15 June 2025, Volume 58 Issue 6

    

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  Research Progress of High-Temperature Corrosion Resistant Coatings on Titanium Alloy

  WU Yawen, DING Xiaoyun, CUI Menghui, CHENG Yingchun, ZHANG Jin, LIAN Yong

  Materials Protection. 2025, 58(6): 1-12. https://doi.org/10.16577/j.issn.1001-1560.2025.0092

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  Titanium alloys are widely used in aerospace, shipbuilding and other fields, owing to their excellent comprehensive properties such as low density and high specific strength.However, the poor high-temperature corrosion resistance of titanium alloy restricts its application in hightemperature reactive environments.Preparing a protective coating on the surface of titanium alloy can greatly improve its high-temperature corrosion resistance.Firstly,the common high-temperature corrosion resistance coating systems of titanium alloy were reviewed,and its protection mechanism was analyzed.Secondly,the common preparation methods of high-temperature corrosion resistance coating of titanium alloy were summarized.Finally,the development direction of high-temperature corrosion resistance coating was summarized and prospected, and it was proposed that utilizing advanced technologies such as computation and simulation to assist in designing coatings with superior comprehensive performance will be a future trend.
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  Research Progress on Surface Modification of Bipolar Plates for PEMFC

  LI Cong, JIN Rongzhen, REN Yanjie, TANG Chunmei, HONG Yue

  Materials Protection. 2025, 58(6): 13-31. https://doi.org/10.16577/j.issn.1001-1560.2025.0093

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  The bipolar plates are one of the core components of the proton exchange membrane fuel cell (PEMFC),and its performance directly affects the output power and service life of the battery stack.Bipolar plates not only connect individual cells into stacks and provide support,but also provide gas flow paths and isolate the anodes and cathodes, playing a key role in the operating performance and lifetime of fuel cells.Due to the harsh service environment of PEMFC, including high temperature, high humidity and acidic environment, the bipolar plates need to have excellent electrical conductivity and corrosion resistance to ensure the efficient and stable operation of the fuel cell.In this paper, the development status and application progress of PEMFC bipolar plates were briefly described.The research and development of surface modification schemes for electrical conductivity and corrosion resistance were emphatically expounded.Moreover, the surface modification schemes of stainless steel, titanium, titanium alloy, aluminum alloy and other metal bipolar plate’ substrates were systematically introduced.The performance characteristics, development trends and existing problems of different metal bipolar plates and their surface modification schemes were compared.Finally, the common problems and development and application prospects of the surface modification of PEMFC metal bipolar plates were discussed.
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  Research Progress on TiB-Based Protective Coatings

  MENG Lin, WANG Jingjing, ZHU Xinfa, MENG Yi, LU Hongmei, LI Wei

  Materials Protection. 2025, 58(6): 32-43. https://doi.org/10.16577/j.issn.1001-1560.2025.0094

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  To meet the demand for high cutting speeds and feed rates, in addition to requiring a substrate material with high-hardness,excellent coating materials are also essential for protection.In recent years, the modern industry has become increasingly stringent on the performance of materials,and traditional protective coatings have gradually reached their limits.Both nano-multilayer coatings and nanocomposite coatings can effectively compensate for the performance deficiencies of single-layer coatings in terms of hardness, corrosion resistance and wear resistance, which make them widely studied in the field of protective coatings.This paper reviewed recent research progress in titanium boride-based hard coatings,the performance of doped titanium boride-based coatings has been improved to varying degrees.Compared with single-layer coatings, nano-multilayer and composite coatings have superior performance, so the future research directions were also prospected.
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  Effect of Pulse Current Treatment on the Wear Resistance of H13 Steel

  HU Xinxin, WU Mingxia, XUE Ling, LI Qiang, YANG Yi

  Materials Protection. 2025, 58(6): 44-51. https://doi.org/10.16577/j.issn.1001-1560.2025.0095

