Corrosion Inhibition Effect Research Articles

Improving the Protection Performance of Waterborne Coatings with a Corrosion Inhibitor Encapsulated in Polyaniline-Modified Halloysite Nanotubes

Organic coatings provide an effective way to improve the corrosion resistance of metals. Traditional organic varnishes, however, either contain highly polluting or toxic components or lack self-healing ability. In this article, we report a feasible method of preparing polyaniline-modified halloysite nanotubes (PANI@HNTs). They were loaded with a corrosion inhibitor, benzotriazole (BTA), and were tested as multifunctional anticorrosion additives for environmentally friendly epoxy waterborne coatings. The PANI@HNTs were formed via the in situ polymerization of aniline in the presence of halloysites. The BTA loading was then carried out and reached up to 14.5 wt.%. The BTA retention ability of the PANI@HNTs was significantly improved in comparison to that of pure HNT. Electrochemical impedance spectroscopy (EIS) tests of the coatings immersed in a 3.5 wt.% NaCl solution showed that the barrier and corrosion inhibition effects were enhanced by two to four orders of magnitude with the incorporation of BTA-loaded PANI@HNTs. The salt spray tests on artificially scratched coatings revealed that the surfaces protected by varnishes doped with the BTA-loaded PANI@HNTs exhibited the lowest degree of corrosion compared to the control samples, illustrating the self-healing potential of the modified coatings.

Progress of research on gallic acid in corrosion inhibition and rust removal protection of metals

PurposeGallic acid is a substance that is widely found in nature. Initially, it was only used as a corrosion inhibitor to retard the rate of corrosion of metals. In recent years, with intensive research by scholars, the modification of coatings containing gallic acid has become a hot topic in the field of metal protection. This study aims to summarize the various preparation methods of gallic acid and its research progress in corrosion inhibitors and coatings, as well as related studies using quantum chemical methods to assess the predicted corrosion inhibition effects and to systematically describe the prospects and current status of gallic acid applications in the field of metal corrosion inhibition and protection.Design/methodology/approachFirst, the various methods of preparation of gallic acid in industry are understood. Second, the corrosion inhibition principles and research progress of gallic acid as a metal corrosion inhibitor are presented. Then, the corrosion inhibition principles and research progress of gallic acid involved in the synthesis and modification of various rust conversion coatings, nano-coatings and organic resin coatings are described. After that, studies related to the evaluation and prediction of gallic acid corrosion inhibition on metals by quantum chemical methods are presented. Finally, new research ideas on gallic acid in the field of corrosion inhibition and protection of metals are summarized.FindingsGallic acid can be used as a corrosion inhibitor or coating in metal protection.Research limitations/implicationsThere is a lack of research on the synergistic improvement of gallic acid and other substances.Practical implicationsThe specific application of gallic acid in the field of metal protection was summarized, and the future research focus was put forward.Originality/valueTo the best of the authors’ knowledge, this paper systematically expounds on the research progress of gallic acid in the field of metal protection for the first time and provides new ideas and directions for future research.

Corrosion inhibition mechanism of vitamins on steel bars in chloride environments: Experimental analysis and quantum chemical calculation

The inhibition potency of thiamine (VB1), nicotinic acid (VB3), pyridoxine (VB6) and ascorbic acid (VC) against the reinforcement corrosion and their adsorption behavior on the surface of steel bars in chloride environments are studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. Based on the density functional theory (DFT), quantum chemical calculation is also performed to further reveal the corrosion inhibition mechanism of vitamins at the electronic level. The results indicate that these four kinds of vitamins are proven to be potentially applied as corrosion inhibitors to effectively reduce the risk of chloride-induced reinforcement corrosion in a simulated concrete pore solution with 0.05 M NaCl, and VB6 shows the best corrosion inhibition effect since the bonding stability between its highest occupied molecular orbital (HOMO) and the 3d-orbital of iron is the strongest among these vitamins. Under the experimental conditions of this study, there is a specific concentration value for each vitamin to achieve the optimum corrosion inhibition efficiency (IE%). At this time, VB1 and VB3 act as anodic corrosion inhibitors, while VB6 and VC act as mixed-type corrosion inhibitors. With the increase of vitamin concentration, IE% shows a fluctuating value, which is ascribed to the further aggravated imbalance between the cathode and the anode when the cathodic reaction is inhibited due to the adsorption of polar groups on the steel surface.

