Cultural heritage，as a vital material carrier of the development of human civilization，plays a critical role in sustaining historical-cultural lineage，advancing cultural inheritance，and passing down civilizations via its conservation，restoration and utilization. Most extant cultural heritage has suffered varying degrees of deterioration due to its long history as well as natural and human-induced damage，making scientific and rational condition assessment and the design of conservation and restoration plans essential. In recent years，numerical simulation has attracted increasing attention in cultural heritage conservation. Among various numerical approaches，finite element analysis (FEA) has been widely adopted because of its well-established theoretical framework，high computational accuracy，and ease of implementation，and has been extensively applied to the conservation of ancient architecture，sculptures，ceramics，metal artefacts，and other types of cultural heritage. Focusing on the research and application progress of FEA in cultural heritage conservation，this review first introduced the basic principles of FEA and summarized the current applications of mainstream numerical simulation software，including Ansys，Abaqus，and COMSOL，in cultural heritage restoration，mechanical stability assessment，and related areas. It then discussed the common key issues that constrained the further application of FEA in cultural heritage conservation. Owing to the heterogeneity of heritage materials，the complexity of geometric structures，and the non-uniformity of deterioration states，significant technical bottlenecks remained in accurate model construction，realistic assignment of physical-field parameters，and improvement of computational accuracy. Finally，future development trends of FEA in cultural heritage conservation were discussed. Future research should focus on refined modelling of small-scale cultural heritage objects，multidisciplinary integration involving artificial intelligence and experimental characterization，and optimization of numerical algorithms，thereby promoting the establishment of a more broadly applicable and reliable FEA-based technical framework for cultural heritage conservation and facilitating the development of more scientific and sustainable cultural heritage conservation practices.

Metal artifacts are susceptible to corrosion and deterioration during long-term burial and preservation，placing higher requirements on the compatibility，stability，and reversibility of conservation and restoration materials. Owing to their tailorable structures and tunable properties，polymer materials have considerable potential for applications in the bonding and consolidation，surface protection，corrosion inhibition and protection，controlled cleaning，and temporary protection of metal artifacts. This review summarized the application progress of polymer materials in the conservation of metal artifacts. It particularly emphasized the compositional characteristics，modification methods，current-day applications，and performance characteristics of different polymer material systems. It analyzed their application scopes and existing problems. On this basis，the limitations of existing research concerning the long-term stability，interfacial compatibility，reversibility，and environmental safety of polymer conservation and restoration materials were further analyzed. Future development of polymer materials toward higher precision and functionality in metal artifact conservation was also discussed，with a view to providing a reference for the research and application of related conservation and restoration materials.

Ancient murals are precious cultural heritage assets that embody important civilizational and artistic values，yet they are subject to severe deterioration caused by both natural weathering and human disturbance. According to the Chinese national standard GB/T 30237-2025，mural deterioration can be systematically classified into 35 types，including cracking，flaking，and salt-related deterioration，and generally results from the coupled effects of multiple factors. This review analyzed the formation mechanisms of mural deterioration from multiple perspectives. It summarized five major categories of causes:water and salt migration，material aging，structural instability，environmental factors，and human activities. Among these，water and salt migration represents a major mechanism responsible for deterioration of the ground layers，such as salt damage and blistering. Crystallization stress generated by repeated dissolution and crystallization of soluble salts within mural pores directly damages the ground-layer structure and can further induce deterioration of the paint layer，including flaking and powdering. Material aging mainly involves degradation of binding media and chemical alteration of pigments. Oxidation and hydrolysis of binding media，together with photochemical and microbially mediated transformations of pigments，constitute major intrinsic causes of flaking，powdering，and discoloration.Structural instability is an integrated consequence of these processes and is manifested mainly as delamination，cracking，and related defects，which can in turn accelerate cascading deterioration. Fluctuations in temperature and relative humidity，biodeterioration，deliberate alteration，inappropriate visitor activities，and previous restoration interventions act as important external drivers of deterioration.On this basis，this review systematically summarized research progress in conservation and restoration materials for ancient murals. Current materials are mainly classified into three categories:consolidants，cleaning materials，and surface protection materials，while specialized material systems used for mural detachment and relocation are also reviewed. Consolidation materials have evolved from traditional materials，such as clarified clay-lime grouts and natural adhesives，to modern acrylic resins，organosilicon materials，nano-calcium hydroxide，and organic-inorganic hybrid materials. Each material system has distinct advantages and limitations. For example，nano-calcium hydroxide exhibits excellent compatibility but is limited by insufficient penetration depth，whereas organosilicon materials show good weather resistance but relatively weak bonding with calcareous substrates. Cleaning materials include water-based cleaning agents，organic solvents，and gel-based cleaning systems.Among these，gels offer significant advantages for cleaning delicate areas and fragile murals because of their controlled and sustained release of cleaning agents. Surface protection materials can be broadly divided into organic and inorganic systems. Traditional materials，such as natural adhesives and limewater，exhibit good compatibility but are susceptible to aging and may leave whitening residues，whereas newer materials，including fluorosilane-modified polyacrylic resins and nano-calcium hydroxide suspensions，have achieved substantial improvements in weather resistance and penetrability. Specialized material systems for mural detachment and relocation are designed to achieve safe separation，stable transportation，and reliable reinstallation，and typically include reversible consolidants，separation-layer gels，and rigid backing materials.A major challenge in the current research and application of mural conservation materials is the substantial gap between laboratory performance and practical requirements in the field. Long-term reliability data for new materials under complex multifactorial environments remain insufficient，their compatibility with field application procedures is often inadequate，and systematic solutions for severe and compound deterioration are still scarce. Complex preservation environments and the fundamental principles governing cultural heritage conservation further intensify these challenges. Future research should therefore focus on developing multifactorial coupled-aging evaluation systems that more closely reflect field-site conditions，designing smart materials and modular treatment processes for specific conservation scenarios，and strengthening engineering-oriented studies and standardized field pilot-scale tests. By promoting the paradigm shift of mural protection from passive restoration to active prevention and precise intervention，combined with digital monitoring and early warning technology，a “material structure environment” integrated protection system is constructed to provide solid technical support for the sustainable preservation of murals.

