Additive manufacturing (AM), particularly selective laser melting (SLM), offers significant potential for nuclear power industry due to its ability to fabricate complex components with exceptional design flexibility. However, the inherent characteristics of the AM process produce unique, non-equilibrium microstructures, such as columnar grains and melten pool boundaries, which can significantly affect the stress corrosion crack (SCC) behavior in high temperature pressurized water. This paper provides a comprehensive review of the microstructural features and recent advances in understanding the SCC behavior of SLM stainless steel. Special attention is given to the governing roles of chemical composition, microstructural evolution, and service conditions on the SCC behavior of SLM stainless steels. Finally, the prevailing challenges and future perspectives for the application of SLM stainless steels in the nuclear power system are critically discussed.

Additive manufacturing (AM) technologies, including laser powder bed fusion (LPBF), directed energy deposition (DED), and wire arc additive manufacturing (WAAM), have started a revolution in materials manufacturing due to their significant advantages such as high precision, high processing efficiency, capability for complex structures and material cost savings. These technologies demonstrate immense application potential in nuclear energy sectors, particularly in fabricating critical alloy components such as reactor cores, fuel claddings and advanced heat exchangers. However, the extreme environments within reactor systems including high temperatures, high pressures, radiation and highly corrosive media, put forward strict demands on the service performance of additively manufactured alloys. Among others, the corrosion resistance of alloys has become a primary focus of concern. This review summarizes recent research progress on corrosion behavior in simulated nuclear conditions of typical additively manufactured alloys, such as stainless steels, FeCrAl alloys and complex composition alloys etc. It comparatively examines the differences between AM alloys and conventionally forged counterparts, analyzing the influence of microstructural characteristics on corrosion mechanisms. Furthermore, the application prospects of additively manufactured alloys in future advanced nuclear energy systems are discussed.

Hydraulic support is one of the important coal mining machinery equipment for underground coal mining, whilst, the reliability of the hydraulic support has a direct impact on the safety of underground coal mining operations. Which is long-term exposed to complex underground service conditions featuring high humidity, high corrosive media containing chloride ions, hydrogen sulfide, sulfur oxide and various adhesive dusts, as well as high mechanical load. Hence, the surface of hydraulic support column cylinder will be suffered from corrosion wear. Therefore, to improve the reliability of the hydraulic support and extend its service life is the key to ensure safe mining operations. The preparation of high-performance coatings on the surface of hydraulic support columns is an important technical means to solve the problem of corrosion and wear and improve safety and reliability. Coating preparation technology in industrial applications has a variety of forms, which can be directly in the active stent surface preparation of anti-corrosion wear-resistant coatings, enhance the hydraulic stent column cylinder surface performance, to extend the service life, can also be used as a means of remanufacturing, such as to repair damaged cylinders, reduce mining costs, to ensure the sustainable development of resources. This paper first summarizes the common protective coating preparation methods, describes several preparation methods of hydraulic support column protective coatings, including electroplating, thermal spraying, laser cladding, arc melting copper, etc., and discusses the preparation methods, in terms of their advantages and disadvantages. Secondly, the materials with excellent comprehensive performance used in the laser cladding technology are further reviewed, and different coating materials are analyzed from aspects of different processing conditions and different needs of the inner and outer surfaces of the bracket cylinder, including Fe-based self-fusing powder, Ni-based self-fusing powder, Cu-based powder and composite powder. Finally, from the two aspects of coating preparation technology and material system, the anticorrosion and wear-resistant coating of laser cladding hydraulic support column is expected.

Additive Manufacturing (AM), as an advanced manufacturing technology, is widely used in fields such as aerospace, medical, and automotive industries. However, due to its characteristics of rapid melting and layer-by-layer stacking, it is prone to introducing defects such as porosity, residual tensile stress, and surface roughness in the formed parts. This can lead to corrosion problems such as pitting, intergranular corrosion, and stress corrosion cracking in complex service environments, severely affecting the corrosion resistance and mechanical properties of AM parts. Therefore, heat treatment processes are widely applied in the post-processing of AM parts to enhance their corrosion resistance. In this article, the corrosion behavior characteristics of additive manufacturing parts and the relevant influencing factors are reviewed, focusing on the three typical heat treatment processes: annealing, solution treatment, and hot isostatic pressing, as well as their effects on corrosion behavior. It follows that an appropriate heat treatment process can significantly enhance the uniform corrosion resistance and localized corrosion resistance of materials while improving their mechanical properties by releasing residual stress, optimizing grain morphology, and adjusting element distribution. This review aims to provide a reference for the optimization of heat treatment processes and corrosion protection strategies for additive manufacturing metallic materials.

