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The present research deals with the production and characterization of geopolymers prepared by mixing metakaolin with sodium silicate, sodium hydroxide solution and different amounts of electric arc furnace dust derived from the production of carbon steel, to be used by the construction industry. Specimens with compositions containing 90, 80, 70, 60 and 50 g of metakaolin and respectively 10, 20, 30, 40 and 50g of electric arc furnace dust powder were prepared. A blank composition containing metakaolin, sodium silicate, sodium hydroxide solution and free from electric arc furnace dust were also prepared for comparison. After production and hardening, all samples were characterized regarding compressive strength and water absorption. Hardened samples with compositions containing 10 and 30g of electric arc furnace dust were then submitted to a release test in order to evaluate the heavy metals elution. It has been observed that the addition of electric arc furnace dust worsens the pastes workability during their production in this way limiting the amount of electric arc furnace dust which may be added to the geopolymeric matrix. However, samples containing 90 g of metakaolin and 10 g of electric arc furnace dust still maintain fair compressive strength (about 27 MPa), low water absorption (about 28 %) and display limited elution of heavy metals. An additional thermal treatment of 1h at 700 °C, performed to induce sintering of the geopolymeric composites and therefore to reduce their porosity, did not lead to materials with improved performances. [ABSTRACT FROM AUTHOR]

Industrial boilers operate in extreme environments and are prone to degradation caused by high temperature oxidation, corrosion, and erosion. Protective coatings provide boiler components with protection to prolong their operation lifetime. Thus, a glass-ceramic coating has been developed using a slurry spray technique on carbon steel AS/NZS 3678 substrates. Microstructure, mechanical characteristics, and high temperature performance of the coating were investigated. The coating composed of chemically inert oxide ceramics dispersed in a glassy silicate binder matrix. The adhesion strength of the coating was 10.79 ± 0.86 MPa. Coating mass loss after abrasion test was 0.013 % of the tested specimen. The coating withstood at least 75 air quenched thermal shock cycles from 800 °C to the room temperature without any visible spallation and cracks. The coating mostly remained undamaged after cyclic oxidation at 800 °C for 10 cycles. However, minor iron oxide formation was observed, specifically, in relatively thin sections of the coating. The oxidation resistance of the boiler steel has been improved with the developed coating. The linear oxidation rate constant of the boiler steel has been statistically reduced from 6.90 × 10−4 mg cm−2 s−1 to 1.95 × 10−4 mg cm−2 s−1 for coated steel (p = 0.007). The developed slurry spray glass-ceramic coating is a potential candidate for boiler environments. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) presents a major challenge for water splitting due to its slow kinetics. In this study, Co-Fe-Gr nanocomposite coatings were developed on carbon steel via electrodeposition using graphene (Gr) at concentrations of 0.02, 0.04, and 0.06 g/L to enhance OER performance. The sample with 0.02 g/L Gr exhibited a unique cauliflower-like morphology with aligned cobalt, as revealed by FE-SEM, leading to an increased electrochemical surface area. This optimal nanocomposite (Co-Fe-Gr (0.02 g/L)) demonstrated a low overpotential of 88 mV at 10 mA cm2, high stability (4.2 mF cm⁻2), and low resistance (R = 7.5 Ω cm⁻2). Additionally, it showed a small Tafel slope of 6.6 mV/dec and maintained stability after 12 h. A turnover frequency (TOF) of 73.6 s⁻1 indicated that graphene doping significantly reduced the adsorption energy of intermediates, greatly enhancing OER activity for efficient water splitting applications. [Display omitted] • Co-Fe-Gr nano-composite electrocatalysts were fabricated using an electrodeposition process. • Increasing the Gr content increased the Gr sheets and reduced the number of active sites. • The Co-Fe-Gr (0.02 g/L) with cauliflower-like morphology had an electrochemically active surface. • The Co-Fe-Gr (0.02 g/L) nano-composite showed the highest electrocatalytic activity. [ABSTRACT FROM AUTHOR]

• This study conducted a life-cycle carbon assessment of the steel industry in China. • Carbon emissions of various phases from the steel industry were compared. • CO 2 emission intensity of crude steel in China reached 2.33 tCO 2 /t. • Optimized power structure and increased scrap ratio showed similar carbon reduction. China is the most important steel producer in the world, and its steel industry is one of the most carbon-intensive industries in China. Consequently, research on carbon emissions from the steel industry is crucial for China to achieve carbon neutrality and meet its sustainable global development goals. We constructed a carbon dioxide (CO 2) emission model for China's iron and steel industry from a life cycle perspective, conducted an empirical analysis based on data from 2019, and calculated the CO 2 emissions of the industry throughout its life cycle. Key emission reduction factors were identified using sensitivity analysis. The results demonstrated that the CO 2 emission intensity of the steel industry was 2.33 ton CO 2 /ton, and the production and manufacturing stages were the main sources of CO 2 emissions, accounting for 89.84% of the total steel life-cycle emissions. Notably, fossil fuel combustion had the highest sensitivity to steel CO 2 emissions, with a sensitivity coefficient of 0.68, reducing the amount of fossil fuel combustion by 20% and carbon emissions by 13.60%. The sensitivities of power structure optimization and scrap consumption were similar, while that of the transportation structure adjustment was the lowest, with a sensitivity coefficient of less than 0.1. Given the current strategic goals of peak carbon and carbon neutrality, it is in the best interest of the Chinese government to actively promote energy-saving and low-carbon technologies, increase the ratio of scrap steel to steelmaking, and build a new power system. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, Co–W and Co–W/Si 3 N 4 coatings were electrodeposited at different temperatures and Si 3 N 4 concentrations, respectively, to investigate the effects of these parameters on the chemical composition, thickness, morphology, structure, and corrosion behavior of the resulting coatings. Increasing the bath temperature from 25 to 65 °C resulted in less defective Co–W coatings with fine nodular morphologies, higher tungsten content (43.1 wt% at 65 °C), and smaller corrosion current density (2 vs. 7.8 μA cm−2). With the addition of 2–25 g L−1 Si 3 N 4 particles to the electrodeposition bath and the co-deposition of up to 8.1 wt% of these particles within the Co–W matrix, the nodular morphology gradually changed to cauliflower and then powdery form, and the tungsten content of the coatings decreased. The decrease in tungsten content resulted in structural changes from amorphous to nanocrystalline. According to the potentiodynamic polarization and EIS results, the Co–W/Si 3 N 4 coatings deposited from baths containing 5 and 10 g L−1 of Si 3 N 4 particles had the best corrosion resistance among the samples. The corrosion current density of Co–W/10 g L−1 Si 3 N 4 coating was 0.7 μA cm−2, which is significantly smaller than that of bare steel substrate (27 μA cm−2). [ABSTRACT FROM AUTHOR]