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  The annealed H13 hot-work die steel was treated by pulse current, and the resulting changes in microstructure, phase composition,hardness and wear resistance were systematically investigated, which were then compared with those of quenched and tempered specimens.Results showed that pulse current treatment could significantly enhance the wear resistance of H13 hot-work die steel.The treated specimens exhibited a microhardness of 708.2 HV, while the quenched and tempered states showed hardness values of 411.9 HV and 341.6 HV, respectively.Under identical friction conditions, the H13 hot-work die steel specimens treated with pulse current displayed significantly smaller wear volume and shallower wear scar depth than those of both quenched and tempered specimens.Phase analysis and microstructural comparisons further revealed that the pulse current treatment effectively induced grain refinement.
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  Effect of Y₂O₃ on the Microstructure and Properties of Selective Laser Melting TC4 Alloys

  CHENG Yulong, LI Zhenhua, YIN Bo, HUANG Jieqing, ZHANG Yu, SONG Dudu

  Materials Protection. 2025, 58(6): 52-64. https://doi.org/10.16577/j.issn.1001-1560.2025.0096

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  The microstructure of TC4 titanium alloy prepared by selective laser melting(SLM) technology is prone to the phenomenon of coarse grains and poor wear resistance.To address this issue, an appropriate amount of Y2O3 was added during the SLM preparation process of TC4 titanium alloy, and its impact on the microstructure and properties of the resulting alloy was analyzed.Results showed that the appropriate addition of Y2O3 could significantly refine the microstructure of the TC4 titanium alloy, leading to improved mechanical properties and enhanced wear resistance.Compared to samples without Y2O3, when the Y2O3 content was 0.10%, the yield strength increased from 700 MPa to 1 086 MPa (a 55%increase), the tensile strength rose from 819 MPa to 1 255 MPa (a 50%increase), and the elongation decreased from 8.04%to 7.00%(a 12.9% reduction), which resulted in a good balance between strength and ductility.When the Y2 O3 content was increased to 0.15%, the microhardness of the TC4 titanium alloy increased from 308.8 HV to 377.1 HV (a 22%increase), indicating a significant improvement in wear resistance.In general,this study provided valuable theoretical insights and robust empirical evidence to support the enhancement of the mechanical properties of TC4 titanium alloys fabricated via SLM.
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  Effect of Sc/Y Co-Doping on Microstructure and High-Temperature Oxidation Properties of FeCoNiCrAl High-Entropy Alloys

  LI Dongqing, ZHENG Shuhui, GU Jian, LIU Shengchun, SI Jiajun

  Materials Protection. 2025, 58(6): 65-73. https://doi.org/10.16577/j.issn.1001-1560.2025.0097

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  To improve the oxidation resistance of FeCoNiCrAl high-entropy alloy in high-temperature environments, Sc/Y was co-doped in FeCoNiCrAl alloy.The high-entropy alloys FeCoNiCrAl and FeCoNiCrAlScY were prepared by vacuum induction melting method, and the microstructure morphology of the alloys was analyzed by optical microscope,scanning electron microscope and transmission electron microscope.Meanwhile, the phase composition of the high-entropy alloy was tested by X-ray diffractometer, and the influence of doping Sc and Y elements on the high-temperature oxidation performance of the alloy was studied by high-temperature tube furnace.Results showed that both FeCoNiCrAl and FeCoNiCrAlScY high-entropy alloys were composed of two nanoscale phases, namely the A2 phase enriched with Fe and Cr elements, and the B2 phase enriched with Ni and Al elements.The FeCoNiCrAl alloy had a body-centered cubic structure (BCC).When Sc and Y elements were added, a face-centered cubic structure (FCC) enriched with Sc and Y elements appeared,and the hardness of the alloy increased significantly at the same time.After short-term oxidation at 1 200 ℃, both the FeCoNiCrAl and FeCoNiCrAlScY alloys developed oxide scales composed exclusively of α-Al2O3, while their substrate matrices underwent a phase transformation from BCC to FCC structure.The FeCoNiCrAl alloy exhibited oxide scale spallation after only 5 min of high-temperature oxidation, whereas the FeCoNiCrAlScY alloy demonstrated oxide scale spallation after 30 min of high-temperature oxidation.
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  Study on Corrosion Behavior of A106 Carbon Steel in Dense-Phase CO₂ Environment

