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To evaluate the inhibition efficiency of 1‐methyl 2‐mercapto imidazole (MMI) in controlling the corrosion of carbon steel in sulphuric acid and to study its action mechanism.

The effect of concentration, immersion time and temperature on the behaviour of this inhibitor has been studied using weight loss, d.c. polarisation and a.c. polarisation techniques.

The results show that MMI is a mixed type inhibitor. Changes in impedance parameters (charge transfer resistance, R_t; and double layer capacitance, C_dl) were indicative of adsorption of MMI on the metal surface, leading to the formation of a protective film that grew with the increasing exposure time. Adsorption of MMI on the carbon steel is found to obey the Langmuir adsorption isotherm. The inhibition efficiency of MMI is temperature‐independent and its addition leads to a small increase in activation corrosion energy.

Surface analytical techniques such as X‐ray photoelectron spectroscopy and Auger spectroscopy can enlighten more on the mechanism of corrosion inhibition.

A survey of literature has shown that no work using electrochemical techniques has yet been done on MMI as corrosion inhibitor for carbon steel in sulfuric acid.

In this work, a kind of Mannich base (C₂₁H₂₅NO) was synthesized with cinnamal aldehyde, acetophenone and diethylamine in a condensing reflux device based on the conventional method. Optimization of the inhibitor concentration was explored.

Spectral properties of this compound was investigated by FTIR, and its inhibition efficiency and mechanism on N80 steel in 20% hydrochloric acid solution were studied by weight loss measurement, electrochemical measurement (potentiodynamic polarization and electrochemical impedance spectroscopy) and surface analytical measurement (scanning electron microscope with energy dispersive spectrometer).

The results showed that the new inhibitor reduced the double-layer capacitance and increased the charge transfer resistance. The inhibition efficiency is 99.7% when the concentration of C21H25NO is 3%. The adsorption of C₂₁H₂₅NO on N80 steel surface in 20% HCl solution was found to be spontaneous and steady. Observed from the steel surface, an inhibition film was confirmed to be presented after adding inhibitor and successfully hindered the corrosive ions from reaching the bulk steel.

A new Mannich base (C₂₁H₂₅NO) was synthesized by cinnamal aldehyde, acetophenone and diethylamine for the corrosion prevention of N80 steel in 20% hydrochloric acid solution.

This study aims to investigate the inhibition effect of a newly synthesized1,2,3-triazole containing a carbohydrate and imidazole substituents, namely, 1-((1-((2,2,7,7-tetramethyltetrahydro-5H-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)-1H-benzo[d]imidazole (TTB) on the corrosion of mild steel in aerated 1 M H₂SO₄.

The authors have used weight loss measurement, potentiodynamic polarization, electrochemical impedance spectroscopy, FT-IR studies, scanning electron microscopy analysis and energy dispersive X-ray (EDX) spectroscopy techniques.

It is found that, in the working range of 298-328 K, the inhibition efficiency of TTB increases with increasing concentration to attain the highest value (92 per cent) at 2.5 × 10⁻³ M. Both chemisorption and physisorption of TTB take place on the mild steel, resulting in the formation of an inhibiting film. Computational methods point to the imidazole and phenyl ring as the main structural parts responsible of adsorption by electron-donating to the steel surface, while the triazol ring is responsible for the electron accepting. Such strong donating–accepting interactions lead to higher inhibition efficiency of TTB in the aqueous working system.

This work is original with the aim of finding new acid corrosion inhibitors.

Tannic acid (TA) is one of the green corrosion inhibitors for mild steel; its anti-corrosive performance in alkaline water on mild steel when it is used together with polyaspartic acid (PASA) still has not been investigated. The purpose of this study is to develop an effective, biodegradable and environment-friendly novel corrosion inhibitor based on TA and PASA as an alternative to the conventional inorganic inhibitors for mild steel in decarbonised water, which is common in cooling systems.

Corrosion inhibition mechanism is investigated by electrochemical techniques such as polarisation measurements and electrochemical impedance spectroscopy, and results were evaluated to determine the optimum inhibitor concentration for industrial applications. Additionally, practice-like conditions are carried out in pilot plant studies to simulate the conditions in cooling systems. Thus, the efficiencies of the inhibitors are evaluated through both weight loss and linear polarisation resistance measurements. Moreover, the corrosion product is characterised by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR) analysis.

TA shows high inhibition efficiency especially towards pitting corrosion for mild steel in decarbonised water. PASA addition in the cooling systems improves the inhibition efficiency of TA, and at lower concentrations of TA + PASA, it is possible to obtained better inhibition efficiency than TA alone at higher inhibitor amounts, which is essential in economic and environmental aspect.

A blended inhibitor program including TA and PASA with suggested concentrations in this work can be used as an environmental friendly treatment concept for the mild steel corrosion inhibition at cooling systems.

This paper aims to show the effectiveness of methyl red (MR) alone and in combination with KI as corrosion inhibitor for carbon steel in 0.5 M H₂SO₄.

Corrosion rates charge transfer resistance values were determined using gravimetric and electrochemical techniques. The efficiency of inhibition was calculated by comparing corrosion rates and charge transfer resistance values in absence and presence of the inhibitor, while the mechanism of inhibition was proposed by considering temperature influence on corrosion and inhibition processes.

The inhibition efficiency of MR increased with concentration and synergistically increased in the presence of the KI. Polarisation curves reveal that MR is a mixed type inhibitor. Changes in impedance parameters were indicative of adsorption of MR on the metal surface. The trend of inhibition efficiency with temperature suggests that inhibitor molecules are physically adsorbed on the corroding metal surface in the absence of KI and chemically adsorbed in its presence. MR was found to obey Langmuir adsorption isotherm both with and without KI.