The advancement of additive manufacturing has provided new opportunities for the personalized customization of biomedical Ti-alloys. In this study, a novel β-Ti alloy, Ti15Nb2.5Zr4Sn, was fabricated by using electron beam melting (EBM), and its microstructure, mechanical properties, electrochemical behavior in simulated body fluid (SBF), and biocompatibility were systematically investigated in comparison with the conventional Ti-6Al-4V (TC4). The results showed that EBM-Ti15Nb2.5Zr4Sn exhibits a β-phase-dominated microstructure with a pronounced crystallographic texture. Its elastic modulus is approximately 40 GPa, which is closer to that of human cortical bone (10-30 GPa), thereby may be favor to alleviate the so called “stress shielding effect” caused by bone implants with a higher elastic modulus. The EBM-Ti15Nb2.5Zr4Sn alloy in SBF solution presented a wide passivation range (0.22-1.12 V) with a low corrosion current density (308 nA·cm^-2), indicating the formation of a stable and protective passive film on its surface. X-ray photoelectron spectroscopy (XPS) analysis identified that the formed passive film composted of TiO₂, Nb₂O₅, ZrO₂ and SnO₂. Cell culture experiments further demonstrated that MC3T3-E1 pre-osteoblasts adhered well to the Ti15Nb2.5Zr4Sn surface with intact cytoskeleton structures, indicating excellent biocompatibility of the alloy. In summary, the EBM-fabricated Ti15Nb2.5Zr4Sn alloy combines low elastic modulus, high corrosion resistance, and favorable biological activity, making it a promising candidate for next-generation orthopedic implant applications.

A bulk Al-Mg-Sc-Zr alloy was fabricated by using selective laser melting (SLM) technique. Then its corrosion behavior of the alloy was investigated by immersion in Pseudomonas aeruginosa (P. aeruginosa) inoculated artificial seawater for 14 d, meanwhile the distribution of P. aeruginosa on the alloy surface was observed via fluorescence microscopy, and the trend in cell population changes was statistically analyzed. The corrosion behavior and mechanism of the alloy in both sterile and inoculated environments were investigated through electrochemical tests, scanning electron microscopy (SEM), white light interferometry, and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the Al-Mg-Sc-Zr alloy exhibited excellent corrosion resistance in the sterile group, with virtually no observable pitting on the surface. In contrast, in the inoculated group, P. aeruginosa could adhere to the alloy surface and induced severe localized corrosion. P. aeruginosa could extract electrons from Al and Mg elements to sustain its metabolic activities, while oxygen concentration cells were formed inside the heterogeneous biofilm, significantly exacerbating the development of localized corrosion and reducing the corrosion stability of the alloy.

The microstructure and high-temperature oxidation resistance of two TiAl based Ti-43.5Al-4Nb-1Mo-0.1B alloys with addition of Nb and Mo (TNM) are comparatively assessed, which are prepared by casting and laser-electric hybrid additive-manufacturing (AM) respectively. Microstructural analysis indicates that: the cast TNM alloy is mainly composed of coarse lamellar α₂-Ti₃Al + γ-TiAl structureand a small amount of β₀-TiAl phase, with an average grain size of 15.56 μm; while the AM alloy is mainly composed of basket-weave α₂-Ti₃Al + fine γ-TiAl and a small amount of β₀-TiAl, and the grain size is significantly refined to 2.45 μm. The 900 °C oxidation test shows that the oxidation rate of the AM TNM alloy is higher than that of the cast ones, and a protective Z-phase (Ti₅Al₃O₂) is formed at the oxide layer/matrix interface of the cast alloy after oxidation for 20 h. The difference in oxidation behavior between the two alloys may be mainly attributed to: the fine-grained structure of the AM alloy generates a high density of grain boundaries, accelerating the outward diffusion of metal ions in the matrix and the inward diffusion of oxygen; compared with the cast ones, the AM alloy cannot form a protective Z-phase at the oxide scale/matrix interface, which aggravates the oxidation rate of the alloy.

