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AbstractLocalized corrosion in steel heat exchangers is a major concern, occurring mostly during operational shutdowns. Due to the absence of flow and moisture content availability, corrosion reduces operation efficiency. A study aimed to optimize the proportions of Zinc and Chromium (Zn-Cr) for developing a hybrid multi-layer electroplating method to inhibit corrosion in hypo-eutectoid carbon steel commonly used in heat exchangers. The Zn-Cr coating was performed using the amperometric method in an electrochemical workstation, producing coatings of varying thicknesses by varying the potential and time. The surface morphology was characterized using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analysis. The average thickness of the Zn-Cr coating was found to be 2.5 µm using the scanning probe microscope analysis. The corrosive action of a standard 3.5% NaCl solution was investigated on both coated and uncoated specimens through open circuit potential measurement and electrochemical impedance spectroscopy. The results indicated that the Zn-Cr coating effectively resisted corrosion. Contact angle measurement of water particles with the Zn-Cr coated specimen revealed a near-super hydrophobic nature with the highest contact angle of 146.8°. [ABSTRACT FROM AUTHOR]

The use of simulated solutions is a common practice in corrosion studies to assess easily and quickly the corrosion behaviour of materials in real situations. In this context, it is frequent to substitute tests performed in concrete or mortar with tests performed in porous‐like solutions. Particularly, to simulate carbonated concrete, different carbonated porous‐like solutions (CPS) are found in the literature. However, it is not known whether the use of these solutions accurately predicts the behaviour of steel bars embedded in carbonated concrete. In the present work, a comparison between the corrosion behaviour of carbon steel in carbonated mortar and in different CPS was performed. It was found that none of the CPS studied in the present work adequately simulate the corrosion behaviour of the steel in carbonated mortar, but the CPS containing high concentrations of carbonates/bicarbonates is the only one that provides corrosion rates close to those obtained in carbonated concrete. [ABSTRACT FROM AUTHOR]

In this work, a series of durability requirements are proposed for the construction of long-service-life reinforced concrete (RC) structures in a coastal environment with extreme atmospheric corrosivity. RC specimens were exposed in a coastal outdoor site in Cuba for three years. Carbon steel corrosion evaluation revealed an annual average atmospheric corrosion rate over the maximum limit established (ISO 9223:2012) for extreme (CX) atmospheric corrosivity. The service life of the RC structures, considered as the sum of the time-to-corrosion-initiation and time-to-corrosion-induced concrete cracking, was determined as a function of durability requirements. The most important durability requirements to achieve a long service life (>70 years) in RC structures subjected to a CX corrosivity category were defined as follows: water/cement ratio, compressive strength, percentage of effective capillary porosity, and concrete cover thickness. Under these hostile environments, the expansion of the corrosion products formed on the reinforcement steel and the induced cracking of the concrete could be attributed partially to the formation of the akaganeite phase in reinforcement steel, which revealed a different morphology compared to the akaganeite typically formed in bare carbon steels. [ABSTRACT FROM AUTHOR]

Urgent action is required to mitigate the severe corrosion of carbon steel in low-latitude regions. The combination of high humidity, temperature, and salinity in these areas significantly accelerates steel corrosion, posing a substantial threat to the service safety of offshore engineering equipment. This study aims to elucidate the atmospheric corrosion mechanisms of 45# steel in low-latitude coastal areas. Samples of 45# steel were exposed to atmospheric conditions over various durations in the following three geographically distinct regions: Guangzhou, Wanning, and the South China Sea. The corrosion rates were calculated using weight loss tracking and potentiodynamic polarization measurements, while surface corrosion products were examined using X-ray diffraction (XRD) tests. The findings indicate a clear correlation between the corrosion rate of 45# steel and the latitude and specific location of the test area, with the highest to lowest rates observed in the South China Sea, Wanning, and Guangzhou, respectively. Similarly, the extent of corrosion rust penetration in defective coatings followed the same order. Moreover, the protection ability index (PAI) calculations revealed that none of the tested samples formed a protective corrosion film. [ABSTRACT FROM AUTHOR]

The stem extract of Solanum Lycopersicum prepared using the methanol extraction method has been investigated as an environment-friendly inhibitor for low-carbon steel in monoprotic(1N HCl) and diprotic(1N H2SO4) solvents and characterized with FT-IR. A maximal inhibition efficiency of 81.8% in 1 N Hydrochloric acid and 92.92% in 1 N Sulfuric acid is assessed under a certain set of conditions of inhibitor concentration and temperature using weight loss, electrochemical impedance spectroscopy and potentiodynamic polarization. The results present Solanum Lycopersicum extract as a mixed-type inhibitor that predominantly influences the cathodic reaction and followed the Langmuir adsorption isotherm. Reduction in the value of average roughness (Ra)of the surface from 217 nm to 55 nm (in 1 N HCl) and 139.6 nm to 28 nm (in 1 N H2SO4) was observed with AFM after the application of the inhibitor which confirms the formation of a protective membrane and provides green inhibition on the low-carbon steel/solution interface. [ABSTRACT FROM AUTHOR]

The corrosion behavior of 1018 carbon steel in LiCl/H2O mixtures has been evaluated by using potentiodynamic polarization curves, electrochemical noise and electrochemical impedance spectroscopy techniques. Two different concentrations of LiCl were employed, namely 35 and 40 wt. %, and the testing temperatures included 25, 35 and 70 °C. It was found that the steel showed a passive zone; the corrosion current density value increased with an increase in the solution temperature and concentration. The pitting potential value decreased with an increase in the testing temperature and the solution concentration. The corrosion process was under charge transfer control. This mechanism was unaltered either by the solution temperature or concentration. The charge transfer resistance value decreased with an increase in both the solution temperature and concentration. A localized, pitting type of corrosion dominated the corrosion morphology at 25 and 35 °C, whereas at 70 °C, the main type of attack was a mixed type of corrosion. [ABSTRACT FROM AUTHOR]