Improvement of carbon dots corrosion inhibition by ionic liquid modification: Experimental and computational investigations

Chemical modification is effective in improving the corrosion inhibition efficiency of carbon dots (CDs) on steel. Here, the imidazolium ionic liquids (IL) modified-CDs (IL-CDs) are synthesized and proved to be mixed-type corrosion inhibitors. The IL increases the pyrrole N content and facilitates the formation of a denser inhibitor film. Molecular simulations confirm that the IL reduces the π-π interaction between CDs, endowing IL-CDs with higher water solubility and better corrosion inhibition effect than CDs. The lower orbital energy gap and larger positive electrostatic potential distribution enable the inhibition efficiency of IL-CDs of 97.11% in 1 M HCl, much superior to CDs (90.80%).

Corrosion of pipelines in urban water systems: Current research status and future trends based on bibliometric analysis

The urban water systems are of vital importance to the society and the infrastructure is increasing largely due to population growth and urbanization. Corrosion is an inevitable problem faced by urban water pipelines, which causes not only the system failure leading to serious economic losses, but also the deterioration of drinking water quality. This paper quantitatively analyzed 3204 publications related to corrosion in urban water systems in the Web of Science (WoS) Core Collection Database since 1997 through bibliometric analysis. The results showed that research interest on corrosion in urban water systems increased exponentially, and the related publications mostly belonged to “Environmental sciences”, “Water resources” and “Environmental engineering” WoS categories. China and the USA have published far more papers than other countries, while Belgium is more influential with the highest citation per publication. Researchers collaborated actively globally, especially Chinese and American authors. The most cited publications showed that researchers mostly focused on the formation and composition of corrosion scales and deposits, and the release of contaminants such as heavy metals from them. The keyword analysis implied continuous research interests in lead leaching from corrosion scales in drinking water systems, and highlighted the hydrogen sulfide emission and the associated concrete biocorrosion in sewers. Future research suggestions were also proposed, including the adsorption and desorption of emerging contaminants from corrosion products in drinking water system, the effect of corrosion inhibitors and biocides dosed in sewers on the wastewater treatment processes and the biocorrosion mechanisms of the pipes in reclaimed water distribution system.

Licorice (Glycyrrhiza glabra) as corrosion inhibitor of carbon steel reinforcing bars in mortar and its synergic effect with nitrite

Nitrites are effective corrosion inhibitors for concrete structures, but their toxicity leads to their total or partial substitution. Licorice and its synergic effect with nitrites are studied both in simulated pore solutions and in mortars with chlorides. EIS and polarization studies show that a 50% licorice + 50% Na2NO2 mix can reduce the corroding surface and the corrosion rate in solution. Moreover, the efficiency of this mix is higher than that of Na2NO2 when it is added to mortars with 0.8% Cl-. The tested inhibitors, in the amount considered (0.2%), do not affect the mechanical properties of the mortars.