  YU Zhixia, ZHANG Guoqing, LI Yan, WAN Mingqi, WANG Zhi, WANG Yuesong, JIN Zhengyu, LIU Haixian, CHEN Jiongming, LIU Hongwei

  Materials Protection. 2025, 58(6): 72-82. https://doi.org/10.16577/j.issn.1001-1560.2025.0098

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  The corrosion problem of metal materials in supercritical-dense phase CO2 environment is a key factor influencing Carbon Capture,Utilization and Storage (CCUS) technology.However, the corrosion behavior in the micro-water environment with strong corrosive ions is still in need of further investigation.This study focused on investigating the corrosion behavior of A106 steel in dense-phase (liquid) CO2 environments.A high-pressure autoclave was employed to simulate the dense-phase CO2 conditions, while weight loss measurements, scanning electron microscopy (SEM), X-ray diffraction (XRD) and super-depth-of-field 3D microscopy were utilized to systematically examine the effects of micro-water content (200, 1 000, 1 500, 2 000, 2 500 and 3 000 μL/L) on the corrosion behavior of A106 steel.Results showed that in dense-phase CO2 environments, A106 steel exhibited its maximum uniform corrosion rate of 0.086 7 mm/a at a water content of 3 000 μL/L.An uneven ferrous carbonate corrosion product film formed on the specimen surface, creating favorable conditions for localized corrosion development, with the maximum pitting rate reaching 0.548 mm/a.Furthermore, water content was the critical factor affecting metal corrosion in dense-phase CO2 environments, and under the conditions of 25 ℃and 10 MPa, water and CO2 become mutually soluble.In the micro-water environment, water primarily existed in a dissolved state within the liquid CO2 phase,and trace amounts of free water accumulated on the specimen surface, forming discontinuous liquid films or droplets that accelerated the corrosion of A106 steel.
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  Analysis of Acid Salt Spray Corrosion Process and Mechanism of Antique Cast Iron

  WANG Qiang, WEI Cheng, NIU Wenjuan, QIAN Runling

  Materials Protection. 2025, 58(6): 83-92. https://doi.org/10.16577/j.issn.1001-1560.2025.0099

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  Corrosion causes severe damage to iron-based cultural relics.Studying the corrosion process of simulated antique cast iron (as a representative of such relics) holds significant importance for revealing the corrosion mechanisms of iron artifacts.In this work, the surface morphology and corrosion products of cast iron specimens after different durations of salt spray corrosion were characterized and analyzed by laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and laser Raman spectroscopy (LRS).Results showed that after 24 h of acid salt spray corrosion, corrosion pits began to form on the cast iron specimen surface.Following 72 h of exposure,microcracks developed on the surface,creating accelerated corrosion channels that led to generalized corrosion.After 192 h corrosion, the corrosion rate stabilized at a final constant rate of 1.2 g/(cm2∙h).After 240 h of corrosion, the cast iron specimen surface exhibited severe unevenness with a roughness of 8.25 μm, and the corrosion products darkened in color, with partial exfoliation of rust layers observed.With prolonged corrosion time, the O content exhibited an increasing trend, while the Fe content showed a decreasing trend.The final corrosion products were identified as α-Fe2O3, γ-FeOOH, Fe3O4 and α-FeOOH.In the acid salt spray environment, the cast iron specimen underwent surface oxidation during the initial corrosion stage.Moreover, the corrosive solution penetrated through pores to attack the substrate, generating internal stress, and cracks appeared in the surface rust layer accompanied by spallation, leading to micro-galvanic corrosion on the substrate surface.
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  Sand Erosion Wear Analysis of 300M Steel Sand Based on Johnson-Cook Model

  JI Yun, DING Kunying, FAN Jinhu, LIN Guoding

  Materials Protection. 2025, 58(6): 93-101. https://doi.org/10.16577/j.issn.1001-1560.2025.0100

