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Abstract Corrosion processes are often discussed as stochastic events. Here, it is shown that some of these seemingly random processes are not driven by nanoscopic fluctuations but rather by the spatial distribution of micrometer‐scale heterogeneities that trigger fast reactions associated with corrosion. Using a novel excitable reaction‐diffusion model, corrosion waves traveling over the metal surface and the associated material loss are described. This resulting nonuniform corrosion penetration, seen as a height loss in modeling, exposes buried intermetallic particles, which depending on the local electrochemical state of the surface trigger or block new waves. Informed by quantitative experimental data for the Mg–Al–Zn alloy AZ31B, wave speeds, wave widths, and average material loss are accurately captured. Morphogenic mitigation based on wave‐breaking microparticles is also simulated. While AZ31B corrosion is identified as a process driven by rare‐wave events, this study predicts several other corrosion regimes that proceed via spots or patchy patterns, opening the door for new protection, design, and prediction strategies.

Abstract Aluminum alloy AlSi10Mg is a widely used engineering material that offers a very high strength‐to‐weight ratio and easy processing. It is common in the aerospace, medical, and automotive industries and has excellent machining and casting properties, as well as being easily made into fine powder. In recent years, it has become one of the most common light‐weight materials for additive manufacturing (AM). Its chemical composition and stability in powder form make it particularly ideal for laser powder bed fusion (LPBF) applications. It is one of the few available aluminum alloys that can be reliably processed using AM. Numerous studies have been dedicated to mechanical properties and design strategies, but much less attention has been given to corrosion behavior. This article reviews the corrosion behavior and the correlation between the microstructure and corrosion for AlSi10Mg when fabricated using an LPBF process. Specific topics reviewed include corrosion performance, corrosion issues (pores, surface roughness, and residual stresses), and passive film formation mechanisms and compare these to conventionally‐manufactured counterparts. In addition, this review discusses available methods for mitigating and avoiding corrosion in LPBF‐processed AlSi10Mg parts, including relevant post‐processing methods.

Abstract Anaerobic microbial corrosion of iron‐containing metals causes extensive economic damage. Some microbes are capable of direct metal‐to‐microbe electron transfer (electrobiocorrosion), but the prevalence of electrobiocorrosion among diverse methanogens and acetogens is poorly understood because of a lack of tools for their genetic manipulation. Previous studies have suggested that respiration with 316L stainless steel as the electron donor is indicative of electrobiocorrosion, because, unlike pure Fe0, 316L stainless steel does not abiotically generate H2 as an intermediary electron carrier. Here, we report that all of the methanogens (Methanosarcina vacuolata, Methanothrix soehngenii, and Methanobacterium strain IM1) and acetogens (Sporomusa ovata and Clostridium ljungdahlii) evaluated respired with pure Fe0 as the electron donor, but only M. vacuolata, Mx. soehngenii, and S. ovata were capable of stainless steel electrobiocorrosion. The electrobiocorrosive methanogens required acetate as an additional energy source in order to produce methane from stainless steel. Cocultures of S. ovata and Mx. soehngenii demonstrated how acetogens can provide acetate to methanogens during corrosion. Not only was Methanobacterium strain IM1 not capable of electrobiocorrosion, but it also did not accept electrons from Geobacter metallireducens, an effective electron‐donating partner for direct interspecies electron transfer to all methanogens that can directly accept electrons from Fe0. The finding that M. vacuolata, Mx. soehngenii, and S. ovata are capable of electrobiocorrosion, despite a lack of the outer‐surface c‐type cytochromes previously found to be important in other electrobiocorrosive microbes, demonstrates that there are multiple microbial strategies for making electrical contact with Fe0.

Abstract Film forming amines (FFA) are corrosion inhibitors added to power plant water. The major concern associated with their application is the thermal stability in the high temperature power plant water medium, along with the risk of decomposition into low molecular weight organic acids that can cause corrosive damages in the water/steam cycle. However, there is still a lack of sufficient data on the thermal stability of FFA corrosion inhibitors. This paper presents a comprehensive critical review and state‐of‐the‐art assessment of the results obtained from studying the thermolysis of FFA corrosion inhibitors in power plant water/steam cycle conditions, highlighting the relevance for practical application and research needs. Temperature, exposure time, initial concentration, and alkalizing agents were identified as key factors influencing the thermal stability of FFA in high temperature power plant water. Organic acids are found in concentrations harmless to metal tubes. Advanced scientific background information and additional research are required on this topic.

