It can be foreseen that the construction of offshore photovoltaic (PV) power generation will facilitate the transfer of green power generation systems from land to sea, expand the space for the development of renewable energy, create new opportunities for the development of the photovoltaic industry, hence it is an important development direction for the photovoltaic industry. However, the marine environment is characterized by high humidity, and high salinity, which poses new challenges for the development of the offshore PV industry. In particular, the corrosion of key structural components such as PV module racks and pile foundations has become a key factor limiting its large-scale development and application. Considering this, herein, the corrosion issues of key structures in offshore PV systems were focused on. Such as the corrosion characteristics of the engineering structures of PV power generation systems may encounter in the marine environment are analyzed in terms of the structure types, structural features, material varieties, and service conditions etc. In addition, systematic countermeasures for corrosion protection of structural components were proposed, therewith providing a reference for the construction, operation and maintenance of offshore PV systems.

Marine biofouling and corrosion pose severe threats to the safe operation of offshore equipment, ships, and oil/gas pipelines. Coating technology, as an economical, environmentally friendly, and highly efficient surface/interface modification approach, has demonstrated significant advantages in mitigating these issues. However, traditional marine protective coatings suffer from inherent limitations, including high environmental toxicity, poor substrate compatibility, and insufficient durability, making them inadequate for long-term protection in complex marine environments. Consequently, the development of more environmentally friendly, efficient, and durable marine protective coatings has become a key research focus. Furthermore, the research progress of four typical superwetting marine protective coatings and their future development directions are reviewed, so that providing reference for the design of next-generation marine protective coatings.

Wooden cultural relics, as an important component of human cultural heritage, possess irreplaceable historical, artistic, and scientific value. However, due to their porous, hygroscopic, and nutrient-rich nature, wooden materials are highly susceptible to degradation caused by environmental and biological factors, thereby posing a serious threat to their long-term preservation. This paper presents a statistical analysis of international and domestic research on the corrosion of wooden cultural relics, including publication output and keyword clustering, and systematically reviews recent advances in corrosion mechanisms, influencing factors, and protective technologies. Regarding corrosion behavior, the paper elaborates on the coupled destructive mechanisms triggered by microorganisms, chemical factors, and aging. In terms of influencing factors, it summarizes the regulatory effect of chemical composition and microstructure of the wooden materials, as well as the effect of environmental parameters such as moisture, temperature, pH, and salinity etc. Concerning protective technologies, it reviews the current applications and development trends of non-destructive/mini-destructive detection methods, as well as the stabilization, dehydration, drying, and environmental-control techniques. Finally, this paper underscores the necessity of constructing an intelligent protection platform based on multi-source data integration and digital twins, providing systematic solutions for risk assessment, intervention decision-making, and sustainable preservation of wooden cultural relics through real-time monitoring and AI-based early warning.

The UN fuel, characterized by its high melting point, high uranium density, and high thermal conductivity, demonstrates significant advantages over UO₂ fuel in enhancing the safety and economy of reactors, making it one of the promising new high-performance fuels with great potential in the Accident Tolerant Fuel (ATF) program. However, the UN fuel exhibits poor resistance to hydrothermal corrosion. Previous studies have indicated that doping can improve the corrosion resistance of UN fuel to some extent. The doping substances that have been investigated include UO₂, U₃Si₂, UB₂, Zr, Cr, Al and Ni etc., which have achieved certain success in raising the initiation temperature of corrosion and reducing the corrosion rate of UN materials. This paper provides a comprehensive summary of the corrosion behavior of UN fuel and the research progress on improving the corrosion resistance of UN fuel through doping. Additionally, it analyzes the deficiencies in the present research and feasible directions for improvement, offering references for further research and enhancement of the corrosion resistance of UN fuel.

The binary Al-alloy Al-10%RE (Ce, Nd, Y, La) was placed in two atmospheric corrosion test stations (Sanya and Qingdao) for the purpose of conducting atmospheric exposure tests. The corrosion behavior in typical marine atmospheric environments was studied by measuring mass loss, observing corrosion morphology, analyzing corrosion products and performing electrochemical tests. The findings demonstrated that the corrosion rate relationship between the two test stations was Qingdao > Sanya during the 110 d test cycle, which may be associated with the SO₂ content in the atmosphere. And the corrosion rate relationship of the four binary aluminium alloys is Al-10Nd > Al-10La > Al-10Y > Al-10Ce, which may be related to the number and distribution of their microstructural precipitated phases. The corrosion at the two test stations was mainly localized, and the composition of the corrosion products formed did not differ significantly, with the main products being Al₂O₃, AlO(OH) and Al(OH)₃. In addition, a small amount of Al₂(SO₄)₃ was generated at the Qingdao station. The corrosion product film that is generated exerts an effect on the corrosion process, and the protective ability of the alloy changes over time.