Ti-6Al-3Nb-2Zr-1Mo (Ti80) alloy is a novel home-made Ti-alloy for marine engineering applications. However, conventional forming methods for Ti-alloys present challenges, including complex processes, lengthy procedures, and high costs, etc. Electron beam freeform fabrication (EBF³) technology, utilizing a high-energy electron beam as the heat source and metal wires as raw material for rapid deposition in vacuum conditions, is well-suited for the high-quality rapid forming of highly reactive Ti-alloys ofhigh melting points. Herein, Ti80 alloy was fabricated by using the EBF³ technique. Meanwhile, the influence of post-heat treatment procedures on the microstructure, and the corrosion behavior in 3.5%NaCl solution of the prepared Ti80 alloy was assessed by means of XRD, SEM+EBSD as well as electrochemical measurements. The results reveal that the microstructures of all the Ti80 alloys subjected to three different post-heat treatments are predominantly composed of the α phase, but with three distinct microstructural morphologies: coarse basket weave, fully lamellar and hierarchical structures, respectively, which contrast significantly with the traditional forged state ones (equiaxed structure). Among others, the hierarchical microstructure exhibits the highest corrosion resistance, followed by the fully lamellar microstructure. The coarse basket-weave microstructure demonstrates the lowest corrosion resistance but still outperformed the wrought alloy. The differences in the corrosion resistance are closely related to the thickness of the passivation films formed on the alloys surface. The findings of this study provide a reference for enhancing corrosion resistance by adjusting the heat treatment process to regulate the microstructure for Ti-alloys.

TiC nanoparticle modified Al-Mg-Sc-Zr alloy was fabricated via laser powder bed fusion (LPBF) technique. The microstructure and corrosion behavior of the as-fabricated alloy were systematically investigated through microstructural analysis of grain structures and precipitates combined with corrosion evaluations, including room-temperature immersion in 3.5% (mass fraction) NaCl solution and slow strain rate tensile tests both in air and 3.5%NaCl solution. The results indicate that the addition of TiC nanoparticle promotes the formation of abundant Al₃(Ti, Sc, Zr) precipitates of nano-size, which induces the transition from columnar-equiaxed bimodal grain distribution to fully equiaxed grains in LPBF-fabricated alloy. This refined grain structure significantly improvethe corrosion resistance and stress corrosion cracking (SCC) resistance. Furthermore, the molten pool boundaries and micron-sized TiC particles formed by the agglomeration of nano-particle serve as the preferential sites for localized corrosion, which also act as the preferential initiation and propagation regions for stress corrosion cracks.

In comparison with those prepared by ordinary hot extrusion method, the 17-4PH stainless steel fabricated by laser directed energy deposition (DED) has finer grains and retained austenite. However, current research mainly focuses on its mechanical properties, and there is still a lack of studies on its passivation and pitting corrosion behavior. In this work, the microstructural characteristics, passivation, and pitting behavior in 3.5%NaCl solution of 17-4PH stainless steel prepared with three different DED heat inputs were assessed by taking the hot extruded 17-4PH steel as comparison, via potentiodynamic polarization curves, electrochemical impedance spectroscopy, potentiostatic polarization, critical pitting temperature, and Mott-Schottky curves, as well as XRD, SEM, EBSD, and XPS. The results show that the DED steel prepared with a heat input of 1440 J·cm^-1 contains 6.9% retained austenite (EBSD volume fraction). Compared with the hot extruded steel the lath martensite size of DED steel is reduced by 67.5%, the pitting potential is increased by 0.131 V (vs. Ag/AgCl), the resistance to metastable pitting is higher, the critical pitting temperature is elevated from 47.9 ^oC to 67.2 ^oC, besides, the point defect density is lower and the Cr oxide content is higher for the passivation film. These findings indicate that the DED sample has stronger passivation ability and superior pitting corrosion resistance.

Herein, the corrosion behavior of two CoCrNi medium entropy alloys (MEA) with the same chemical composition, but prepared by laser powder bed fusion (LPBF) and rolling respectively, was comparatively investigated beneath a molten mixed salt film of 50%KCl + 50%Na₂SO₄ (mass fraction) at 650 ^oC by means of electrochemical impedance spectroscopy. The results reveal that the LPBF-fabricated alloy exhibits a double capacitive response, whereas the rolled alloy displays a transition from double capacitive characteristics to diffusion-dominated behavior with increasing corrosion time. Microscopic characterization shows that the LPBF-fabricated alloy surface forms a layered multi-product consisting of Co₃O₄, NiO, Ni₃S₂ and Cr₂O₃, while the rolled alloy surface generates only a single Cr₂O₃, accompanied by severe internal oxidation. The distinct corrosion behavior may be attributed to the influence of grain boundary density and grain boundary distribution characteristics on the metal atom diffusion and corrosive medium permeation, thereby affecting the characteristics of electrochemical impedance spectra and the composition and structure of corrosion product films.