Abstract This research aims at investigating the idea of anti‐bacterial self‐healing coatings based on polyurea formaldehyde microcapsules (MCs), with the repair agent being ZnO‐containing linseed oil. ZnO nanoparticles were added to the repair agent with the idea of developing an antibacterial coating. The idea was to entrap some ZnO nanoparticles inside microcapsules, aiming for some local release of ZnO nanoparticles where the coating is damaged. The corrosion resistances of the coatings were studied using the Tafel polarization test. The structure of the coating samples was evaluated using a scanning electron microscope. To check the antibacterial properties of ZnO‐containing self‐healing samples, Escherichia coli and Staphylococcus aureus bacteria were used. Results showed that ZnO nanoparticles were distributed not only inside microcapsules but also over the walls, inferring that overall protection can also be attained in addition to local anti‐bacterial performance. Results showed that the proposed multi‐functional coating has promising antibacterial and self‐healing responses.

Abstract Aluminum and aluminum alloys are light materials with some of the preferences such as lightweight, high specific strength, good elasticity, and good workability that play an important role in today's modern and industrial world. The economic loss and environmental and safety problems are also the most concerning aspects of these materials. As a result, numerous studies are performed by the researchers to improve the overall environment throughout the materials world. That is why, in this study, the surface morphology and corrosion behavior of pure aluminum and its alloys, such as 7S10 and 7003H, were investigated in aqueous sulfuric acid medium through immersion process at different temperatures. Open‐circuit potential and potentiodynamic polarization techniques were used to evaluate the resistance to corrosion of pure aluminum and its alloys 7S10 and 7003H. The current density increased with increasing temperature in the case of the alloys, and pure aluminum showed the highest corrosion resistance properties. The surface roughness measurement was performed using atomic force microscope to find out the amount of roughness of the used materials before and after the immersion process. Surface roughness was higher on the alloys than in pure Al, which indicates that less corrosion was formed in pure Al than in the alloys. The surface morphology analysis was also carried out using scanning electron microscopic data. The results revealed that the alloy 7003H undergoes more corrosion than pure aluminum and 7S10 in sulfuric acid medium, which clearly indicates that pure aluminum has higher corrosion resistance than the alloys 7S10 and 7003H. The corrosion rate of the test materials decreased with increasing immersion time.

Abstract Poststent restenosis is caused by insufficient endothelialization and is one of the most serious clinical complications of stenting. We observed a rapid endothelialization rate and increased fibrin deposition on the surfaces of the corroded iron stents. Thus, we hypothesized that corroded iron stents would promote endothelialization by increasing fibrin deposition on rough surfaces. To verify this hypothesis, we conducted an arteriovenous shunt experiment to analyze fibrin deposition in the corroded iron stents. We implanted a corroded iron stent in both the carotid and iliac artery bifurcations to elucidate the effects of fibrin deposition on endothelialization. Co‐culture experiments were conducted under dynamic flow conditions to explore the relationship between fibrin deposition and rapid endothelialization. Our findings indicate that, from the generation of corrosion pits, the surface of the corroded iron stent was rough, and numerous fibrils were deposited in the corroded iron stent. Fibrin deposition in corroded iron stents facilitates endothelial cell adhesion and proliferation, which, in turn, promotes endothelialization after stenting. Our study is the first to elucidate the role of iron stent corrosion in endothelialization, pointing to a new direction for preventing clinical complications caused by insufficient endothelialization.

Abstract Corrosion of iron‐containing metals under sulfate‐reducing conditions is an economically important problem. Microbial strains now known as Desulfovibrio vulgaris served as the model microbes in many of the foundational studies that developed existing models for the corrosion of iron‐containing metals under sulfate‐reducing conditions. Proposed mechanisms for corrosion by D. vulgaris include: (1) H2 consumption to accelerate the oxidation of Fe0 coupled to the reduction of protons to H2; (2) production of sulfide that combines with ferrous iron to form iron sulfide coatings that promote H2 production; (3) moribund cells release hydrogenases that catalyze Fe0 oxidation with the production of H2; (4) direct electron transfer from Fe0 to cells; and (5) flavins serving as an electron shuttle for electron transfer between Fe0 and cells. The demonstrated possibility of conducting transcriptomic and proteomic analysis of cells growing on metal surfaces suggests that similar studies on D. vulgaris corrosion biofilms can aid in identifying proteins that play an important role in corrosion. Tools for making targeted gene deletions in D. vulgaris are available for functional genetic studies. These approaches, coupled with instrumentation for the detection of low concentrations of H2, and proven techniques for evaluating putative electron shuttle function, are expected to make it possible to determine which of the proposed mechanisms for D. vulgaris corrosion are most important.