Brass，as an important metal alloy in ancient times，has been a focus of academic attention for its corrosion products and corrosion mechanisms in cultural relics. In this study，a Qing Dynasty leaded-brass tripod censer exhibiting three differently colored corrosion products on its body was investigated. X-ray fluorescence spectroscopy (XRF)，X-ray diffraction (XRD)，scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) were employed to systematically characterize the matrix composition，corrosion morphology，and phase composition of the artifact，and its corrosion mechanisms were further investigated. The results showed that the tripod censer was made of leaded brass containing approximately 2％-3％ Pb. The major corrosion product phases identified on the artifact were (Cu2.81Zn2.19)(CO3)2(OH)6，Cu2(OH)2CO3，K2Cu(C2O4)2·2H2O，CaCO3，and CuO. Among these，(Cu2.81Zn2.19)(CO3)2(OH)6 and Cu2(OH)2CO3 were identified as products of the natural atmospheric corrosion of brass. K2Cu(C2O4)2·2H2O was an uncommon corrosion product and was inferred to be associated with contamination by chemical reagents containing oxalic acid and potassium oxalate. CaCO3 was mainly attributed to reaction and deposition involving lime-containing components in incense during burning，together with exogenous deposition from the surrounding environment. CuO was identified as a high-temperature oxidation product formed as a result of localized heating during incense burning. The results demonstrated that the leaded-brass tripod censer had undergone predominantly long-term atmospheric electrochemical corrosion，accompanied by localized high-temperature oxidation as a secondary corrosion process. They revealed the close relationship between corrosion behavior and the material，function and storage environment of artifacts，offering practical references and a theoretical basis for corrosion mechanism study，conservation and preventive protection of similar brass antiquities.

To further elucidate the scientific significance of the manufacturing process of Warring States-period openwork bronze square dou vessels in museum collections and to clarify the causes of corrosion-related deterioration of the artifacts，two Warring States-period bronze square dou vessels from the collection of the Gansu Provincial Museum were scientifically investigated using portable X-ray fluorescence spectrometry (p-XRF)，scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS)，metallographic microscopy，ultra-depth-of-field microscopy，Raman spectroscopy，polarized light microscopy，and ion chromatography. The results showed that all parts of the two bronze dou vessels were composed of ternary Cu-Sn-Pb alloys，with an average matrix composition of82.58％ Cu，10.68％ Sn，and 4.90％ Pb. Both the vessel bodies and lids were each cast as a single piece. The corrosion products on the artifact surfaces included malachite (CuCO3·Cu(OH)2)，cuprite (Cu2O)，anglesite (PbSO4)，atacamite (Cu2(OH)3Cl)，and chalcocite (Cu2S)，with localized deposits of calcium carbonate and silicon dioxide. The corrosion layers exhibited a typical oxidation-type stratified structure:the outer corrosion layer consisted mainly of malachite，whereas the intermediate oxidation layer contained cuprite and cassiterite (SnO2). The energy spectrum data of the rust layer showed a decrease in the Cu/Sn ratio from the substrate to the surface layer，while the lead content increased. However，the soil rust layer exhibited higher copper content，lower lead content，and no detectable tin，indicating that tin and lead were mostly deposited in situ during the corrosion process，with less migration to the soil，while copper element migrated and lost more to the soil. During the corrosion process，chloride and sulfate ions migrated toward the bronze surfaces，resulting in the formation and deposition of secondary corrosion products such as atacamite and lead sulfate. The formation of abundant Cu2S on the bronze surfaces may have been associated with microorganisms，particularly sulfate-reducing bacteria，in the burial environment. In addition，differences in the degree of corrosion and mineralization among different parts of the artifacts were attributed to the combined effects of adhering soil and the openwork structure. These findings provided important scientific evidence for understanding the manufacturing technology of similar artifacts and for their conservation and restoration.