Fish skin, a major component of fish waste, has been utilized in this study for the facile synthesis of phosphorus‐doped carbon dots (PCDs). The study aimed to synthesize and investigate the potential application of PCDs as an effective material against corrosion when reinforced in different epoxy polymers. The UV‐visible and fluorescence spectroscopic characterization of PCD from fish skin confirmed the presence of multifluorophores and P doping, while transmission electron micrograph images revealed that the synthesized PCD had a diameter ranging from 6 to 8 nm. Fourier transform infrared spectrometer analysis showed the presence of a carbon skeleton with conjugated carbon double bonds, amines, ‐OH groups, aromatic rings, and phosphate groups. PCD reinforcement in three epoxy polymers and their coating over BIS 2062 carbon steel showed that PCD and epoxy polymers synergistically acted to improve the corrosion resistance of the coatings. An optimum concentration range of 0.01%–0.02% PCD was found to provide maximum corrosion resistance. PCD reinforcement has a potential impact on surface morphologies and electrochemical characteristics of epoxy coatings. [ABSTRACT FROM AUTHOR]

Cathodic protection is an electrochemical technique used to control the corrosion of metals. It does this by sending a proper amount of current equal to the current required by the cathodic processes at the protection potential. One of the chemical effects of cathodic protection is a local pH increase at the surface, which is an important factor in the reduction of corrosion rate, as carbon steel may work in a passive condition. In the present study, a tertiary current distribution finite element method model is introduced. A dynamic boundary condition is considered, by defining a Fe anodic Tafel slope as a pH function, and oxygen reduction reaction limiting current density as a function of available oxygen at the cathode surface. The model has been validated by direct pH measurement during a short‐term polarization test, and subsequently used to predict the pH and the available oxygen at the cathode surface for long‐term condition. [ABSTRACT FROM AUTHOR]

In Northern Chile, large amounts of highly corrosive solutions are currently generated in the process of cathode washing after completing the electrowinning or electrorefining process of copper. This study investigates the electrochemical behavior of ASTM A36 carbon steel in pregnant-leach-solution (PLS) wash water. Measurements of electrochemical impedance spectroscopy and linear sweep voltammetry, complemented with weight loss measurements, were performed. Four ratios of PLS containing reverse osmosis (RO) water are evaluated, considering both quiescent and rotating conditions of the steel specimen. The results indicate that oxygen reduction, hydrogen evolution, and iron oxidation reactions are all involved during the corrosion of carbon steel in pure RO water, with the corrosion rate increasing up to 4 times under rotating conditions. In the case of corrosion in RO wash water containing PLS, a galvanic process occurs whereby copper is reduced at the expense of iron oxidation, superimposed on former partial reactions. The deposited copper induces notable corrosion inhibition of steel, observed as a significant drop in corrosion rate from high initial to constant residual values. Morphological and X-ray analyses support that corrosion is affected by oxide layer formation and galvanic copper deposition, confirming the results obtained from electrochemical analysis and weight loss measurements. [ABSTRACT FROM AUTHOR]

Co3O4 nanoparticles (Co3O4-NPs) are synthesized using the facile solvothermal method. FT-IR and XRD spectroscopic analyses verify the creation of cobalt oxide nanoparticles with an average size of 13.20 nm. Furthermore, Zeta potential assessments were carried out to identify the electrical charge of the surface of the produced Co3O4-NPs, which was found to be -20.5 mV. In addition, the average pore size of Co3O4-NPs is 19.8 nm, and their BET surface area is 92.4 m/g. The study also concerned the effect of Co3O4-NPs on epoxy's improvement of mechanical and corrosion protection for carbon steel in salt solution. By including Co3O4-NPs in an epoxy (EP) coating, corrosion is effectively prevented by non-permeable protective coatings that effectively reduce the transfer of corrosion ions and oxygen. [ABSTRACT FROM AUTHOR]

The package of the applied programs with base of the thermodynamic data is used and the theoretical analysis of physical and chemical conditions of complex- saturation carbon steel by silicon and chrome in medium of chlorine in the closed reactionary space is carried out at the lowered pressure of a gas phase. Simultaneous saturation of steel 40 with chrome and silicon in chlorine atmosphere for 6 hours at a temperature of 1323 K and a pressure of 102 Pa of the gas phase is carried out in this work. By means of the x-ray diffraction studies, it is found that, under the assumed conditions of saturation on the steel 40 surface, diffusion layer with thickness of 100-110 µm is formed, which corresponds to the phase of the corresponding chromium carbides Cr23C6 and Cr7C3 doped with silicon, and a solid solution of chromium and silicon in α-iron. The corrosion studies carried out in this work show that chromosilicide coatings applied onto carbon steel 40 are less stable in solutions of 10% hydrochloric and sulphuric acids, and the most stable in solutions of nitric acid. [ABSTRACT FROM AUTHOR]

The global impact of metal corrosion is significant, as it poses both economic and environmental repercussions. The corrosion refers to the process by which metals undergo surface degradation due to an electrochemical reaction with the surrounding intrusive environment, leading to its initiation and acceleration. Corrosion inhibitors are widely recognized as the most effective and cost-efficient method for preventing corrosion. The utilization of conventional and harmful corrosion inhibitors has led to environmental concerns, prompting the creation of eco-friendly, readily available, biodegradable, and economically efficient green substitutes. This review examines the utilization of green corrosion inhibitors sourced exclusively from renewable origins, focusing specifically on recent progress in employing extracts from fruits, vegetables, and rice peels as green corrosion inhibitors. Fruits and vegetables, specifically, contain abundant phytochemicals with corrosion-inhibiting properties. The experimental methodologies employed in corrosion inhibition, along with the underlying mechanism of corrosion inhibition, are extensively examined to elucidate the actual capabilities of these extracts in safeguarding steel in acidic surroundings. The study emphasizes the capacity of fruit and vegetable extracts to serve as environmentally friendly and economical substances that can prevent corrosion, thus contributing to the advancement of green chemistry. This review focuses on the most important inhibitors removed from the peels of fruits, vegetables, and rice, where an efficiency of 98.8% was achieved. [ABSTRACT FROM AUTHOR]