Ordinary, the weld joint of 20# steel of the steam boiler to 316L stainless steel of the steam pipeline was made by argon arc welding method with the following welding parameters: a welding current of 80 A, an arc voltage of 11 V, and a welding speed ranging from 6 to 8 cm/min. In this way, the weld joints of 20#/20# steel and 20#/316L steel were welded with carbon steel and 316L steel as filler material respectively. However, even under normal operating conditions, instability fractures occur at the joints before the specified service time is reached. To investigate the corrosion fracture mechanism, samples of the above two types of joints are immersed in a simulated water to analyze the weight of environmental factors on the corrosion rate of the joints. Additionally, four-point bending tests are conducted to simulate the conditions experienced of the joints during service. Surface morphologies are observed using scanning electron microscopy, while the phase composition of corrosion products is analyzed via infrared spectroscopy and Raman spectrometer. The results indicate that the corrosion rates of 20#/316L steel welded joints are higher than those of 20#/20# steel welded joints across different environments, with temperature being the decisive factor influencing the corrosion rate. A significant amount of strip-like ferrite is present in the heat-affected zone on the 20# steel side of the 20#/316L steel welded joint, which is prone to initiating pitting corrosion. Under the combined effects of residual stress and structural stress caused by welding, severe stress concentration occurs at the bottom region of the prefabricated notch, inducing stress corrosion.

The surface state of the pre-treated steel substrate is a key factor affecting the coating structure and corrosion resistance of the tinplate. As a surface pretreatment method, the pickling process can effectively change the surface state of the steel substrate. In this paper, electrolytic pickling and chemical pickling were used for pretreatment of steel substrates with different surface roughness levels. Then, the changes in the surface state of the steel substrates pre-treated by different pickling processes and their effect on the corrosion resistance of the tinplates were systematically assessed by means of electrochemical analysis, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that for rough surface of steel substrates, electrolytic pickling can effectively reduce the surface roughness, promote the uniform deposition of the tin layer and the formation of columnar grains in the galvanizing coatings, and improve their interface bonding and corrosion resistance; For the substrate steel of initial higher roughness that was subjected to chemical pickling, it will suppress the growth of the tin plating layer, resulting in a fine structure of the galvanizing coating and a decrease in corrosion resistance. For substrates steel of smooth surface, the effect of the pickling process induced changes is small. The surface state of the substrate steel plays a key role in the coating formation and its corrosion resistance. It follows that these changes affect the uniformity of the tin layer deposition interface and the microstructure of the Sn-Fe alloy layer, which in turn determines the corrosion resistance of the coating.

To address the corrosion issues of B30 alloy for ships during service in conditions such as S^2--polluted seawaters while with conditions of alternating changes in oxygen content, herein, the corrosion behavior and reaction mechanisms of B30 alloy in S^2- polluted simulated seawaters with alternating changes in oxygen content were studied via methods such as polarization curves and electrochemical impedance spectroscopy (EIS). The results show that in a simulated clean seawater, the dissolved oxygen acts mainly as accelerant for the formation of passivation film. As the oxygen content increases, the protective properties of the surface film on B30 alloy were enhanced, and the influence degree of oxygen content on the corrosion resistance of B30 alloy may be ranked as follows: high-oxygen > alternating oxygen > low-oxygen. However, in simulated S^2--polluted seawater, the influence order of oxygen content changes to: high-oxygen > low-oxygen > alternating oxygen. In the condition of alternating changes in oxygen content, B30 alloy experiences the most severe corrosion, characterized by a significant increase in corrosion current density, a substantial decrease in electrochemical impedance, a marked reduction in polarization resistance, and the predominance of localized pitting. Correspondingly, the surface film exhibits serious cracking and delamination, leading to a significantly increased risk of localized corrosion and leakage. Mechanism analysis indicates that in sulfur-containing environments, the quality of surface film on B30 alloy was deteriorated due to the action of S^2-. Alternating oxygen conditions disrupt the dynamic equilibrium of oxygen-dominated "film formation-dissolution" processes, allowing O₂ to dominate the corrosion acceleration at local film damage sites, thus enhancing the alloy's susceptibility to localized corrosion.