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  Exposed components such as aircraft landing gear sleeves are prone to erosion wear from hard sand and gravel particles due to prolonged exposure to high fluid velocities and particle-concentrated environments.In order to explore the influence of this process on 300M steel,the actual working conditions were simulated by pneumatic sandblasting equipment, and the finite element simulation model of the multi-particle erosion target material based on the Johnson-Cook damage evolution model was established by ABAQUS/Explicit.In addition, the morphological characteristics of 300M steel were observed using X-ray diffractometer and laser confocal microscope.The erosion and wear amounts of sand and gravel under different environmental factors were analyzed through the combination of experiments and simulations, and an erosion rate model suitable for 300M steel was proposed to achieve quantitative analysis of the counter-erosion and wear process.Results showed that compared to fine sand particles (20 mesh), coarse sand particles (60 mesh) increased the average surface roughness by 14.29%and enlarged the average maximum erosion pit size by 23.08%.With the increase of the erosion angle and erosion speed, the surface roughness of 20 mesh and 60 mesh sand grains exhibited a trend of first increasing and then decreasing, and the maximum surface roughness was achieved at 30°,which correlated with morphological fluctuations.When the erosion angle was fixed at 30°, with the increase of erosion pressure (0.3～0.5 MPa), the overall increase ranges of erosion wear caused by 20 mesh and 60 mesh sand particles were 6%～8%and 4%～5%, respectively.
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  Effect of Micro-Arc Pre-Oxidation on Wear and Corrosion Resistance of Low-Temperature Plasma Nitrided Layer on Ti6Al4V Titanium Alloy

  YANG Jiale, XU Lixin, LI Dongshan, PENG Zhenjun, ZHANG Guangan, JIANG Changjun

  Materials Protection. 2025, 58(6): 102-115. https://doi.org/10.16577/j.issn.1001-1560.2025.0101

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  In order to improve the wear resistance and corrosion resistance of Ti6Al4V (TC4) titanium alloy, surface modification of TC4 titanium alloy was carried out using micro-arc oxidation (MAO),low-temperature plasma nitriding (PN) and plasma nitriding after micro-arc oxidation.Subsequently, the microscopic morphology, friction and corrosion resistance of the substate and the samples modified by three processes were studied by scanning electron microscopy, friction and wear testing machine and electrochemical workstation.Results showed that the micro-arc oxidation layer was mainly composed of rutile TiO2 and anatase TiO2 phases.The microhardness of the PN sample was (602±10)HV0.05, and the microhardness of the MAO-PN sample was (1 232±20) HV0.05, significantly higher than the microhardness of the TC4 titanium alloy substrate (352±5) HV0.05.In the atmospheric environment, compared to the TC4 titanium alloy substrate, the wear rates of MAO and MAO-PN samples decreased from 1.48×10－3 mm3/(N∙m) to 5.54×10－4 mm3/(N∙m) and 3.64×10－4 mm3/(N∙m), respectively.Under the lubrication of hydrochloric acid solution,compared with TC4 titanium alloy substrate,the friction coefficient of MAO and MAO-PN samples decreased from 0.35 to 0.25 and 0.18, respectively, and the wear rate decreased significantly from 3.62 × 10－4 mm3/(N∙m) to 3.50 × 10－6 mm3/(N∙m) and 1.57 × 10－6 mm3/(N∙m),respectively.This indicated that micro-arc pre-oxidation could greatly improve the wear resistance of plasma nitride layer.In hydrochloric acid solution, both MAO and MAO-PN samples exhibited abrasive wear mechanisms, while under atmospheric conditions and hydrochloric acid lubrication,TC4 titanium alloy and PN samples demonstrated adhesive wear mechanisms.Furthermore, the MAO-PN composite modified layer exhibited a lower corrosion current density (0.015 μA/cm2) and higher impedance value (9.90×105 Ω∙cm2) in hydrochloric acid solution, indicating that the micro-arc pre-oxidation process significantly enhanced the corrosion resistance of the plasma-nitrided titanium alloy layer.
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  Study on the Water Resistance of Silane-Modified Epoxy Styrene-Acrylic Emulsion