Japanese tap water is Ca2+-poor and SiO2-rich in comparison with that of other counties. Thus, there have been few studies on its corrosivity. We sampled tap waters at 70 different sites and in different seasons in Japan, subjected the samples to chemical analysis and measured localized corrosion depth and the total corrosion loss of carbon steel placed in these waters. The average corrosion rate vavg and maximum localized corrosion rate vmax were calculated. The ratio of vmax to vavg, which was defined as localized corrosion factor LCF (=vmax/vavg), was also studied. The multiple regression method was applied to obtain the dependence of vavg (objective variable) on concentrations of chemical species (explanatory variables). In the same manner, the relation of vmax and LCF to concentrations of chemical species was derived. As a result, we showed that SiO2 and SO42− mainly dominate the corrosivity of Japanese tap water. In particular, as SO42− increased, vavg became larger and vmax became smaller. Also, as SiO2 increased, vmax became larger and vavg became smaller. The behavior of LCF was similar to that of vmax. The findings of this study will be useful for estimating the corrosivity of tap waters that have low Ca2+ and high SiO2 concentrations. [ABSTRACT FROM AUTHOR]

The durability of reinforced concrete structures exposed to aggressive environments is affected by corrosion of carbon steel reinforcement. For this reason, it is of great practical interest to look for alternative solutions guaranteeing durability through the incorporation of corrosion‐resistant materials, such as stainless steel rebars. This type of steel is specially recommended for structures with a long lifespan, located in aggressive environments, with chlorides or de‐icing salts, and for structures where repair, inspection and rehabilitation is complicated. This solution presents a challenge from the point of view of the materials themselves, the mechanical design and their durability. This article presents the material properties of stainless steel and their influence on concrete structures. Furthermore, it is explained how these properties have been taken into account in the latest draft of the second‐generation Eurocode 2. [ABSTRACT FROM AUTHOR]

In this work, magnetic responses from artificial corrosion defects were investigated using a differential fluxgate probe. Different rates of corrosion defects were prepared based on the electrolytic corrosion process on the surface of a carbon steel plate by manipulating the corrosion period. Then, the differential fluxgate probe, consisting of two miniature fluxgates arranged in a planar configuration and a circular excitation coil, was used to measure the real and imaginary components of magnetic responses from the corrosion defects in the range of 5 to 510 Hz. The real differential magnetic response from the probe showed that the magnetic signal change was proportionally increased with the corrosion period, revealing the increased depth of the corroded region with the electrolytic corrosion period. The magnetic response induced by an excitation field from 10 to 110 Hz could be utilized to enable a sensitive depth estimation of a corrosion defect on high-permeability steel at a sub-millimeter resolution. [ABSTRACT FROM AUTHOR]

The effect of the benzimidazole-2-ylcarbamate methyl (Carbendazim) in corrosion inhibition for carbon steel has been studied using stationary and transient electrochemical techniques. The potentiodynamic curves show that Carbendazim acts as a mixed-type inhibitor. The electrochemical impedance diagrams show a capacitive response of carbon steel with and without inhibitors at different concentrations in 1M HCl. The polarization resistance increases with increasing inhibitor concentration. Consequently, the inhibition efficiency increases and reaches 84% at 10-2M and its adsorption follows the Langmuir isotherm. This shows that the protective effect of Carbendazim is significant in an acidic medium. The study of the synergistic effect with KI shows that an equimolar mixture of KI and Carbendazim compound enhances the inhibition efficiency. The theoretical investigation of the tested compound ability to inhibit corrosion using DFT shows that the HOMO, LUMO, and electrostatic potential maps surfaces can qualitatively identify the most nucleophilic and electrophilic centers, this will enable us to give an adsorption mechanism for the inhibitor studied on the metal surface. [ABSTRACT FROM AUTHOR]

The ethanolic extract of Lentinula Edodes, a fungal species, was evaluated as an ecological, green inhibitor to mitigate corrosion of carbon steel (CS) in acidic media. The Lentinula Edodes body fruit extract (LEBFE) was obtained using a well-established chemical method. Various electrochemical methods were employed to investigate the LEBFE's corrosion inhibition efficiency under different operating conditions. The results showed that LEBFE is an effective mixed-type corrosion inhibitor, with a maximum corrosion protection efficiency 88.5 ± 0.2%. The inhibitor demonstrated efficient corrosion inhibition of the carbon steel surface over extended immersion periods and at various electrolyte temperatures. The FTIR and UV/Vis results indicated that the LEBFE extract contains compounds containing oxygen and nitrogen heteroatoms, which are known to interact strongly with carbon steel. The adsorption mechanism of the inhibitor on the carbon steel surface was based on physisorption, following the Langmuir isotherm. The results support the conclusion that LEFBE can be considered an effective and eco-friendly green inhibitor to control low-carbon steel corrosion in acid media. [ABSTRACT FROM AUTHOR]

In this study, experiments were carried out to assess the microbially influenced corrosion (MIC) risk in the context of the French high‐level radioactive waste disposal. The exposures were carried out at 80°C in different repository relevant conditions, including the presence of different cement‐grout mixtures as filling material. Biotic conditions with nutrient and nonsterile conditions with indigenous microbes added from Callovo Oxfordian clayey rock and without nutrients were considered. For biotic conditions, specific preparations of microbial inoculum were carried out from samples collected at Andra's Underground Research Laboratory and microorganisms from microbial culture collection centers. Corrosion kinetics were determined using traditional coupons and completed with real‐time corrosion sensors. Microbiological characterizations consisted of cultural approach, quantitative polymerase chain reaction, and next‐generation sequencing. The obtained results show no significant MIC and a reduced risk with the use of more alkaline filling material. [ABSTRACT FROM AUTHOR]