Valve metals are metals that can undergo surface modification through micro-arc oxidation (MAO). Iron is not considered a valve metal and cannot undergo MAO. Steel is a widely used alloy due to its excellent properties, including high toughness, good workability, and low cost. However, its weak corrosion and abrasion resistance limit its range of application and service life. Al 2 O 3 ceramic coating is formed on the surface of non-valve metal low carbon steel using MAO technology. The surface morphology and composition of the MAO coatings on non-valve metals are investigated through characterization. Tribological experiments show that the coefficient of friction of the samples obtained from the MAO power supply frequency of 1400 Hz is the smallest. After conducting a corrosion resistance test following MAO treatment, the impedance increased by three orders of magnitude and the corrosion rate decreased by one order of magnitude. The use of MAO treatment can expand the use of steel and shows promise for application to other non-valve metals. [ABSTRACT FROM AUTHOR]

To evaluate the possibility of hydrogen storage in depleted gas reservoirs, natural gas storage facilities, aquifers and salt caverns, the applicability of ferritic pearlitic K55 and tempered martensitic L80, both very frequently used as casings and tubings, has been investigated. Materials were investigated by means of high-pressure, high-temperature autoclave tests and analyses of the hydrogen uptake. The autoclave tests were performed on tensile specimens loaded with a spring at 90 % of the specified minimum yield strength, additionally the samples were analysed to determine the hydrogen uptake. Different gas compositions were considered (pure hydrogen, with or without the presence of CO 2 /H 2 S) under a hydrogen partial pressure of 120 bar. The tests were conducted in dry or wet environments. From the results, it can be seen that the hydrogen uptake is low even under the most severe conditions. However, from the mechanical test conducted in this study, it appears that the ferritic pearlitic K55 steel seems to be a suitable pipe material for underground hydrogen storage, and the higher strength steel L80 steel can be used only in non-sour environments (no significant amount of H 2 S in the reservoir, which is a priori the case of underground storages). • Hydrogen uptake from dry pressurized hydrogen up to 120 bar partial pressure is small compared to hydrogen uptake from brine. • Presence of H 2 S in humid environments increases hydrogen uptake substantially but no ruptures occurred. • K55 and L80 are applicable for underground hydrogen storage within the tested conditions. • Constant Load Tests and low cycle fatigue Ripple Load Tests did not result in any failure of K55 and L80 steel. • Normalized K55 takes up slightly more hydrogen than quenched and tempered L80 due to higher corrosion rate. [ABSTRACT FROM AUTHOR]

Green hydrogen is a renewable gas that can help to reach the goal of decarbonizing the energy sector. The use of the natural gas grid for seasonal storage and transport of hydrogen needs previous assessment of its tolerance, ensuring safe and viable operation. In this work, the tolerance of the most typical material pipelines and key elements of high-pressure gas grids to the transport of 20 mol% hydrogen blends at 80 barg has been investigated at pilot scale. For this, the experimental campaign carried out at a testing platform replicating a high-pressure gas grid lasted 3000 h. The tightness of different kind of valves led to hydrogen losses below 1 Nml·h−1. No embrittlement or other kind of damage was found on these valves or the different parts of the equipment (regulator, flowmeter) tested. C-ring, 4pb and CT-WOL specimens have been prepared from carbon steel pipes (API5L Gr X42 to X70), showing no damage after exposure to hydrogen. H 2 /CH 4 deblending has also been successfully achieved using Pd-based membrane technology, obtaining a high-purity separated streams. [Display omitted] • Study of the behavior of high-pressure natural gas grids under 20 mol% H 2 blends. • No critical gas leakages on tests with representative valves and their couplings. • No signs of hydrogen embrittlement on carbon steels up to API 5L X70 quality. • No damage due to hydrogen found on different parts of the components and equipment. • H 2 /CH 4 separation achieved with Pd-based membranes with hydrogen purity over 99 mol%. [ABSTRACT FROM AUTHOR]

Wire Arc Additive Manufacturing (WAMM) consists in the manufacture of metallic preforms from the deposition of multilayer weld beads on a substrate, that is, from a three-dimensional model, the object is divided into layers defining the trajectories in which the addition of metal will be made, with the use of a robotic manipulator. The objective of this work is to study the influence of the addition of cold wire and the effect of interlayer temperature in the WAAM process, comparing it with the deposition made with a single wire, observing mechanical properties such as tensile strength, hardness, in addition to the cooling time for different interlayer temperatures and the geometry of the manufactured parts. A GMAW (Gas Metal Arc Welding) system was used coupled to a robotic manipulator, with multiple wires of 1.6 mm in diameter for the energized wire and 1.0 mm for the cold wire, both classified as ER70S-6. In order to manufacture the specimens for the tensile test, 20 layers were superimposed in a straight line, forming a wall, varying the interlayer temperature between each layer, using 100°C, 150°C and directly, with no waiting interval between layers. In general, a shorter cooling time was observed for the walls manufactured with the addition of cold wire when compared to depositions with a single wire. In addition, it was noted that the cold wire also influences the height and thickness of the pieces. In the mechanical tests, the cold wire did not significantly influence the hardness values. The highest values were found in the 100°C samples. For the tensile tests, it was observed that, in general, the addition of cold wire tended to increase the maximum tensile strength of the samples. [ABSTRACT FROM AUTHOR]

Ni(II) and Co(II) ions are recovered from real leached positive electrodes of spent Ni–Cd batteries, and subsequently co-deposited on A36 carbon steel using direct and pulsed currents. The idea is to evaluate how variations in texture and composition of recycled coatings affect their catalytic activities for H 2 production at microelectrolysis levels, and using an oxy-hydrogen gas (HHO) cell. The most active Ni–Co electrocatalyst in 0.1 M HClO 4 or KOH towards hydrogen evolution reaction (HER) is formed using pulsed current at −50 mA cm−2, according to electrochemical measurements and gas chromatography (GC). This plating mode favors grain size refinement and pH rise during metal deposition, to prevent the formation of oxides/hydroxides with low catalytic activity arising in direct current. In the HHO cell, the most active Co–Ni coating produces 21.63 mL min−1 H 2 , while A36 carbon and 304 stainless steels present lower generations of 7.30 and 7.55 mL min−1, respectively. [Display omitted] • Active Co–Ni cathodes for H 2 yield from recycled components of spent Ni–Cd batteries. • Ni–Co coatings formed by pulsed current are more catalytic than using direct current. • Textural properties and composition of Co–Ni surfaces determine H 2 production. • Co–Ni catalysts are more active than carbon and stainless steels in the HHO cell. • 0.05 μm thick metallic coating can be enough catalytic for H 2 generation. [ABSTRACT FROM AUTHOR]

Erosion-corrosion resistance is a critical factor in the service life extension of metallic structural materials in front of complex flow and solid impingement. To improve the erosion-corrosion resistance, a CrN/Cr gradient coating was fabricated on carbon steel by the double glow plasma alloying technique. The CrN/Cr gradient coating mainly consists of the CrN phase and (Fe, Cr) metal phase. Debye rings from the X-ray pattern illustrated that the coating was under a compressive stress of 868 MPa. Residual stress and fine toughness of the gradient structure enhanced its adhesion strength, endowing it with the potential to accommodate strains caused by external forces. The potentiodynamic polarization test illustrated that the addition of solid particles and the increase in flow velocity severely weakened the protective ability. The mass loss rate results illustrated that the synergistic effect made the greatest contribution to the erosion-corrosion damage of the CrN/Cr gradient coating, while its proportion increased as the flow velocity increased. Compared to the substrate, the gradient structure of the coating facilitated interruption of the sharp interfaces, thereby reducing the deformation mismatch and enhancing the damage tolerance of the coating. [ABSTRACT FROM AUTHOR]

