Surface characterization and electrochemical corrosion behaviour of 304 stainless steel in aqueous media

A formulation consisting 100 ppm of 3-phosphonopropionic acid, 50 ppm of Zn²⁺ and 150 ppm of Tween 80 (polyoxyethylene sorbitan monooleate) offered 97.4% inhibition to the corrosion of 304 austenitic stainless steel immersed in a groundwater environment. This formulation functioned as a mixed inhibitor. The protective film was analysed by luminescence, XRD and FTIR spectra and pit morphology and was also observed by scanning electron microscopy. Electronic Publication     

Aqueous extract of <Emphasis Type="Italic">Argemone mexicana</Emphasis> roots for effective protection of mild steel in an HCl environment

The inhibition effect of aqueous Argemone mexicana root extract (AMRE) on mild steel corrosion in 1 M HCl has been studied by weight loss, Tafel polarization curves, electrochemical impedance spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy techniques. Results indicate that inhibition ability of AMRE increases with the increasing amount of the extract. A maximum corrosion inhibition of 94 % is acknowledged at the extract concentration of 400 mg L^?1. Polarization curves and impedance spectra reveal that both cathodic and anodic reactions are suppressed due to passive layer formation at the metal–acid interface. It is also confirmed by SEM micrographs and FTIR studies. Furthermore, the effects of acid concentration (1–5 M), immersion time (120 h) and temperature (30–60 °C) on inhibition potential of AMRE have been investigated by the weight loss method and electrochemical techniques. An adsorption mechanism is also proposed on the basis of weight loss results, which shows good agreement with the Langmuir isotherm.     

Study on the Inhibition of Mild Steel Corrosion by Cationic Gemini Surfactant in 1 M HCl

The cationic gemini surfactant 1,2-bis(N-tetradecyl-N,N-dimethylammonium)ethane dibromide (14-2-14) was synthesized using a previously described method. The surfactant was characterized using ¹H NMR. The corrosion inhibition effect of 14-2-14 on mild steel in 1 M HCl at temperatures 30–60°C was studied using weight loss measurements, potentiodynamic polarization measurements and electrochemical impedance spectroscopy. Morphology of the corroded mild steel specimens was examined using scanning electron microscopy (SEM). The results of the studies show that gemini surfactant is an efficient inhibitor for mild steel corrosion in 1 M HCl; the maximum inhibition efficiency (IE) of 98.06% is observed at surfactant concentration of 100 ppm at 60°C. The %IE increases with the increasing inhibitor concentration and temperature. The adsorption of inhibitor on the mild steel surface obeys Langmuir adsorption isotherm. SEM studies confirmed smoother surface for inhibited mild steel specimen.     

Spectral and thermal studies of 4-(phenyldiazenyl)phenyl 2-furoate as corrosion inhibitor for carbon steel

The azo-ester, namely 4-(phenyldiazenyl)phenyl 2-furoate (PPF) by a coupling reaction between 4-(phenyldiazenyl)phenol and 2-furoyl chloride in the presence of pyridine was obtained. For characterization of this compound UV–Vis, FTIR, and thermal analysis were used. PPF was investigated as corrosion inhibitor for carbon steel in saline waters using potentiodynamic polarization. Morphology of the surface before and after corrosion was examined by optical microscopy. Potentiodynamic polarization shows that the corrosion current densities decrease and values of polarization resistance and inhibition efficiency increase with PPF concentration reaching a maximum of 89.6 %, at 0.1 mmol L^?1.     

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.     

Adsorption and Corrosion Inhibition Behavior of Schiff Base-Based Cationic Gemini Surfactant on Mild Steel in Formic Acid

The adsorption and corrosion inhibition behavior of synthesized Schiff base-based cationic gemini surfactant bis[p-(N,N,N-tetradecyldimethylammonium bromide)benzylidene]thiourea (14-S-14) on mild steel in 20% formic acid in the temperature range of 30°C to 60°C was evaluated using weight loss measurements, solvent analysis of iron ions and potentiodynamic polarization measurements. The synthesized inhibitor was characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and thin layer chromatography (TLC). The surface morphology of the corroded mild steel specimen was evaluated using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDAX), and atomic force microscopy (AFM). Thermodynamic/kinetic parameters were calculated to elaborate the adsorption and corrosion inhibition mechanism of the inhibitor. The inhibition efficiency of the compound was found to vary with inhibitor concentration, immersion time, and temperature. The adsorption of the compound on the steel surface was found to obey Langmuir adsorption isotherm.      