To conserve ten severely corroded Western Xia iron artifacts in the Ningxia Museum，stereomicroscopy，X-ray fluorescence spectroscopy (XRF)，X-ray diffraction (XRD)，and laser Raman spectroscopy were used to analyze the micromorphology，elemental composition，and phase structure of their corrosion products. The results showed that the corrosion products exhibited multiphase composite characteristics，mainly composed of hematite，magnetite，and goethite. At the same time，highly active goethite and high-chloride akaganeite(β-FeOOH) were detected，and sporadic detection of jarosite was also observed. In areas with high-chlorine corrosion，the electrochemical process driven by chloride ions was the main factor causing corrosion；The mixed composition of multiphase corrosion products indicated that the object was in a complex burial or preservation environment for a long time；The detection of sulfate further indicated that the corrosion cause of this batch of artifacts was the result of multiple coupled factors. Based on the above analysis，following the principle of minimal intervention，measures such as mechanical cleaning，alkali desalination，and corrosion inhibition sealing were adopted for graded protection，which achieved good results and can provide reference for the selection of protection methods for similar iron cultural relics.

Algal biodeterioration is a common type of deterioration on the surfaces of archaeological sites. To investigate techniques for controlling algal biodeterioration on archaeological profiles within enclosed protective shelters, the Nanzuo Site was selected as the study site. Six biocidal materials or treatments, including 4,5-dichloro-2-octyl-4-isothiazolin-3-one(DCOIT), octylisothiazolinone(OIT), benzalkonium chloride(BC), carvacrol(XQF), nano-ZnO(nZnO), and ultraviolet-C(UVC) irradiation, were evaluated using multiple concentration and irradiation-condition gradients. The inhibitory and algicidal effects of the different treatments on algal activity and regrowth were comprehensively assessed using ATP fluorescence assays, microscopic analysis, and the maximum photochemical efficiency of photosystem II(F_v/F_m). The results showed that DCOIT and OIT exhibited the highest inhibitory and algicidal efficiencies at all tested concentrations. Both treatments significantly reduced algal photosynthetic activity and inhibited biofilm regrowth. BC and XQF showed good short-term inhibitory effects on algae, but their long-term efficacy decreased over time. In contrast, nZnO and UVC irradiation showed only limited inhibitory effects. This study established a standardized experimental and efficacy-evaluation system for algal biodeterioration at archaeological sites, providing a scientific basis and technical reference for the prevention and control of microbial biodeterioration at loess archaeological sites.

Thread-by-thread tear mending is the most suitable technique for repairing local cracks in canvas that adheres to the principles of minimal intervention and authenticity in cultural relic restoration，and the adhesive is a key factor in this technique. To achieve a more comprehensive and systematic evaluation of adhesives for thread-by-thread tear mending and overcome the limitation of existing studies that rely on relatively limited evaluation criteria，three adhesives—Lineco® EVA-methylcellulose，sturgeon glue-Arbocel® BWW40 cellulose，and sturgeon glue-wheat starch—were selected for investigation. Four types of canvas supports，namely linen，jute，cotton-linen blend，and pure cotton，were introduced. The visual appearance，mechanical properties，swelling behavior，and reversibility of the adhesives before and after ultraviolet(UV) aging were evaluated. Their resistance to UV aging was analyzed，the aging mechanisms were investigated，and their handling properties were further examined in detail. The results showed that，in terms of UV-aging resistance and mechanical properties，Lineco® EVA-methylcellulose exhibited the best overall performance，sturgeon glue-Arbocel® BWW40 cellulose showed intermediate performance，and sturgeon gluewheat starch showed relatively weaker performance. For the other evaluated properties，each of the three adhesives exhibited its own advantages and limitations. Based on the conservation treatment of Menglianggu Campaign，an oil painting in the collection of the National Museum of China，the practical application of Lineco® EVA-methylcellulose was further examined. It is found that in actual crack repair work，it is necessary to consider the material of the oil painting body，the location of the crack，the degree of damage，and the stress state，comprehensively consider the various properties of the adhesive，and selectively screen and adapt to different crack parts of the adhesive for line by line bonding.