A new type of cermet coating, with potential use as low-cost solar thermal absorber has been developed using spray pyrolysis. It consists of crystalline silver nanoparticles embedded in amorphous zirconia and was obtained by spraying aqueous precursor solutions onto aluminized carbon steel sheets at 200 °C. It was found that simultaneous spraying of silver and zirconium solutions led to a considerable reduction, in the nanometer range, of silver particle size distribution. Hence, we comparatively studied the cermet coatings obtained by A) sequentially or B) simultaneously spraying silver and zirconium solutions. For the latter case, a zirconia anti-reflection layer was sprayed on top. Both coating systems were studied by SEM, AFM, HRTEM/EDS and UV-VIS-IR spectroscopy with respect to silver particle size distribution. Optical parameters like solar absorptance (AM 1.5) and thermal emittance (373 K) were determined from absolute hemispherical reflectance, and a performance coefficient was calculated in order to evaluate the solar selectivity of the coatings. The comparison showed that smaller silver particles lead to an increase in solar selectivity and that the size reduction is due to an effective encapsulation by zirconia of the silver particles when spraying silver and zirconium precursors simultaneously. Furthermore, HRTEM confirmed the metallic and crystalline state of the silver nanoparticles embedded in amorphous zirconia. [ABSTRACT FROM AUTHOR]

Stress corrosion cracking (SCC) is a serious problem threatening structural integrity and safety. Metal corrosion pits can develop into more harmful cracks under mechanical stress. It is known in abiotic corrosion that fast corrosion does not necessarily cause more severe SCC. This is because fast corrosion can prevent or dissolve crack tips and convert them into less harmful pits if the uniform corrosion rate is fast enough. This work experimentally proved the hypothesis that the same phenomenon occurs in biotic corrosion. It was found that a highly corrosive SRB (sulfate reducing bacterium) strain, namely Desulfovibrio ferrophilus (strain IS5), caused fast uniform corrosion and dull pits, but no SCC cracks against X80 carbon steel U-bend coupons (stressed). In comparison, Desulfovibrio vulgaris , a far less corrosive SRB strain caused less corrosion, but generated sharp pits and SCC cracks in a 3-month lab test. This work also revealed that the X80 U-bend had a 44% higher sessile cell count and 34% higher weight loss after a 14-d D. ferrophilus incubation in deoxygenated enriched artificial seawater culture medium at 28 °C when compared with the (flat) square coupons (no stress). This weight loss trend was corroborated by transient electrochemical measurements. [Display omitted] [ABSTRACT FROM AUTHOR]

The work is devoted to developing a mechanism for returning the mechanical energy expended during braking of the vehicle, lost during transmission to the body and proportional to the loss of volume of the combustible engine. The withdrawal of mechanical energy from the wheel braking system is carried out by a cable having a connection with an additional element between the body and the rotating wheels. This element is an additional weight, which increases the wheel system in insignificant volume and weight - only a few %. The other end of the cable is connected to a special mechanical energy storage spring. The mechanical pulling force of the cable compresses the spring system of the special design and accumulates mechanical energy in a volume of approximately 60–70% of the braking energy. The same end of the cable is also connected to the freewheel clutch and the return spring. After the mechanical energy has been transferred, the cable and the brake disc (additional element) are freely returned to their original position by a return spring. The mechanical energy accumulator is constructed of springs made of good quality steel. It is possible to create a design that stores the energy of all four wheels of the vehicle with a single spring. For the design investigated in the work, a carbon steel spring was selected using the characteristics of this steel. The electric generator installed in the structure, mechanically connected with the mechanical energy accumulator, converts mechanical energy into electrical energy by rotation of the rotor under the action of spring forces. Electricity from the electric generator is directed for collection in the battery banks. [ABSTRACT FROM AUTHOR]

Green synthesis has become very significant for sustainable development and health concern. The multicomponent is applied as an eco-friendly procedure to synthesize N-((2-aminoethyl) carbamothioyl) acrylamide (ACA). The structure of ACA is verified using FTIR and 1HNMR spectroscopy. The inhibitory effect of ACA for carbon steel in 1 M HCl is assessed using electrochemical measurements and weight loss. The Langmuir adsorption isotherm model fits the inhibitive effect caused by adsorption on the metal surface. Additionally, the surface morphology is examined using SEM and AFM. The photos demonstrate a smoothing of the protective surface and a 0.45 nm reduction in average roughness. Different quantum descriptors using DFT theory were calculated and found to be corroborated with the experimental results. By creating successive resistive adsorption films, the ACA, at a concentration of 10−3 M, protects the carbon steel in 1MHCl with a 97% efficiency as a mixed-type inhibitor. [ABSTRACT FROM AUTHOR]

With the advancement of science and technology, metallographic research on metal materials has made remarkable progress. In this paper, the authors processed metallographic images using machine learning algorithms to classify the different elements in the images. The classification results divide the elements into three categories, which are metal elements, non-metal elements and metal-nonmetal combination elements. On the basis of this research, a metallographic compression algorithm based on adaptive threshold is also explored, and grayscale experiments are carried out on carbon steel samples. The recognition rate is 98.3%, and the compression rate is 1.06. Experimental results verify the effectiveness of the algorithm in processing metallographic compressed images of metal materials in power grids. [ABSTRACT FROM AUTHOR]

Carbon concentration and distribution has a dramatic impact on mechanical properties of steel. The manufacture technology of ancient steel is an important question in archaeometallurgy, especially during medieval times when the production process evolves between indirect and direct modes. Steel is an iron alloy incorporating up to a few % of carbon in weight, heterogeneously clustered in various carbide phases that are usually imaged by metallographic microscopy after acid etching. We have investigated the capability to obtain in a direct, non-destructive way and quantitative maps of carbon in steel samples using the 12C(d,pγ)13C reaction with the simultaneous detection of the emission of the 3089 keV γ-ray (d-PIGE) and of the p 0 proton group (d-NRA). Carbon spot measurements and mappings were carried out using an external deuteron microbeam of 1.5 MeV at the New AGLAE facility of the Centre de Recherche et de Restauration des Musées de France. The beam diameter on the target was around 50 µm and its mean intensity 4nA, monitored by using the PIXE signal (Fe K α line) emitted by the sample. Spectra were fitted using the SIMNRA program and the calculated composition checked against standard reference steel targets. Carbon distribution maps were extracted from the collected γ-ray and proton spectra datacubes. Spot measurements acquired in 2 min yielded a limit of detection of 200 ppm carbon weight for d-PIGE and 10 ppm for d-NRA. Proton detection appeared more effective than γ-ray detection owing to better statistics, mainly due to higher detection efficiency and better S/N ratio while γ-rays detection is affected by the spurious emission from nitrogen contained in the exit foil. Carbon concentration was mapped on a medieval archaeological iron alloy sample (140 × 32 points, 7 mm × 1.6 mm area) using a 1.6 sec dwell time, yielding a carbon content of 0.395 % with an uncertainty of 10 %. Heterogeneities could be evidenced in the maps, and incidentally the presence of oxygen. A simple methodology was developed to derive the depth distribution maps of carbon in the first microns of the sample. [ABSTRACT FROM AUTHOR]

