenzothiazole (ABT) compounds on ST-37 carbon steel in 1 M hydrochloric acid solution was investigated by electrochemical impedance spectroscopy (EIS), and it was observed that both of these compounds have corrosion inhibition effect on carbon steel. Evaluation of electrochemical behavior in test solutions showed that by increasing the immersion time from 15 to 300 min, corrosion resistance of samples is increased and at the same immersion time MBT has a better corrosion inhibition in comparison to ABT. AFM technique was performed for MBT and ABT. The results of calculations showed superior inhibition efficiency of MBT in comparison to ABT. This can cause easier protonation and consequently adsorption on the metal surface occurs.     

Ethoxylated Melamine as Corrosion Inhibitor for Carbon Steel in 1M HCl

The inhibition effect of a new 1,3,5-triazine-2,4,6-triaminoethoxylate (ethoxylated melamine, MEO) on the corrosion of carbon steel in 1 M HCl was studied at 298 K. Surface activity, thermodynamic properties, and potentiodynamic polarization methods were used for the evaluation of the prepared surfactants. Results show that MEO is a good inhibitor, and inhibition efficiency reaches 91% at 500 ppm. Polarization curves revealed that this organic compound acts as a mixed-type inhibitor. The concentration effect on the corrosion behavior of steel in 1 M HCl with and without MEO at 100–500 ppm was studied at a temperature of 298 K. Additionally, the associated activation energy was determined.     

Corrosion Inhibition Efficiency of Polytriethanolamine Surfactants for Pipe-Lines Carbon Steel in 1M HCl

Fifteen organic compounds were prepared from triethanolamine and its derivative. The triethanolamine was polymerized by condensation to get P₄, P₆, and P₈ at different molecular weight. The P8 was ethoxylated at different ethylene oxide units (en) (40, 100, and 120) to obtain three compounds (E(en)P₈). Every degree of ethoxylate was esterified with 1, 4, and 8 moles of oleic acid to get on 9 ethoxylated polytriethanolamine esters (E(en)P₈Om). The effect of adding these organic compounds on the electrochemical behavior of carbon steel in 1 M HCl was investigated by using the weight loss technique. The reported results in this study show that the addition of these surfactants inhibits the corrosion of carbon steel. The inhibition efficiency (I%) for each inhibitor increases with increasing the concentration. The maximum inhibition efficiency (95%) was obtained by (E(40)P₈O₁) at 600 ppm. The inhibitive efficiency was discussed on the light of chemical structure of the used inhibitors.     

Corrosion Behavior of Mild Steel in Presence of 2-Chloromethylbenzimidazole and Sodium Molybdate in 1 M HCl

Russian Journal of Electrochemistry - Abstract—Corrosion behavior of mild steel in 1 mol/L HCl with 2-chloromethylbenzimidazole (2-CBI) and sodium molybdate (Na2MoO4) as inhibitor was studied...     

Corrosion behavior of aluminum exposed to a biodiesel

Aluminum was exposed to biodiesel with different levels of contaminants and impurities, and its corrosion behavior was evaluated by conventional electrochemical techniques. It was found that the corrosion behavior of aluminum in biodiesel contaminated with alkalis is similar to the corrosion behavior of aluminum in aqueous solutions. In addition, it was demonstrated that corrosion of aluminum can be used as a quantitative indication of the biodiesel purity.     

Corrosion inhibition behavior of cefuzonam at mild steel/HCl acid interface

The adsorption and corrosion inhibition behavior of cefuzonam (CZM) at mild steel surface were studied gravimetrically and electrochemically by using electrochemical impedance spectroscopy and Tafel polarization techniques. The increase in concentration and immersion time showed a positive effect. Inhibitor molecules directly adsorb on the surface on the basis of donor acceptor interactions between the p-electrons of benzene, sulfur and nitrogen atoms and the vacant d-orbital of iron atoms. The adsorption of CZM followed the Langmuir adsorption isotherm. A potentiodynamic polarization study revealed that CZM acted as mixed type of inhibitor. The results obtained from different methods are in good agreement. The adsorption behavior of CZM was experimentally investigated by contact angle measurement on metal surface. The contact angle of metal surface to the acid solution increased with inhibitor concentration, thereby confirming the increased hydrophobic nature of metal surface to the acid solution having the inhibitor.     