Synthesis of phytic acid-modified chitosan and the research of the corrosion inhibition and antibacterial properties

In this study, chitosan (CS) and phytic acid (PA) were employed as raw materials to synthesize a range of chitosan–phytic acid complexes (CP) with different ratios (CS:PA = 12:1, 9:1, 6:1, 3:1, 1:1). The structures and elemental compositions of the compounds were characterized using Fourier-Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDS). The thermal stability of the synthesized materials was analyzed using a Thermogravimetric Analyzer (TG). Electrochemical testing was conducted to explore the corrosion inhibition effect of the modified inhibitors with varying ratios on Q235 steel in 3.5 wt% NaCl solution. Additionally, Scanning Electron Microscopy (SEM) was utilized to investigate the surface morphology of the immersed samples. When the CS:PA ratio was 3:1, CP exhibited an impressive corrosion inhibition efficiency of 94.9 %. Furthermore, the antimicrobial properties of CP were evaluated using the colony plate counting method. At a CS:PA ratio of 1:1, CP demonstrated the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) at 0.1250 % and 0.5000 %, respectively. This research introduces a novel green corrosion inhibitor capable of simultaneously reducing the electrochemical corrosion of Q235 while inhibiting biocorrosion, avoiding the antagonistic effects arising from the simultaneous use of biocides and corrosion inhibitors in the system.

Chitosan-Based Sustainable Coatings for Corrosion Inhibition of Aluminum in Seawater

Metals are widely used in various industrial applications due to their advantageous properties, but they often exhibit signs of degradation over time because of prolonged exposure to environmental conditions. To prevent corrosion, coatings have gained popularity owing to their practicality in maintaining the original shape and dimensions of the object being protected. Nevertheless, traditional coatings may pose significant toxicological and environmental concerns, leading researchers to explore eco-friendly alternatives such as chitosan-based coatings. Chitosan, a biopolymer derived from chitin, is abundant in nature and has been extensively studied for its physicochemical properties, including its potential in the development of new materials. Chitosan-based coatings have shown promise as effective corrosion inhibitors, and this study aims to develop a crosslinked chitosan-based coating from shrimp waste as an alternative to expensive, commercial coatings. Chitosan, and chemically modified polyethylene glycol, polyvinylpyrrolidone, and ammonium paratungstate chitosan coatings of high- and medium molecular weight prepared by the sol-gel technique, were used for the study of corrosion protection of aluminum in 3.5% synthetic seawater. The molecular interactions and structural alterations following cross-linking of chitosan-based coatings was supported by FTIR-ATR. Surface morphology analysis by AFM indicated good coating adsorption on aluminum surfaces. Contact angle measurements showed hydrophilic properties with contact angles >62° and <90°. Physicochemical characterization (molecular weight (kDa), deacetylation (%), humidity (%), and ash (%)) was also carried out. The corrosion inhibition effectiveness was assessed by gravimetric tests after immersion studies, and the results highlighted the MMW-Chi-based coating’s performance.

Expired Antifungal Drugs as Effective Corrosion Inhibitors for Carbon Steel in 1 M HCl Solution: Practical and Theoretical Approaches.

The anticorrosion potency of two expired antifungal drugs, namely, bifonazole (BIF) and terconazole (TER), for X65 carbon steel (X65CS) in a 1.0 M HCl solution was estimated using practical and computational measurements. The results of all methods applied showed that the percentage of anticorrosive efficacy (% AE) increased for expired BIF and TER and reduced at elevated temperatures. The % AE values of expired BIF and TER (375 mg L-1) reached 92.08 and 94.19%, respectively, using polarization methods. The anticorrosion activities of the two expired drugs were interpreted based on their adsorption on the X65CS surface. The adsorption occurred according to the Langmuir isotherm model. The polarization results indicated that the expired drugs BIF and TER were mixed inhibitors. The impedance results showed a single capacitive loop, confirming that the charge transfer process controlled the corrosion of X65CS. Expired BIF and TER served as good pitting inhibitors by shifting the pitting potential to positive values. The thermodynamic functions of activation and adsorption were defined and explained. Density functional theory and Monte Carlo simulations were used to investigate the BIF and TER inhibitors. The theoretical parameters were consistent with the experimental results. The anticorrosion efficiencies determined using the various methods were in complete agreement.