The long‐term disposal of nuclear waste in deep geological repositories requires safe containment for up to one million years. To understand how the waste will respond to the gradually evolving environment, researchers can perform sensitive experiments in the laboratory to replicate the repository conditions at specific time points. In Belgium, spent nuclear fuel will be housed within a carbon steel overpack, which is encased within a cement buffer, which may include a stainless steel liner (the "envelope"). The range of corrosion behaviors for carbon steel, and to a lesser extent, stainless steel, has been studied through hydrogen evolution, an end‐product of oxidation under repository conditions. Considerable time may be required for metallic surfaces to approach a steady hydrogen evolution and this is dependent upon the starting condition of the specimen surfaces. The use of nominally‐similar materials can result in significant variation in the reported corrosion rates. The presence of cements, which generate their own hydrogen and influence water chemistry as a function of time, add complexity to even simple experimental configurations that requires careful interpretation. [ABSTRACT FROM AUTHOR]

In this paper, carbon steel corrosion rates from experiments performed in situ (performed in an underground rock laboratory) and ex situ (performed in a conventional laboratory) test methods in anaerobic saturated bentonite are compared. The results indicate that the long‐term corrosion rate follows a power law decay curve, with a higher initial rate and greater rate of decay at higher temperature. In compacted bentonite blocks, varying the density has no significant effect on the corrosion rate measured during in situ testing, whereas granular bentonite of an equal dry density leads to a higher corrosion rate. Precorrosion of test specimens in an aerated solution at room temperature has a negligible effect on the subsequent anaerobic corrosion rate when tested ex situ for durations up to 11.8 years. The main difference between in situ and ex situ tests is the formation of silicon‐rich corrosion products in the ex situ tests but not in the in situ tests. Despite these differences, the corrosion rates in both tests exhibit the same general temporal evolution and similar magnitudes, suggesting that the main steel degradation processes are maintained in both configurations. [ABSTRACT FROM AUTHOR]

In this study, short‐term experiments were carried out to assess the microbially influenced corrosion (MIC) risk in the context of the French high‐level radioactive waste disposal CIGEO (Centre Industriel de Stockage Géologique). The exposures were carried out in different representative media, including the presence of different cement‐grout mixtures as filling material. Nonsterile and biotic conditions with nutrients were considered. For biotic conditions, specific preparations of microbial inoculum were carried out from samples collected at ANDRA's Underground Research Laboratory and microorganisms from the library. Corrosion kinetics were determined using both traditional coupons and completed with real‐time electrical resistance sensors. Microbiological characterizations consisted of cultural approach, quantitative polymerase chain reaction, and next‐generation sequencing. The obtained results show no significant MIC, but a reduced risk was observed using more alkaline filling materials. [ABSTRACT FROM AUTHOR]

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This study provides two case studies involving carbon steel and 3%-Cr steel exposed to a CO2–H2S environment with a moderate scaling index. The carbon steel tubing show shows pitting and severe corrosion, whereas the 3% chromium steel tubes are undamaged. XRD results showed that the chromium-rich layer did not alter scaling on both tubes. Investigations using SEM and EDS reveal the formation of a dense and compact layer in the 3%-Cr steel, which serves to resist corrosion. In contrast, carbon steel has a porous structure and is easily detachable due to wall shear stress caused by slug movement. In 3%-Cr steel, the EDS analysis reveals a compact layer with a significant number of chromium, which is an indication of a Cr-rich iron oxide layer. Potentiodynamic polarization shows that the anodic curve is shifting, which means that the rate of corrosion is slowing down. This study shows that 3% Cr steel is a good choice for a mixed CO2–H2S environment with a high total dissolved solid (TDS). [ABSTRACT FROM AUTHOR]

Using gravimetric and electrochemical research methods, the corrosion-electrochemical behavior of carbon steel grade St3 in Kura river water has been. Gravimetric measurements were carried out under operating conditions of the Shemkir and Yenikend hydroelectric power stations for one year. Along with this, the ionic and bacteriological composition, as well as some physicochemical parameters of these waters were established. It revealed that St3 in the Kura water corrodes at a rate of (0.04÷0.05) g/m2•hour, which is characteristic of steel corrosion in fresh waters. In the atmosphere of hydraulic structures, steel corrodes at rather a low rate, i.e. (5÷6)10-3 g/m² hour. As a result of biochemical analysis, sulfate-reducing bacteria (SRB) were discovered in these waters, which are a dangerous organism that releases the corrosive substance of H2S. By taking the anodic and cathodic polarization curves, a quasi-stationary steel corrosion rate was established to be 0.06g/m² h [ABSTRACT FROM AUTHOR]

A novel alanine ternary complex (ALA-T) is prepared by the reaction of alanine (ALA), phosphoric acid, and dibutylamine. FTIR technique is used to characterise its structure. The weight-loss experiments in the closed space study the volatility of the alanine ternary complex. The ultrathin coating is formed on the surface of carbon steel by vapour phase assembly of the alanine ternary complex. The thickness of the coatings is measured using spectroscopic ellipsometry. The inhibition effect of ultrathin coatings on the corrosion of carbon steel is studied by the volatile-inhibiting ability (VIA) and the electrochemical tests. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are utilised to examine the morphology and composition of the carbon steel surface. It shows that the complex ultrathin coating has good corrosion inhibition for carbon steel. The protection mechanism of the ultrathin coating is discussed and analysed. [ABSTRACT FROM AUTHOR]

Carbon steel suffers from serious corrosion in NaCl solution, the development of effective inhibitor has become a hot issue. The corrosion inhibition performance of sodium lauryl ether sulfate (AES) and lauryl betaine (BS‐12) and the mixture of the two inhibitors were studied using electrochemical and weight‐loss methods. Results showed the corrosion inhibition efficiency order is AES + BS‐12 > BS‐12 > AES, the inhibition efficiency of the inhibitor increases with the increasing of concentration and the maximum inhibition efficiency is 95.9% in the solution with 200 mg L−1 AES + BS‐12. Inhibitor can adsorb on Q235 surface through physical and chemical interactions and the adsorption obeys Langmuir isotherm. The migration of the corrosive ions to the metal is hindered and the metal is protected. [ABSTRACT FROM AUTHOR]