Corrosion inhibition of aluminum in 1 M H3PO4 solutions by ethanolamines

The inhibitive effect of the investigated compounds (ethanolamine (I), diethanolamine (II) and triethanolamine (III)) on the corrosion behavior of aluminum in 1 M H₃PO₄ solution using weight loss, galvanostatic polarization and quantum chemical calculation methods was studied. The inhibition efficiency was found to depend on type and concentration of the additives and also on temperature. The effect of addition of halide ions to various concentrations of these compounds has also been studied. The apparent activation energy (E_a) and other thermodynamic parameters for the corrosion process have also been calculated and discussed. The galvanostatic polarization data indicated that these inhibitors were of mixed-type. The slopes of the cathodic and anodic Tafel lines (β_c and β_a) are approximately constant and independent of the inhibitor concentration. The adsorption of these compounds on aluminum surface has been found to obey the Freundlich adsorption isotherm. Some quantum chemical parameters and Mulliken charge densities for investigated compounds were calculated by the AM1 semi-empirical method to provide further insight into the mechanism of inhibition of the corrosion process. The theoretical results are then compared with experimental data.     

The Effect of Magnetic Field on Corrosion Inhibitor of Copper in 0.5 M HCl Solution

Corrosion of metals within magnetic field (MF) had been actively studied for better understanding of the corrosion mechanism when the magnetic sources are presented. However, findings regarding the effect of MF on metals are inconclusive, and there is a lack of studies of MF interaction with various corrosion control techniques, such as corrosion inhibitor. In this paper, the effect of MF on the corrosion of copper in 0.5 M hydrochloric acid (HCl) solution, with or without corrosion inhibitor were studied. Benzotriazole (BTA), a common copper inhibitor, was chosen as the inhibitor for this study. To determine the effect of MF, a MF of 13 mT, generated using a pair of permanent neodymium magnet, was applied during weight loss and electrochemical tests. The results showed that corrosion inhibition efficiency of BTA decreased when it is under an applied MF. A decrease from 47% to 60% in inhibition efficiency had been observed for all samples in an applied MF. By using Tafel extrapolation technique on the polarization curves, it revealed that MF had increased the corrosion current of copper in HCl, causing a decrease in the inhibition efficiency.     

Corrosion behavior of magnesium and its alloy in NaCl solution

The electrochemical behavior of cast Mg, AZ91, and cast AZ91 in 0.1 M NaCl solution is investigated by measuring open-circuit potential (OCP), steady-state current-potential, and electrochemical impedance spectra (EIS). The similar electrochemical impedance behavior is found of three corrosion electrodes. There are two capacitances in high-and medium-frequency domains and one inductive loop or component in low-frequency domain. From equivalent circuit simulation, cast AZ91 has the worst corrosion resistance. The EIS results are in good agreement with those obtained by OCP and polarization curves. Based on the Cao theory, a simple corrosion mechanism is put forward, supplying a possible explanation for low-frequency inductive behavior for Mg and its alloy in NaCl solution at OCP. Published in Russian in Elektrokhimiya, 2007, Vol. 43, No. 7, pp. 878–885. The text was submitted by the authors in English.     

Preparation and electrochemical corrosion behavior of bulk nanocrystalline ingot iron in HCl acid solution

Bulk nanocrystalline ingot iron (BNII) was produced by the severe rolling technique. The corrosion behaviors of BNII and as-received conventional polycrystalline ingot iron (CPII) in 1 M HCl solution were investigated by potentiodynamic polarization tests, electrochemical impedance spectroscopy measurement, and immersion tests at room temperature. For BNII, the anodic dissolution process is inhibited, but the cathodic process is enhanced. The corrosion current and average corrosion rate of BNII are 0.479 and 0.391 those of CPII, respectively. The resistance of the charge transfer of BNII is about 1.59 times higher than that of CPII. These results indicate that the corrosion resistance of BNII is improved in comparison with CPII.     