To investigate the effect of WC contents on the wear and corrosion performance of laser claddings of high-entropy eutectic alloy AlCoCrFeNi_2.1, i.e. AlCoCrFeNi_2.1-WC _x with WC contents of 0%, 10%, 30%, and 50% respectively were fabricated on the surface of 45# steel by laser cladding technologywith a dual powder feeding system. The influence of WC content on the microstructure, microhardness, wear resistance, and corrosion resistance of the coatings was systematically studied. The results show that the addition of WC promoted the formation of metal carbides such as WC, W₂C and η phases in the coatings, in addition to the original existed FCC and BCC phases. With the increasing WC content, the volume fractions of hard carbide phases increased, leading to a significant enhancement in microhardness of the composite coatings. The AlCoCrFeNi_2.1-WC₅₀ coating exhibited the highest microhardness of 775.8 HV_0.2, approximately 3.8 times that of 45# steel matrix. Moreover, the wear resistance was markedly enhanced with the increasingWC content, and correspondingly the wear rate decreased from 1.3 × 10^-3 mm³·N^-1·m^-1 for the WC-free AlCoCrFeNi_2.1 coating to 8.6 × 10^-6 mm³·N^-1·m^-1 for the AlCoCrFeNi_2.1-WC₅₀ coating. However, a higher WC content led to increase the emerging of galvanic corrosion between different phases in the coating, thereby deteriorating the corrosion resistance. Comprehansively considering the microhardness, wear resistance and corrosion resistance, the AlCoCrFeNi_2.1-WC₃₀ coating exhibited the best comprehensive properties, featured with a good combination of wear resistance and corrosion resistance, and can be viewed as a promising material for engineering application.

The oxidation behavior in air and corrosion behavior beneath NaCl salt deposit film of selective laser melting prepared 316 stainless steel (SLM-316) and traditional cast 316 stainless steel (Cast-316) at 700 ^oC was comparatively studied. The results showed that the SLM-316 stainless steel exhibited superior high-temperature oxidation and corrosion resistance. After 200 h of oxidation, its weight gain was only 0.047 mg/cm², and the formed oxide scale was uniform and compact, with a thickness of less than 1 μm; whereas the oxide scale of the Cast-316 stainless steel showed obvious zoning, with local thickness exceeding 10 μm and the corresponding weight gain reaching 0.083 mg/cm². In the high-temperature corrosion environment with deposited solid NaCl, the two steels are suffered from corrosion but their corrosion degrees are different: SLM-316 stainless steel showed only a slight weight gain of 0.23 mg/cm², while the Cast-316 stainless steel suffered severe corrosion accompanied by spallation of the corrosion products, resulting in a mass loss of -2.4 mg/cm². The formed corrosion products of the two steels are composed mainly of Fe₂O₃ and NiCr₂O₄. It is proposed that the ultra-fine sub-grain structure introduced by the SLM process may promote the rapid formation of the Cr₂O₃ protective scale, significantly enhancing the high-temperature oxidation resistance and salt corrosion resistance of the 316 stainless steel.

Four different bulk AlSi10Mg alloys were fabricated by laser additive manufacturing with powder bed fusion, while their growth along either vertical, angle horizontal, or 45-degree inclined orientation, as well as on a proper supporter. The corrosion behavior of the four bulk alloys in 3.5%NaCl solution was assessed by means of electrochemical techniques. The results showed that the alloys exhibited a combination of columnar and equiaxed grains with different size and distribution. The growth orientations and supporter have effect on the porosity and residual stress of the alloys, and the vertical growth alloy had the highest porosity and residual stress. Electrochemical results showed that the alloy grown along 45-degree inclined orientation had the best corrosion resistance and the highest pitting potential and polarization resistance. The effect of microstructure on corrosion resistance of the LPBF-AlSi10Mg alloys was discussed.

Mo-alloys are widely used in high-temperature environments foraerospace, nuclear energy and nuclear power industries due to their high melting point, excellent electrical and thermal conductivity and outstanding high-temperature mechanical properties. However, Mo-alloys are very susceptible to oxidation and failure in high-temperature service environments. In this study, Si-ZrB₂-Ti-Cr multicomponent anti-oxidation coatings were fabricated on Mo-alloys via laser cladding, and the effect of laser power on themicrostructure, phase composition, and high-temperature oxidation resistance of the acquired coatings was systematically investigated. The results show that when the laser power for cladding is 2000 W, the main constituents of the coating is metastable Mo₅Si₃ phase rather than the stable MoSi₂ phase, the metastable Mo₅Si₃ phase tens to generate MoO₃ during high-temperature oxidation process, which is highly volatile,, thus the coating has poor oxidation resistance. When the laser power is 3000 W, the acquired coating is ~900 μm in thickness, which showed the best oxidation resistance at 1200 ^oC with formation of a dense oxide scale on surface composed of SiO₂, TiO₂, and ZrO₂. As the laser power was increased to 4500 W, the excessive heat input caused too much Mo to be incorporated into the coating from the substrate. During the oxidation process MoO₃ was prone to volatilize, making the oxide scale porous and loose, thereby reducing the oxidation resistance. These findings may provide a reference for further R & D of high-temperature protective coatings on Mo-alloys.