Abstract In recent years, there have been many cases of transformer failures caused by corrosive sulfides. At present, research mainly focuses on the single sulfide dibenzyl disulphide, but few research on multiple sulphur or the oil‐paper hybrid insulation. In this study, three typical sulfides dibenzyl disulfide, hexadecyl mercaptan and benzothiophene were selected to form seven sulfide‐oil‐paper models. Then relaxation calculations were carried out, and through molecular dynamics simulation, the synergistic effect of different sulfides on the properties of insulating paper and insulating oil was discussed. Results show that the coexistence of the three sulfides has the most severe weakening on the mechanical properties of cellulose, and it also causes great damage to hydrogen bonds. Hexadecyl mercaptan has a weaker effect on hydrogen bond destruction, but it will greatly aggravate the cellulose chain movement. The viscosity of insulating oil is generally increased by the influence of sulfide. Hexadecyl mercaptan is the main factor affecting the viscosity. Thiophene has little effect on the viscosity, ctive protection technology on sulphur corrosion.

Abstract The antagonism between strength and corrosion resistance in graphene‐reinforced aluminum matrix composites is an inherent challenge to designing reliable structural components. Heteroatom microstructural modification is highly appreciated to conquer the obstacle. Here, a bottom‐up strategy to exploit the heterogeneous phase interface to enable high corrosion durability is proposed. Deformation‐driven metallurgy derived from severe plastic deformation is developed to produce Mg‐alloyed fluorinated graphene structures with homogeneous dispersion. These structures allow for absorbing corrosion products, forming a dense protective layer against corrosion, and local micro‐tuning of the suppression of charge transfer. This results in superior corrosion resistance with an outstanding strength‐ductility balance of the composites via ultrafine‐grained and precipitation strengthening. The anti‐corrosion polarization resistance remains 89% of the initial state after 2‐month immersion in chloride‐containing environment, while the ultra‐tensile strength and elongation of 532 ± 39 MPa and 17.3 ± 1.2% are obtained. The economical strategy of heteroatom modification broadens the horizon for anti‐corrosion engineering in aluminum matrix composites, which is critical for the design of carbonaceous nanomaterial‐reinforced composites to realize desired performances for practical applications.

Abstract Zinc‐ion batteries (ZIBs) have been extensively investigated and discussed as promising energy storage devices in recent years owing to their low cost, high energy density, inherent safety, and low environmental impact. Nevertheless, several challenges remain that need to be prioritized before realizing the widespread application of ZIBs. In particular, the development of zinc anodes has been hindered by many challenges, such as inevitable zinc dendrites, corrosion passivation, and the hydrogen evolution reaction (HER), which have severely limited the practical application of high‐performance ZIBs. This review starts with a systematic discussion of the origins of zinc dendrites, corrosion passivation, and the HER, as well as their effects on battery performance. Subsequently, we discuss solutions to the above problems to protect the zinc anode, including the improvement of zinc anode materials, modification of the anode–electrolyte interface, and optimization of the electrolyte. In particular, this review emphasizes design strategies to protect zinc anodes from an integrated perspective with broad interest rather than a view with limited focus. In the final section, comments and perspectives are provided for the future design of high‐performance zinc anodes.

Abstract Insufficient availability of molten salt corrosion‐resistant alloys severely limits the fruition of a variety of promising molten salt technologies that could otherwise have significant societal impacts. To accelerate alloy development for molten salt applications and develop fundamental understanding of corrosion in these environments, here an integrated approach is presented using a set of high‐throughput (HTP) alloy synthesis, corrosion testing, and modeling coupled with automated characterization and machine learning. By using this approach, a broad range of CrFeMnNi alloys are evaluated for their corrosion resistances in molten salt simultaneously demonstrating that corrosion‐resistant alloy development can be accelerated by 2 to 3 orders of magnitude. Based on the obtained results, a sacrificial protection mechanism is unveiled in the corrosion of CrFeMnNi alloys in molten salts which can be applied to protect the less unstable elements in the alloy from being depleted, and provided new insights on the design of high‐temperature molten salt corrosion‐resistant alloys.