Hereon, a novel strategy of synergistic nano enzyme-catalyzed sterilization and low surface energy antifouling was proposed. Initially, hollow tetrahedral nano-Co₃O₄ with peroxidase-like activity was synthesized, followed by surface modification using isophorone diisocyanate (IPDI) and castor oil. The successful modification was then confirmed through comprehensive material characterization. Concurrently, polyethylene glycol-based polyurethane (PEG-DAF) was combined with silicone-polyurea (PDMS-PU) to form a polymer resin matrix. The surface-modified nano-Co₃O₄ was then incorporated into this mixed resin, successfully fabricating a novel nanocomposite coating designated as PDMS/PEG-F-Co₃O₄. The resulting nanocomposite coating demonstrated outstanding comprehensive performance. The results demonstrated that the coating exhibits excellent substrate adhesion (GFE: (1.72 ± 0.05) MPa, steel: (1.87 ± 0.09) MPa), with water contact angle (105.3 ± 1.2)° and low surface energy (21.1 ± 2.5) mJ/m². More importantly, the synergistic interplay between the nano enzyme-catalyzed antibacterial activity of Co₃O₄ nanoparticles and the low surface energy characteristics of silicone significantly enhanced the static antifouling performance of the coating. The composite coating demonstrated exceptional antibacterial efficacy, achieving inhibition rates of (93.1 ± 1.5)% against Pseudomonas aeruginosa and (92.2 ± 1.4)% against Staphylococcus aureus, along with remarkable inhibition of Chlorella adhesion (91.6 ± 0.9)%. Furthermore, radical trapping experiments were systematically conducted to elucidate and validate the underlying antifouling mechanism. This work established a novel approach for developing high-performance and eco-friendly antifouling coatings.

The corrosion behavior of EH40 steel in oligotrophic seawater environments inoculated with R. sulfidophilum, sulfate-reducing bacteria (SRB), and their mixed consortia was assessed by means of electrochemical tests and surface morphology analyses. Particular attention was given to the role of interspecies electron transfer in modulating corrosion. Results show that R. sulfidophilum can utilize sodium thiosulfate as an electron donor to enable photoautotrophic growth in anaerobic conditions, thereby mitigating the corrosion of EH40 steel. In contrast, SRB alone induced severe mass loss and localized pitting. However, when co-cultured, the mixed community significantly suppressed the electrochemical reaction rate of EH40 steel, reducing SRB-induced corrosion damage. Linear sweep voltammetry (LSV) and current-time (I-t) measurements confirmed the occurrence of extracellular electron transfer between R. sulfidophilum and SRB. By harvesting photogenerated electrons released from R. sulfidophilum, SRB were less dependent on directly extracting electrons from the steel surface, thereby, alleviated the electrochemical corrosion. This study highlights the regulatory role of interspecies electron transfer in microbial interactions governing the steel corrosion.

Recycled Mg-alloys with high Al content (~2.3%) exhibit undesirable corrosion resistance due to their high second phase impurities, thus proper surface treatment is required for practical applications. In this work, a novel micro-arc oxidation (MAO) process was applied to a high-Al recycled Mg-alloy, while without introducing any extra particles into the electrolyte, a layered double hydroxide (LDH) film was formed, enabling the one-step fabrication of a MAO/LDH composite film. The surface and cross-sectional morphologies of the alloys with MAO/LDH film were analyzed using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), and their corrosion performance was also assessed by electrochemical tests and hydrogen evolution measurement. It is revealed that the MAO/LDH composite layer exhibits a dual-layer structure with uniform elemental distribution. The inner MAO layer with a thickness of ~2.72 μm mainly consists of MgO whereas the outer layer, confirmed as Mg-Al LDH via TEM analysis, shows a thickness of ~60 nm, which is rich in Mg, O, P, and Al. Compared to the bare Mg-alloy, the MAO/LDH-coated Mg-alloy demonstrated significantly enhanced corrosion resistance: the hydrogen evolution rate was reduced by 28-fold, and the free-corrosion current density decreased by three orders of magnitude. This study provides a feasible strategy for one-step fabrication of MAO/LDH composite coatings on Mg-alloys, offering insights into improving the corrosion resistance of recycled Mg-alloys with high impurity content.

Carbon fiber reinforced silicon carbide composites (C/SiC) have low density and thermal expansion coefficient, and excellent resistance to wear and oxidation, and they have become one of the important materials for braking systems. However, there are few reports on the friction- and wear-performance for friction-pairs of identical C/SiC material, resulting in the lack of reliable theoretical support in engineering design. In this work, needle-punched weftless and needle-punched nonwoven composite materials of C/SiC (with SiC content of 60% and 75%, respectively) were prepared by improved reaction melt infiltration through the ceramization of micro-nano porous carbon. The influence of preform structures and testing temperatures (25, 200, 400 and 500 ℃) on the friction- and wear-performance for friction-pairs of the two C/SiC composite materials respectively were investigated by means of X-ray diffraction, scanning electron microscopy and laser scanning confocal microscopy after high-temperature pin-disk friction and wear tests. The results show that with the increasing temperatures, the friction coefficients of the two C/SiC composite materials first increase and then decrease until they stabilize, while the wear rates first decrease and then increase. Such behaviour may be ascribed to that the abrasive wear occurs at lower temperatures on the materials surface, while the formed wear debris fill in the surface depressions resulting the friction film formation, and thus frictional resistance decreases; with the further increasing temperature the fatigue wear may emerge, resulting in the alternative formation and detachment of friction films. In addition, when the temperature reaches up to 500 ℃, compared with the needle-punched weftless C/SiC, the needle-punched nonwoven C/SiC composite has a higher friction coefficient of 0.53 and lower wear rate of 710.7 mg/cycle, suggesting better friction and wear performance. It is due to the higher content of SiC in the needle-punched nonwoven C/SiC composite.