Non-magnetic drill collars are critical components in directional drilling, and their failure can severely compromise drilling safety, leading to significant economic losses. To enhance their service life, a laser cladding coating on the surface of P550 stainless steel, which is commonly used for non-magnetic drill collars was made via laser cladding technique with powders of the same composition of P550 stainless steel as filler material. The results indicate that the laser cladding presents significantly refined the grain size of 10.37 μm, in contrast to 42.85 μm of the substrate steel, meanwhile the cladding process also promots the enrichment of N at the grain boundaries. Consequently, the passivation zone of the cladding coating was broadened by 2.7 times compared to the substrate when immersion in 3.5% (mass fraction) NaCl solotion. During dynamic wear processits potentiodynamic polarization curve also exhibited the continuous passivation characteristics of the cladding, demonstrating its enhanced electrochemical stability. Furthermore, owing to the excellent re-passivation capability of the cladding coating and the formation of an Fe²⁺-rich oxide scale on the worn surface, its wear volume loss was lower than that of the substrate.

TC4 Ti-alloy has garnered significant attention in industrial applications due to its excellent comprehensive properties, but its difficult machinability makes additive manufacturing technologies a promising alternative processing method. Hence, in the article, the passivation behavior of three TC4 Ti alloys fabricated by wire arc additive manufacturing (WAAM), selective laser melting (SLM) additive manufacturing and conventional forging was comparatively assessed by means of electrochemical testing in 3.5%NaCl solution of pH = 6.8 ± 0.2 at 25 ^oC, and XPS analysis. The results demonstrate that while the passive films formed on the three alloys share similar characteristics in primary constituent elements and semiconducting properties, but notable differences exist in the relative proportions of constituents and defect concentrations of films.

Lead-cooled fast reactors (LFRs) characterized by their high safety, high economic efficiency, and the ability to transmute radioactive nuclides, represent one of the most promising Generation IV reactor designs for practical implementation. Liquid lead-bismuth eutectic (LBE) is the preferred coolant for LFRs. However, LBE with high temperature, high density, and high flow rate will cause intensive corrosion towards the reactor structural materials, which poses a threat to the operational safety of reactors. 304L stainless steel is a candidate structural material for this reactor, and arc additive manufacturing is a novel way to alternate the microstructure of this steel. Therefore, this paper focuses in the influence of δ-ferrite generated in the wire arc additive manufactured (WAAM) 304L stainless steel on its corrosion behavior in saturated oxygen/poor oxygen liquid LBE at 550 ^oC. The results reveal that the corrosion resistance of δ-ferrite is superior to that of austenite. A spinel Fe-Cr protective oxide scale may form on the peripheries of δ-ferrites, which hinder the inward growth of the oxide scale. Consequently, a pincer-like morphology of oxide scale developed within the internal oxidation zone. In poor-oxygen LBE, WAAM 304L stainless steel mainly undergoes dissolution corrosion. Despite a Cr-rich protective scale cannot be formed on its surface due to oxygen content limitations, thereby failing to effectively inhibit dissolution corrosion, even so δ-ferrite still exhibits great resistance to dissolution corrosion. This is mainly attributed to the low Ni content in δ-ferrite, whereas dissolution corrosion is primarily controlled by the dissolution of Ni element.