The deposition of high-quality alumina (Al2O3) thin films by high-power impulse magnetron sputtering (HiPIMS) faces a fundamental process trade-off. To maintain discharge stability and suppress target poisoning during reactive sputtering，the process is generally operated at relatively low oxygen flow rates. However，the above operation will inevitably lead to insufficient oxygen content and deviation from the stoichiometric ratio of the film，seriously reducing its functional characteristics such as insulation resistance，hardness，and corrosion resistance. Alumina thin films are widely used in microelectronics，protective coatings，optical devices，and corrosion protection，and their performance strongly depends on an oxygen content close to the stoichiometric composition. Therefore，overcoming the long-standing trade-off between plasma stability and complete film oxidation remains an important objective in ceramic thin-film deposition. In this study，a hybrid process combining an anode-layer ion source (ALIS) with HiPIMS was proposed to address this challenge. The ALIS independently generated a high flux of reactive oxygen species，including ions and radicals，without relying on the cathode discharge，thereby decoupling film oxidation from the conditions required for stable magnetron sputtering. Unlike conventional reactive sputtering，in which oxidation is constrained by the dissociation of molecular oxygen near the target，the ALIS supplied controllable energetic reactive oxygen species that directly participated in oxidation reactions at the growing film surface. This configuration allowed the HiPIMS cathode to operate in the metallic discharge mode with minimal target poisoning，while the film oxidation state was regulated by the ALIS power.The effects of ALIS power over the range of 0-2 200 W on the chemical composition，microstructure，and properties of the alumina thin films were systematically investigated. Compositional analysis showed that，without ALIS assistance，the films were severely oxygen-deficient，with an Al/O atomic ratio of 1.04，indicating incomplete oxidation and the possible presence of suboxide phases or metallic Al components.With increasing ALIS power，the degree of oxidation increased markedly and controllably，and the Al/O ratio decreased to 0.58，indicating a substantial transition toward a more fully oxidized Al2O3 state. The decrease in the Al/O ratio was directly associated with the increased supply of reactive oxygen species，which promoted oxidation reactions at the growing film surface. The improved film composition was attributed to enhanced oxygen activation and ionization by the ALIS，which supplied sufficient reactive species to the growth surface. The transition toward a more fully oxidized state significantly improved the film properties. Owing to the formation of a more strongly bonded Al-O network，the film hardness increased substantially，reaching a maximum of 959 HV. The variation in hardness reflected both densification of the oxide structure and a reduction in oxygen-deficiency-related defects，thereby enhancing the mechanical strength. The electrical insulating properties were also markedly improved，as evidenced by substantial increases in breakdown strength and surface resistance，indicating a pronounced reduction in charge-carrier density. Electrochemical corrosion tests further demonstrated enhanced protective performance:the corrosion potential shifted positively from -0.771 to -0.544 V，while the corrosion current density decreased by nearly two orders of magnitude，indicating a significant enhancement in the anti-corrosion effect of the thin film. These results demonstrated a close relationship between the degree of film oxidation and electrochemical stability，because oxygen-deficient films tend to exhibit porous microstructures and high defect densities that facilitate the penetration of corrosive species.An optimized process window was also identified. Although increasing the ALIS power was critical for promoting complete oxidation，excessively high power produced an overly dense plasma and could induce plasma-related surface damage，highlighting the need for parameter optimization. When the ALIS power was too high，high-energy oxygen ion bombardment and charge accumulation might cause sputtering，re-etching，and ignition problems on the growth surface，increasing film roughness or introducing microstructural defects，thereby partially offsetting the performance optimization brought about by the improvement of stoichiometry. These observations highlight the importance of balancing oxidation enhancement against plasma-induced damage to ensure the growth of high-quality films. Overall，the ALIS-assisted HiPIMS process effectively alleviated the long-standing conflict between discharge stability and oxidation completeness in reactive sputtering. by externally supplying reactive oxygen species，this method significantly expanded the available process window，providing a robust and controllable pathway for depositing high-performance，fully stoichiometric Al2O3 films with good mechanical，electrical，and corrosion resistance properties，which can meet the needs of advanced technology applications. The proposed strategy could also be extended to other oxide systems subject to similar limitations in oxygen activation，providing a feasible route toward next-generation dielectric and protective coatings.

Epoxy coatings are extensively used for corrosion protection of metallic substrates because of their excellent film-forming capability，high adhesion，and favorable mechanical properties. However，in harsh marine environments，their long-term service stability is often limited by micro defects generated during the curing process，the water absorption behavior of polar resin networks，and the subsequent continuous penetration of chloride ions，oxygen，and water molecules into the coating/substrate interface. To address these limitations，an epoxy composite coating system containing a tannic acid-modified bismuth-based metal-organic framework (TA-BiMOF) as a multifunctional filler was developed，aiming to simultaneously enhance the mechanical stability and long-term anti-corrosion performance of the coating.

TA-BiMOF was synthesized through a mild room-temperature solution route and systematically characterized by scanning electron microscopy (SEM)，energy dispersive spectrometry (EDS)，X-ray photoelectron spectroscopy (XPS)，Fourier-transform infrared spectroscopy(FT-IR)，X-ray diffraction (XRD)，Raman spectroscopy，N2 adsorption-desorption，and thermogravimetric analysis. The results confirmed that tannic acid modification preserved the primary framework structure of BiMOF while regulating crystal growth，suppressing agglomeration，and enriching the particle surface with oxygen-containing functional groups. Compared with pristine BiMOF，TA-BiMOF showed a more homogeneous and refined morphology，and its elemental composition changed from 18.14％(mass fraction，the same below) C，8.18％ O，and 73.05％ Bi to 20.31％ C，11.06％ O，and 68.62％ Bi，indicating successful tannic acid incorporation. XPS analysis further revealed an approximately 0.3 eV positive shift in the Bi 4f peaks，suggesting altered coordination environments around Bi sites after polyphenol modification. In addition，tannic acid significantly optimized the pore characteristics of the framework:the Brunauer-Emmett-Teller (BET) specific surface area of TA-BiMOF increased from 194.68 to 321.74 m2/g，whereas the average pore diameter decreased from 5.38 to 2.91 nm，and the microporous surface area reached 277.98 m2/g with a micropore volume of0.11 cm3/g. These changes indicate that TA-BiMOF possesses a finer and more developed porous architecture，which is beneficial for strengthening matrix-filler interactions and increasing the tortuosity of diffusion pathways for corrosive species. Thermogravimetric analysis also showed that TA-BiMOF exhibited continuous mass loss over a broader temperature range than BiMOF，indicating that tannic acid modification altered the thermal decomposition behavior of BiMOF and broadened its massloss temperature range.