Comparative Eco-toxicological Effect of Corrosion Inhibitors on Aquatic Nitrogen Fixing Bacterium in Fresh and Brackish Water Ecosystem

Aquatic nitrogen-fixing bacteria play a crucial role in maintaining the nitrogen cycle and supporting primary productivity in freshwater and brackish water ecosystems. The activities of oil and gas industries operating within the coastal region of PortHarcourt releases effluents that contain various chemicals including corrosion inhibitors into the aquatic environment which can significantly affect the aquatic organisms including the nitrogen-fixing bacteria. Hence, this study was aimed to determine the comparative eco-toxicological effect of corrosion inhibitors on aquatic nitrogen fixing bacterium (Nitrosomonas sp.) in Fresh and Brackish water ecosystem. Fresh water and brackish water samples were collected from Chokocho stream in Etche Local Government Area and Eagle Island Port Harcourt, all in Rivers State, Nigeria. Standard toxicity procedure was applied on rectangular cut-out crude oil pipeline metal (ME) coated with corrosion inhibitors: Ambercil (AMB) and X-PRO 99 inhibitor (XPRO) immersed in freshwater (FW) prepared at concentrations of 25%, 50%, 75% and 100% for Nitrosomons sp. These inhibitors were tested with Nitrosomonas sp. at 0, 4, 8, 12 and 24hrs separately for each toxicant. The median lethal concentration (LC50) was employed to compare the toxicities of the different toxicants on the test organisms. The result for percentage survival of Nitrosomonas sp decreased when exposed to various concentrations listed above for 24. The LC50 (%) result (noting, that the lower the LC50, the more toxic the toxicant): of Nitrosomonas sp decreased in the following order: FW + ME (85.5) > BW + ME (86.7) > Both FW + AMB & FW + XPRO (86.8) > BW + XPRO (87.9) > BW + ME + XPRO (89.1) > BW + AMB (89.7) > FW + ME + XPRO (94.9). The above results revealed that Nitrosomonas sp decreased in percentage survival with an increase in concentration. The result showed that the effluents of metals coated with corrosion inhibitors (ME + AMB & ME + XPRO) were more toxic to Nitrosomonas sp in brackish water than freshwater while the effluents of XPRO & AMB not coated on metals were more toxic in freshwater than in brackish water. In conclusion, corrosion inhibitors when coated on metals, AMB corrosion inhibitor was more toxic than XPRO corrosion inhibitors in brackish and freshwater. Based on the findings, the use of XPRO corrosion inhibitor should be a best option for coating crude oil pipeline due to its relative low toxicity in upstream sector of the Nigeria petroleum industry.

Adsorption films based on indazole derivatives for application to protect Cu in sulfuric acid: Experimental and theoretical approaches

BackgroundFinding more cost-effective, low-toxicity corrosion inhibitors to reduce copper corrosion in acidic environments is critical. MethodsThe anti-corrosion abilities and mechanisms of 5‑bromo-1H-indazole (5-BIA) and 7‑bromo-1H-indazole (7-BIA) on Cu in 0.5 M H2SO4 environment have been explored by a way of combining both experimental and theoretical approaches. Significant findingsElectrochemical experiments have shown that both 5-BIA and 7-BIA are capable of acting as highly effective corrosion inhibitors for copper, and 5-BIA has a more prominent protective ability than 7-BIA, which has also been proved by weight loss experiments, SEM and AFM. The corrosion inhibition efficiency (ηE) of 1.5 mM 5-BIA and 1.5 mM 7-BIA is as high as 97.1 % and 94.0 %, respectively. The adsorption of 5-BIA and 7-BIA on the metal surfaces conforms to the Langmuir monolayer adsorption model, and both chemosorption and physical adsorption exist. In addition, quantum chemical calculations reveal that 5-BIA has smaller energy gap (ΔE) and hardness (η) values, and larger dipole moment (μ), absolute electronegativity (χ), and chemical softness (σ) values, thus exhibiting better anti-corrosion ability. Molecular dynamics simulations display that both 5-BIA and 7-BIA can be adsorbed on the Cu (111) surface in an approximately parallel approach, which is conducive to achieving 5-BIA and 7-BIA to hinder the process of copper corrosion as much as possible.