The unique lamellar structure of cations and anions in hydrotalcite (LDH) endows the interlayer anions with the characteristic of easy ion exchange with the environment, making it an excellent inorganic nanocontainer. In this study, a corrosion inhibitor ZnAlCe-NO₂ LDH loaded with NO{}_{\mathrm{2}}^{-} was prepared by one-step co-precipitation method and which then was added to the sol gel silane coating. It may be reasonably inferred that at defect sites of the coating Ce ions within the LDH lamellae may be response and release where local hydrolysis acidification environment has been generated during the coating service, which then act as a means to inhibit the corrosion of the substrate metal; Meanwhile, the NO{}_{\mathrm{2}}^{-} of high energy state situated between the ZnAlCe-NO₂ LDH lamellae and will spontaneously exchange-react with the infiltrated chloride ions (Cl^-) in the coating, which result in not only capturing and fixing the free Cl^- in the LDH lamellar structure, but also releasing the pre-loaded corrosion inhibitor within the LDH lamellae so that to enhance the protective performance of the coating, just like a Chinese proverb “kill two birds with one stone”. Electrochemical tests in a 0.05 mol/L NaCl solution showed that ZnAlCe-NO₂ LDH had a corrosion inhibition efficiency of 97.57% for carbon steel. Compared with the blank sol gel coating, the corrosion protection performance of the sol gel coating doped with 2.5 mg/mL ZnAlCe-NO₂ LDH has been significantly improved.

To solve the problem of under-deposit corrosion of X65 steel in CO₂-saturated oilfield-produced water, the corrosion inhibition performance of alkyl imidazolines (IM), thiourea (TU) and their compound corrosion inhibitors (TU/IM) on X65 steel under SiO₂ and CaCO₃ inert deposits was investigated using electrochemical analysis and surface analysis. The results show that the corrosion inhibition efficiency η of the three inhibitors may be ranked as η (TU/IM) > η (TU) > η (IM). When adopting IM as inhibitor, the formation of a continuous protective corrosion inhibitor film is difficulty on the steel surface under the two type scales of inert deposits, while the corrosion of metal under the SiO₂ deposits is accelerated, thus IM is poor in corrosion inhibition performance. For TU as a mixed-type inhibitor, both the cathodic and anodic reactions are suppressed, which may be due to that the S atoms of TU tend to coordinate with the empty d-orbitals of Fe atoms, thereby generate coordination chemical bonds, resulting in an electrons rich band in this region, which in turn enhance the stability and protection ability of the formed inhibitor film. Whereas, the TU/IM combination inhibitor demonstrate excellent synergistic inhibition effect, which may be ascribed to that TU initially formed a primary adsorption film on the steel through its superior diffusivity and adsorption capacity, while IM subsequently contributed hydrophobic chains to establish a secondary adsorption film, this dual-layered structure significantly enhances the corrosion inhibition effectiveness.

The corrosion behavior of 40Cr steel in 3.5%NaCl solution under the combined effect of plastic tensile stress and ultraviolet (UV) illumination was investigated. The results demonstrate that UV illumination accelerates the corrosion of 40Cr steel, which is primarily attributed to the lower charge-transfer resistance and higher flat-band potential of the rust layer formed on the surface of the steel under illumination. Furthermore, the formation of a honeycomb inner rust layer under UV illumination facilitates the accumulation of NaCl within the rust layer. The rust layer formed on the surface of 40Cr steel under plastic tensile stress was more porous, exhibiting a higher photoelectric response and lower charge transfer resistance. These factors contributed to the accelerated anodic dissolution of 40Cr steel under the combined effect of plastic tensile stress and UV illumination.

Zwitterionic citrulline (Cit) was introduced as an additive into a 2 mol/L ZnSO₄ electrolyte. Cit molecules preferentially adsorb onto the Zn²⁺ surface, displacing reactive water molecules within the Zn²⁺ solvation sheath, thereby optimizing the Zn²⁺ solvation structure. Simultaneously, Cit coordinates with Zn²⁺ to form a dynamic electrostatic shielding layer, which suppresses the uncontrolled growth of Zn dendrites caused by localized high current density. The synergistic effect of Cit not only effectively reduces and suppresses the hydrogen evolution reaction (HER) rate but also significantly enhances the electrochemical performance of aqueous zinc-ion batteries (ZIBs). Test results show that batteries assembled with Cit/ZnSO₄ electrolyte exhibit superior electrochemical properties compared to those using pristine 2 mol/L ZnSO₄. Specifically, the Zn||Cu asymmetric cell with Cit/ZnSO₄ electrolyte achieves a cycle life exceeding 500 cycles at 0.5 mA·cm^-2 and 0.5 mAh·cm^-2. The Zn||Zn symmetric cell maintains stable operation for over 5,000 hours at 1.0 mA·cm^-2 and 1.0 mAh·cm^-2, and even under harsh conditions of 5.0 mA·cm^-2 and 5.0 mAh·cm^-2, it sustains 2,500 h of cycling. Furthermore, the Zn||V₂O₅ full cell retains high-capacity retention after 1,000 cycles by 1.0 A·g^-1. This work provides novel insights into the development of efficient electrolyte additives and highlights the practical potential of Cit for high-performance ZIBs.