The microstructure degradation of coating and substrate single crystal superalloy of a gas turbine first-stage rotor blade after service for more than 30,000 h was characterized, especially the rafting degree at various locations of the substrate alloy., Then the corresponding coating removal and refurbishment processes were conducted to restore the Pt modified aluminide for the blades. It was found firstly that the original coating for the blade is composed of a single-phase Pt modified aluminide, after service, on which micro-cracks, Al-depletion, and internal oxidation were identified. Some cracks were even penetrating onto the nickel-based superalloy, however, there was no coating on the tenon and root of the blade. In general, the Pt modified aluminide coating presents great overall performance after the long-term service, except the appearance of cracks. Subsequently, the microstructure rafting of substrate alloy was commonly observed at the tail end and center of the blade body due to the differences of service conditions, resulting in varying degrees of rafting. After successive processes of stripping, sandblasting, electroplating, annealing and aluminizing, an Al-rich Pt modified aluminide coating on the bade was restored once again. As indicated by cross-section view, there were no micro-cracks or internal oxidation inside the coating, which confirmed a successful restoration of Pt-modified aluminide coating for the blades.

The corrosion performance for different areas on the cross-section of high strength low alloy (HSLA) thick steel plate was comparatively assessed in simulated marine environments via neutral salt spray tests, electrochemical impedance spectroscopy, and microstructural analyses (SEM, XRD, EBSD). It is especially concerned the corrosion behavior of the top surface layer (lath martensite, LM) and the center region (granular bainite (GB)/lath bainite (LB) mixed microstructure) of the thick plate. Results demonstrated that the LM-dominated surface exhibited superior long-term corrosion resistance, with a higher free-corrosion potential and lower corrosion current density in contrast to that of the center ones. The LM structure may facilitate the formation of a dense α-FeOOH rust layer, therewith effectively blocking Cl^- and O₂ ingress, while the heterogeneous GB-LB center initially delayed corrosion via low-energy coincidence site lattice (CSL) grain boundaries but suffered accelerated degradation due to microcracks and residual metastable γ-FeOOH caused by internal stress. Weight loss analysis revealed the surface's corrosion rate of the top surface decreased from 0.672 mm/a (6 h) to 0.214 mm/a (168 h), outperforming the center. XRD and SEM confirmed higher α-FeOOH/γ-FeOOH + Fe₃O₄ ratios (α/γ*) in the surface rust layer, indicating the enhanced stability. EBSD highlighted fewer high-angle grain boundaries and higher localized strain in the LM structure, reducing the Cl^- inward diffusion, whereas due to the heterogeneous phase interfaces and grain boundary defects in the GB-LB center's mixed microstructure, although the corrosion was initially delayed by the relatively large number of low-energy CSL grain boundaries, but the internal stress in the rust layer later could induce microcracks, leading to a decline in protective performance. Besides, electrochemical tests further validated the top surface's superior barrier properties, with higher charge transfer resistance. This work elucidates the critical role of microstructure homogeneity and grain boundary characteristics for R&D of corrosion resistant marine-grade HSLA steels.

Ferritic FeCrAl alloys have emerged as a highly promising candidate material for accident-tolerant fuel (ATF) claddings due to their outstanding oxidation resistance. In this article, the permeation behavior of deuterium in hot-rolled plate of a FeCrAl alloy Fe-13Cr-4.5Al-2.2Mo-1.1Nb was studied via a home-made set in temperature range of 300-550 ℃ aiming in quantifying the deuterium permeability. Meanwhile, the tested samples were characterized by means of SEM with EDS, AES and XPS in terms of the influence of the in situ formed oxide scale on the deuterium permeation behavior in the alloy. The results revealed that the in situ formed nanometer-thick oxide scale on the alloy surface consisted mainly of Cr₂O₃, Al₂O₃, and Fe₂O₃. Notably, the former oxide scale during the testing process at temperatures below 450 ℃ had negligible influence on the deuterium permeation behavior in FeCrAl alloy. However, during the measurement process at 550 ℃, the in-situ formed oxide scale led to a significant reduction in deuterium permeability, diffusivity, and solubility compared to that at 450 ℃. In terms of the oxygen distribution on the tested sample at 360 ℃, oxygen was mainly concentrated within a depth of approximately 150 nm on the top surface. Conversely, after testing at 550 ℃, oxygen distribution exhibited a deeper and more homogeneous profile, with a maximum penetration depth of around 500 nm. Collectively, the deuterium permeation test results demonstrated that an in-situ formed surface oxide scale with a thickness of approximately 500 nm exerted a pronounced deuterium-barrier effect, providing critical insights into the utilization of FeCrAl alloys for ATF applications.