The modified filler was then incorporated into epoxy at a loading of 1％ to fabricate TA-BiMOF/EP composite coatings，while neat epoxy and BiMOF/EP coatings were prepared as controls under identical conditions. The SEM results of the cross-section after liquid nitrogen embrittlement showed that the pure EP coating had a relatively flat cross-section and typical brittle fracture characteristics，with irregular micropores and local defects inside，whereas BiMOF/EP displayed increased roughness but also obvious interfacial gaps and local particle aggregation，reflecting insufficient compatibility between unmodified BiMOF and the epoxy matrix. In contrast，TA-BiMOF/EP exhibited a much denser microstructure and a more compact filler/matrix interface without obvious debonding features，demonstrating that tannic acid effectively improved filler dispersion and interfacial compatibility. This microstructural optimization directly translated into improved surface and mechanical properties. The static water contact angle of TA-BiMOF/EP coating increased from 59.5°of pure EP to 74.5°，significantly higher than the 69.1°of BiMOF/EP，indicating a decrease in surface wettability and an enhancement in resistance to water infiltration. The pull-off adhesion strength increased from 10.21 MPa for neat EP to 14.84 MPa for BiMOF/EP and 14.00 MPa for TA-BiMOF/EP，corresponding to a 37.1％increase for the TA-BiMOF-filled coating relative to the unfilled system. Tensile testing revealed a pronounced difference between unmodified and modified filler effects. Although pristine BiMOF increased stiffness，it also caused premature failure，reducing the tensile strength to approximately 45 MPa and the elongation at break to about 2.5％，indicating severe stress concentration arising from poor interfacial compatibility. By contrast，TA-BiMOF/EP achieved the best balance of strength and ductility，with a tensile strength of 71.8 MPa，representing a 19.7％ increase over neat EP (～60 MPa)，while maintaining an elongation at break of about 6％，exhibiting the best balance of strength and toughness. These results indicate that tannic acid modification enables more efficient stress transfer across the filler/matrix interface and mitigates the embrittlement typically associated with rigid particulate fillers. The anti-corrosion performance of the coatings was evaluated by electrochemical impedance spectroscopy in 3.5％ NaCl solution during immersion for up to 70 d. Neat EP showed rapid electrochemical degradation，as evidenced by a strong shrinkage of the Nyquist capacitive arc，a decrease in low-frequency impedance modulus to 9.55×107 Ω·cm2 after70 d，and a concomitant increase in coating capacitance to 7.76×10-9 F/cm2，indicating severe water uptake and loss of barrier integrity. In contrast，BiMOF/EP maintained a much higher low-frequency impedance of6.92×1010 Ω·cm2 and a much lower coating capacitance of2.00×10-11 F/cm2 after 70 d，confirming that the introduction of MOF particles effectively retarded electrolyte penetration by increasing diffusion-path tortuosity. TA-Bi-MOF/EP maintained a stable electrochemical response throughout the entire immersion period. Its Nyquist plots remained highly overlapped over time，and the low-frequency phase angle stayed close to 90°，indicating persistent capacitive behavior and excellent coating integrity. After 70 d of saline exposure，TA-BiMOF/EP still retained a low-frequency impedance modulus of4.79×1010 Ω·cm2 and a low coating capacitance of 1.62×10-11 F/cm2，with its low-frequency impedance being approximately 2.7 orders of magnitude higher than that of neat EP. Equivalentcircuit fitting further showed that TA-BiMOF/EP maintained the highest charge-transfer resistance throughout the test period，confirming the most effective suppression of interfacial corrosion reactions. Post-immersion substrate characterization after coating delamination further corroborated the electrochemical results. Severe underfilm corrosion，abundant corrosion products，and obvious pitting were observed on the steel surface beneath neat EP，accompanied by an oxygen content of 14.8％(atomic fraction，the same below) and a small amount of chlorine. Bi-MOF/EP offered partial protection，preserving a relatively smooth substrate with only minor discoloration and an oxygen content of 1.7％. Notably，the steel protected by TA-BiMOF/EP retained a bright metallic appearance with clear grinding marks，a Fe content of85.5％，and no detectable oxygen，indicating that corrosion was nearly completely suppressed during prolonged immersion.

The superior performance of TA-BiMOF/EP can therefore be attributed to the synergistic integration of multiple mechanisms，including MOF-induced tortuous diffusion pathways for physical barrier enhancement，tannic acid-mediated interfacial strengthening between filler and epoxy matrix，reduced curing-induced microdefects through improved filler dispersion，and possible metal-chelation-assisted passivation by the polyphenolic groups of tannic acid. Overall，this work demonstrated that tannic acid functionalization was an effective strategy for tailoring Bi-MOF toward high-performance epoxy anti-corrosion coatings，offering a viable materials design route for constructing mechanically reinforced and electrochemically durable protective systems for marine metallic infrastructure.