Electrodeposition and characterization of zinc–nickel–iron alloy from sulfate bath: influence of plating bath temperature

The electrodeposition of ternary zinc–nickel–iron alloy was studied in acidic sulfate bath. The comparison between Zn, Ni, and Fe deposition and Zn–Ni and Zn–Ni–Fe co-deposition revealed that the remarkable inhibition of Ni and Fe deposition takes place due to the presence of Zn²⁺ in the plating bath. The increase in corrosion resistance of ternary deposits is not only attributed to the formation of γ-Ni₂Zn₁₁ phase but also to iron co-deposition and formation of iron phase. It was also found that the bath temperature has a great effect on the surface appearance and the deposit composition. The investigation was carried out using cyclic voltammetry and galvanostatic techniques for electrodeposition, while linear polarization resistance and anodic linear sweeping voltammetry techniques were used for corrosion study. Morphology and chemical composition of the deposits were characterized by means of scanning electron microscopy and atomic absorption spectroscopy.     

Surface morphological and impedance spectroscopic studies on the interaction of polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) with mild steel in acid solutions

The inhibition of mild steel corrosion in aerated acid mixture of 0.5 N H₂SO₄ and 0.5 N HCl solution was investigated using potentiodynamic polarization studies, linear polarization studies, electrochemical impedance spectroscopy, adsorption, and surface morphological studies. The effect of inhibitor concentration on corrosion rate, degree of surface coverage, adsorption kinetics, and surface morphology is investigated. The inhibition efficiency increased markedly with increase in additive concentration. The presence of PEG and PVP decreases the double-layer capacitance and increases the charge-transfer resistance. The inhibitor molecules first adsorb on the metal surface following a Langmuir adsorption isotherm. Both PEG and PVP offer good inhibition properties for mild steel and act as mixed-type inhibitors. Surface analysis by scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows that PVP offers better protection than PEG.     

Experimental and Theoretical Studies on Synthesized Compounds as Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution

Imidazole derivatives, namely, 1-((1-(piperazinomethyl)-1H-benzoimidazol-2-yl)methyl)-2-phenylhydrazine (PBIP), and 1-((1-(morpholinomethyl)-1H-benzoimidazol-2-yl)methyl)-2-phenylhydrazine (MBIP) were synthesized and investigated as inhibitors for mild steel corrosion in 15% HCl solution using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. It was found that the inhibition efficiency of both the inhibitors increases with increase in concentration of inhibitors and decreases with increase in temperature. The inhibitors, PBIP and MBIP, show corrosion inhibition efficiency of 92.6% and 91.4% at 300 ppm concentration, respectively, at 303 K. Polarization studies showed that both the studied inhibitors were of mixed type in nature. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were performed for surface study of uninhibited and inhibited mild steel samples. The semi-empirical AM1 method was employed for theoretical calculations.     

Experimental and theoretical investigation on adsorption and corrosion inhibition properties of imidazopyridine derivatives on mild steel in hydrochloric acid solution