Abstract Aqueous zinc‐ion batteries (ZIBs) have been intensively investigated as potential energy storage devices on account of their low cost, environmental benignity, and intrinsically safe merits. With the exploitation of high‐performance cathode materials, electrolyte systems, and in‐depth mechanism investigation, the electrochemical performances of ZIBs have been greatly enhanced. However, there are still some challenges that need to be overcome before its commercialization. Among them, the obstinate dendrites, corrosion, and hydrogen evolution reaction (HER) on Zn anodes are critical issues that severely limit the practical applications of ZIBs. To address these issues, various strategies have been proposed, and tremendous progress has been achieved in the past few years. In this article, we analyze the origins and effects of the dendrites, corrosion, and HER on Zn anodes in neutral and mildly acid aqueous solutions at first. And then, a scientific understanding of the fundamental design principles and strategies to suppress these problems are emphasized. Apart from these, this article also puts forward some requirements for the practical applications of Zn anodes as well as several cost‐effective‐modifying strategies. Finally, perspectives on the future development of Zn anodes in aqueous solutions are also briefly anticipated. This article provides pertinent insights into the challenges on anodes for the development of high‐performance ZIBs, which will greatly contribute to their practical applications.

Summary Understanding of surface evolution is important in applications that require engineering prescribed surface structures. Novel crystalized formations have been observed on titanium specimens etched with sulfuric acid as part of an ongoing implantology research. Crystal formations resembling rosettes were discovered via scanning electron microcopy near the edges of several commercially pure titanium specimens etched by immersion in 18M (98%) sulfuric acid at 60°C for 30 minutes to 1 hour. These crystallized formations were composed of numerous thin sheets (in the neighborhood of 20‐50 nm thick) resembling “petals” that form in an approximately hexagonal arrangement. Energy dispersive X‐ray spectroscopy analysis identified these as sulfur oxide formations, probably titanyl sulfate. Literature documentation of similar formations has not been found. Further investigation of the thermal‐chemical potential, activation energies, or other factors involved in the nucleation and growth of these formations is needed. Such understanding could help advance knowledge in areas related to surface engineering and corrosion mechanisms. Furthermore, it is inferred that this novel formations could have applications in certain processes where chemical reactions in bypassing fluids are assisted by surface chemistry and enhanced by surface roughness.

A pantograph–catenary system (PCS) – an essential component to supply a high-speed train (HST) – faces a variety of new challenges due to the continuously increasing train speeds. The HST traction system receives power via an electrical contact between the pantograph strip and the high-voltage contact wire. This electrical contact is subject to serious mechanical shocks and significant electrochemical corrosion, making the modelling of the dynamic processes complicated, especially under high-speed and heavy-load conditions. The damage to the PCS – which is particularly noticeable at the edges of the pantograph strip – may become severe as the speed of the train rises. Moreover, as the speed increases, the distribution of the electrical current in the strip becomes uneven due to the velocity skin effect (VSE). To assess the impact of the VSE on the performance of PCSs, a multi-physics model has been created and is reported in this study. The model has been validated through experiments and the main aspects of its functionality – such as the VSE, friction, and air convection – have been identified and analysed at different speeds. The impact of speed on the traction current and the behaviour of thermal sources have been explored. With the increasing speed, the phenomenon of current clustering at the trailing edge of the strip becomes quite dramatic, resulting in a thermal surge in the region of the strip with high current density. To mitigate the negative impact caused by VSE in the PCSs, an improved kriging optimisation methodology has been utilised to optimise the parameters of the PCS. Recommendations regarding the optimal design of the PCS are put forward to improve the current-carrying performance and reduce the local temperature rise in the strip.

Abstract The effect of high temperature variation on the corrosion resistance of EN‐1.4405, EN‐1.4404, and EN‐1.4539 stainless steels in 2 M H2SO4/3.5% NaCl solution was studied. Untreated EN 1.4405 exhibited the highest corrosion rate at 4.775 mm/year compared to untreated EN 1.4539 with the lowest corrosion rate (1.043 mm/year). Repetitive heat treatment significantly decreased the corrosion rate of the steels by 54.61%, 27.83%, and 50.28% to 2.167, 1.396, and 0.519 mm/year. EN‐1.4539 steel exhibited the shortest metastable pitting activity among the untreated steels due to higher resistance to transient pit formation while heat treated EN‐1.4404 and EN‐1.4539 steels exhibited double metastable pitting activity. Heat treated EN‐1.4405 was unable to passivate after anodic polarization signifying weak corrosion resistance. Pitting current of heat‐treated steels was generally higher than the untreated counterparts. Heat treatment extended the passivation range value of EN‐1.4405 and EN‐1.4539 steels compared to those of the untreated steels. The corrosion potential of heat‐treated steels significantly shifted to electronegative values. The optical image of untreated and heat treated EN‐1.4404 and EN‐1.4539 steels were generally similar while the images for EN‐1.4405 significantly contrast each other.