The nanocrystalline coatings of Ni-based single crystal superalloy N5 with and without addition of 0.5%(mass fraction) Y were prepared on the superalloy N5 by magnetron sputtering technology, and then their short-term hot corrosion behavior was studied beneath deposit films of 75%Na₂SO₄ + 25% K₂SO₄ at 850 ^oC, and 75%Na₂SO₄ + 25%NaCl (in mass fraction) at 900 ^oC in air. The results showed that the bare N5 exhibited poor corrosion resistance. Although, the N5 alloy with nanocrystalline coatings showed excellent corrosion resistance to the mixed salts, but, the enhanced corrosion resistance to the NaCl containing salts was not obvious for the N5 nanocrystalline coating and the Y-modified ones. Besides, scale spallation and internal corrosion occurred for the coatings after 5 h corrosion test. The corrosion resistance of nanocrystalline coatings can be significantly improved by proper pre-oxidation at 1000 ^oC for 20 h, the pre-formed oxide scale was able to suppress the attack of the molten salts to certain extent and thus delay the corrosion.

The corrosion inhibition performance and mechanisms of five cyclic amino acids, namely tryptophan, histidine, proline, phenylalanine, and tyrosine, for Fe in HCl solution were investigated by means of molecular dynamics (MD) simulations and density functional theory (DFT) calculations. The results demonstrate that all the five cyclic amino acids exhibit significant corrosion inhibition effect. Among others, tryptophan (Trp) exhibits the most outstanding inhibition performance, which may be attributed to the unique π-electron conjugation effect of its indole ring and the strong coordinating ability of its amino group. MD simulations reveal that Trp forms a dense adsorption film on the metal surface, with a significantly higher adsorption energy (-381.45 kJ/mol) rather than other amino acids (e.g., histidine: -307.11 kJ/mol). Its molecular orientation facilitates the construction of a hydrophobic barrier, effectively impeding the ingress of H⁺/Cl^- ions. DFT analysis further elucidates that the highest occupied molecular orbital (HOMO) of Trp is localized on the indole ring and amino group, enabling strong chemical bonding with vacant d-orbitals of metal Fe via electron back-donation. Conversely, the lowest unoccupied molecular orbital (LUMO) is distributed over the indole ring and carboxyl group, enhancing its adsorption stability. Trp's global reactivity parameter (ΔN = 0.456) is considerably higher than that of other amino acids (e.g., proline ΔN = 0.325), indicating superior charge transfer capability. This results in a pronounced synergistic effect suppressing both anodic metal dissolution and cathodic hydrogen evolution. Consistent with the theoretical findings, electrochemical evaluation confirms that Trp also delivers the best corrosion inhibition performance.

Reinforced concrete piles were prepared and placed in an indoor marine environment simulation set, which then were subjected to applied electric accelerated corrosion so that to be corroded up to 5%, 10%, and 15% of the mean corrosion degree derived theoretically respectively. Subsequently, textile reinforced concrete (TRC) was wrapped around the tidal zone of the piles, and electric current was applied to provide cathodic protection to the steel bars for 90 days in the indoor marine environment simulation set. Along with the corrosion process, by different corrosion degrees and cathodic protection times, the cracking propagation of the concrete surface was acquired to calculate the fractal dimension, and the variations of polarization resistance and electrochemical impedance spectroscopies were detected. The results indicate that the fractal dimension, the polarization resistance R_p, the low-frequency capacitance arc radius in the Nyquist plot, and the low-frequency phase angle in the Bode plot all change regularly with the corrosion process. Specifically, corresponding to 15% corrosion degree, the fractal dimensions of the atmospheric zone, tidal zone, and underwater zone were 1.206, 1.317, and 1.381 respectively. After 90 d, the values in the atmospheric zone and underwater zone were 1.235 and 1.391, respectively. At the same time, the R_p values in each zone increased by 41.51% (atmospheric zone), 44.90% (tidal zone), and 49.39% (underwater zone) compared to those without applied cathodic protection. A reasonable equivalent circuit was further proposed to quantify the variation patterns of concrete resistance (R_con) and charge transfer resistance (R_ct). After 90 d of cathodic protection, the R_ct values in the atmospheric zone, tidal zone, and underwater zone showed average increases of 548%, 506%, and 300%, respectively. The findings provide reference for the evaluation and monitoring of the corrosion status and cathodic protection effect of pile foundations in marine environments.