Imidazopyridine derivatives, namely 4‐methoxy‐N‐((2‐(4‐methoxyphenyl)H‐imidazo[1,2‐a]pyridin‐3‐yl)methylene)benzenamine (MMPIPB) and 4‐chloro‐N‐((2‐(4‐methoxyphenyl)H‐imidazo[1,2‐a]pyridin‐3yl)methylene)benzenamine (CMPIPB), were investigated as inhibitors for mild steel corrosion in 15% HCl solution using the weight loss and electrochemical techniques. According to electrochemical impedance spectroscopy studies, MMPIPB and CMPIPB show corrosion inhibition efficiency of 84.8 and 77.2% at 10‐ppm concentration and 98.1 and 94.8% at 80‐ppm concentration, respectively at 303 K. The corrosion inhibition efficiency of both inhibitors increased with increasing inhibitor concentration and decreased with increasing temperature. The adsorption of both inhibitor molecules on the surface of mild steel obeys Langmuir adsorption isotherm. Polarization studies showed that both studied inhibitors were of mixed type in nature. Electrochemical impedance spectroscopy studies showed that for both inhibitors, the value of charge transfer resistance increased and double‐layer capacitance decreased on increasing the concentration of inhibitors. Scanning electron microscopy, energy‐dispersive X‐ray spectroscopy (EDX), and atomic force microscopy were performed for surface study. The density functional theory was employed for theoretical calculations. Copyright © 2014 John Wiley & Sons, Ltd.     

Conducting polyaniline/nano-zinc phosphate composite as a pigment for corrosion protection of low-carbon steel

Zinc phosphate (Zn₃(PO₄)₂) nanocrystals were synthesized and used for making conducting polyaniline/nano-zinc phosphate composite by chemical oxidative method. The product was characterized by UV–visible absorption spectroscopy. The crystal structure, morphology and thermal stability of the product were studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and thermo gravimetric analysis, respectively. The epoxy-based paint containing conducting polyaniline/nano-zinc phosphate composite pigment was applied on low-carbon steel samples. Corrosion protection performance of the painted low-carbon steel samples in 3.5 mass % sodium chloride solution was evaluated using electrochemical technique. Transmission electron microscopic image revealed the formation of core shell structure of the composite. Composite was found to be more thermally stable than the conducting polyaniline. The corrosion rate of conducting polyaniline/nano-zinc phosphate-painted low-carbon steel was found to be 5.1 × 10^?4 mm per year, about 34 times lower than that of unpainted low-carbon steel and 10 times lower than that of epoxy nano-zinc phosphate paint-coated steel. The study reveals the possibility of using conducting polyaniline/nano-zinc phosphate as a pigment for corrosion protection.     

Hydroclathrus clathratus marine alga as a green inhibitor of acid corrosion of mild steel

The corrosion inhibitive and adsorption behaviors of Hydroclathrus clathratus on mild steel in 1 M HCl and 1 M H₂SO₄ solutions at 303, 313 and 323 K were investigated by weight loss, electrochemical, and surface analysis techniques. The results show that H. clathratus acts as an inhibitor of corrosion of mild steel in acid media. The inhibition efficiency was found to increase with increase in inhibitor concentration but to decrease with rise in temperature, suggestive of physical adsorption. The adsorption of the inhibitor onto the mild steel surface was found to follow the Temkin adsorption isotherm. The inhibition mechanism was further corroborated by the results obtained from electrochemical methods. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses supported the inhibitive action of the alga against acid corrosion of mild steel.     

曲唑酮的两步法制备及对碳钢的缓蚀机理

以3-氯苯胺、N-氯丙基二乙醇胺和吡啶三唑酮为原料，两步法制备出曲唑酮（TZD）.通过动态失重、极化曲线与电化学阻抗谱研究了TZD在0.5 mol/L盐酸溶液中对20#钢的缓蚀性能；借助扫描电子显微镜、原子力显微镜、衰减全反射红外光谱与吸附活化参数分析研究了TZD在碳钢表面的作用机理.结果表明，TZD可显著降低碳钢在盐酸溶液中的腐蚀速率，缓蚀率随TZD添加浓度的增加而增大，随温度升高而降低；298 K下，添加6 mmol/L TZD时，缓蚀率达95.8%；TZD可自发吸附组装于碳钢表面，同时抑制腐蚀反应的阴、阳极过程，显著增加界面极化阻抗；吸附为放热过程，符合Langmuir等温式.理论计算结果显示，TZD倾向以平行取向组装于碳钢表面.     