Titanium alloys and high-temperature alloys are core materials in aerospace engineering，widely used in aero-engine transmission components such as end teeth and splines，which operate under harsh conditions of high temperature，high pressure，high speed，and severe wear. Fretting wear is a major cause of failure for these components，seriously affecting their service life and reliability. Under extreme conditions like high temperature and load，the fretting wear behavior of materials becomes more complex，imposing stricter requirements on material performance. Key factors influencing titanium alloy fretting wear include frequency，displacement amplitude，normal load，and ambient temperature. This study aimed to investigate the effect of different normal loads on the fretting wear performance of titanium alloy-high-temperature alloy friction mating pairs at 500 ℃，reveal the underlying wear mechanisms，and provide theoretical data and practical references for the antifretting damage design of aerospace components.

Cylindrical specimens of titanium alloy (18 mm×20 mm) and high-temperature alloy (18 mm×21 mm) were selected. All specimens underwent standardized grinding，polishing，cleaning，and drying to ensure no oil，rust，or impurities，with consistent initial surface roughness.Their key physical and mechanical properties are as follows:titanium alloy has a tensile strength of 1 130 MPa，yield strength of885 MPa，elastic modulus of 120 GPa，Poisson’ s ratio of0.33，density of4.48 g/cm3，and elongation of 8％；high-temperature alloy exhibits a tensile strength of 1 654 MPa，yield strength of 1 321 MPa，elastic modulus of 218 GPa，Poisson’ s ratio of0.29，density of 8.3 g/cm3，and elongation of 16.4％.

Fretting wear tests were conducted using a tangential fretting wear tester. Normal load was applied via a voice coil motor-driven electric cylinder with closed-loop compensation，and horizontal displacement was provided by another voice coil motor with grating sensor feedback. The ambient temperature and humidity were constant，and a program-controlled heating mode ensured the specimens stably reached 500 ℃. Test parameters included normal loads of200，210 N，and 230 N，displacement amplitude of20 μm，frequency of4 Hz，cycle number of 10 000， and cylinder-on-cylinder orthogonal contact. After testing，scanning electron microscopy (SEM) was used for wear-scar morphology analysis， energy-dispersive spectroscopy (EDS) for elemental-distribution characterization，and a white-light interferometer for three-dimensional (3D) morphology characterization. Results showed that increasing normal load significantly altered the fretting behavior of the friction pair. At 200 N and 210 N，the friction displacement (F-D) curves exhibited a typical parallelogram shape (slip regime) with distinct loading，slipping，unloading，and reverse slip ping stages，stable friction force plateaus，and complete relative slip. At 230 N，the curve transformed into an elliptical shape (partial slip regime) without obvious plateaus，with only slight edge slip and central adhesion. The parallelogram curve at 210 N was narrower than at 200 N， indicating weakened relative slip with increasing load. The friction coefficient (the ratio of frictional force to normal load) gradually decreased with increasing load:1.00 at 200 N，0.60 at 210 N，and 0.55 at 230 N，with the stabilization time shortening sequentially (ta＞tb＞tc).3D morphology and SEM observations revealed more severe damage to titanium alloy than high-temperature alloy at 200 N and 210 N，with wear debris accumulation and adhesion features on the latter. At 230 N，only slight edge damage was observed，with a flat scar center and minimal material loss. Micro-morphologically，slight plowing marks，debris accumulation，and spalling were seen at 200 N and 210 N (indicating fatigue and adhesive wear)，while 230 N showed only slight scratches and mild fatigue wear. EDS analysis indicated full-area O element distribution at 200 N and 210 N (confirming oxidative wear)，with Ti detected on high-tem perature alloy scars and Ni，Cr，Co on titanium alloy scars (indicating element migration and transfer film formation). At 230 N，O was only slightly distributed at edges，and element migration weakened significantly. The wear mechanism evolved from the synergy of adhesive，fatigue， and oxidative wear at 200 N and 210 N to mild fatigue and weak oxidative wear at 230 N. This study systematically investigated the fretting wear performance of titanium alloy-high-temperature alloy friction mating pairs under dif ferent normal loads at 500 ℃. As the load increased from 200 N to 230 N，the friction coefficient decreased，the fretting regime shifted from slip to partial slip，and material damage was significantly reduced. The wear mechanism transitioned from dominant adhesive wear with syner gistic fatigue and oxidative wear at lower loads to mild fatigue and weak oxidative wear at higher loads，attributed to suppressed relative slip and reduced oxygen penetration under high loads. These findings provided critical theoretical data and practical guidance for the anti-fretting design of aerospace components，and offered valuable references for tribological research on high-performance alloy pairs under extreme temperature and load conditions.

