Synergistic inhibition between 1-octadecanethiol and iodide ions on X60 pipeline steel for corrosion protection

The corrosion protection of carbon steel in 1?M HCl by 1-octadecanethiol (ODT) alone and in combination with iodide ions was investigated at ambient temperature using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. Results obtained showed that ODT alone offered low corrosion protection ability at very low concentrations. However, on addition of iodide ions, the corrosion protection potential was enhanced due to synergistic effect. Potentiodynamic polarization data revealed that ODT acts as mixed-type inhibitor influencing both the cathodic hydrogen evolution and anodic metal dissolution reactions. Adsorption of ODT onto the carbon steel surface followed Langmuir adsorption isotherm model. The existence of synergism phenomenon between ODT and iodide ions was confirmed from synergism parameter, which was found to be greater than unity. Quantum chemical calculations provide greater insight into the mechanism of electron transfer and mechanistic aspects of ODT on steel surface.     

Comparative studies on the corrosion inhibition efficacy of ethanolic extracts of date palm leaves and seeds on carbon steel corrosion in 15% HCl solution

The work reports on the study carried out to comparatively assess the corrosion inhibition efficacy of crude ethanolic extracts of date palm leaves and seeds on X60 carbon steel corrosion in 15% HCl solution at 25–60 °C. The corrosion inhibition studies was carried out using weight loss and electrochemical (potentiodynamic polarization and linear polarization resistance) techniques. Preliminary phytochemical screening was performed in order to determine the phytoconstituents present in the crude extracts. The influence of extractive solvents on the corrosion inhibition performance of the extracts was also investigated. It is found that the crude extracts of both date palm leaves and seeds contain saponins, flavonoids, cardiac glycosides and reducing sugars. Tannins is only present in the leaves and absent in the seeds while anthraquinones is absent in both extracts. The crude ethanolic extracts inhibited the corrosion of X60 steel in the aggressive 15% HCl solution with the leaves extract showing superior performance. Inhibition efficiency increased with increase in concentration of the extracts and temperature. Potentiodynamic polarization results reveal that the extracts function as mixed type inhibitors. Corrosion inhibition occurs by virtue of adsorption of components of the extract on the steel surface and was found to follow Langmuir adsorption isotherm model. On the influence of the extractive solvents on the corrosion inhibition performance, the order of inhibition efficiency at 60 °C follows the trend DPLAE (73.6%) > DPLEE (62.5%) > DPSAE (59.9%) > DPSEE (55.9%) with the optimum extract concentration (2000 ppm) studied.     

Eco friendly corrosion inhibitors: Inhibitive action of quinine for corrosion of low carbon steel in 1 m HCl

Quinine, a natural product, was investigated as a corrosion inhibitor for low carbon steel in 1.0 m HCl solution. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to study the inhibition action in the temperature range 20–50 °C. The corrosion of steel was controlled by a charge transfer process at the prevailing conditions. The electrochemical results showed that quinine is an efficient inhibitor for low carbon steel and an efficiency up to 96% was obtained at 20 °C. The inhibition efficiency increases with inhibitor concentration and reaches a near constant value in the concentration range 0.48 mM and above. Application of the Langmuir adsorption isotherm enabled a study of the extent and the mode of adsorption.     

聚环氧琥珀酸对碳钢的缓蚀协同效应的研究

聚环氧琥珀酸(PESA)是一种新型的绿色生物可降解环保型水处理剂.用失重法研究了在上海自来水中聚环氧琥珀酸对碳钢的缓蚀性能以及PESA与PBTCA、锌盐的缓蚀协同效应.研究表明,聚环氧琥珀酸、PBTCA、锌盐在自来水中对碳钢具有良好的缓蚀协同效应.     

钼膦系药剂缓蚀协同效应的研究

通过旋转挂片失重法研究了钼酸钠,羟基乙叉二膦酸和锌盐组成三元体系在水介质中对Ａ３钢的缓蚀作用,它们之间有着显著的协同效应,实验规律性的研究对开发新的钼膦系药剂具有实际的指导意义。     

碳钢—硝酸体系腐蚀与缓蚀行为研究

采用失重法、容量法和电化学方法研究了碳钢在50g/kg HNO_3中的腐蚀行为,并对Lan-5在碳钢—50g/kg NHO_3体系中的缓蚀行为进行了初步探索研究.实验结果表明:碳钢在50g/kg HNO_3中的阳极腐蚀产物是Fe~(3+),阴极反应主要不是析氢反应.Lan-5是碳钢—50g/kg HNO_3体系的高效缓蚀剂,其缓蚀效率可达到99.9%,缓蚀剂之间具有显著的协同作用.研究结果还发现,碳钢在硝酸—Lan-5介质中有孔蚀倾向,阳极极化加速孔蚀的形成.     