Synthesis and Acidizing Corrosion Inhibition Performance of N-Doped Carbon Quantum Dots

In this paper, citric acid was used as carbon source, diethylenetriamine and urotropine were used as precursors, and N-doped carbon dots (cdh-CDs) with luminescent properties were synthesized by microwave method. The structure of the sample was analyzed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffractometry (XRD), ultraviolet spectrophotometer (UV), fluorescence spectroscopy, etc., and it was proved that cdh-CDs with an amorphous structure about 4–10 nm in diameter was synthesized. The corrosion inhibition performance of cdh-CDs in 1 M hydrochloric acid was evaluated by static weight loss and electrochemical method. The results showed that cdh-CDs have a good corrosion inhibition performance at 60°C, the inhibition efficiency can reach 81.2% when the dosage is 600 ppm. Electrochemical results showed that cdh-CDs are mixed inhibitors which mainly inhibit cathodes.

     

Antibacterial drugs as environmentally-friendly corrosion inhibitors for carbon steel in acid medium

The effect of cefazolin (CZ) and cefotaxime (CT) as corrosion inhibitors for carbon steel in 0.5 M H₂SO₄ solution was investigated by use of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), and scanning electron microscopy (SEM). CZ and CT acted as mixed-type inhibitors. Inhibition increased with increasing inhibitor concentration and decreased with increasing temperature. Adsorption of the inhibitors obeyed the Langmuir adsorption isotherm. SEM confirmed inhibition by the inhibitors. Inhibition by 5 × 10^?4 M CZ and 7 × 10^?4 M CT approached 99.6 % and 90.9 %, respectively. The EIS and EFM results were in good agreement with the potentiodynamic data.     

Poly(3-octylthiophene) and polystyrene blends thermally treated as coatings for corrosion protection of stainless steel 304

The effect of thermal annealing of poly(3-octylthiophene) (P3OT) and polystyrene (PS) blend coatings on the corrosion inhibition of stainless steel in a 0.5 M NaCl solution was investigated. P3OT was synthesized by direct oxidation of the 3-octylthiophene monomer with ferric chloride (FeCl₃) as oxidant. Stainless steel electrodes with mirror finish were coated with P3OT/PS blend by drop-casting technique. In order to study the temperature effect on the function like physical barrier against the corrosive species of P3OT/PS polymeric blend, the coatings were thermally annealed at three different temperatures (55?°C, 80?°C, and 100?°C). The corrosion behavior of P3OT/PS-coated stainless steel was investigated in 0.5 M NaCl at room temperature, by using potentiodynamic polarization curves, linear polarization resistance (LPR), and electrochemical impedance spectroscopy. The LPR values indicated that, at 100?°C, P3OT/PS coatings showed a better protection of the 304 stainless steel in 0.5 M NaCl; the corrosion rate diminished in two orders of magnitude with regard to the bare stainless steel. The superficial morphology of the coatings before and after the corrosive environment was researched by atomic force microscopy, optic microscopy, and scanning electronic microscopy. Morphological study showed that the increased temperature benefited the integration of the two polymeric phases, which improved the barrier properties of the coatings. The coating/metal adhesion and the coating thickness were evaluated. The temperature increases the adhesion degree coating/substrate; thus, the coating annealed at 100?°C showed the best adhesion.     

Schiff’s base derived from the pharmaceutical drug Dapsone (DS) as a new and effective corrosion inhibitor for mild steel in hydrochloric acid

The inhibition ability of Dapsone’s Schiff’s base with salicylaldehyde (1:2) for mild steel corrosion in 1 M HCl solution at 308 K was studied by means of potentiodynamic polarization, electrochemical impedance spectroscopy techniques, and gravimetric analysis. Results showed that Dapsone salicylaldehyde performed well as a good inhibitor for mild steel in 1 M HCl solution with maximum inhibition efficiency of 95 % at 500 ppm. The adsorption isotherm of the inhibitor followed the Langmuir adsorption. The value of free energy of adsorption showed that it is a spontaneous process and followed typical physical adsorption.     