(Ni, Pt)Al- and NiCoCrAlYTa-coating were deposited on the second-generation nickel-based single crystal superalloy DD6 by electroplating Pt + chemical vapor aluminizing, and arc ion plating respectively. The hot corrosion resistance of two coatings was assessed beneath a deposited film of salts mixture Na₂SO₄ + 5%NaCl in air at 800 and 900 ℃. The phase constituents and element distribution of the coatings before and after test were characterized by using scanning electron microscopy and X-ray diffraction. The results show that after 300 h of hot corrosion at 800 and 900 ℃, the NiCoCrAlYTa coatings completely failed, with the formation of a mixed oxide scale with poor protective performance on the surface, and a large amount of spalling occurred, with the corrosion penetrating the coating and entering the interior of the substrate. In the contrast, a single Al₂O₃ scale with relatively few spallations was formed on the surface of (Ni, Pt)Al coating, while certain among of NiAl phase was still retained within the coating. In other word, the (Ni, Pt)Al coatings exhibited superior hot corrosion resistance rather than the NiCoCrAlYTa coatings.

The oxidation behavior of two super-alloys K444 and K452 with and without two TBCs (thermal barrier coatings) PtAl bond coat + YSZ (Yttria-stabilized zirconia) top coat and CoCrAlY bond coat + YSZ top coat, respectively was studied in high-temperature steam, i.e. flowing air +10%H₂O at 1000 ℃ via intermittent weighing of mass, and thermodynamic theoretical calculation. Results show that the oxidation mass gain of the alloys with PtAl+YSZ followed the parabolic oxidation law, and K444, K452 alloys and the alloys with CoCrAlY + YSZ exhibited mass loss. Oxides Al₂O₃, Cr₂O₃ and TiO₂ were formed on the surface of K444 and K452 alloys. It follows that the anti-steam oxidation performance of the tested alloys and coatings may be ranked as follows: PtAl + YSZ coating/alloys > CoCrAlY + YSZ coating/alloys > K452 alloy > K444 alloy. The two coating systems can improve the anti-corrosion performance of the two alloys, however the PtAl+YSZ coating has better anti-steam corrosion performance.

Halloysite nanotubes (HNTs), as natural clay minerals with tubular structures, serve as nanocontainers for loading corrosion inhibitors. In this study, 8-hydroxyquinoline (8-HQ) was loaded into HNTs via an ultrasonic loading method. By utilizing the interaction between Cu²⁺ and 8-HQ, the insoluble Cu-8-HQ complexes were introduced at the ends of HNTs to prepare the enclosed Cu-8-HQ-HNTs nanocontainers with controlled release properties. The morphologies, compositions, and release behavior of the nanocontainers were systematically characterized. Subsequently, the micro-arc oxidation (MAO) coating on AZ31 Mg-alloy was fabricated in an alkaline silicate electrolyte containing these nanocontainers. The morphology and composition of the coatings were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDX). Its corrosion resistance was evaluated through open circuit potential (OCP) measurement and electrochemical impedance spectroscopy (EIS). The results indicated that the MAO coating incorporated with Cu-8-HQ-HNTs exhibited optimal corrosion performance due to its superior self-healing capability. This strategy of in situ doping corrosion-inhibiting nanocontainers to prepare self-healing MAO coatings holds significant potential for corrosion protection of Mg-alloys.

The crevice corrosion behavior of super 13Cr stainless steel in saturated CO₂ oilfield produced fluids in conditions of varying crevice opening widths was investigated using immersion test and electrochemical techniques. The results indicated that under CO₂ pressure of 1.5 MPa at 60 ℃, crevice corrosion behavior of super 13Cr was primarily governed by the cathodic process related with CO₂ hydrolysis products. With the increase in the width of the crevice opening, the crevice corrosion rate of super 13Cr increases, while the Cr₂O₃ within the passivation film gradually transformed into Cr(OH)₃. When the crevice width was 0.125 mm, substances exchange between the inside and outside of the crevice was restricted. The depletion of cathodic reducing agents within the crevice inhibited the cathodic reaction, allowing the metal to remain in a passivated state with no occurrence of significant corrosion. At a crevice width of 0.25 mm, material exchange between the inside and outside of the crevice was enhanced. Due to the influence of CO₂ hydrolysis products, the passive film within the crevice underwent anodic dissolution, leading to the formation of pitting and an increase in the crevice corrosion rate. When the crevice width was 0.5 mm, a critical concentration of Cl^- was reached within the crevice, inducing the dissolution of inclusions and subsequent pitting corrosion. Despite these changes, in conditions of pitting corrosion and within a range of the entire tested opening crevice widths, super 13Cr all exhibited passivation performance, forming a surface film composed mainly of Cr₂O₃ and Cr(OH)₂. Regardless of the crevice width, corrosion products tended to accumulate at the crevice openings; however, their impact on the material exchange remained relatively minor. The elevated concentrations of H⁺ and Cl^- near the crevice opening promoted pitting corrosion of the metal outside the crevice.