Insight into Anti-Corrosion Behavior and Mechanism of 8-Hydroxyquinoline Inhibitor on AZ91D Alloy in Different Concentrations of Sodium Chloride Solution

The inhibition behavior of the promising eco-friendly inhibitor 8-hydroxyquinoline (8HQ) in two concentrations of sodium chloride solution was studied by hydrogen evolution, scanning electron microscope (SEM), three-dimensional morphology, electrochemical testing, and computational calculations. The results indicated that the 8HQ inhibitor showed satisfactory inhibition effect due to its fast, excellent adsorption capacity and self-healing ability. The corrosion inhibition effect is related to the concentration of the inhibitor. There was a competitive adsorption relationship between 8HQ and [Cl−], and the adsorption morphology was obviously affected by the concentration of [Cl−]. At the lower concentration of NaCl solution, the adsorption of 8HQ was more orderly, faster, and the adsorption amount was larger, which led to the formation of a denser protective layer. Density functional theory (DFT) results showed that the most stable adsorption configuration of 8HQ was NO-Top. N and O atoms are the active sites, and there is a strong coupling between them and Mg atoms, which is consistent with the experimental results.

Assessment of corrosion inhibition performance of olive leaf extract mediated chitosan–Ag nanocomposites and influence of KI addition for X60 steel in acid solution

Chitosan–silver (CHT–Ag) nanocomposite (NCP) containing various dosages of chitosan (0.5, 1.0 and 2.0 g) was synthesized in-situ using olive leaf extract (OLE) as reducing and capping agent. The OLE mediated CHT–Ag NCP was characterized using UV–vis spectrometer, attenuated total reflectance-infrared spectroscopy (ATR-IR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM) techniques. The prepared NCP was assessed as corrosion inhibitor for X60 steel in 5% HCl solution using weight loss (WL) and electrochemical (electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and potentiodynamic polarization (PDP)) methods complemented by surface analysis of the corroded carbon steel (CS) without and with the NCPs utilizing scanning electron microscopy (SEM)/EDS, 3D optical profilometer and atomic force microscopy (AFM). The influence of adding KI on the corrosion inhibition performance of NCPs was investigated as well. TEM results indicate that CHT–Ag nanocomposites are polydisperse and spherical in shape with sizes in the range of 3.7–18.1 nm. The crystalline nature of Ag nanoparticles in the nanocomposites was confirmed by XRD and TEM examination. The prepared NCPs function as effective inhibitors for X60 CS corrosion in the acidic environment. Corrosion inhibition effect was observed to increase with rise in the NCPs concentration with the optimum inhibition efficiency (IE) obtained at the maximum dosage of 0.5% studied. The order of corrosion inhibition performance followed the trend CHT2.0 – Ag > CHT1.0 – Ag > CHT0.5 – Ag NCP. Also, IE was found to decrease with rise in temperature. The PDP data indicates that the NCPs alone and in combination with KI, reduced X60 CS corrosion via the mechanism of active site blocking effect. The addition of KI to the NCPs improves IE but not due to synergism. The surface assessment data confirms the establishment of a protective layer due to NCPs adsorption on the X60 CS surface.

Green synthesis of novel bis structure of (Carbamothioyl) oxalamide derivatives as corrosion inhibitors for copper in 3.5% NaCl; experimental and theoretical investigation