Electrochemical techniques have been used for the first time to study synergistic effect of MR dye and potassium iodide on inhibition of corrosion of carbon steel in H₂SO₄.The results suggest that the mixture (MR + KI) could find practical application in corrosion control in aqueous acidic environment.

Surface pretreatment of iron and its alloys to remove stains and inorganic contaminants on the metal surface undergoes dissolution by virtue of the strong acidic media thereby increasing its susceptibility to corrosion. The purpose of this study is to explore the corrosion mitigation prospects of green corrosion inhibitors on mild steel surface.

Corrosion inhibition performance of Garcinia gummi-gutta leaf extract (GGLE) was explored against mild steel in 1 M HCl solution using the weight-loss method, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques. Surface characterization was carried out to study the mechanism of inhibitor action.

The concentration of GGLE varied from 100 to 6,000 ppm and the result indicates that corrosion inhibition efficiency was amplified by raising the inhibitor concentration. The maximum inhibition efficiency was 82.2% at 6,000 ppm concentration. EIS results show the development of a protective layer of inhibitor molecule over the metal surface and PDP demonstrates that the inhibitor operates as a mixed-type inhibitor. Scanning electron microscopy and atomic force microscopy were executed to assess the surface morphology and roughness, respectively.

To the best of the authors’ knowledge, so far, no studies have been reported on the corrosion inhibition performance of GGLE which is rich in many bioactive components especially hydroxyl citric acid. This work encompasses the corrosion inhibition capability of GGLE against mild steel in an acidic medium.

To assess the protective effect and adsorption behaviour of Azadirachta indica extract in controlling mild steel corrosion in 1 M H₂SO₄ and 2 M HCl.

The inhibitive effect of the plant extract was monitored using the gas‐volumetric technique. The inhibition mechanism was inferred by curve fitting of the experimental data to known adsorption isotherms and the trend of inhibition efficiency with temperature.

Azadirachta indica extract effectively inhibited steel corrosion in the acid media studied by virtue of adsorption. The inhibitor adsorption characteristics were approximated by Langmuir isotherm. The extract functioned as a mixed inhibitor, depending on its concentration. The prime effect at lower concentration was mitigation of the cathodic reaction by physical adsorption of protonated species in the extract and at higher concentration the anodic reaction was inhibited by chemisorption of molecular species.

This paper provides novel information on the effectiveness of Azadirachta indica extract as a green corrosion inhibitor for steel in highly acidic environments as well as possible mechanisms of the inhibitive action.

This paper aims to study the growth and properties of potentiostatic passive films formed on iron electrodes immersed in pH 8.9‐11.0 phosphate solutions.

First, passive films were grown potentiostatically on pure iron electrodes under different experimental conditions (namely the Na₂HPO₄ concentration, time and potential of polarization, solution pH and temperature). Subsequently, the properties of the resulting passive layer were evaluated by electrochemical measurements (open circuit potential and potentiodynamic polarization measurements) and scanning electron microscopy.

The formation of passive films on iron electrodes immersed in weak‐alkaline phosphate solutions was found to occur in three main steps, being the Na₂HPO₄ concentration a very important parameter to promote reduction of iron dissolution. Films with protective properties could be obtained within at least 30 s of polarization at +0.50 V/SCE. The effect of the polarization potential was interpreted according to previous potentiodynamic data and the influences of solution pH and temperature follow thermodynamic laws.

In‐situ surface analytical techniques such as extended X‐ray absorption fine structure (EXAFS) and elipsometry coupled to electrochemical measurements can elucidate more information on the film growth process, and in turn on resulting properties.

This contribution provides useful insights into the potentiostatic behaviour of iron in alkaline phosphate solutions.

The purpose of this paper is to study electrochemically and by weight loss experiments the effect of P,P′‐Bis (triphenylphosphonio) methyl benzophenone dibromide (TPPMB) on the corrosion inhibition of mild steel in 1.0M HCl solution, which will serve researchers in the field of corrosion.

Weight loss measurements were carried out on mild steel specimens in 1.0M HCl and in 1.0M HCl containing various concentrations (2×10⁻⁸M and 2×10⁻⁵M) of the laboratory synthesized TPPMB at temperatures ranging from 303 to 343 K.

TPPMB was found to be a highly efficient inhibitor for mild steel in 1.0M HCl solution, reaching about 98% at the concentration of 2×10⁻⁵M at 303 K, a concentration and temperature considered to be very moderate. The percentage of inhibition in the presence of this inhibitor was decreased with temperature which indicates that physical adsorption was the predominant inhibition mechanism because the quantity of adsorbed inhibitor decreases with increasing temperature.

This inhibitor could have application in industries, where hydrochloric acid solutions at elevated temperatures are used to remove scale and salts from steel surfaces, such as acid cleaning of tankage and pipeline, and may render dismantling unnecessary.

This paper is intended to be added to the family of phosphonium salt corrosion inhibitors which are highly efficient and can be employed in the area of corrosion prevention and control.

The purpose of this paper is to study the inhibition effect of (6-phenyl-3-oxopyridazin-2-yl) acetohydrazide (GP4) on the corrosion of mild steel in acidic medium by gravimetric measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS).

Weight loss measurements, potentiodynamic tests and EIS were performed during this study.

(6-phenyl-3-oxopyridazin-2-yl) acetohydrazide (GP4) was found to be a very efficient inhibitor for mild steel in 1.0 M HCl solution, reaching about 85 per cent with inhibitor concentration 1.0 × 10-3 M at 303 K.

(6-phenyl-3-oxopyridazin-2-yl) acetohydrazide (GP4) was found to play an important role in the corrosion inhibition of mild steel in acidic solution.

This paper is intended to be added to the family of pyridazine derivatives which are highly efficient inhibitors and can be used in the area of corrosion prevention and control.