Self-sustaining hybrid electrode prepared from polyaniline,carbon nanotubes,and carbon fibers: morphological,structural, and electrochemical analyses

The self-sustaining hybrid electrode was prepared via chemical polymerization of aniline in acid medium containing dispersed carbon nanotubes (CNT), using carbon fiber (CF) as conducting substrate. The ternary composites called PAni/CNT/CF were characterized in order to evaluate their morphologies, structures, and thermal properties. The influence of the polyaniline (PAni) layer in the ternary composite properties was studied considering different deposition times on CF samples (30, 60, and 90 min). The ternary composite morphologies were observed by scanning electron microscopy while thermal structural analyses were obtained using thermogravimetric measurements. The structural features were analyzed by Raman scattering spectroscopy and Fourier transform infrared spectroscopy (FTIR). The possible interactions between PAni and CNT were discussed on the basis of Raman and FTIR spectra. These spectroscopic analyses also confirmed that the PAni present in the composite is in the emeraldine (ES) salt form. Furthermore, the ternary composites were also evaluated by electrochemical measurements such as cyclic voltammetry (CV), galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS) techniques. The results showed good charge storage capacity for ternary composites, in particular, for PAni/CNT/CF obtained with 90 min of deposition time, which exhibited specific capacitance of around 500 F g^?1. Therefore, this electrode was selected to build a prototype of type I supercapacitor. This device presented specific capacitance of around 143 F g^?1 after 3200 charge/discharge cycles.     

Aminophylline: thermal characterization and its inhibitory properties for the carbon steel corrosion in acidic environment

Aminophylline (AMF) was studied as corrosion inhibitor for carbon steel in 1.0 mol L^?1 HCl solution using electrochemical measurements associated with UV–Vis spectrophotometry and optical microscopy. Simultaneous thermogravimetry/derivative thermogravimetry and differential scanning calorimetry analysis was performed in order to determine the temperature range in which AMF is an effective inhibitor, without the decomposition risk that could change the inhibition mechanism. Thermal behaviour restricts AMF application as corrosion inhibitor for carbon steel in 1.0 mol L^?1 HCl solution at temperatures ≤45 °C where there are no significant modifications of the adsorption mechanism. According to the results of electrochemical measurements, in association with UV–Vis spectrophotometry and optical microscopy techniques, AMF is a mixed-type inhibitor for carbon steel corrosion in 1.0 mol L^?1 HCl solution, simultaneously suppressing the anodic and cathodic processes and acting via spontaneous physisorption on the metal surfaces.     

Study of the Inhibition Efficiency for Some Novel Surfactants on the Carbon Steel (Type H-11) Pipelines in 0.5 M HCl Solution by Potentiodynamic Technique

In this article, three deferent surfactants as corrosion inhibitor were prepared in two steps. In the first step, maleic anhydride was amidated with dodecylamine to produce 2-ene-4-dodecanamide butanoic acid. In the second step, the resulting product was further esterified with different molecular weights of polyethylene glycol (m.wt. = 200, 400, and 600), namely, polyoxy ethylenyl-x-ene-4-dodecanamide butanoic acid, where x = 2, 4, or 6 according to molecular weights of polyethylene glycol used). The chemical structures of these inhibitors were confirmed by FTIR and ¹H NMR. The corrosion inhibition effect of the synthesized inhibitors has been investigated on the carbon steel (type H-11) pipelines in 0.5 M HCl solution by the potentiodynamic polarization method. From the obtained results, it was found that the maximum inhibition efficiency (90.44%) was exhibited by polyoxy ethylenyl-6-ene-4-dodecanamide butanoic acid, while the minimum inhibition efficiency (79.84%) was obtained by polyoxy ethylenyl-2-ene-4-dodecanamide butanoic acid at 200 ppm and 35°C. Also, the values of activation energy and thermodynamic parameters were calculated and discussed. Adsorption of the synthesized inhibitors was found to follow the Langmuir's adsorption isotherm. Mixed physical and chemical adsorption mechanism is proposed.