Performance evaluation of poly (methacrylic acid) as corrosion inhibitor in the presence of iodide ions for mild steel in H2SO4 solution

The inhibition performance of poly (methacrylic acid) (PMAA) and the effect of addition of iodide ions on the inhibition efficiency for mild steel corrosion in 0.5 M H₂SO₄ solution were investigated in the temperature range of 303–333 K using electrochemical, weight loss, scanning electron microscopy (SEM), and water contact angles measurements. The results show that PMAA is a moderate inhibitor for mild steel in 0.5 M H₂SO₄ solution. Addition of small amount of KI to PMAA significantly upgraded the inhibition efficiency up to 96.7%. The adsorption properties of PMAA and PMAA + KI are estimated by considering thermodynamic and kinetic parameters. The results reveal that PMAA alone was physically adsorbed onto the mild steel surface, while comprehensive adsorption mode characterized the adsorption of PMAA + KI. Adsorption of PMAA and PMAA + KI followed Temkin adsorption isotherm. The SEM and water contact angle images confirmed the enhanced PMAA film formation on mild steel surface by iodide ions.     

Adsorption and anticorrosion behaviour of an imine compound on low carbon steel in HCl solution at different potentials

The inhibition capability of an imine compound named (2-methoxyphenyl)-N-(2-(phenylthio)phenyl)methanimine (MPM) on low carbon steel corrosion in HCl solution was investigated at various concentrations and temperatures by using electrochemical and microscopic techniques. The electrochemical results revealed that the inhibition efficiency increases with an increase in the MPM concentration, and MPM has provided 98.8% protection for 120 h. Electrochemical studies at different potentials showed that electrostatic effects have an important role on the adsorption of MPM on the metal surface. scanning electron microscopy and energy-dispersive X-ray spectroscopy results also confirmed that MPM has reduced the corrosive effect of HCl.     

Synergistic effect of 2-mercapto benzimidazole and KI on copper corrosion inhibition in aerated sulfuric acid solution

2-Mercapto benzimidazole (MBI) was used as a copper corrosion inhibitor in aerated 0.5 mol L^–1 H₂SO₄ solutions. The inhibition efficiency (IE) increased with increasing MBI concentration to 74.2% at the 1 mM level. A synergistic effect existed when MBI and iodide ions were used together to prevent copper corrosion in sulfuric acid. It was found that IE reached 95.3% in 0.5 mol L^–1 H₂SO₄ solutions containing 0.75 mmol L^–1 MBI and 0.25 mmol L^–1 KI. X-ray photoelectron spectroscopy (XPS) analysis of the copper samples showed that a (Cu⁺MBI) complex film formed on the surface to inhibit the copper corrosion and the iodide ions did not participate in the formation of the inhibitor film. The synergistic effect was attributed to the adsorption of iodide anions on the copper surface, which then facilitated the adsorption of protonated MBI and the formation of an inhibitive film.     

Effect of iodide ions on corrosion inhibition of mild steel by 3,5-bis(4-methylthiophenyl)-4H-1,2,4-triazole in sulfuric acid solution

The synergistic effect of iodide ions on the corrosion inhibition of mild steel in 0.5 M sulfuric acid (H₂SO₄) in the presence of 3,5-bis(4-methylthiophenyl)-4H-1,2,4-triazole (4-MTHT) was investigated using weight loss measurements and different electrochemical techniques such as potentiostatic polarization curves and electrochemical impedance spectroscopy (EIS). The inhibition efficiency (E, %) increased with 4-MTHT concentration, but the desorption potential (E _d) remained unchanged with increasing 4-MTHT concentration. The addition of potassium iodide (KI) enhanced E considerably and increased the value of E _d. A synergistic effect was observed between KI and 4-MTHT with an optimum mass ratio of [4-MTHT]/[KI] = 4 × 10^–2. The synergism parameters (S ) calculated from surface coverage were found to be more than unity. This result clearly showed the synergistic influence of iodide ions on the corrosion inhibition of mild steel in 0.5 M H₂SO₄ by 4-MTHT. The adsorption of this inhibitor alone and in combination with iodide ions followed Langmuir's adsorption isotherm.     