This study investigated chloride binding and corrosion of carbon steel in calcium sulfoaluminate (CSA) cement concrete exposed to external chloride solutions. CSA pastes and concrete specimens were prepared using three water-to-cement ratios (w/c) (0.4, 0.5, and 0.6) followed by wet and air curing for 55 days. Ordinary portland cement (OPC) paste and concrete specimens also were prepared and analyzed for comparison. The primary hydration product of CSA was ettringite, and its quantity increased with the increase in w/c. Compared with OPC, the CSA pastes had a significantly lower chloride binding capacity and higher porosity, exhibiting poor performance in protecting the steel embedded in the concrete. In general, considering the compressive strength, chloride binding, and corrosion, air-cured CSA concrete performed worse than wet-cured CSA concrete. [ABSTRACT FROM AUTHOR]

α-aminophosphonate (α-AP) is used as a novel corrosion inhibitor for carbon steel. The aggressive media applied in this study are HCl and H2SO4 acid solutions. The findings indicate that the morphology of the α-AP compound is cubic, with particles ranging in size from 17 to 23 μm. FT-IR, 1HNMR, 31PNMR, and 13CNMR analysis confirmed the synthesis of the α-AP molecule. It has been discovered that the compound α-AP plays an important role in inhibiting the corrosion of carbon steel in both HCl and H2SO4 acids. This was identifiably inferred from the fact that the addition of α-AP compound decreased the corrosion rate. It is important to report that the maximum inhibition efficiency (92.4% for HCl and 95.7% for H2SO4) was obtained at 180 ppm. The primary factor affecting the rate at which steel specimens corrode in acidic electrolytes is the tendency of α-AP compounds to adsorb on the surface of steel through their heteroatoms (O, N, and P). This was verified by SEM/EDX results. The adsorption actually occurs through physical and chemical mechanisms via different active centers which are matched with the calculated quantum parameters. In addition, the adsorption of α-AP follows the Langmuir isotherm. [ABSTRACT FROM AUTHOR]

This study explored the effectiveness of tobacco extract as a corrosion inhibitor for carbon steel in an H2S-containing NaCl solution. The experiments were conducted at room temperature and atmospheric pressure, with a variation in inhibitor concentration and rate of fluid flow. Results showed that the tobacco extract decreases the corrosion rate of carbon steel in the 3.5% NaCl solution. Increasing flow rate and inhibitor concentration significantly affect the corrosion rate of carbon steel. In the NaCl solution, crystalline corrosion product formation of magnetite (Fe3O4) was mainly detected. Furthermore, the presence of H2S leads to forming of a mackinawite (FeS) structure. The inhibition efficiency of 1000 and 2000 ppm tobacco extract in NaCl solution with the presence of H2S is in the range of 24 to 69%. [ABSTRACT FROM AUTHOR]

Acid mine drainage (AMD), resulting from mining activities, poses a significant environmental concern. It adversely affects metallic materials, particularly carbon steel composites used in mining machinery and structures. Highly acidic and oxidizing compounds like sulfuric acid and ferric ions cause corrosion, iron oxide formation, and hydrogen gas release, which degrade carbon steel. AMD also alters the solvent's properties, dissolving heavy metals and contaminants, and intensifying the environmental impact of mining. A 30-week experiment immersed metal plates in AMD to study its effects. Weekly observations of the plates and solvent were made. The plate measurements and physicochemical data were analyzed using graphical–statistical analysis and fuzzy logic techniques to assess the data quality and identify errors. The results reveal consistent findings with prior studies, such as material degradation with weight loss and alterations in acid drainage media, including increased pH and total dissolved solids (TDS). These changes in the solvent characteristics stem from the dissolution of metal ions from corroded surfaces, reacting with the acid solution. Overall, this study discusses the effects of AMD (acid mine drainage) on metallic materials and emphasizes the significance of monitoring and reducing the environmental consequences of mining activities. [ABSTRACT FROM AUTHOR]

A novel PVDF-SiO2-Silane-based superhydrophobic (SHP) coating was fabricated on carbon steel samples with enhanced corrosion resistance and self-cleaning properties. The coating was fabricated by incorporating hydrophobic SiO2 nanoparticles into the PVDF matrix first and then coating with a silane based low surface energy material. Perfluoro octyl triethoxy silane (PFOTES) and hexadecyl trimethoxy silane (HDTMS) were the low surface energy materials used. Field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), energy dispersive x-ray spectroscopy (EDS), attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy and x ray photoelectron spectroscopy (XPS) characterization of the coatings revealed the formation of micro-nano hierarchical structures and also the presence of Si, O, F, and C in the coating. SHP carbon steel samples showed water contact angles (WCA) > 170° and sliding angle ~ 0°. The SHP property was unaffected after immersion in water and showed good chemical repellence to acidic and basic solutions. The prepared SHP samples showed excellent self-cleaning property. Electrochemical impedance spectroscopy (EIS) studies showed that the charge transfer resistance (Rct) of SHP samples was almost 10 times more than that of bare samples in aggressive chloride conditions. [ABSTRACT FROM AUTHOR]

Q235 carbon steel is a commonly used engineering material, but its application in marine environments is limited by its susceptibility to corrosion, especially localized corrosion that can lead to material perforation. Effective inhibitors are crucial to addressing this issue, particularly in acidic environments where localized areas become increasingly acidic. This study reports the synthesis of a new imidazole derivative corrosion inhibitor and evaluates its effectiveness in corrosion inhibition performance using potentiodynamic polarization curve and electrochemical impedance spectroscopy techniques. High-resolution optical microscopy and scanning electron microscopy were employed for surface morphology analysis. Fourier-transform infrared spectroscopy was used to explore the protection mechanisms. The results demonstrate that the self-synthesized imidazole derivative corrosion inhibitor offers an excellent corrosion protection performance for Q235 carbon steel in a 3.5 wt. % NaCl acidic solution. This inhibitor can provide a new strategy for carbon steel corrosion protection. [ABSTRACT FROM AUTHOR]