B10 Cu-Ni alloy is widely used in marine seawater pipeline systems due to its excellent corrosion and erosion resistance. However, in flowing seawater environments, it still faces challenges such as erosion-corrosion. Herein, the corrosion behavior of a B10 Cu-Ni alloy control valve in actual seawater service conditions was assessed by integrating field service analysis, corrosion morphology characterization, and computational fluid dynamics (CFD) simulations. The results indicate that the distribution of seawater flow velocity inside the control valve is highly non-uniform by different valve opening degrees. In certain regions, the local flow velocity exceeds 8 m/s, significantly surpassing the critical velocity of B10 Cu-Ni alloy, leading to intensified turbulence and shear stress effects. Consequently, high-flow regions develop horseshoe-shaped corrosion pits, while low-flow regions exhibit fish-scale-like corrosion patterns.

The cold-sprayed TC4 coating exhibits high porosity, leading to poor corrosion resistance. To enhance the corrosion resistance, this study introduced WC particles with varying volume fractions (15%-30%, volume fraction) into TC4 powder, so that the influence of WC content on the microstructure and corrosion performance of the cold-sprayed TC4-WC coatings on carbon steel Q235 in artificial seawater was investigated by scanning electron microscope, electrochemical measurement and salt spray corrosion tests. The results indicate that the mechanical interlocking effect of WC particles can effectively reduce the coating porosity. When the WC content reaches 25%, the porosity of the composite coating decreases significantly from 10.573% (plain TC4 coating) to 0.464%, demonstrating superior corrosion resistance. Electrochemical tests in 3.5%NaCl solution reveal that the optimal composite coating (TC4-25%WC) exhibits a corrosion current density of three orders of magnitude lower than that of the substrate. Electrochemical and salt spray corrosion tests show that WC particles promote the formation of a dense TC4 matrix through plastic deformation effects, thereby effectively blocks the penetration pathways of corrosive media. Corrosion mechanism analysis confirms that the failure of the plain TC4 coating originates from crevice corrosion induced by pores, whereas the incorporation of WC significantly inhibits the penetration of corrosive media toward the coating/substrate interface. This study provides a meaningful reference for the development of high-performance Ti-based composite protective coatings.

In the circuit of liquid cooling system of electronic devices, there is a widespread problem of galvanic corrosion compatibility of dissimilar metal in ethylene glycol coolant, which seriously threatens the boundary integrity of liquid cooling system and the service safety of electronic devices. Based on this background, the galvanic effect and reaction mechanism between TP2 Cu-alloy and AA1060 Al-alloy in ethylene glycol-water coolent was assessed -by means of electrochemical corrosion testing and static immersion corrosion test. The results show that the corrosion potential difference of AA1060 Al-alloy as anode and TP2 Cu-alloy as cathode is 608.8 mV in ethylene glycol-water coolent, thus the risk of galvanic corrosion is high. At the initial stage of corrosion, the galvanic potential is above the pitting potential of AA1060 Al-alloy, while the spontaneous pitting of AA1060 Al-alloy occurs due to the action of strong anode polarization. The maximum pitting rate corresponding to the maximum pitting depth of AA1060 Al-alloy (188.24 μm) acquired by the immersion test is 2.29 mm/a, which is higher than the corrosion rate calculated by the galvanic current of 1.09 mm/a. This difference in corrosion rate is related to the reverse deposition of Cu²⁺ on AA1060 Al-alloy and the induced local micro-galvanic effect. In this process, due to the large resistance of ethylene glycol coolent and insufficient cathodic polarization of TP2, part of Cu²⁺ can still be dissolved through free-corrosion. The dissolved Cu²⁺ forms a simple Cu on the surface of AA1060 Al-alloy through displacement reaction, and forms a local micro-couple of Cu with Al matrix, which further promotes the local dissolution of AA1060 Al-alloy. Therefore, the corrosion rate acquied by electrochemical test is less than the actual corrosion rate.

Herein, an innovative multi-channel atmospheric corrosion monitoring workstation was designed to evaluate the corrosivity of different atmospheric conditions on engineering materials. The device features a simple structure and user-friendly operation, enabling the real-time collection of long-term corrosion data of materials, and the monitor of key atmospheric parameters such as temperature, humidity, UV intensity, and SO₂ concentration. By comparing the measurement results of two probes with detecting elements of 0.5 and 2 mm thickness respectively, it was found that the 0.5 mm probe performed better in terms of sensitivity and response time. It follows that the device can effectively evaluate the corrosion of mild steel in different atmospheric conditions, with a resolution of up to 0.05 mm. Obviously, it can be expected that this device will become a providing a powerful tool for assessment of corrosion performance of engineering materials.