In this work, the corrosion behavior of Ti₃AlC₂ in high-temperature sulfuric acid solutions containing F^- was investigated by means of potentiodynamic polarization, potentiostatic polarization, and electrochemical impedance spectroscopy (EIS). Meanwhile, the corrosion products were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that in a simulated proton exchange membrane fuel cell working environment (80 ℃, 0.5 mol·L^-1 H₂SO₄ and 2 mg·L^-1 F^-), the Ti₃AlC₂ presented free corrosion potential of -128.7 mV. Passivation occurred within the potential range of 0-370 mV, with a passivation current density of 75-200 μA·cm^-2. As the potential increased, the corrosion current density rose significantly, accompanied by oxidation reactions. After potentiostatic polarization at 0.6 V, the corrosion current density stabilized at 1121.66 μA·cm^-2. The corrosion morphology was mainly manifested as obvious grain boundary corrosion and a small amount of grain corrosion, and the corrosion products compose mainly of TiO₂ and Al₂O₃. The corrosion resistance of Ti₃AlC₂ is improved considerably with the decreasing acidity, whereas elevated solution temperature and increased F^- concentration its corrosion resistance is deteriorated.

The effect of honeysuckle extract (HSE), as a kind eco-friendly Inhibitor of plant extracts, on the corrosion behavior of mild steel in 1 mol/L HCl solution at various temperatures was investigated by means of mass loss measurement, electrochemical test and surface observation. The results of weight losses indicated that the corrosion inhibition efficiency reached to 89% with a dose of 300 mg/L HSE, and then electrochemical test results were consistent with the weight loss measrement. The thermodynamics calculation indicates that both physisorption and chemisorption occurred, which induced the good corrosion inhibition property of HSE.

The intense corrosiveness of marine environments has severely hindered the development of offshore oil and gas industry. In this paper, the initial corrosion behavior of D36 low carbon steel and its welds for offshore platforms in several simulated marine environments was investigated by weight loss measurements and microscopic characterization techniques. The results showed that the evolution of initial corrosion rates for both the base metal and welds of D36 steel were consistent, following the order: tidal zone > splash zone > marine atmosphere > full immersion zone; For the same test conditions, the corrosion rate of the welds exceeded that of the base metal. In the marine atmosphere and splash zones, the base metal exhibited a corrosion pattern of general corrosion accompanied by pitting corrosion, whereas it demonstrated uniform corrosion in the tidal and full immersion zones. The welds displayed general corrosion with pitting corrosion in all the four environments. In the marine atmosphere, corrosion products predominantly consisted of non-protective γ-FeOOH. In the splash zone, wave impacting led to rust layer detachment, maintaining oxygen saturation and resulting in a relatively high corrosion rate. In the tidal zone, wet-dry cycles induced micro-cracks in corrosion products, diminishing their protective performance. In the immersion zone, reduced oxygen content suppressed the cathodic reaction, leading to the lowest corrosion rate. On the D36 steel, micro-galvanic cells of ferrite with pearlite were emerged in the marine environment, where ferrite acted as the anode and underwent dissolution. Therefore, the increased proportion of pearlite in the welds could result in its local corrosion intensity, thereby the corrosion rate of the welds was higher than that of the base metal.

In the domain of electric power generation, the safe and reliable operation of transmission towers is paramount to ensuring the stable delivery of electricity. In order to better understand the corrosion behavior of hot dip galvanizing coatings for tower steels, herein, the corrosion behavior of the three constituent phases, of galvanized coating was comparatively assessed in 3.5%NaCl solution. They are δ-phase, ζ-phase, and η-phases, known as the typical constituent phases of the hot-dip galvanized coatings for the present transmission towers. Hence, regarding to the alloy element ratios of the three phases involved, the cast ingots of δ (FeZn7), ζ (FeZn13) and η (Zn) phases were made. Then their corrosion behavior was comparatively assessed by means of electrochemical measurements in NaCl solution and neutral salt spray test as well as X-ray diffraction (XRD), scanning electron microscopy (SEM), and density functional theory (DFT) calculations. The findings reveal that the corrosion rates of all three phases initially increase and subsequently decrease over time. Among others, the δ phase exhibits the highest corrosion resistance, followed by the η phase, whereas, the ζ phase showing the poorest resistance. These findings may be a good reference provide a for the design-making of corrosion protection strategies of power grid transmission towers, and help clarify the role of every individual constituent phase in the overall corrosion performance of galvanizing coatings for power grid transmission towers as well.