In water resource allocation engineering, the flow velocity is the most important factor influencing corrosion damage in the elbow sections of steel pipes. This study reports the effect of flow velocity on the corrosion performance of carbon steel at different pipe elbow section locations though which freshwater flows. The corrosion damage of carbon steel was accelerated in flowing freshwater; however, this accelerating effect was weakened with high flow velocity. Furthermore, the corrosion rate at the outer wall was higher than that of the inner wall of the pipe elbow section with low flow velocity; when high flow velocity was used, more uniform corrosion damage was found at the pipe elbow section. The influence of flow velocity on the corrosion performance of the carbon steel was closely related to the hydrodynamic parameter distribution and the nonuniform accumulation of corrosion products at different locations of the pipe elbow section in flowing freshwater. [ABSTRACT FROM AUTHOR]

Corrosion of metals is considered a global dilemma that is attracting an increasing number of researchers in the scientific community. One of the fundamental solutions against corrosion is using corrosion inhibitors. Corrosion inhibitors are the substances added to the medium or the metal to inhibit corrosion through different mechanisms, most commonly by the formation of a protective layer on the metal surface. Organic corrosion inhibitors constitute most of the known and used corrosion inhibitors, however, due to the toxicity and cost of synthesis, green replacements are needed. Green nanomaterials corrosion inhibitors provide a green and sustainable solution for corrosion. The low toxicity, availability, and cost-effectiveness of green nanoparticles made them a growing research field. This review article highlights the synthesis, use, and application of green nanomaterials in corrosion inhibition. Moreover, the article provides insight into the different types of green nanomaterials inhibitors and their common characterization techniques. [ABSTRACT FROM AUTHOR]

The current laboratory experiments investigated the corrosion resistance of carbon steel in artificial seawater (ASW) using the steel coupons hanging on a closed glass reactor of ASW with volume-to-specimen area ratios ranging from 0.20 to 0.40 mL/mm2. These coupons were immersed in ASW for varying time durations (7 and 14 d) at room temperature without agitation. Further, the corrosion rates based on the weight loss and electrochemical analytical method were determined. Following exposure to carbon steel for 7 and 14 d, corrosion rates were 0.2780 mmpy and 0.3092 mmpy, respectively. The surfaces appeared to be not protected by oxides based on this result. The electrochemical impedance spectrometer in potentiostatic/galvanostatic mode, in conjunction with EDX analysis, predicted the evolution of oxygen reduction. The 7th-day immersion sample had a higher oxygen content, and the 14th-day immersion sample had a slightly lower oxygen content. Methods of X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterized the surface morphology and composition of their corrosion product. Corrosion products derived from rust minerals hematite, lepidocrocite and magnetite appeared to cover the carbon steel surface after exposure. This result can get insight into the corrosion behavior of low-carbon steel used in marine environments. [ABSTRACT FROM AUTHOR]

Here, potential metallic bipolar plate (BP) materials were manufactured by laser coating NiCr-based alloys with different Ti additions on low carbon steel substrates. The titanium content within the coating varied between 1.5 and 12.5 wt%. Our present study focussed on electrochemically testing the laser cladded samples in a milder solution. The electrolyte used for all of the electrochemical tests consisted of a 0.1 M Na2SO4 solution (acidulated with H2SO4 at pH = 5) with the addition of 0.1 ppm F−. The corrosion resistance properties of the laser-cladded samples was evaluated using an electrochemical protocol, which consisted of the open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) measurements, and potentiodynamic polarization, followed by potentiostatic polarization under simulated proton exchange membrane fuel cell (PEMFC) anodic and cathodic environments for 6 h each. After the samples were subjected to potentiostatic polarization, the EIS measurements and potentiodynamic polarization were repeated. The microstructure and chemical composition of the laser cladded samples were investigated by scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX) analysis. [ABSTRACT FROM AUTHOR]

Corrosion Resistance Enhancement for low carbon steel is very important to extend its life service, the coating process is one of the methods which can using to achieve this, and it's the most important in surface treatments to improve the properties of metals and alloys surfaces such as corrosion resistance. In this work, low carbon steel was nitrided and coated with nano zinc using gas phase coating technical, to enhance the resistance of corrosion. The process included adding two layers. The first, a nitride layer, was added by precipitating nitrogen (N) gas, and the second, a zinc (Zn) layer, was added by precipitating Zn. The process of precipitating was carried out at different periods (5, 10, and 15 minutes). Scan electron microstructure (SEM), X-ray diffraction (XRD) and corrosion tests were carried out. The SEM and XRD results showed a new microstructure with the emergence of new phases (C3N4, Zn(N3)2, and γN). Also, the results of the corrosion test showed a significant improvement in corrosion resistance through a reduction in the corrosion rate (CR) and corrosion current density (icorr) which reached (1.598x10-3 mmpy) and (1.422x10-7 Amp/cm2) respectively, for coated samples, compared with 1.803×10-1 and 1.604x10-5, respectively, for the base metal. also found an appreciable increase in corrosion protection efficiency (CPE), which reached 99.11%. [ABSTRACT FROM AUTHOR]

The corrosion behavior of carbon steel X36 (CSX36) in solutions of soils collected from different areas linked to the main pipe network of a water distribution system in Jeddah City (Obhour Al Shamaliyah, Ob-Sh; Al Shateie, Sh; Al Safa, Sf; Al Samer, Sa; and Al Jameaah, Ja) at an ambient temperature (23 ± 1 °C) was studied. The corrosion behavior was monitored using various techniques, such as weight loss and electrochemical (open circuit potential [OCP]; electrochemical impedance spectroscopy; and potentiodynamic polarization) measurements. Visual and microscopic examinations of the surface morphology of the studied metals were evaluated and discussed. The corrosion rates in all the studied soil solutions decreased with an increase in the immersion period over 80 weeks. The corrosivity of the studied soils based on weight loss measurements followed the order Sh > Ja > Ob-Sh > Sa > Sf. The value of the OCP gradually shifted to more negative values, indicating a higher tendency to corrode. For the soil solutions studied, the Ecorr shifted to more negative values, indicating that the corrosion process was under cathodic control. The values of icorr and 1/Rp tended to increase as the soil resistivity decreased. Moreover, there was good consistency between the corrosivity order of the studied soil solution obtained from electrochemical impedance spectroscopy and PDP measurements in the following order: Ob-Sh > Sh > Ja > Sa > Sf. A comprehensive assessment of the soil corrosivity based on various soil variables revealed that soil solutions of Ob-Sh and Sh are extremely corrosive, while the rest of the soil solutions are noncorrosive. [ABSTRACT FROM AUTHOR]