During a corrosion inhibition test, a combination of common electrochemical corrosion test methods with an in-situ quantification of H 2 evolution could provide a comprehensive analysis of the effectiveness of an organic inhibitor. This work analyzes the corrosion inhibition efficiency of Kleinhovia hospita plant extract on carbon steel specimens polarized in 1 M HCl, based on acquired H 2 bubbles images, by using gray level co-occurrence matrix (GLCM) and support vector machine (SVM) classification. A conformity was established between the classified-algorithm models and the corrosion test results obtained by potentiodynamic polarization test and electrochemical impedance spectroscopy. Hydrogen rate and corrosion rate show the same lowest trends at the addition of 3000 mg/L of KH extract. The inhibitor addition led to 99% of maximum inhibition efficiency. Based on the polarization data, KH extract is a mixed type inhibitor. Supported by Langmuir calculation for adsorption isotherm, a physisorption is stated as the main inhibition mechanism. The feature extraction using GLCM was able to distinguish changes in H 2 bubbles characteristics where the addition of inhibitor affected the corrosion rate. The GLCM/SVM method applied as a linear kernel function and showed 88% accuracy with d = 5 for image data testing. Remarkable changes in H 2 gas bubbles characteristic were observed in the specimen immersed in the solution with 3000 mg/L inhibitor addition, signified by 99% inhibition efficiency. • Combined electrochemical and in-situ H 2 quantification enhances inhibitor-efficiency analysis. • 88% accuracy was obtained by using SVM linear kernel function with GLCM parameter d = 5. • 3000 mg/L of Kleinhovia hospita extract gives optimum inhibition for on carbon steel in 1 M HCl. • Physisorption is the main inhibition mechanism of Kleinhovia hospita extract inhibitor. [ABSTRACT FROM AUTHOR]

A new hypothesis is proposed and verified in this study to clarify the relationship between the progression and the mechanism of the flank wear of cutting tools in the steady-state region, assuming that the flank wear part expands while maintaining a geometrically similar profile. Based on Preston's law, the proposed hypothesis analytically leads to the conclusions that in the steady-state wear region where the cutting temperature is low and the abrasive wear is dominant, the flank wear width increases linearly, and the normal stress on the flank wear part does not change. Furthermore, this hypothesis suggests that the nonlinear and faster wear progression in the initial wear region is caused by an unsteady transition in the flank wear profile. Cutting experiments were conducted using tungsten carbide tools and carbon steel workpieces. The results demonstrated that the flank wear part expands with a certain similarity profile in the steady-state wear region. The normal stress distribution on the flank wear part was estimated from the similarity profile based on the proposed hypothesis, and the result was in rough agreement with that calculated by the finite element method in the literature. • A flank wear progression model in the steady-state region is proposed. • Flank wear progression with similarity is verified analytically and experimentally. • Estimated stress distribution on the flank face agrees with that in the literature. [ABSTRACT FROM AUTHOR]

The high carbon steel bars are widely used in automobile sector, mining, shipping and forging industry. In addition, SAE 52100 steel (carbon 0.93–1.05%) is significantly used in manufacture of mechanical components, especially the bearings due to its high hardness value. Basic production process of the metal bar involves heating the billet in reheating furnace up to 1200–1210 °C followed by passing it through a pair of grooved rolls in a rolling mill. Steel industries have been striving for productivity and better yield of hot rolled bar products. The roll separating force, driving torque and end crop length are the important issues to be controlled for quality production, maximisation of yield, minimisation of rolled bar process scrap, safety of mill and reduction in energy consumption. The response parameters depend on several process parameters – rolling speed, billet temperature, reduction ratio, billet size, roll diameter, etc. This paper presents a study on the effect of process parameters on these response parameters during rolling of SAE 52100 steel. Simulation of the rolling process has been attempted using FORGE® Nxt 1.1. The simulated results so obtained have been validated through experimental results obtained in a rolling mill, following statistical tests. Regression models showing relationship between the process parameters and the response parameters have been developed. Significant model-terms have been obtained using ANOVA. [ABSTRACT FROM AUTHOR]

The cutting saw blade with diamond blade and carbon steel matrix is widely used in stone cutting because of its high strength, impact resistance and good thermal stability. However, the carbon steel matrix is easy to corrode in the circulating cooling water, which shortens its service life. In this study, a new highly efficient benzotriazole-based (BMN) composite inhibitor was synthesized and investigated against the corrosion of carbon steel in stone processing wastewater. The corrosion inhibition properties and mechanism of prepared BMN for carbon steel in real stone processing wastewater were evaluated and deduced using the experimental weight loss, electrochemical and surface morphology characterization techniques. Weight loss methods results showed that a high inhibition efficiency of 99.59% in stone processing wastewater was achieved at ambient temperature, with the stirring speed 200 rpm, the immersion time 7 d, and the BMN concentration is 50 mL·L–1. Electrochemical impedance spectroscopy indicated that resistance from the surface films (R2 ) and charge transfer resistance (R3 ) were enhanced with increase in BMN concentration. Polarisation results revealed the BMN acted as an anodic inhibitor, owing to the addition of BMN resulted in the significant change of anodic Tafel slopes (βa ). Scanning electron microscopy results indicated BMN formed a protective film on the surface of carbon steel through adsorption. In short, the prepared BMN composite inhibitor exhibited superior anti-corrosion performance for saw blade corrosion in stone processing wastewater, which had great application potential in industries. [ABSTRACT FROM AUTHOR]

Circulating cooling water consumes a large amount of water in thermal power plant, and there are some problems such as scaling and corrosion in the system. This study presents a novel circulating cooling water treatment process based on microbes. The mechanism and influencing factors of microbial treatment process of circulating cooling water is studied. Water from circulating cooling system of a 300 MW thermal power unit was used, dynamic simulation test was carried out and compared between the microbial treatment process and the traditional chemical treatment process. The results showed that nutrient solution dosage on calcium hardness is positive, while the interaction between nutrient solution dosage and aeration rate has negative effect. When ammonia concentration is 10–50 mg/L and aeration rate is 1–3 L, and the minimum calcium hardness is 18.3 mmol/L. Reducing the concentration of nutrient solution and increasing the aeration rate are beneficial to slow down the corrosion of carbon steel and stainless steel. When ammonia concentration is 10–50 mg/L and aeration rate is 1–3 L, the minimum corrosion rates are 0.01552 and 0.00110 mm/a, respectively. Compared with traditional chemical treatment process, the microbial treatment process can achieve the scale inhibition and corrosion inhibition target at high concentration ratio, the highest concentration ratio can reach 5.4, and the corrosion rate of carbon steel and stainless steel is low. The green, efficient and environment-friendly microbial treatment process provides a new method for circulating cooling water treatment, which can obtain stable and economical operation of circulating cooling water system under high concentration ratio. [ABSTRACT FROM AUTHOR]