Oxide dispersion-strengthened (ODS) steels are considered promising candidate material for lead-based fast reactor (LFRs) owing to their superior resistance to irradiation-induced swelling and excellent high-temperature mechanical properties. However, improving the corrosion resistance under irradiation conditions remains a major challenge. To investigate the effect of irradiation induced damage on corrosion behavior in molten lead, five ODS steels with varying Cr, Si, Al and Zr contents were subjected to Fe-ion irradiation and subsequent corrosion tests in oxygen-saturated molten lead at 600 ℃. The grain structure and ions irradiation induced damage of the ODS steels were characterized using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) operated at 200 kV respectively. After corrosion tests, the morphology and composition of the formed oxide scales were characterized using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that all ODS steels developed high-density dislocation loops under irradiation, whilst significant void formation was not observed. Comparative analysis of irradiated and unirradiated samples revealed that irradiation had no significant effect on the chemical composition or thickness of the oxide scales formed by the subsequent molten lead corrosion. Among the five ODS steels, the 9Cr0.5Si4.5Al-ODS steel formed a protective Al₂O₃ scale due to the addition of 4.5% Al and its fine-grained structure. In contrast, the other four ODS steels developed relatively thicker duplex oxide scales.

Corrosion behavior of three 17Cr stainless steels with different amount of Al and Mo in LiCl-KCl chloride salts vapor was investigated to simulate the degradation process of the steels in the service conditions of the electrolytic reaction vessel for spent fuel reprocessing, so that to reveal the relevant mechanism. The results indicate that the 17Cr stainless steels present relatively high corrosion rate in 550 ℃ chloride salts vapor, as a dense protective Cr₂O₃ oxide scale could not form, and the corrosion followed the so called “chlorination-oxidation” mechanism. The addition of Al can improve the corrosion resistance to chloride salts vapor at 550 ℃ to certain extent for the 17Cr stainless steel by forming an Al₂O₃ oxide scale of high stability. Meanwhile, the addition of Mo with high stability in chloride salts vapor can also improve the corrosion resistance of the 17Cr stainless steel. It is also noted that the microstructure of the steel may play a very important role in the corrosion process, as the rapid diffusion channel of the element can be reduced by a reduction in the grain- and phase-boundaries, thereby the corrosion of the steel may be slowed down to certain extent.

Titanium is known for its high specific strength and excellent corrosion resistance. However, it is particularly sensitive to hydrogen embrittlement in hydrogen-containing environments. This sensitivity arises mainly due to the formation of brittle hydrides within the grains and along the grain boundaries. Titanium hydrides are formed when hydrogen combines with Ti-atoms through a diffusion process. In this study, commercial pure titanium TA1 plate was subjected to dynamic plastic deformation (DPD) at liquid nitrogen temperature. The aim was to suppress the hydrogen diffusion and the hydride nucleation through low-energy interfaces, thereby significantly enhancing the strength of material and reducing its sensitivity to hydrogen embrittlement. The results indicated that after DPD deformation, the thickness of the hydride layer on the surface of TA1 was drastically reduced, and the hydrides became finer. Furthermore, the microstructural refinement induced by DPD effectively suppressed strain localization and diminished the strength disparity between the titanium matrix and the hydride layer. These findings provide a novel route for enhancing the performance of titanium in hydrogen-containing environments.

To enhance the corrosion resistance, the powder metallurgy (PM) Fe-based material was surface modified by laser surface melting (LSM) technology. By optimizing process parameters (laser power: 200 W, spot diameter: 1.8 mm, scanning speed: 8 mm/s, overlap ratio: 35%-65%), a defect-free melted layer with a thickness exceeding 210 μm was fabricated on the surface of powder metallurgy Fe-based gear hub parts. Neutral salt spray tests and electrochemical analyses demonstrated that the melted layer significantly improved the corrosion resistance of the Fe-based material, namely of which the corrosion rate reduced by 57.0%-81.8%. In a 3.5%NaCl solution, the electrochemical performance was notably enhanced with an increase of free-corrosion potential by 12.4%-16.7% and an increase free-corrosion current density by 14.4%-65.2%. Additionally, the diameter of the capacitive arc and impedance modulus increased markedly, while the corrosion resistance improved with higher overlap ratios. Microstructural characterization revealed that the melted layer effectively blocked corrosive medium penetration and improved the corrosion resistance through synergistic effects related with surface densification, pore closure, grain refinement, and phase transformation. The study confirms that LSM treatment significantly enhances the corrosion resistance of PM Fe-based materials, primarily attributed to the combined protective effects of physical barrier formation and microstructural optimization.