  BU Xingyu, WANG Lei, WEN Jinglong

  Materials Protection. 2025, 58(6): 116-123. https://doi.org/10.16577/j.issn.1001-1560.2025.0102

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  In order to improve the performance bottleneck of traditional styrene-acrylic emulsion in terms of water resistance and long-term stability, epoxy resin E-51 and silane coupling agent KH-560 were introduced to synergistically modify the styrene-acrylic emulsion.The silane-modified epoxy/styrene-acrylic emulsion was prepared by using epoxy resin E-51, silane coupling agent KH-560, and styrene-acrylic emulsion through emulsion polymerization.The factors affecting the performance of the emulsion, such as solid content, gel content, conversion rate, water absorption rate and emulsion stability, were studied.Additionally, the mechanism of water resistance of styrene-acrylic emulsion modified by silane coupling agent KH-560 was explored.Emulsion was synthesized using the seed polymerization method, and the key influencing factors were studied through orthogonal experiments.The performance of the emulsion in each experimental group was tested and analyzed.Simulations of the unmodified and silane-modified emulsions were performed using the Materials Studio software.Models of the unmodified styrene-acrylic emulsion and the silane coupling agent-modified styrene-acrylic emulsion were built, and the transport of water molecules within the coatings was analyzed and calculated under NPT and NVT ensemble models.Results showed that the modified styrene-acrylic emulsion with an OP-10 to SDS mass ratio of 1.5 ∶1.0, an emulsifier content of 7.5%(mass fraction, the same below), a soft-to-hard monomer mass ratio of 1.3 ∶1.0, 4%epoxy resin E-51,and 9%silane coupling agent KH-560 exhibited good performance.It had a favorable water absorption rate of 71.43%, along with desirable solid content, gel content, and conversion rate of 43.75%, 0.98%and 87.5%, respectively, and demonstrated good stability.Additionally, simulation analysis using Materials Studio compared the diffusion coefficients of water molecules in the unmodified and modified styrene-acrylic emulsions.Under NPT simulation, the diffusion coefficients were 2.72×10－5cm2/s and 9.34×10－6 cm2/s, respectively, while under NVT simulation, they were 6.23×10－6 cm2/s and 3.18×10－6 cm2/s, respectively.The diffusion coefficients of the modified styrene-acrylic emulsion were lower than those of the unmodified emulsion in both cases.Silane-modified epoxy styrene-acrylate emulsion was prepared by emulsion polymerization of epoxy resin E-51, silane coupling agent KH-560 and styrene-acrylate emulsion, which effectively improved the basic properties of the emulsion, such as solid content, gel content, conversion rate and emulsion stability.The simulation analysis and calculations using Materials Studio clearly showed the water molecule diffusion coefficients of the silane-modified styrene-acrylic emulsion compared to the unmodified emulsion.The modified emulsion had a lower diffusion coefficient, indicating that the silane-modified styreneacrylic emulsion exhibited better water resistance.
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  Effect of Ultrasonic Shot Peening on the Cavitation Erosion Resistance of SLM316L Stainless Steel

  WANG Zenan, CHENG Feng, WANG Shuo, SUN Jie

  Materials Protection. 2025, 58(6): 124-133. https://doi.org/10.16577/j.issn.1001-1560.2025.0103