Abstract In this paper, a unique, innovative liquid metal infiltration process for the dispersion of graphene in the aluminum (Al) matrix in the presence of nickel spheres is introduced. The nickel spheres impart a reaction that induces wettability with molten Al, hence facilitating the infiltration of Al encapsulating graphene. Raman spectroscopy shows the two‐dimensional bands, thereby confirming the presence of graphene in the infiltrated composite. The microstructure of the infiltrated composite shows the dispersion of graphene, Al‐silicon eutectic, and a reaction product between nickel and Al around nickel spheres. The sample of composite tested in this study exhibits a high contact angle and hydrophobicity, possibly due to the dispersion of graphene particles on the surface of the samples. This presence of graphene on the surface causes a reduction of wetting by water and a decrease in corrosion rate which is demonstrated by polarization testing results.

Fretting corrosion of metal implants has been associated with implant failure and revision surgeries. This report describes the fixation failure of a femoral neck fracture in a 61-year-old male patient due to corrosion of three cannulated screws. Radiographic evaluation at the time of primary surgery demonstrated well-positioning of the cannulated screws. The patient had no significant medical comorbidities at the time of surgery. However, screw loosening and avascular necrosis were diagnosed after 5 years. At the revision surgery, inflammatory serological markers, C-reactive protein and erythrocyte sedimentation rate showed no signs of infections, and screws were retrieved. Scanning electron microscopy observations showed that all screws were subjected to fretting corrosion which led to discolouration, pitting attack, and cracking. Thus, Fretting corrosion may have contributed to the failure of the fixation of screws.

Several kinds of widely used detection technology of wire clamp on overhead lines were introduced. Although infrared temperature measurement technology can detect the overheating defects of the clamp, it is difficult to ensure the effectiveness of on-site testing due to the environmental factors, the accuracy of testing instruments, and the experience of test personnel. X-ray inspection technology can accurately measure the exact size of the steel core without damaging the wire, and find the problem of poor crimping of the clamp. According to the field test, the typical clamp defect spectrum of X-ray inspection was listed in this study. It could effectively improve the hydraulic quality detection efficiency of the strain clamp in field work. A method was proposed, to judge the inside corrosion condition of the strain clamp, and to evaluate the current conduction capability, by detecting the current on the clamp and the wire.

This study examines the use of computer-aided analysis to evaluate the biomechanical performance of Schanz screws made from different additive manufacturing materials (Ti6Al4V, 316 L, Inconel 625, and Inconel 718) in a pertrochanteric fixator for the treatment of intertrochanteric femoral fractures. Intertrochanteric fractures (ITFs) are severe traumas often seen in the elderly population and can lead to serious consequences. The primary objective of ITF surgery is to provide stability and allow for early ambulation and rehabilitation. The Pertrochanteric Fixator is a surgical implant used to treat hip fractures near the greater trochanter, and is attached to the femur with screws. The procedure is performed under general anesthesia and typically takes 1-2 h. Possible complications include infection, nerve injury, and hardware failure. The aim of this study is to evaluate the biomechanical performance of Schanz screw using computer-aided analysis, comparing the effects of various additive manufacturing materials including Ti6Al4V, 316 L, Inconel 625 and Inconel 718 in a pertrochanteric fixator for intertrochanteric femoral fractures. Additionally, this study will also consider the corrosion resistance of these materials to ensure long-term durability and effectiveness in a clinical setting. The stress values mentioned for the implant materials are as follows. Ti6Al4V: 153.33 MPa, 316 L: 180.98 MPa, Inconel 625: 158.94 MPa, Inconel 718: 148.91 MPa. Higher stress values indicate a greater load transfer to the bone, which can potentially lead to stress shielding. Stress shielding occurs when an implant bears a significant portion of the load that should be transferred to the bone. This reduced stress at the fracture site can prevent the healing process, as bones require adequate stress levels for optimal remodeling and regeneration., (© 2023 John Wiley & Sons Ltd.)