To investigate the corrosion behavior and corrosion-resistance mechanism of 825 nickel-based alloy in different service environments，cyclic polarization，potentiostatic polarization，and X-ray photoelectron spectroscopy (XPS) were used to examine the alloy in NaCl and NaOH solutions，and its corrosion resistance mechanism was deeply analyzed. The results showed that in NaCl solution，the 825 alloy exhibited a significant passivation range. When the potential increased above the pitting potential (0.35 V)，the Fe and Ni elements in the passivation film dissolved，leading to the occurrence of pitting corrosion. The resistance of the passivation film rapidly decreased to 2.67 kΩ·cm2.In alkaline NaOH solution，the alloy did not exhibit a flat passive region，but no pitting occurred even above the pitting potential of 0.41 V.Higher potentials promoted Cr enrichment in the passive film，increasing the enrichment factor to 2.2，far above the value of0.38 at 0 V in the passive region，and thereby inhibited pitting. However，dissolution of Fe and Ni oxides reduced the film thickness，increased its defect concentration，and raised the passive current density. Compared with the chloride-containing solution，the strongly alkaline solution provided 825 alloy with superior resistance to pitting.

Stress concentration caused by surface roughness is a key factor in metal fatigue failure，and establishing the relationship between surface roughness and fatigue life is important for the safe design of mechanical components. Existing calibration of physical-model parameters through empirical formulas and testing makes it difficult to achieve the required fatigue-life prediction accuracy，whereas the data-driven fatigue life prediction model has shortcomings in expressing the influence of parameters on fatigue life. To address these problems，medium-carbon steel with surface roughnesses of Ra＝0.4，0.8，and 1.6 μm was investigated，and a fatigue-life prediction method combining a physical model with machine learning was proposed. Rotating-bending fatigue lives at the three roughness levels were evaluated. Crack-propagation theory and the Murakami criterion were used to develop a roughness-governed physical fatigue-life model by considering the equivalence between roughness and initial crack size and the quantitative relationship between fatigue limit and roughness. The model parameters included fatiguelimit constants，material constants，and roughness. To overcome the difficulty of determining multiple physical-model parameters simultaneously，a data-driven fatigue-life model was developed using stress amplitude and surface roughness as input features and fatigue life as the output.To eliminate the influence of dimensionality，the input features were normalized. At the same time，taking the logarithm of the original fatigue life to reduce its magnitude difference. During the modeling process，three algorithms were used:Random Forest (RF)，Gradient Boosting Decision Tree (GBDT)，and Gaussian Process Regression (GPR). Samples with Ra＝0.4 and 1.6 μm were randomly divided into training and test sets at a ratio of80％ to 20％. For RF and GBDT，five-fold cross-validation and a root mean square error (RMSE)-based grid search were used to select hyperparameters within the training set；for GPR，the L-BFGS-B algorithm was used to maximize the marginal log-likelihood.The models were then retrained with the optimal hyperparameters，and an iterative validation procedure involving 50 repeated random dataset divisions was used to evaluate model stability and prevent overfitting under small-sample conditions. The GPR model showed the best predictive accuracy and statistical robustness. Its test-set coefficient of determination (R2) was 10.29％ higher than that of RF and 1.30％ higher than that of GBDT，and it had the lowest root mean square error (RMSE). An improved whale optimization algorithm with a global-search strategy(GSWOA) was subsequently introduced to optimize the GPR hyperparameters. After GSWOA tuning，R2 reached 0.965，an increase of 3.54％，whereas RMSE decreased by 29.19％ to 0.114. Validation based on repeated random dataset divisions also confirmed a marked reduction in the dispersion of prediction errors. The GSWOA-GPR model has achieved its precise ability to capture the nonlinear laws of fatigue life and enhanced its generalization stability under different roughness and stress levels. The GSWOA-GPR model was then combined with the physical fatigue-life model，and a differential evolution algorithm was used for global inversion of the physical parameters. The material constants m and C were determined as 2.100 0 and 6.89×10-9，respectively，and the fatigue-limit constants α and β were 348.81 and 10.00，respectively.A roughness-controlled fatigue-life prediction equation for medium-carbon steel was thereby established. Independent validation using fatiguelife data at Ra＝0.8 μm yielded an RMSE of 0.090 0，confirming the accuracy and robustness of the physical model. The model effectively captured the nonlinear fatigue behavior under coupled stress and roughness. It provided a methodological reference for fatigue-reliability assessment and life design of medium-carbon steel components.

High-strength 0Cr13Ni8Mo2Al martensitic precipitation-hardening stainless steel used in airborne aviation products reached a peak strength of 1 515 MPa after aging and exhibited excellent overall mechanical properties and corrosion resistance. To obtain weld-performance data for this material，specimens that had been solution treated at 910 ℃ and cold treated at 0 ℃ were welded by tungsten inert gas (TIG)welding using X-1 or X-2 wire，the welded specimens were subsequently aged at 538 ℃. Transmission electron microscopy (TEM)，electron backscatter diffraction (EBSD)，and tensile testing were used to characterize the weld microstructure and mechanical properties. Results showed that both wires produced welds with strengths exceeding 90％ of the base-metal strength，the hardness at the center of the weld seam decreased slightly. As the distance from the center of the weld seam increased，the hardness showed an upward trend until it returned to the hardness of the base metal. The average grain size of the weld seam and fusion line of X-1 welding wire was4.95 μm and 2.35 μm，respectively，while that of X-2 welding wire was 1.51 μm and 1.81 μm. The average grain size of the weld seam and fusion line of X-2 welding wire was smaller than that of X-1，due to the addition of Si element in X-2，which could improve the fluidity of the melt pool，increase the material’ s absorption rate of heat source energy，make the cooling process more uniform，reduce the spacing between dendrites，and make the structure denser，ultimately resulting in a smaller grain size.