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  In order to investigate the effect of ultrasonic shot peening on the cavitation erosion resistance of SLM316L stainless steel, the surface of SLM316L stainless steel was treated for varying durations (5, 25 and 45 min) using an ultrasonic shot peening apparatus.Subsequently, cavitation tests were conducted on both the untreated and shot-peened samples by means of an ultrasonic vibration device.The phase composition, residual stress, microhardness, surface morphology evolution and micro morphology of the samples were analyzed using X-ray diffraction (XRD), indentation tester, digital microhardness meter, digital 3D video microscope and scanning electron microscopy (SEM).Results showed that the SLM316L stainless steel sample and the ultrasonic shot peening sample exhibited different cavitation behaviors.Residual stresses were introduced into the surface of the samples by ultrasonic shot peening, the surface microstructure was refined, and the surface hardness was enhanced,which led to the mitigation of grain deformation caused by cavitation impacts.As a result,crack initiation was resisted,and cavitation damage was delayed.Additionally, the samples that were subjected to 25 and 45 min of shot peening underwent a transformation from austenite to martensite, and the martensite phase was found to further enhance the cavitation erosion resistance of the shot-peened specimens due to its superior hardening characteristics.The analysis of the weight loss curves and surface morphology during the cavitation process revealed that the 45 min shot-peened sample was found to exhibit the best cavitation erosion resistance.The cavitation erosion resistance of SLM316L stainless steel was effectively improved by the ultrasonic shot peening process, and it was demonstrated that extending the peening duration could further optimize the cavitation erosion resistance of the shot-peened samples.
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  Study on the Preparation and Performance of High-Pressure Sea Water Resistant Epoxy-Modified Polyurethane Urea Elastomer Coating Material

  QI Xinyu, XIAO Mingming, TIAN Pan, WANG Yang, WU Zhengjiang

  Materials Protection. 2025, 58(6): 134-142. https://doi.org/10.16577/j.issn.1001-1560.2025.0104

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  In order to address the corrosion issues of metallic components in marine engineering,polyurethane urea elastomers were synthesized using polytetrahydrofuran ether diol (PTMG1000), diphenylmethane diisocyanate (MDI) and 4,4'-methylenebis(2-chloroaniline) (MOCA)as raw materials.The elastomers were modified with epoxy resin, and epoxy segments were introduced into the polyurethane molecular structure to prepare an amorphous structure of epoxy resin-modified polyurethane urea elastomer (PUU-s) as coating material.This modification was intended to enhance the mechanical properties, adhesion, water resistance and other properties of the coating material.A systematic investigation was conducted to evaluate the effects of epoxy resin E51 content on the mechanical properties, adhesion, water resistance, permeability resistance and corrosion resistance of the coating material in a synthetic seawater environment at 4.5 MPa and 25 ℃.The results showed that, with the increase in the amount of epoxy resin E51, the tensile strength, elongation at break and adhesion of the coating material first increased and then decreased, while the water absorption rate was gradually decreased.The permeability resistance and corrosion resistance were initially improved and subsequently were diminished.When the epoxy resin E51 content was maintained at 5%(mass fraction),the modified polyurethane urea was found to exhibit optimal overall performance.The tensile strength, elongation at break and adhesion of the modified polyurethane urea were measured to be 25.8 MPa, 605%and 14.5 MPa, respectively, representing improvements of 4.2 MPa, 45%and 5 MPa compared to the unmodified polyurethane urea.After soaking for 960 h, superior permeability resistance was demonstrated by the modified polyurethane urea；moreover, the substrate protected by the modified polyurethane urea was found to show no significant corrosion points compared to the unmodified polyurethane urea, indicating a certain degree of protective capability for the substrate.
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  Study on the High-Temperature Corrosion Behavior of Cr₃C₂/Cr₂AlC MAX Phase Composite Coatings on Stainless Steel Surfaces in Molten Sodium Polysulfide

  CUI Xingcheng, REN Yanjie, XIAO Biao, LI Yanhua, CHEN Jian, ZHOU Libo, QIU Wei, HUANG Weiying, NIU Yan

  Materials Protection. 2025, 58(6): 143-150. https://doi.org/10.16577/j.issn.1001-1560.2025.0105