The compatibility problems become the main concern in the utilization of biodiesel especially regarding degradation and corrosion. The present study is conducted to describe the corrosion behaviour that occurs in steel tanks after contact with palm-based biodiesel for a period of 7 months. The storage tank used is respectively made of galvanised steel (GS), carbon steel (CS) and stainless steel (SS). It is performed in vertical cylinders with a floating-roof model. In every 30 days of storage time, the profile changes in the wall, roof and base surface of each tank were observed. The oil fuel properties were monitored in the parameter of viscosity, acid numbers, water content and oil colour. The topographic profiles on the surface of the walls and bottom of each tank wetted by biodiesel were examined over three zones inside the tanks using an endoscope imager. The main results of this study indicate that tank steel with different protective layers exhibits different types of corrosion. The corrosion was localized in SS tanks but generalized in GS and CS tanks. The oil contamination in SS tanks was relatively lower than that in CS and GS tanks. The type of corrosion performed differently in different zones on the inside of the tank. The potential for leaks is greater at the base than on the walls and roof of the storage tank. [ABSTRACT FROM AUTHOR]

The peculiarities of the interaction of hydrogen with low-carbon steels were studied by the magnetoacoustic emission method (MAE). It was established that the low concentration of hydrogen in the steel structure has an insignificant effect on their elastic characteristics. Hydrogen in the steel structure contributes to the increase of MAE by 16% under the induction of a magnetic field of 0.92 T, and for plastically deformed steel, the presence of hydrogen contributes to the increase of MAE by 23% compared to non-hydrogenated material. The less carbon in the steel, the greater the influence of hydrogen on MAE. The dualistic nature of the effect of low hydrogen concentration on the generation of MAE is illustrated: increase of MAE activity up to a certain concentration of hydrogen, and then its decrease. It is important to take this into account when developing methods for non-destructive control of the local concentration of hydrogen in metals. • The hydrogen in low-carbon steels leads to the relaxation of internal stresses. • Annealing of steel and hydrogen in its structure contribute to the increase of MAE. • The growth of the MAE by the influence of hydrogen has a dualistic character. [ABSTRACT FROM AUTHOR]

The effect of AC and cathodic protection (CP) potentials on hydrogen evolution and absorption in carbon steel 1010 is investigated by hydrogen permeation tests, using a Devanathan-Stachurski electrochemical cell. Hydrogen evolution reaction occurs via the coupled discharge-recombination mechanism under CP and AC. Hydrogen permeation is controlled by bulk diffusion and less than 1% of the total hydrogen permeates through the steel membrane. A significant increase in the hydrogen uptake occurs as the AC voltage increases with more negative CP potentials. More negative CP potentials increase the hydrogen flux and absorption under AC imposition. The highest effective hydrogen diffusivity (∼5 × 10−8 cm2/s) and subsurface hydrogen concentration (∼3.5 × 10−5 mol/cm3) are found at −1.5 V SCE with AC imposition. These results demonstrate a synergy between the CP potential and AC voltage on the hydrogen evolution and absorption behavior in steel and provide insights into the implications of AC interference with CP on hydrogen embrittlement. • Empirical relationship is established for H evolution and diffusion under CP & AC. • Hydrogen permeation increases with increasing AC voltage under CP. • Less than 1% of total H generated permeates through steel by bulk diffusion. • Effective H diffusivity increases with CP & AC to a maximum of 5 × 10−8 cm2/s. • Subsurface H concentration increases with CP & AC to a maximum of 3.5 × 10−5 mol/cm3. [ABSTRACT FROM AUTHOR]

To investigate frictional properties of carbide ceramics and carbon-containing steels reciprocating friction experiments were conducted in air. For these experiments, SiC, WC, TiC, and TiCN were used as carbides. Also, Al 2 O 3 , Si 3 N 4 , TiN, and TiAlN were used as non-carbides. In addition, experiments were conducted using three types of steel as plate materials: JIS SKH4 (carbon content 0.73–0.83%), JIS SUS430 (carbon content lower than 0.12%), and JIS 312L (carbon content lower than 0.02%). As a result of the experiment, a low coefficient of friction was obtained for all combinations of identical carbides. After the friction experiment, the wear debris adhering around the wear scar was analyzed by Raman spectroscopy. As a result, it was found that the wear debris of all carbide ceramics showing a low coefficient of friction contained a graphite-like material. These results demonstrated that a graphite-like material is generated by friction between identical carbide ceramics, as in the case of carbon-based materials such as diamond and DLC. In friction between ceramic balls and steels, the SKH4 plate showed a low coefficient of friction similar to that produced by friction between identical carbides. Raman spectroscopy revealed that the SKH4 plate wear debris contained a large amount of graphite-like materials, while the SUS430 plate wear debris, which showed a high coefficient of friction, contained only a small amount. Moreover, SUS430 showed stronger adhesion to the friction surface than SKH4 did, probably because the graphite-like material generated by friction reduces metal adhesion. These results demonstrated that carbon in steel also produces a graphite-like material by friction, and demonstrated that it lowers the friction coefficient by reducing the shear force and by suppressing adhesion. • In the friction of carbides in air, the carbides oxidize, producing a graphite-like material. • Carbon in steel also contributes to the formation of graphite-like materials. • Wear debris containing graphite-like material lowers the coefficient of friction. [ABSTRACT FROM AUTHOR]

A range of Desulfovibrio spp. can reduce metal ions to form metallic nanoparticles that remain attached to their surfaces. The bioreduction of palladium (Pd) has been given considerable attention due to its extensive use in areas of catalysis and electronics and other technological domains. In this study we report, for the first time, evidence for Pd(II) reduction by the highly corrosive Desulfovibrio ferrophilus IS5 strain to form surface attached Pd nanoparticles, as well as rapid formation of Pd(0) coated microbial nanowires. These filaments reached up to 8 µm in length and led to the formation of a tightly bound group of interconnected cells with enhanced ability to attach to a low carbon steel surface. Moreover, when supplied with high concentrations of Pd (≥ 100 mmol Pd(II) g−1 dry cells), both Desulfovibrio desulfuricans and D. ferrophilus IS5 formed bacteria/Pd hybrid porous microstructures comprising millions of cells. These three-dimensional structures reached up to 3 mm in diameter with a dose of 1200 mmol Pd(II) g−1 dry cells. Under suitable hydrodynamic conditions during reduction, two-dimensional nanosheets of Pd metal were formed that were up to several cm in length. Lower dosing of Pd(II) for promoting rapid synthesis of metal coated nanowires and enhanced attachment of cells onto metal surfaces could improve the efficiency of various biotechnological applications such as microbial fuel cells. Formation of biologically stimulated Pd microstructures could lead to a novel way to produce metal scaffolds or nanosheets for a wide variety of applications. • First evidence that D. ferrophilus IS5 forms surface attached Pd(0) nanoparticles. • Unlike D. desulfuricans , IS5 rapidly forms Pd(0) coated microbial nanowires. • Nanowire production leads to enhanced attachment of IS5 to steel surfaces. • Desulfovibrio spp. can form 3D mm-sized bacteria/Pd hybrid microstructures. • Desulfovibrio spp. can form 2D nanosheets of Pd metal up to several cm in length. [ABSTRACT FROM AUTHOR]