To resolve the pervasive dezincification failure of conventional scale-resistant alloys in hard water environments, herein, a multicomponent Cu-Zn based high-entropy alloy (HEA) as an advanced anti-scaling material was designed and prepared via vacuum induction furnace smelting and casting. Then the corrosion behavior of Cu-Zn based HEA in an artificial hard water was assessed comparatively with a commercial Cu-Zn based KDF55 alloy. Electron backscatter diffraction (EBSD) results confirmed that the HEA exhibits a microstructure of single solid solution phase with face-centered cubic (FCC) crystal structure. Electrochemical measurements demonstrated that the HEA alloy presented superior corrosion resistance, with a free-corrosion current density (I_corr) of (2.37 ± 0.39) µA·cm^-2, which was 40% lower than the KDF55 alloy. In contrast to KDF55, the HEA exhibited an average corrosion rate (V_corr) of (0.09 ± 0.01) mm·a^-1, which was 61% lower. Microstructural characterization and corrosion product analysis revealed that the HEA surface developed a dense passive film enriched with Ni/Co/Fe oxides, resulting in minimal corrosion damage. In contrast, the KDF55 alloy exhibited pronounced uniform corrosion accompanied by severe dezincification. This work provides a good reference for the further research and development of highly stable anti-scaling alloys.

In oil and gas fields, water pipelines often suffer from erosion-corrosion problems caused by liquid-solid two-phase flow, leading to frequent pipeline leakages and affecting normal production. Hence, the erosion-corrosion characteristics of 90° horizontal elbows of carbon steel in liquid-solid two-phase flow conditions (namely sand and 3.5%NaCl solution) was assessed via a home-made pipeline two phase flow experimental setup to simulate the actual service conditions of oil and gas field water pipelines. The aim is to reveal the erosion-corrosion damage mechanism of carbon steel elbows in these conditions and to provide guidance for corrosion protection. Meanwhile, the weight loss method was used to quantify the erosion-corrosion rates, and surface analysis techniques were used to characterize the erosion-corrosion morphologies. The results show that in corrosion conditions of merely 3.5%NaCl solution without sand, the elbow has good corrosion resistance; in erosion conditions of merely 3.5%NaCl solution without sand, it has good wear resistance. However, in liquid-solid two-phase flow conditions, the elbow suffers severe erosion-corrosion damage, particularly on the outward facing side, bottom and outlet of the elbow. The erosion-corrosion, where at the outer edge at the bottom area of the pipe with an axial angle of 30°-60° is relatively less. In general, the erosion-corrosion rate should include items such as pure corrosion, pure erosion, and the interaction between corrosion and erosion. In the present case, the item of erosion-corrosion interaction rate is rather higher, and the other two items is relatively lower. In fact, the erosion-corrosion interaction rates reached 41~56 times the pure corrosion rates and 45-112 times the pure erosion rates. In the interaction rates, the change in corrosion rate caused by erosion accounts for as much as 70% to 80%, which is significantly higher than the change in erosion rate caused by corrosion, and both are positive values. Therefore, the interaction between erosion and corrosion is the main cause for the sharp increase in erosion-corrosion of the elbow, as the two factors promote each other. In summary, erosion in the liquid-solid medium is the main factor leading to the failure of the carbon steel elbow. The results provide a scientific basis for pipeline protection in erosion-corrosion environments.

Forged plates of high-manganese austenitic heat-resistant steels with and without addition of V and W were made, and then subjected to solution treating at 1050 ℃ for 1.5 h and quenching in water. Their hot-corrosion behavior was comparatively assessed in molten Na₂SO₄ at 900 ℃ in air. The microstructure of the steels, as well as the morphology, phase constituents and composition of corrosion products were characterized by means of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results showed that the high-manganese austenitic heat-resistant steel containing V and W exhibited resistance to molten Na₂SO₄ superior to the steel without addition V and W. The corrosion kinetics curves of the two steels presented a double parabolic relationship, indicating that with the extension of corrosion time, the two steels suffered from accelerated corrosion. However, the high-manganese austenitic heat-resistant steel containing V and W had a longer incubation period for accelerated corrosion compared to the ones without V and W. The accelerated corrosion behavior of the steel without V and W was mainly influenced by internal oxidation and internal sulfidation. The (Cr, V)₂O₃ inner oxide scale formed on the high-manganese austenitic heat-resistant steel containing V and W could protect the matrix in the early stage of corrosion, enhancing the hot corrosion resistance to molten salts for the steel. However, when (Cr, V)₂O₃ transformed into (Cr, Fe)VO₄, it could react with the molten salt, thus facilitated the inward infiltration of molten salt to form metavanadate/vanadate, causing the accelerated corrosion of the high-manganese austenitic heat-resistant steel containing V and W.