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  In order to address the issue of thermal expansion coefficient mismatch between Cr3C2 coatings and 304 stainless steel, and to enhance the corrosion resistance of 304 stainless steel, two different structural Cr3C2/Cr2AlC MAX composite coatings were prepared on the surface of 304 stainless steel using magnetron sputtering technology.The microstructure and phase composition of the coatings were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) techniques.A comparative analysis was conducted on the corrosion resistance and behavior of Cr3C2/Cr2AlC MAX composite coatings with different structures in molten sodium polysulfide, as well as a single-layer Cr2AlC MAX coating.Results showed that the Cr3C2/Cr2AlC MAX composite coatings were dense and uniform, and were primarily composed of Cr3C2 and Cr2AlC MAX phases.After 120 h of corrosion, the corrosion rate of the Cr3C2/Cr2AlC MAX composite double-layer coating was measured at 0.03 mg/(m2∙h), while the corrosion rate of the Cr3C2/Cr2AlC MAX composite multilayer coating was recorded at 0.02 mg/(m2∙h),which was two orders of magnitude lower than that of the single-layer Cr2AlC MAX coating.Following corrosion in sodium polysulfide,a dense layer of Cr2S3 corrosion products was formed on the surfaces of both types of Cr3C2/Cr2AlC MAX composite coatings.After 120 h of corrosion,cracks were observed on the surface of the composite double-layer coating,which were attributed to thermal stress concentration leading to surface cracking.In contrast, the composite multilayer coating remained dense and defect-free even after prolonged exposure to corrosion, and was shown to demonstrate excellent corrosion resistance and stability in sodium polysulfide environments.
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  Effect of Sensitization Time on Intergranular Corrosion of Super304H Austenitic Stainless Steel

  LI Jing, YUE Xizhong, NIE Xiaohong, GAO Tianlanxing, SHI Qiuheng, LI Pengwen, TANG Mingqi

  Materials Protection. 2025, 58(6): 151-158. https://doi.org/10.16577/j.issn.1001-1560.2025.0106

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  Super304H austenitic stainless steel is an important structural material in ultra-supercritical power plant boilers, which is susceptible to intergranular corrosion when subjected to long-term service within its sensitization temperature range.The effects of solution treatment and sensitization at varying durations on the grain size, intergranular corrosion susceptibility and electrochemical corrosion properties of Super304H were investigated in this study.Metallographic microscopy, scanning electron microscopy, double-loop electrochemical potentiokinetic reactivation (DL-EPR) and potentiodynamic polarization methods were utilized.Results showed that high temperatures during the solution treatment resulted in an increase in austenitic grain size.With the prolongation of sensitization time, precipitates such as chromium carbides gradually emerged at the grain boundaries in both treatment states.This led to an increase in the quantity of boundary precipitates and a more pronounced grain boundary, thereby exacerbating intergranular corrosion.The uniformity of the chemical composition within the alloy was enhanced by the solution treatment, and the heterogeneous phase interfaces that may contribute to corrosion were reduced.Consequently, intergranular corrosion resistance and electrochemical corrosion performance of solution-treated Super304H stainless steel were significantly improved.
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  Study on the Microstructure, Mechanical Properties and Wear Performance of Nickel-Chromium-Based Alloy Coatings

  DU Dianxi, RUI Shuju, YANG Xingbin

  Materials Protection. 2025, 58(6): 159-166. https://doi.org/10.16577/j.issn.1001-1560.2025.0107

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  In order to enhance the mechanical and wear properties of the surface of 12Cr1MoV steel,a mixture of nickel-chromium alloy powder and nickel-coated tungsten carbide (WC) powder were utilized as raw materials.Laser cladding technology was employed to fabricate a nickelcoated WC nickel-chromium-based alloy coating on the surface of 12Cr1MoV steel.The microstructure, phase composition, mechanical properties and wear performance of the coating were analyzed using scanning electron microscopy, X-ray diffraction (XRD), microhardness testing, impact testing and wear testing machines for particle wear, erosive wear and frictional wear.The effects of varying amounts of nickelcoated WC on the microstructure, phase composition, microhardness, impact performance and resistance to erosive wear, abrasive wear and frictional wear of the coating were investigated.Results showed that the nickel-coated WC coating was characterized by a dense microstructure,with phases including (Ni,Cr) solid solution,Cr23C6,Fe3W3C,Fe6W6C and WC.As the content of nickel-coated WC was increased,the microstructure of the coating was refined,and simultaneous improvements in mechanical and wear properties were achieved.When the nickel-coated WC content reached 30%(mass fraction), the coating structure was dense and significantly refined, and the coating showed high hardness, toughness and wear resistance.The microhardness of the 30%nickel-coated WC coating was 760 HV, with an impact absorbed energy of 54.1 J, along with a low friction coefficient and excellent resistance to frictional wear.The mass loss due to erosive wear and abrasive wear was determined to be 1/28 and 1/48 of the substrate’s mass, respectively.The mechanical and wear properties of the 30%nickel-coated WC coating were found to surpass those of other coatings and the substrate.
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  Facile Preparation and Protective Performance Study of Porous Low Carbon Steel Surface Injected with Lubricating Fluid