The industrial and medical sectors have a great interest in chitosan due to its unique properties, such as abundance, renewability, non-toxicity, antibacterial activity, biodegradability, and polyfunctionality. In this work, two modified chitosan Schiff bases (ChSB-1 and ChSB-2) were made using condensation methods, and their potential as corrosion inhibitor for carbon steel in 1 M HCl was investigated using chemical and electrochemical techniques. The ChSB-1 and ChSB-2 inhibitors exhibited remarkable inhibitory performance, as evidenced by the mass loss data, which showed 89.3 % and 91.5 % efficacy at 1 mM concentration, respectively. Because of the electron-donor substituent of methoxy (–OCH 3), ChSB-2's active sites have more delocalized electrons than ChSB-1's. The PDP results showed that both ChSB-1 and ChSB-2 inhibitors have anti-corrosion characteristics because heteroatoms caused a protective layer to develop that functioned as mixed-typed inhibitors. The calculated adsorption-free energy ∆ G ads o for ChSB-1 and ChSB-2, respectively, was found −36.1 and − 37.1 kJ mol−1. The ChSB-1 and ChSB-2 inhibitors adsorb on carbon steel in acidic conditions through physisorption and chemisorption interactions, and their adsorption is in line with the Langmuir adsorption model. Inhibited and uninhibited metallic surfaces were subjected to surface morphological assessments using contact angle (CA), the scanning electron microscopy and the energy dispersive X-ray (SEM/EDX) analysis. The DMol3 part of Materials Studio 7.0 software was used to perform the quantum chemical calculations based on DFT to visualize the structural features. Studies from quantum chemistry suggest the possibility of surface interaction between the unoccupied orbitals of the metal surface and the inhibitors ChSB-1, ChSB-2, ChSB-1H+, and ChSB-2H+. The results clearly show that the two inhibitors work well as environmentally friendly carbon steel corrosion inhibitors in acidic medium. This could be advantageous for industrial procedures such as pickling, cleaning, acidizing oil drilling in oil wells, and using citrus to de-sediment boilers. • Chitosan-Schiff base derivatives (ChSBs) were synthesized and confirmed. • ChSBs were investigated as corrosion inhibitors in 1 M HCl solution. • Polarization studies indicated that ChSBs acted as a mixed-type inhibitor. • Adsorption studies indicated that the inhibitor obeyed the Langmuir isotherm model. • The theoretical calculations are correlated well with experimental techniques. [ABSTRACT FROM AUTHOR]

This study investigates the influence of adding graphene nanoplatelets (GNPs) to mortar mixtures on the corrosion behavior of embedded carbon steel rebars. Mortar mixtures were prepared with a water-to-cement ratio of 0.42 and GNP replacement levels of 0, 0.05, and 1 percent by weight of cement. After 28 days of curing in an environmental chamber, the passivity and kinetics of chloride induced corrosion initiation for the rebars were studied using a suite of electrochemical tests. The results suggest that incorporating GNPs at low concentrations may enhance the passivity and resistance to chloride-induced corrosion of carbon steel rebars; however, due to the large variability in the data, the findings are inconclusive. Potentiodynamic measurements revealed that the estimated average polarization resistance of steel rebars in 0 G (no GNP), 0.05 G, and 1 G specimens in the passive state was on average −182.3, −276.5, and −304.2 kΩ, respectively. Upon exposure to chloride solution, 0 G specimens, with an average corrosion potential of −600 mV vs. SCE, exhibited the lowest resistance, whereas 0.05 G specimens, with an average of −491 mV vs. SCE, showed the highest corrosion resistance. Results from electrical impedance spectroscopy were consistent with the potentiodynamic findings. Surface characterization also revealed that the inclusion of GNPs does not alter the surface roughness of the interface between steel rebar and paste. However, the interface between rebar ribs and mortar paste had higher surface roughness and porosity in all specimens regardless of GNPs replacement level. Visual inspections confirmed that the area around the rebar ribs at the interface is more conducive to the formation of crevice and pitting corrosion. • GNPs boost passivity in steel rebars. • Low GNP levels enhance corrosion resistance. • Increased surface roughness and porosity noted at rebar-mortar interface. [ABSTRACT FROM AUTHOR]

[Display omitted] • Eco-friendly Dryopteris filix mas L. (DFM) extract demonstrated as an effective green corrosion inhibitor. • Achieved up to 88% inhibition efficiency for A210Gr steel in a 3% NaCl environment. • Significant corrosion rate reduction verified through both weight loss measurements and electrochemical techniques. • Adsorption behavior follows Langmuir isotherm, with mixed-type inhibition confirmed by Tafel slope analysis. • Surface characterization via FTIR/ATR, XRD, SEM, and AFM reveals the formation of a protective organic layer. • DFT simulations provide insight into the molecular interactions driving DFM's adsorption on steel surfaces. This study investigates the corrosion inhibition effectiveness of Dryopteris filix-mas L. (DFM) extract for A210Gr carbon steel in a 3 % NaCl solution. The DFM ethanolic extract was successfully prepared and comprehensively characterized using a combination of spectroscopic and physicochemical techniques, including HPLC, FTIR, and NMR (1H and 13C). These analyses confirmed the presence of key phenolic compounds, with Quercetin-3-O-diglucoside (Q3ODG) being the major component, comprising 82.14 % peak area as identified by HPLC. The extract, obtained via an economical ethanol extraction method, exhibited a maximum inhibition efficiency up to 88 % at a concentration of 400 ppm, as determined through electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), potentiodynamic polarization (PDP), and weight loss measurements. Temperature studies revealed a drop in efficiency to 70.14 % at 323 K, indicating a temperature-sensitive inhibition mechanism. Extended immersion times led to a slight decrease in efficiency due to partial desorption, though significant protection remained after 72 h. The primary corrosion inhibition mechanism was determined to be physisorption, following the Langmuir isotherm model, with a Δ G ads 0 value of − 24.02 kJ/mol, indicating a spontaneous adsorption process. Thermodynamic analysis revealed an increase in E a from 22.11 kJ/mol (blank) to 56.61 kJ/mol (400 ppm), confirming the formation of a strong protective barrier. Surface characterization techniques, including FTIR, XRD, SEM, and AFM, further confirmed the presence of a protective film rich in polar organic compounds. Complementary Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) studies provided detailed insights into the molecular interactions, highlighting the key role of hydrogen bonding and van der Waals forces in the adsorption of Q3ODG onto the steel surface. These findings underscore the potential of DFM extract as an effective and sustainable corrosion inhibitor, advancing the application of biocompounds in corrosion control and encouraging further exploration of their industrial applications and environmental benefits. [ABSTRACT FROM AUTHOR]