Although austenitic and martensitic stainless steels exhibit good corrosion resistance and high-temperature performance，they remain susceptible to intergranular corrosion during long-term service，and conventional methods have difficulty providing accurate identification and quantitative evaluation，the refore a combination of various modern analyticed technigues is required to uncover its corrosion mechanism discrepancies. To systematically analyze the intergranular corrosion behavior of welded stainless steel fittings for power plant boiler furnace tubes after long-term service (5×104 h)，various analysis methods such as inductively coupled plasma emission spectroscopy (ICP-OES)，X-ray diffraction (XRD)，optical microscopy，scanning electron microscopy (SEM)，Raman spectroscopy，and electrochemical workstation wereused to compare and study the welded fittings of P91 martensitic stainless steel and 347 austenitic stainless steel. After being corroded by a special deposit etchant (4％ HF＋4％ HNO3＋92％ H2O，volume fraction ratio) for 10 s，the sample was subjected to microstructure observation，Raman spectrum collection，and electrochemical testing in a 3.5％(mass fraction) NaCl solution. Microstructural observation showed the P91 consisted mainly of martensite with a small amount of ferrite and exhibited obvious intergranular corrosion，whereas 347 consisted mainly of austenite and retained ferrite and showed no significant corrosion. A characteristic Raman peak at 1 492 cm-1 assigned to N-Fe2＋in ferrous pyridine ions was detected only in P91，indicating intergranular corrosion and the formation of Fe/Fe2＋products；the peak was absent from the weld and 347 steel. The electrochemical test results indicated that P91 had the lowest corrosion potential (-0.998 5 V) and highest corrosion current density (2.077 9×10-5 A/cm2)，whereas 347 had a higher corrosion potential (-0.648 8 V) and lower current density (1.040 6×10-6 A/cm2)；the weld exhibited the best corrosion resistance. Thus，P91 was more susceptible to intergranular corrosion than 347 and the weld region. The Raman peak at 1 492 cm-1 served as an indicator for identifying and quantitatively evaluating intergranular corrosion in stainless steels. These findings provided an experimental basis and a new method for performance evaluation and life prediction in high-temperature corrosive environments.

Accurate evaluation of oil-and-gas pipeline failure risk is an important component of integrity management. Based on the analysis of relevant research results and corrosion mechanisms at home and abroad，a risk quantification evaluation method for corrosion failure was proposed to address the problem of circumferential non-uniform internal corrosion of pipelines in wet natural gas environments containing CO2.Pipeline-design data，operating parameters，medium composition，failure history，and corrosion-inspection data were comprehensively analyzed to establish classification criteria for failure probability and consequences，construct a 5×5 risk matrix，quantify the pipeline corrosionfailure risk，and determine the corresponding inspection and evaluation interval. Laboratory loop tests were conducted at a gas velocity of7 m/s to compare corrosion morphology and rates at the 0，3，6，and 9 o’ clock positions. The result show the highest corrosion rate，5.99 mm/a，occurred at the 6 o’ clock position and corresponded to a high risk level；the remaining positions were classified as medium-high risk. The results provided a scientific basis for identifying high-risk locations，establishing inspection intervals，and managing the integrity of wet natural gas gathering and transportation pipelines containing CO2，while helping reduce failure risk and operating costs.

The growth of the new-energy battery steel-shell industry has driven capacity upgrades in the Ni-plated steel-strip industry and imposed more stringent requirements on surface protection. The existing water-based alcohol amine protectants have limitations in their protective performance and require the use of auxiliary substances to improve their performance. Therefore，thiols were added at 5％，10％，and 20％ of the concentrate content. The working solutions were characterized through chemical oxygen demand (COD)，pH value，and refractive-index measurements. Protective performance was evaluated using salt-spray tests and electrochemical measurements，and the surface -protection mechanism was examined by scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) and Fourier-transform infrared spectroscopy (FT-IR). The results showed that after further addition of thiol based substances，the organic matter content in the aqueous protective agent working solution increased significantly，from the original 4.65×103 mg/L to a maximum of 4.93×103 mg/L. In terms of the protective effect on the surface of Ni coated steel shells，it was found that the introduction of thiol improved the 8 h salt spray test results significantly，and the number of rust spots decreased. At the same time，during electrochemical testing，the electrochemical impedance increased and the corrosion potential shifted significantly after adding thiol. Among the three additions，10％ thiol produced the best salt-spray resistance，with only a few rust spots. The electrochemical impedance reached a maximum of 4.39×104 Ω，the corrosion potential shifted positively，and the corrosion risk was reduced. A dense film formed on the specimen surface，with distinct characteristic absorption peaks of thiol groups(S-H)detected，which can effectively block the attack and damage induced by external corrsive factors. When the thiol content increased to 20％，protection declined markedly:more rust spots appeared after 8 h，impedance decreased to 2.17×104 Ω，the corrosion potential shifted negatively，and microscopic pores were observed. Excess thiol therefore inhibited adsorption of the protectant on the specimen surface and reduced its protective effect.