Two environmentally friendly inhibitors of imidazolium-based ionic liquids namely 3-benzyl-1-hexadecyl-1H-imidazol-3-ium chloride (IL-H), and 3-(4-chlorobenzyl)-1-hexadecyl-1H-imidazol-3-ium chloride (IL-Cl) were manufactured and their chemical structures were confirmed by spectra tools (FT-IR, and 1H NMR). The utilizing of these two new ionic liquids as green corrosion inhibitors for low carbon steel (LCS) in 1.0 M HCl under altered experimental conditions. Mass loss (ML), potentiodynamic polarization (PP), AC impedance spectroscopy (EIS) and surface morphology are take place in this study. The protection performance found to increase with increasing ionic liquid dose and temperature, reaching 92.9% and 95.1% for IL-H and IL-Cl at 120 ppm, respectively. Based on the PP records, the investigated ionic liquids behave as mixed-type inhibitors, influencing both anodic and cathodic responses. The inhibitory activity from these explored ionic liquids was stimulated by their adsorption on the effective surfaces of the steel surface in accordance with the Langmuir adsorption isotherm. The Density Functional Theory (DFT) method is used to analyze the relationship between quantum chemical calculations and the protection efficiency of ionic liquids. [ABSTRACT FROM AUTHOR]

In this work, the essential oil of black pine (Pinus nigra J. F. Arnold) was used for the first time as a natural, ecological, and sustainable corrosion inhibitor for the acid cleaning of carbon steel. The essential oil was extracted by hydrodistillation using a Clevenger-type apparatus, and the oil was analyzed by gas chromatography–flame–ionization detection (GC–FID) and gas chromatography–mass spectrometry (GC–MS). The most abundant components in the essential oil were α-pinene, germacrene D, (E)-cariophyllene, and β-pinene. The inhibition efficiency was determined by electrochemical methods (electrochemical impedance spectroscopy and potentiodynamic polarization measurements). The results showed that the inhibitory efficiency of the black pine essential oil increases with time, reaching the highest values after 4 h of immersion for all inhibitor concentrations. It was also shown that black pine essential oil is a mixed-type inhibitor. The contact angle measurements confirmed that the black pine essential oil, as a new natural, environmentally safe inhibitor, is able to protect carbon steel from corrosion in a 1 M HCl solution. [ABSTRACT FROM AUTHOR]

Microgalvanic activity of carbon steel API 5L X52 was investigated by scanning vibrating electrode technique (SVET). Two types of corrosion inhibitors were used for the protection of carbon steel. The first one is based on primary amine function with linear carbon chain (inhibitor A). The second one contains primary amine with Ethylene oxide branched chain (inhibitor B). The evolution of microgalvanic activity was studied at different imposed currents ranging up to 200 mA without and in the presence of 20 ppm and 50 ppm of each corrosion inhibitor. In absence of inhibitors, the maps given by SVET analysis showed a uniform microgalvanic activity with imposed currents ranging from 0 to 1 mA and tend towards less cathodic area. For high imposed currents (10mA, 25mA, 50mA, 100mA and 200mA); a clear evolution in the microgalvanic activity is noticed considering the presence of several anodic area. The dissolution of the carbon steel was accelerated and the microgalvanic potential tends to electronegative values. With the corrosion inhibitors, no anodic area was observed for weak currents ranging from 0 to 10mA. The best protection is assured by the inhibitor B due to the improvement of its solubility. Beyond 25 mA, the protection from corrosion decreases but inhibitor B still demonstrates a better efficiency. [ABSTRACT FROM AUTHOR]

The corrosion of carbon steel (CS) is a disastrous threat to artificial engineering in harsh environments, such as underground mines and seawater environments. Herein, we employed facile one-step electrodeposition to prepare a superhydrophobic intertwining structure on a CS surface in an effort to alleviate corrosion. Sophisticated characterization methods suggested that La tetradecanoate formed during the electrodeposition process via an electrochemical reduction reaction. Silicone lubricant acted as the insoluble phase and was infused into the superhydrophobic matrix to yield a biomimetic slippery lubricant-infused surface (LIS) due to the capillary effect from the superhydrophobic intertwining structure to the lubricant phase. Using natural seawater, salt spray and sulfate-reducing bacteria (SRB) suspension as the harsh media, LIS shows excellent corrosion resistance to the underlying metal compared with bare CS and the superhydrophobic surface covering CS because the oil phase acts as a barrier to inhibit the penetration of corrosive species. For the LIS sample after seawater immersion for 20 d, the Icorr was approximately 2 orders of magnitude smaller than that of the bare CS. In addition, after a 5.0 wt% salt spray test for 20 d, the |Z|0.01 Hz of the LIS surface was ca. 3 orders of magnitude larger than that of CS. Furthermore, when immersed in an extremely harsh SRB suspension for 15 d, the |Z|0.01 Hz of LIS was ca. 3 orders of magnitude larger than that of bare CS because LIS can dually prohibit the bioattachment of SRB and avoid the penetration of the highly corrosive metabolite. Thus, the LIS was proven to have prominent anticorrosion properties in harsh corrosive environments. [ABSTRACT FROM AUTHOR]