This review discusses the necessity of surface modification to effectively use fibre-reinforced polymers (FRPs) as reinforcements for seawater and sea sand concrete (SWSSC). FRPs can be a viable reinforcement material for SWSSC as an alternative to the traditional carbon steel reinforcement that will suffer unacceptably high rates of corrosion due to the very high chloride content of the SWSSC environment. FRPs exhibit mechanical properties similar to steels but suffer insignificant degradation/corrosion due to chloride. However, the fibres in certain FRPs (such as basalt FRPs and glass FRPs) suffer degradation due to attack by the alkaline environment of concrete, causing degradation in fibre-matrix interfacial strength and loss of FRPs's overall mechanical strength and durability. Therefore, fibres used in such FRPs require suitable surface modification to ameliorate their degradation, enabling their practical use as reinforcements of SWSSC. While carbon fibre-reinforced polymers (CFRPs) demonstrate superior resistance to alkali-induced degradation, their widespread use in large-scale civil engineering is hindered by high costs. In this review, more economic alternatives, i.e., basalt fibre-reinforced polymers (BFRPs) and glass fibre-reinforced polymers (GFRPs) are critically reviewed. To enhance the durability of FRPs and mitigate alkali-induced degradation of the basalt/glass fibres, suitable surface modifications are necessary to safeguard the mechanical properties of FRPs. Underpinned by a comprehensive discussion on the necessity of surface modification of fibres for the use of FRPs in SWSSC environment, this review focuses on the potential of advanced approaches for surface modifications of the fibres, i.e., coatings of silanes, and silanes impregnated with graphene nanoplatelets (GNPs), graphene oxide (GO) and its functionalised derivatives or metal oxides (such as SiO 2 , ZrO 2 , Al 2 O 3 , TiO 2 and CeO 2). This review critically discusses the opportunities for suitable surface modification of basalt and glass fibres for enabling the durable use of FRPs as reinforcements for sweater sea sand concrete. • Review of silane coatings for basalt/glass fibres for enabling use of FRPs for reinforcement for seawater concrete. • Review of suitable silanes as coatings on the fibres for FRPs for seawater concrete. • Critical review of critical parameters for silane coating process. • Review of the benefits of impregnation of graphene derivatives into the silane coatings. [ABSTRACT FROM AUTHOR]

High performance concrete (HPC) is a quite novel material which has been rapidly developed in the last few decades. It exhibits superior mechanical properties and durability comparing to normal concrete. HPC can achieve also superior tensile performance if strong fibres (steel or carbon) are implemented in the matrix. Thus, there exist the unabated interest in studying how the addition of different types of fibres modifies the behaviour of HPC. Nowadays, a standard numerical approaches to model the behaviour of fibre reinforced concrete (FRC) are carried out by means of the smeared or discrete crack modelling of homogenous media with appropriately changed stress-strain relationships. The objective of this paper is to develop a new and efficient mesoscale modelling approach for steel fibre reinforced high-performance concrete. The main idea of presented approach is to assume the fully 3D modelling with taking into account explicitly the distribution and orientation of the steel fibres. As a benchmark, results obtained from experimental campaign on beams and panels made from high-performance concrete with steel fibres of different sizes and dosages were taken. Results of numerical simulations were directly compared with experimental outcomes in order to validate and calibrate FE-model and to introduce the efficient numerical modelling tool. • The new material design of low-carbon high performance concrete with steel fibres for wave energy converter floater was done. • 3D analysis for structural members with explicitly modelled fibres to investigate the behaviour of FRHPC was introduced. • FRHPC beams and panels were experimentally and numerically investigated. • Results of numerical calculation were discussed and verified based on experimental results. • Ability to simulate the real composite characteristics in particular the influence of the number of fibres was proven. [ABSTRACT FROM AUTHOR]

The present study reports a novel Nb 1 Zr 2 Ti 1 W 2 high entropy alloy (HEA) exhibiting exceptional strength and energy release properties, thereby demonstrating its promising potential for utilization in extreme conditions such as penetration. The penetration of Nb 1 Zr 2 Ti 1 W 2 HEA fragments into a semi-infinite high carbon steel target was investigated through an experiment utilizing a 14.5 mm ballistic gun, covering a wide range of impact velocities from 800 to 1600 m/s. The experimental data, encompassing DOP (the depth of penetration) and VOP (the volume of penetration) of HEA fragments at various impact velocities, were acquired. After conducting both macroscopic and microscopic analyses of the crater and residual fragments, we have determined that the penetration pattern of HEA fragments undergoes a transition from a "self-sharpening" to a "mushroom head" across a wide range of impact velocities. The findings indicate that the impact velocity, as well as the biphase structure of Nb 1 Zr 2 Ti 1 W 2 HEA (BCC1 and BCC2), are crucial external and internal factors influencing the penetration process. The present study unveils this intriguing physicochemical phenomenon and investigates the correlation between microscopic structure and macroscopic penetration behavior. • Nb 1 Zr 2 Ti 1 W 2 demonstrates promising potential for utilization in extreme conditions such as penetration. • The penetration pattern of Nb 1 Zr 2 Ti 1 W 2 undergoes a transition from "self-sharpening" to "mushroom head" across a wide range of impact velocities. • The biphase structure (BCC1 and BCC2) of Nb 1 Zr 2 Ti 1 W 2 plays a crucial role in influencing the penetration process. [ABSTRACT FROM AUTHOR]

• Polyureathane surfactants with flexible structure were designed as corrosion inhibitors. • The gemini type polyureathane surfactant possessed excellent performance. • The formation of densely packed adsorption layer is the key to the high performance. • This work proved a strategy for the synthesis of special structural corrosion inhibitors. Three cationic polyurethane surfactants (LC1–1, LC2–2, and LC2–3), each featuring different hydrophobic structures, were synthesized using isophorone diisocyanate, N-methyl diethanolamine, 1-bromohexadecane, and 1-bromobutane. The synthesized cationic polyurethane surfactants exhibited low surface tension, excellent foaming properties, and resistance to salt, attributed to steric hindrance among long-chain alkyl groups and their "multi-point anchoring" ability. The corrosion inhibition performance of polyurethane surfactants on carbon steel in 1 M HCl solution was evalutated, and LC2–2 showing a considerable corrosion inhibition efficiency of 97.0 %. This film effectively reduced/isolated contact between the corrosive solution and the steel interface. Furthermore, quantum chemical calculations corroborated the electrochemistry experiment results, affirming that the molecular structure of LC2–2 is particularly conducive to inhibiting the corrosion of carbon steel. This study explores the relationship between the molecular structure of surfactants and its impact on both surface activity and corrosion inhibition efficiency. [Display omitted] [ABSTRACT FROM AUTHOR]