Corrosion behavior of PEO-treated AZ31 Mg alloy in chloride solution

Corrosion behavior and resistance of plasma electrolyte oxidation (PEO)-treated AZ31 Mg alloy were investigated by immersion and potentiodynamic polarization tests in 0.5 M NaCl solution in view of the PEO film thickness and sealing treatment of the PEO films in boiling water. The PEO films were formed using pulse current for various durations in 1 M NaOH?+?0.5 M NaF solution. Filiform corrosion was observed during the immersion test while pitting corrosion occurred during the potentiodynamic polarization test, irrespective of sealing treatment of the PEO films. Corrosion resistance of AZ31 Mg alloy was improved remarkably by the formation of thicker PEO films and their sealing treatments.     

噻唑衍生物在酸性介质中对A3钢的缓蚀性能

噻唑衍生物在酸性介质中对A3钢的缓蚀性能;噻唑;缓蚀剂;A3钢     

Copper(II) complexation with 1-methyl-2-mercaptoimidazole in 7 M HCl

The complexation of copper(II) with 1-methyl-2-mercaptoimidazole in 7 M HCl was potentiometrically studied. The compositions of complexes were determined, and their stepwise formation constants were calculated. The complexes were shown to become less stable with increasing temperature. The thermodynamic functions of complexation were estimated. The copper complexes were shown to surpass the rhenium complexes in stability.     

A new bipyrazolic compound as corrosion inhibitor of armco iron in 1M HCl medium

The inhibitory effect of the new synthesized bipyrazolic compound 1,3-Bis(3,5-dichloromethylpyrazolyl) propane (BDCMPP) on the corrosion of Armco Iron in 1M HCl medium has been studied by weight loss, electrochemical polarisation and impedance studies. The maximum inhibition efficiency reached was about 90% at 10⁻³M. The inhibition effect is caused by geometrically blocking the surface of iron by adsorbed inhibitive molecules which follow an S-shaped adsorption isotherm.     

Preferred conformations of pilocarpine,pilocarpine.HCl and isopilocarpine.HCl in solution,deduced from 200 MHz 1H NMR spectra

The 200 MHz ¹H NMR spectra of pilocarpine, pilocarpine.HCl and isopilocarpine.HCl have been studied. Evidence is presented for the preferred conformations of the compounds in aqueous solution, with the methylimidazolyl moiety antiperiplanar with respect to the α-carbon of the butanolide ring.     

Corrosion inhibitive evaluation and DFT studies of 2-(Furan-2-yl)-4,5-diphenyl-1H-imidazole on mild steel at 1.0M HCl

A novel heterocyclic compound 2-(Furan-2-yl)-4,5-Diphenyl-1H-Imidazole (FDPI) was synthesized by a simple and cost effective one pot synthetic protocol and the structure of FDPI was confirmed by FT-IR, ¹H NMR and ¹³C NMR spectra. The corrosion inhibition activity of FDPI was investigated using gravimetric and electrochemical methods. It resulted a maximum inhibition efficiency of 95.84% at 10 mmolL⁻¹ concentrations of FDPI. The excellent inhibition efficiency is reasoned as the adsorption of FDPI on the mild steel surface as a protective layer immersed in the 1 ​M HCl. The adsorbed layer obeys Langmuir adsorption isotherm and the ΔG^o_ads values of FDPI suggested that process involves physisorption. The polarization curves showed that the FDPI behaves as a mixed type inhibitor. Surface morphology studied by SEM confirmed the formation of a protective film of FDPI on the mild steel surface. The computational studies using DFT have been analyzed for the FDPI to determine the HOMO-LUMO energy gap.     