Carbamothiol oxalamide derivatives as new compounds are synthesized and named N1, N2-bis (2- ((2-hydroxyethyl) amino) ethanethiol) oxalamide (bis 1), and N1, N2- bis(2-(bis(2-hydroxyethyl) amino) ethanethiol) oxalamide (bis 2). The noteworthy highlights of this method are eco-friendly, excellent yields, economic, catalyst-free, and solvent-free. Their chemical structures are clarified and validated using elemental analysis and spectroscopic techniques such as Fourier-transform infrared spectroscopy (IR), 1H, and 13C- nuclear magnetic resonance. Then, Weight loss (WL), electrochemical impedance spectroscopic (EIS), and potentiodynamic polarization (PDP) techniques are applied to examine the inhibition impact of these new derivatives on copper in 3.5% NaCl. The density functional theory is used to apply theoretical computations. The results of the experiments indicate that these substances are effective corrosion inhibitors, and their inhibition efficiencies rise with concentration. The bis 2 compound having four OH groups, give the highest efficiency compared to bis 1. There was good agreement on the outcomes of the various procedures. Utilizing 0.01 M of bis 2 to examine the surface under the SEM reveals the existence of an adsorbed layer. All organic molecules, including nitrogen, sulfur, and oxygen, block the metal surface as shown by the electronic parameters highest occupied and lowest unoccupied molecular orbital energy, and ΔEg. The results from theoretical calculations and those from experimental measurements correspond well.

Corrosion inhibition effect of benzimidazole and two derivatives on copper in alkaline environments: Experimental and theoretical analyses

Copper (Cu) is an important interconnect metal material in the semiconductor field. While removing excess copper in the chemical mechanical polishing process, it is necessary to add corrosion inhibitors to the slurry to protect copper from excessive corrosion. Numerous studies have shown that the heteroatoms and functional groups of corrosion inhibitors are crucial factors affecting their corrosion inhibition ability. The corrosion inhibition performance of benzimidazole (BI) and its two derivatives, 5-methyl benzimidazole (MBI) and 5-methyl benzotriazole (MBTA), on copper in glycine + N-methylglycine solution at pH 9 was studied, and their structure-activity relationship was revealed. Electrochemical measurements and adsorption isotherm fittings show that the three corrosion inhibitors cover the copper surface mainly through the chemisorption to prevent the anodic reaction of copper. The corrosion inhibition efficiencies of BI, MBI, and MBTA were 97.22 %, 98.00 % and 98.73 % at the concentration of 8 mM, respectively, reaching their maximum values. The contact angle testing reveals that MBI and MBTA containing methyl groups are relatively more hydrophobic. X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and scanning electron microscope (SEM) results confirm that the three corrosion inhibitors were successfully adsorbed on the copper surface and formed a dense passivation film to protect the copper from corrosive solutions. In addition, a multi-module collaboration with density functional theory (DFT) and molecular dynamics (MD), further demonstrates that BI, MBI, and MBTA are all adsorbed on the copper layer in a mixed way, and MBTA has the strongest binding capacity to copper. The introduction of the methyl and N atom increased the adsorption area and attachment sites between the corrosion inhibitor and copper, which coincides with the experimental results.

Electrodeposition of nanotubes for corrosion inhibition: Dual role as superhydrophobic matrix and nanocontainer for storing-releasing corrosion inhibitor

The lotus leaf-inspired superhydrophobicity to prevent metal corrosion has garnered significant interest. The prevailing approach employs micro/nanoscale matrices to trap air and support water, resulting in short-term effectiveness due to air dissolution. Basic zinc carbonate nanotube (BZC NT), created via electrochemical anodization, dually achieves superhydrophobicity and contains 1-dodecanethiol as corrosion inhibitor for zinc. During the immersion under the water phase, the release of 1-dodecanethiol enables a corrosion inhibitor-air cushion, which is remarkably distinguished from the typical single air cushion formed in the superhydrophobic matrix. Using scanning Kelvin probe, the local micro-zone surface potential of Zn increases about 286 mV after being covered by superhydrophobic BZC NT (SHS BZC NT), exhibiting the high decrement of atmospheric corrosion tendency. Through typical electrochemical corrosion tests, the |Z|lf (lf = 0.036 Hz) of SHS BZC NT is about 9.78 × 106 Ω cm2, and the value is ca. 3 orders of magnitude larger than pure Zn (1.46 × 103 Ω⋅cm2). After soaking in a strong alkaline solution (pH = 11) for 24 h, the inhibitive efficiency of SHS BZC NT is 99.99%, demonstrating high corrosion inhibition effect.