Sodium alginate (SA) was used to modify phytic acid conversion coating (PACC) for reinforcing steel. The corrosion protection performance of the modified PACC was examined in chloride-contaminated concrete pore solution through electrochemical measurements and surface characterization techniques. Results show that the modified PACC significantly enhances the corrosion resistance of carbon steel. The modification effect progressively intensifies as the dosage of SA increases from 0.2 % to 0.8 %. The modified PACC on the steel surface displays the highest inhibition efficiency of 93.5 % at the dosage of 0.8 % SA. After prolonged exposure to chloride, the corrosion rate of steel with the modified PACC is 2.17 μm/a, marking a 72.8 % reduction compared to the unmodified PACC. The presence of SA effectively fills natural cracks in PACC and facilitates the formation of the modified PACC with a complex bilayer structure. • SA is used to modify natural PACC layer to improve its anti-corrosion performance. • The modified PACC significantly reduces corrosion rate vs. the natural one. • The modified PACC with a complex bilayer structure acts as a physical barrier. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the corrosion inhibition effect of seaweed extract abbreviated as SAE on carbon steel (CS) in 1.0 mol/L hydrochloric acid (HCl) solution. The functional groups in SAE were characterized using Fourier transform infrared (FTIR) spectroscopy. The corrosion inhibition effect of SAE on CS was determined through weight loss experiments, electrochemical tests, and scanning electron microscopy (SEM). Additionally, the composition of the corroded CS surface after immersion in SAE solution was measured through X-ray photoelectron spectroscopy (XPS) analysis. The results indicate that SAE achieves a corrosion inhibition efficiency of 95.0 % for CS in 1.0 mol/L HCl. Furthermore, SAE was identified as a mixed-type inhibitor. The adsorption of SAE on the CS surface follows the Langmuir adsorption isotherm model. UV–visible spectroscopy (UV–vis) studies confirmed that the corrosion inhibition of CS was achieved through the formation of CS-SAE phytoconstituents complex. Moreover, Molecular dynamics simulations (MS) and quantum chemical (QC) calculations were utilized to predict the adsorption properties of several major SAE components and the chemical parameters associated with inhibitory efficiency. This work offers insightful information for developing and applying eco-friendly CI for acid pickling or rust removal from CS. [Display omitted] [ABSTRACT FROM AUTHOR]

Two types of imidazole analogs, namely 1-((4RS,5SR)-2,4,5-tris(4-methoxyphenyl)-4,5-dihydro-1 H-imidazol-1-yl)ethan-1-one (TOIE) and (4SR,5RS)-2,4,5-tri(furan-2-yl)-4,5-dihydro-1 H-imidazole (TFMI), were probed as corrosion-inhibiting substances for carbon steel in hydrochloric acid (HCl) milieu by dint of potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), ultraviolet-visible spectroscopy (Uv-visible), and scanning electron microscopy (SEM), together with theoretical approaches. The findings reveal that anticorrosion performance depends on both temperature and concentration; it reached 94.9 % for TOIE and 89.2 % for TFMI at 0.001 M under 303 K, respectively, but it was 90.2 and 79.4 %, respectively, at 0.001 M under 333 K. Examination of PDP revealed that all imidazole analogs perform as mixed-type inhibitors. Additionally, the adsorption mode of imidazole analogs on carbon steel complies with the Langmuir adsorption isotherm and includes a chemisorption process. The surface (SEM) and milieu (UV–visible) analyses substantiate that corrosion protection happens as a result of imidazole molecules' adsorption at the carbon steel interface. The obtained quantum chemical indices, such as global softness, electron transfer fraction, and energy gap, together with Fukui indices, can give a good interpretation of the effectiveness of inhibition. Molecular dynamics simulations (MDS) discovered that the TOIE and TFMI molecules, in a flat manner, are adsorbed on carbon steel orbitals, thus giving rise to more effective adsorption and corrosion inhibition. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Eco-friendly La-HAp derived phosphate sludge was developed. • Achieves 82% corrosion inhibition efficiency via dual anodic and cathodic mechanisms. • Protective layers of lanthanum hydroxide and iron orthophosphates enhance durability. • Smart coatings with synergistic barrier, ion release, and trapping effects. • Innovative use of waste materials for superior corrosion protection performance. Intelligent anti-corrosive coatings have gained considerable interest as a method to protect metals. This approach offers an effective strategy for mitigating corrosion by providing advanced control over the process. In this research, lanthanum-loaded hydroxyapatite pigment (La-HAp) was successfully synthesized using phosphate sludge (PS) waste. The pigment was incorporated into an alkyd resin coating to provide smart corrosion protection for mild steel exposed to a saline solution. The synthesized pigments were characterized using various analytical techniques, including FTIR, XRD, and SEM−EDS. The inhibitory performance of La-HAp on mild steel submerged in a 3% NaCl solution was evaluated using linear polarization and EIS techniques. The findings demonstrated substantial inhibitory effectiveness, achieving 82% inhibition efficiency. Further investigation compared the protective capabilities of modified (C-La-HAp) and reference (C-Ref) alkyd coatings on carbon steel using EIS. The results indicated significant corrosion protection enhancement with 5% La-HAp, showing a polarization resistance of 19.7 MΩ·cm2 after four weeks of immersion in the aggressive solution. This corrosion resistance is primarily attributed to the formation of a barrier against the corrosive environment and the trapping of Cl- ions by the HAp, accompanied by the release of La, phosphate, and calcium ions. La ions react with OH- ions produced in the cathodic zones to form a uniform protective layer of Lahydroxides, while iron orthophosphates provide additional protection at anodic sites. This synergistic blend of mechanisms imparts intelligent corrosion-inhibiting properties to the alkyd resin, effectively guarding against the damaging effects of corrosive agents. [ABSTRACT FROM AUTHOR]

The respective roles of IOB and SRB in mixed microbial corrosion of carbon steel pipelines were investigated by surface analysis and electrochemical measurements. The results indicate that in initial corrosion stage the extracellular polymeric substances (EPS) of SRBs can hinder the adhesion of IOB and inhibit corrosion nodulation formation. As SRB:IOB increases from 0:22500 cells/mL to 22500:22500 cells/mL, the size and number of corrosion nodulations decrease by two orders of magnitude. In latter corrosion stage, the SRBs become the dominant microbes, accelerating the propagation of corrosion nodulations in mixed microbial system due to low dissolved oxygen (DO). [Display omitted] • Carbon steel presents uniform corrosion in single SRBs but nodulation corrosion in single IOBs. • In the initial corrosion stage corrosion is inhibited with mixed microbes compared with single IOBs or SRBs. • The EPS of SRBs can hinder IOB adhesion and further inhibit nodulation corrosion. • Corrosion nodulation dimensions are inversely proportional to the content ratio of SRBs: IOBs. • In the latter corrosion stage nodulation corrosion is accelerated by SRBs in mixed microbes. [ABSTRACT FROM AUTHOR]