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[Display omitted] • DAD-GO & DADD-GO were investigated as inhibitors against X60 carbon steel corrosion in simulated oil/gas well acidizing environment. • DAD-GO showed excellent performance with over 84 % %IE and DADD-GO exhibited %IE of just above 78 %. • The GO, and the functionalized GOs (FGOs) were characterized by the FTIR, Raman, TEM and TGA characterization techniques. • The TGA analysis suggested the FGOs to be far more stable than GO, this observation was supported by the results obtained from theoretical calculations. • PDP study suggests the inhibitors to act predominantly as mixed-type inhibitor and the inhibitors adsorption follows the Langmuir adsorption theory. • SEM and AFM micrographs showed a significantly decrease in the protected steel surface roughness as compared to the unprotected steel surface. Experimental weight loss and electrochemical measurements were used at ambient and high temperatures to evaluate the corrosion inhibition efficacies of diaminodecane functionalized graphene oxide (DAD-GO) and diaminododecane functionalized graphene oxide (DADD-GO) against carbon steel corrosion in 15.0 % HCl, mimicking an acidizing environment in an oil/gas well. The GO was made from waste graphite and then grafted with the diaminoalkanes (DAD & DADD). The GO and functionalized GOs were described using FTIR, Raman, TEM, and TGA. Concentration and temperature effects on the inhibitors' performance were also looked into. The inhibition efficiency increased with concentration at room temperature, reaching a maximum of 84 % for DAD-GO and 78 % for DADD-GO at a concentration of 5 ppm for both. At the temperatures studied, the inhibitors performed well at extremely low concentrations; however, as the temperature rises, the inhibitor's performance decreases. According to the PDP measurement, the inhibitors function primarily as mixed-type inhibitors. The Langmuir adsorption theory was found to be followed by the studied compound. AFM, SEM, EDX, and FTIR characterization of the steel surfaces revealed that the functionalized GOs molecules adsorbed on the steel to create a protective layer that insulated the steel from aggressive acid assault after the immersion time (24 h) in the inhibited solutions. DFT calculations were utilized to determine the relative stability of functionalized GOs to GO and to learn more about the inhibitor molecules' interactions with the steel surface. The DFT calculations corroborated the experimental findings. This study is important in tackling two significant environmental concerns: corrosion and waste management because GO is manufactured from waste graphite. [ABSTRACT FROM AUTHOR]

Sulfate reducing bacteria (SRB) can adhere to the internal surface of the pipelines to form a biofilm under which a serious localized corrosion could easily occur. Therefore, the reduction of the adhesion of SRB biofilm and the inhibition of SRB corrosion are highly significant for the safety of oil and gas production. In this work, two types of zinc oxide (ZnO) particles, the unmodified ZnO particles with smaller specific surface area and the modified one with a larger specific surface area, were employed to inactivate SRB in the test solution. The results show that the sterilization rates of modified ZnO particles are much higher than the unmodified ZnO particles. This can be attributed to the fact that the modified ZnO particles with larger specific surface areas result in the generation of more Zn2+ which limits the growth of SRB. As a result, the adhesion of biofilm on the specimen surface and the corrosion under the biofilm are effectively inhibited. [ABSTRACT FROM AUTHOR]

Nanotechnology is a discipline of science and engineering that emphasizes developing, modifying, characterizing, and using nanoscale components in a variety of applications. Owing to their multiple advantages, including adhesion strength, surface hardness, long-term and extra-high-temperature corrosion resistance, improvement of interfacial behavior, etc., nanocoatings are efficiently utilized to minimize the influence of a corrosive environment. Additionally, nanocoatings are often applied in thinner and finer concentrations, allowing for greater versatility in instrumentation and reduced operating and maintenance costs. The exemplary physical coverage of the coated substrate is facilitated by the fine dimensions of nanomaterials and the significant density of their grounded boundaries. For instance, fabricated self-healing eco-sustainable corrosion inhibitors including PAC/CuONPs, PAC/Fe3O4NPs, and PAC/NiONPs, with uniform distributions and particulate sizes of 23, 10, and 43 nm, correspondingly, were effective in producing PAC/MONPs nanocomposites which exhibited IE% of 93.2, 88.1, 96.1, and 98.6% for carbon steel corrosion in 1M HCl at the optimum concentration of 250 ppm. Therefore, in this review, further steps are taken into the exploration of the significant corrosion-mitigation potential and applications of nanomaterial-based corrosion inhibitors and nano-modified coatings, including self-healing nanocoatings, natural source-based nanocoatings, metal/metallic ion-based nanocoatings, and carbon allotrope-based nanocoatings, to generate defensive film and protection against corrosion for several metals and alloys. These have been illuminated through the in-depth discussion on characterization techniques such as scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), etc. After providing a general summary of the various types of nanomaterials and their protective mechanisms in wide corrosive media, we subsequently present a viewpoint on challenges and future directions. [ABSTRACT FROM AUTHOR]

The method is proposed to protect the carbon steel from corrosion by silicate coatings filled with powdered zinc and graphene nanoplates obtained by thermal splitting of graphite. The conditions for steel pre-treatment in an alkaline solution containing citrate ions and a nonionic surfactant, for the production of potassium liquid glass composition with the addition of zinc and graphene powders are selected. It is shown that coatings 70–80 µm thick, cured at room temperature for three days and containing 80–90 wt. % zinc, 7– 12 wt. % silicon dioxide and 0.2 wt. % carbon have the highest adhesion, water resistance and protective ability. The study of steel corrosion in 3.5% NaCl solution using methods of voltammetry and the dependence of open circuit potential on the test duration showed that silicate coatings filled with zinc and graphene provide cathodic polarization of steel and protect it from corrosion better than twice as thick coatings obtained by hot galvanizing. Graphene nanoplates enhance the contact of zinc particles with each other and with steel, promoting its cathodic polarization. Using scanning electron microscopy and X-ray spectral microanalysis, it has been shown that zinc corrosion products fill the pores of the near-surface layer of coatings, enhancing their protective ability. [ABSTRACT FROM AUTHOR]