Investigation on anodized 5052 aluminum alloy and its corrosion resistance in simulated acid rain

5052 Al alloy commonly used for construction structures was anodized from the mixed acid electrolyte of citric acid and sulfuric acid to further improve the durability of Al alloy construction components. Different anodized aluminum alloys were prepared by changing the concentration of citric acid in the electrolyte. The surface morphology, structure, thickness and corrosion resistance of the anodized aluminum alloys were characterized and analyzed. The results show that adding appropriate amount of citric acid has a certain corrosion inhibition effect, which reduces the corrosion dissolution degree of the anodized aluminum alloy. At the same time, adding appropriate amount of citric acid in the electrolyte is beneficial to increase the thickness of anodized aluminum alloy, resulting in the enhancement of corrosion resistance in simulated acid rain. When the concentration of citric acid in the electrolyte is 70 g/L, the anodized aluminum alloy is uniform with higher thickness and better corrosion resistance in simulated acid rain.

Corrosion inhibition effect of sycamore leaf extract on copper in H2SO4 solution

Utilizing natural plants as a source material for the extraction of corrosion inhibitors aligns with the principles of ecologically sustainable development. This study investigated the corrosion inhibition effects and mechanisms of sycamore leaf extract (SLE) on copper in a 0.5 M sulfuric acid solution. The electrochemical results revealed that sycamore leaf extract showed significant corrosion-inhibiting properties against copper corrosion in a 0.5 M sulfuric acid solution, with greater corrosion to be observed at elevated temperatures. At 298 K, the corrosion current density of copper in 300 mg/L SLE solution is 4.35 μA/cm2, which is two orders of magnitude lower than that in blank solution (123 μA/cm2). The adsorption isotherm demonstrated that the adsorption type between the copper/solution interface at each temperature was comprised of physicochemical interactions. Functional groups and chemical components of SLE and soaked copper samples were characterized using FTIR, UV-Vis, and XPS. The presence of the Cu-N bond on the Cu surface after dipping into the SLE solution indicated that SLE created a shield-like layer that safeguards the copper. Moreover, molecular dynamics (MD) simulation revealed that strong multiple anchor adsorption of SLE molecules because of the existence of N, O atom.

Research on Evaluation of Corrosion Inhibitors for Oxygen Reducing Air Drive Gas Wells

Severe CO2 corrosion and O2 corrosion occurred during the extraction of a certain gas well. Six commonly used corrosion inhibitors for a certain gas well were evaluated through indoor weight loss tests. It was found that the corrosion inhibition effect of No. 1 corrosion inhibitor in CO2 and O2 environments was the best compared to the other five corrosion inhibitors. The corrosion inhibition efficiency can be divided into 96% and 93%, and the dosage is small, which meets the requirements of the target gas well corrosion inhibitor. The corrosion inhibition mechanisms of the six corrosion inhibitors all conform to the adsorption mechanism, and their action mechanisms are all "negative catalytic" effects. Through adsorption, the activation energy of the cathodic and anodic reactions is increased, which hinders the occurrence of corrosion reactions. Among them, corrosion inhibitors 1, 2, 3, and 5 are mixed corrosion inhibitors that mainly inhibit anodic reactions, while corrosion inhibitors 4 and 6 are mixed corrosion inhibitors that mainly inhibit cathodic reactions.

Molecular Dynamic Simulation on the Synergistic Corrosion Inhibition Effect and Mechanism of Quinoline Quaternary Ammonium Salt and L-Methionine

Molecular Dynamic Simulation on the Synergistic Corrosion Inhibition Effect and Mechanism of Quinoline Quaternary Ammonium Salt and L-Methionine