The anodic behaviour of lead amalgam electrodes in HCl solution

The anodic behaviour of the lead amalgam electrode has been investigated in aqueous hydrochloric acid solutions. Both voltammetric and potential pulse results are described. The mechanism of passivation is shown to be the nucleation and growth of three-dimensional nuclei of PbCl₂ which progressively block the electrode. The nuclei are considered to be right circular cones, distributed at random on the electrode surface. As in the case of solid lead electrodes, a simultaneous dissolution of PbCl_n^2?n complexes is observed, which diffuse away from the electrode under mass transport control. Evidence is also presented that the first stage in the growth of the anodic film is the two-dimensional nucleation and growth of a monolayer of PhCl₂. Unfortunately, this process is partially obscured by the dissolution reaction. A reaction scheme is proposed.     

Inhibition of mild steel corrosion in HCl solution using chitosan

The efficiency of chitosan (a naturally occurring polymer) as a corrosion inhibitor for mild steel in 0.1 M HCl was investigated by gravimetric, potentiodynamic polarization, electrochemical impedance spectroscopy measurements, scanning electron microscopy, and UV–visible analysis. The polymer was found to inhibit corrosion even at a very low concentration. Inhibition efficiency increases with a rise in temperature up to 96 % at 60 °C and then drops to 93 % at 70 °C, while it slightly increases with an increase in chitosan concentration. Polarization curves indicate that chitosan functions as a mixed inhibitor, affecting both cathodic and anodic partial reactions. Impedance results indicate that chitosan was adsorbed on the metal/solution interface. Adsorption of chitosan at the mild steel surface is found to be in agreement with Langmuir adsorption isotherm model. Chemical adsorption is the proposed mechanism for corrosion inhibition considering the trend of protection efficiency with temperature. Calculated kinetic and thermodynamic parameters corroborate the proposed mechanism.     

4-phenyl-decahydro-1H-1,5-benzodiazepin-2-one as novel and effective corrosion inhibitor for carbon steel in 1 M HCl solution: A combined experimental and empirical studies

The heterocyclic system, namely 4-phenyl-decahydro-1H-1,5-benzodiazepin-2-one (POBZ) was inspected as a corrosion inhibitor of carbon steel (CS) in a 1 M HCl medium through electrochemical impedance spectroscopy (EIS), potentiodynamic polarization measurements (PDP), and scanning electron microscopy (SEM). The experimental data indicate that the inhibiting action augments with augmenting POBZ amount and reduces with augmenting temperature. The inhibiting action efficiency of 90.98% is obtained with 0.001 M at 303 K. The potentiodynamic polarization (PDP) results mentioned that the POBZ is of mixed type. The adsorption of POBZ on the CS followed Langmuir isotherm. SEM exams affirmed that the steel surface is smooth in presence of POBZ. In light of the calculations of density functional theory (DFT) and molecular dynamics simulation, the mechanism of POBZ inhibitory activity was addressed.     

An Eco-Friendly Quaternary Ammonium Salt as a Corrosion Inhibitor for Carbon Steel in 5 M HCl Solution: Theoretical and Experimental Investigation

The corrosion of industrial material is a costly problem associated with global economic losses reaching trillions of US dollars in the repair of failures. Injecting corrosion inhibitors is the most practically promising method for decelerating corrosion reactions and protecting surfaces. Recent investigations have focused on surfactants as corrosion inhibitors due to their amphiphilic nature, low cost, and simple chemical preparation procedures. This study aims to investigate the performance of an environment-friendly Quaternium-22 (Q-22) surfactant which is widely used in cosmetics for C-steel corrosion inhibition in a 5 M HCl medium. Weight loss experiments were performed at different concentrations and immersion times, presenting a maximum efficiency at 2.22 mmol·L⁻¹. The influence of Q-22 on the corrosion behavior of C-steel was elucidated using non-destructive electrochemical measurements. The overall results revealed that adding varied concentrations of Q-22 significantly decreases the corrosion rate of C-steel. The results revealed the physisorption nature of Q-22 onto the C-steel surface, with adsorption following the Freundlich isotherm (∆Hads= −16.40 kJ·mol⁻¹). The relative inhibition performance of Q-22 was also evaluated by SEM and AFM analyses. Lastly, quantum chemical calculations based on density functional theory (DFT) demonstrated that Q-22 has promising molecular features concerning the anticorrosive mechanism.