Investigation on inhibition of CrO4 2− and MoO4 2− ions on carbon steel pitting corrosion by electrochemical noise analysis

The inhibition effect of chromate (CrO₄ ^2–) and molybdate (MoO₄ ^2–) anions on the pitting corrosion of 16Mn carbon steel in 0.1 M NaCl containing bicarbonate solution was studied based on electrochemical noise analysis (ENA) and the potentiodynamic polarization method. The experimental results indicated that, once the pits occur on the surface of the carbon steel after 4–6 h of immersion, increasing the concentration of CrO₄ ^2– and MoO₄ ^2– ions accelerate the repassivation process, and attenuate the duration and the nucleation rate of metastable pits. Further analysis demonstrated that noise resistance R _n might not be suitable for the evaluation of the inhibition efficiency of CrO₄ ^2– and MoO₄ ^2– anions on pitting corrosion in the present system. However, the transient charge q _pit, which is an integral of all current transients during a certain period, can characterize the inhibition performance on pitting corrosion. A new definition of inhibition efficiency based on q _pit is given.     

Biomaterials for corrosion protection: evaluation of mustard seed extract as eco-friendly corrosion inhibitor for X60 steel in acid media

The toxic nature of most organic and inorganic corrosion inhibitors has necessitated the search for corrosion inhibitors with an excellent environmental profile. The present work is focused on the widening utilization of plant extracts for metallic corrosion control and reports on the corrosion inhibition effect of mustard seed extract (MSE) for typical X60 pipeline steel in 2 M HCl and 1 M H₂SO₄ solutions. Gravimetric and electrochemical (electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization) methods were employed. The effect of immersion time and temperature on the corrosion inhibition effect of the plant extract was also studied. Results obtained show that MSE inhibited the corrosion of steel in both media which was more pronounced in H₂SO₄ than in HCl environment. Inhibition efficiency increased with increase in the concentration of the extract but decreased with increase in temperature. The potentiodynamic polarization studies revealed that MSE functions as a mixed-type inhibitor. The corrosion inhibition is assumed to occur via adsorption of the components of the extract on the steel surface which was found to obey Langmuir adsorption isotherm model. The morphology of the corroding steel surface in the absence and presence of the MSE was visualized using scanning electron microscopy.     

Enhanced corrosion inhibition behavior of carbon steel in aqueous solution by Phosphoserine-Zn2+ system

The corrosion inhibition effect of carbon steel in aqueous solution was using a synergistic mixture of an environmentally friendly inhibitor system phosphoserine (PS) and Zn²⁺ using gravimetric studies, potentiodynamic polarization, and electrochemical impedance studies. Potentiodynamic polarization studies showed that the inhibitor system is a mixed type inhibitor. Electrochemical impedance studies of the metal/solution interface indicated that the surface film is highly protective against the corrosion of carbon steel in the aqueous solution. X-ray photoelectron spectroscopic analysis of the protective film exhibited the presence of the elements viz., iron, phosphorus, nitrogen, oxygen, carbon, and zinc. The chemical shifts in the binding energies of these elements inferred that the surface film is composed of oxides/hydroxides of iron, Zn(OH)₂, and [Fe(II)/(III)-Zn(II)-PS] complex. Further, the surface examination techniques viz., FTIR, SEM, and AFM studies confirm the formation of an adsorbed protective film on the carbon steel surface. Based on the results obtained, a suitable mechanism of corrosion inhibition is presented.     

4-Aminoantipyrine as an inhibitor of mild steel corrosion in HCl solution

4-aminoantipyrine (AAP) was tested as a corrosion inhibitor for mild steel in 2 M HCl solution using different techniques: weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that AAP is an inhibitor for mild steel in this medium. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the metal surface. In the 20 to 60 C temperature range, the AAP adsorption follows the Flory–Huggins isotherm and/or the El-Awady et al. kinetic-thermodynamic model. The protection efficiency increases with increasing inhibitor concentration (in the range 10–310–2 M) but decreases with increasing temperature. The thermodynamic functions of dissolution and adsorption processes were calculated.     

盐酸介质中头孢硫脒对碳钢的缓蚀作用

采用动电位极化曲线和交流阻抗实验,研究了抗生素——头孢硫脒的缓蚀剂在盐酸介质中对碳钢的缓蚀性能和缓蚀作用机理。结果表明,头孢硫脒对碳钢在1.0 mol/L盐酸溶液中具有良好的缓蚀性能,当头孢硫脒浓度为0.4 mmol/L时,缓蚀率达86%以上,为抑制阴极反应为主的混合型缓蚀剂。头孢硫脒在碳钢表面的吸附符合Langmuir等温式,属于单分子层吸附,其吸附行为是以化学吸附为主的物理和化学混合吸附。     

Inhibitive effect of 4-amino-N-benzylidene-benzamide Schiff base on mild steel corrosion in HCl solution