  YANG Hongwei, WANG Caihua, WANG Haifeng, KANG Cheng, GU Xiaojia, GAO Zhejie, HE Yongjie

  Materials Protection. 2025, 58(6): 167-173. https://doi.org/10.16577/j.issn.1001-1560.2025.0108

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  In order to enhance the corrosion resistance of low carbon steel in NaCl solution,a facile one-step electrochemical etching and lubricant injection method were used to construct a slippery lubricant-infused porous surface (SLIPS) on low carbon steel.The influence of the concentrations of hydrochloric acid and perfluorolauric acid on the contact angle of the obtained porous surface was investigated.The anti-corrosion property of the fabricated superhydrophobic surface (SHS) and SLIPS on low carbon steel was evaluated by potentiodynamic polarization curve analysis and electrochemical impedance spectroscopy (EIS) in a 3.5%(mass fraction) NaCl solution.It was revealed that when the concentrations of hydrochloric acid and perfluorolauric acid were adjusted to 0.02 mol/L and 0.8 mmol/L, respectively, the contact angle reached 151°.After silicone oil was infused into the prepared SHS, the contact angle was reduced to 106°.Results from potentiodynamic polarization suggested that both the anodic and cathodic reaction rates were simultaneously suppressed by the designed SHS and SLIPS on low carbon steel.A lower corrosion current density was exhibited by the prepared SLIPS on low carbon steel, and the corrosion protection efficiency was calculated to be 99.7%.EIS measurements revealed that the charge transfer resistances of the designed SHS and SLIPS on low carbon steel were measured to be 7 384 Ω∙cm2 and 22 635 Ω∙cm2, respectively.Superior corrosion protection performance was demonstrated by the fabricated SLIPS.The SLIPS on low carbon steel prepared from a facile electrochemical etching and lubricant injection method on low carbon steel was expected to extend the practical applications of low carbon steel materials.
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  Study on the Mechanical Properties of Q235 Steel Roof Trusses in Industrial Atmospheric Corrosive Environment

  WANG Fenglu, HAN Tengfei, LI Yonglu, QU Yunong, ZHAO Liyong

  Materials Protection. 2025, 58(6): 174-181. https://doi.org/10.16577/j.issn.1001-1560.2025.0109

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  In order to investigate the impact of corrosion on the mechanical performance of steel roof truss membersin an industrial atmospheric environment, appropriate strength degradation models and indices were selected to characterize the deterioration of steel material properties.Thirty Q235B corroded steel specimens were sampled on-site from a steel slag processing plant’s roof truss system.After processing, uniaxial tensile tests were conducted on the specimens.The mechanical performance degradation model of corroded steel was theoretically analyzed based on the residual load-bearing capacity assumption, and the significance of various strength degradation models was qualitatively evaluated.An equivalent strength degradation model and a comprehensive corrosion damage parameter were chosen to represent the strength degradation caused by corrosion.Finally,based on the tensile test data,the relationship between steel strength degradation and the comprehensive corrosion damage parameter was quantitatively analyzed.Results showed that equivalent yield strength and equivalent tensile strength decreased with increasing comprehensive corrosion damage parameters, with degradation rates of 0.89 and 1.21, respectively, suggesting that as corrosion progressed, the ratio of yield to tensile strength increased, rendering the steel more susceptible to brittle failure.Additionally, the elongation diminished with increasing corrosion damage, with a degradation rate of 1.29.