Abstract

A newly Schiff base, 4-amino-N-benzylidene-benzamide (4-BAB) protection ability was synthesised from a condensation reaction of 4-aminobenzamide (4-AB) and benzaldehyde (BA). Adsorption and corrosion inhibition effect of this compound on mild steel (MS) in 1.0?M HCl solution were studied. The data obtained from measurments of this compound were compared with that of 4-AB and BA using many electrochemical, microscopic and hydrogen gas evolution techniques to clarify superiority of the Schiff base. Some thermodynamic parameters were calculated from experimental results and discussed. The value of ΔG_ads showed that adsorption of 4-BAB on MS from acidic solution obeys the Langmuir adsorption isotherm model. Surface SEM images of the MS specimens which were exposed to 1.0?M HCl solution in the absence and presence of the inhibitors showed that a homogeneous and protective inhibitor film forms on the metal surface, which hinder corrosive attack. It was concluded that synthesising the Schiff base improves protection ability with respect to related amine and aldehyde and the inhibitive action is in the order of 4-BAB > 4-AB?>?BA.

• Highlights

• 4-Amino-N-benzylidene-benzamide (4-BAB) is synthesized by condensation reaction between 4-aminobenzamide (4-AB) and benzaldehyde (BA)

• The inhibitor efficiencies calculated from all the applied methods are in agreement and are found to be in the order: 4-BAB >4-AB?>?BA

• The adsorption process of inhibitors on mild steel surface obeys the Langmuir adsorption isotherm

     

Effect of surface nanocrystallization on corrosion and corrosion inhibition of low carbon steel: Synergistic effect of methionine and iodide ion

The corrosion properties of a nanocrystalline low carbon steel coating (SNCLCS) fabricated on a low carbon steel substrate by magnetron sputtering and the bulk steel (BLCS) were investigated in aerated 0.5 M H₂SO₄ solution by EIS and polarization techniques. The corrosion inhibiting effect of methionine and synergistic KI additives was also studied. The results show that both specimens underwent active corrosion with no transition to passivation in the potential range studied. Surface nanocrystallization was observed to increase the corrosion susceptibility of low carbon steel, leading to a decrease in interfacial impedance and an increase in the kinetics of the anodic reaction. Methionine inhibited the corrosion of both specimens with comparable inhibition efficiencies and iodide ions synergistically increased the inhibition efficiency. This synergistic effect was, however, more pronounced for BLCS. This has been discussed vis-à-vis the more positive surface charge on BLCS compared to SNCLCS.     

Investigation on the inhibition effect of aspartic acid and Zn2+ ions on carbon steel surface in aqueous solution

A protective film has been formed on the surface of carbon steel in aqueous environment using a synergistic mixture of an environment-friendly inhibitor, aspartic acid, and Zn²⁺. The synergistic effect of aspartic acid (AS) in controlling corrosion of carbon steel has been investigated by gravimetric studies in the presence of Zn²⁺. The formulation consisting of AS and Zn²⁺ has an excellent inhibition efficiency. The results of potentiodynamic polarization revealed that the formulations are of mixed-type inhibitor. Impedance studies of the metal/solution interface indicated that the surface film is highly protective against the corrosion of carbon steel in the aqueous environment. X-ray photoelectron spectroscopic analysis of the protective film showed the presence of the elements iron, nitrogen, oxygen, carbon, and zinc. The spectra of these elements in the surface film showed the presence of oxides/hydroxides of iron(III), Zn(OH)₂, and [Fe(III)/Fe(II)–Zn(II)-AS] complex. Further, surface characterization techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy are used to ascertain the nature of the protective film formed on the carbon steel surface.     

Effect of carboxymethyl cellulose on the corrosion behavior of aluminum in H2SO4 solution and synergistic effect of potassium iodide

Abstract

The corrosion inhibition of aluminum in 2?M H₂SO₄ solution by carboxymethyl cellulose (CMC) alone and in combination with iodide ions has been investigated using electrochemical measurements and surface analysis techniques. The results showed that CMC moderately inhibited aluminum corrosion in the H₂SO₄ solution, and the inhibition efficiency of CMC was increased with the addition of inhibitor concentration, indicating the physical adsorption mechanism. The synergistic effect of 5?mM KI at all concentrations of CMC was assessed by calculating the synergism parameters, indicating that the increased inhibition efficiency of the CMC caused by addition of iodide ions is due to synergism. Additionally, the analysis of the morphology and composition of the aluminum surface suggests that with addition of iodide ions, more CMC molecules are adsorbed on the aluminum surface, thereby enhancing the inhibition efficiency of CMC.