Corrosion poses a major threat to the safety of transportation pipelines.Therefore,it is crucial to have an in-depth understanding of corrosion mechanisms in pipeline steels for the effective management of pipeline in...Corrosion poses a major threat to the safety of transportation pipelines.Therefore,it is crucial to have an in-depth understanding of corrosion mechanisms in pipeline steels for the effective management of pipeline integrity.Conducting research on corrosion mechanisms relies on the use of efficient and reliable corrosion monitoring and analysis techniques.The advancements in corrosion monitoring techniques specifically designed for the localized corrosion monitoring were aimed to be introduced,and a comprehensive overview of recent progress in understanding the localized corrosion mechanisms in pipeline steels was provided.Based on the different corrosive environments encountered,the localized corrosion issues inside pipelines are classified into two categories:localized corrosion primarily influenced by electrochemical processes and localized corrosion controlled by both electrochemical and mechanical factors.Additionally,a thorough analysis of the synergistic effects between micro-cell and macro-cell currents,as well as the interplay of mechanics and electrochemistry is presented.Finally,recommendations for future research on the mechanisms of internal localized corrosion in pipelines are provided.展开更多
The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties ...The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties of organic coatings.This study compared a bare epoxy coating with one containing zinc phosphate corrosion inhibitors,both applied on ACM sensors,to observe their corrosion protection properties over time.Coatings with artificial damage via scratches were exposed to immersion and alternating dry and wet environments,which allowed for monitoring galvanic corrosion currents in real-time.Throughout the corrosion tests,the ACM currents of the zinc phosphate/epoxy coating were considerably lower than those of the blank epoxy coating.The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis.This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings.Compared with the blank epoxy coating,the zinc phosphate/epoxy coating showed much-decreased ACM current values that confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating.展开更多
The rust layer is a critical factor in determining the corrosion resistance performance of weathering bridge steel.Understanding the evolution mechanism of this rust layer is fundamental for the design and optimizatio...The rust layer is a critical factor in determining the corrosion resistance performance of weathering bridge steel.Understanding the evolution mechanism of this rust layer is fundamental for the design and optimization of such steel.This study investigates the evolu-tion of the rust layer on high-Cr-content weathering bridge steel,using an atmospheric corrosion monitoring(ACM)sensor and big data mining techniques in a simulated tropical marine atmosphere.Results reveal that the protective properties of the rust layer follow a peri-odic pattern of“ascending–constant”rather than a continuous ascending.Correlation analysis indicates that this phenomenon is attributed to the introduction of Cr,which promotes the formation of FeCr_(2)O_(4) in the rust layer.FeCr_(2)O_(4) helps prevent chloride ions from penetrating the rust layer,exerting a protective effect.These findings provide a strong scientific foundation for the design and improvement of new high-Cr-content weathering bridge steels.展开更多
The corrosion behavior of deposit-covered aluminum alloy 7075(AA7075)caused by fungus Aspergillus terreus(A.terreus)was thoroughly investigated in artificial seawater aiming to offer some new insights into the under-d...The corrosion behavior of deposit-covered aluminum alloy 7075(AA7075)caused by fungus Aspergillus terreus(A.terreus)was thoroughly investigated in artificial seawater aiming to offer some new insights into the under-deposit corrosion mechanism of aluminum alloys in marine environments containing fungi.Electrochemical impedance spectroscopy,polarization curves,wire beam electrodes,and surface analysis were performed.Results indicate that A.terreus can survive beneath the deposit but the counts of sessile spores decline as the increase of deposit thickness,suggesting a poor biological activity of A.terreus beneath the deposit.Both the uniform corrosion and pitting corrosion are accelerated by A.terreus,while the pitting corrosion of AA7075 alloys beneath the deposit derives from a galvanic cell with a small anode and a large cathode.Deposits have a corrosion inhibition effect on AA7075.However,the galvanic effect caused by the bare and deposit-covered AA specimens is obviously enhanced by A.terreus.展开更多
A new type of corrosion-resistant alloyed-steel rebar,Cr10MoV,was researched using techniques such as corrosion electrochemistry,X-ray computed tomography,and zero resistance ammeter to systematically study the macro-...A new type of corrosion-resistant alloyed-steel rebar,Cr10MoV,was researched using techniques such as corrosion electrochemistry,X-ray computed tomography,and zero resistance ammeter to systematically study the macro-cell corrosion behavior and corrosion resistance of alloyed-steel rebar in mortar and concrete samples induced by chloride ion concentration in the marine environment.The macro-cell corrosion characteristics and development patterns induced by chloride ion concentration in alloyed-steel rebar were preliminarily revealed.In the macro-cell corrosion system of rebar mortar samples induced by 29 times chloride ion concentration,the corrosion current density of the alloyed-steel rebar combination stabilizes at 1.6–2.4μA/cm^(2),which is only one-third of that of the carbon-steel rebar combination,while the dissimilar steel rebar combination stabilizes at 0–0.4μA/cm^(2).Alloyed-steel rebar and carbon-steel rebar are configured in high concentration and low concentration chlorine salt areas,respectively.With the help of high corrosion resistance,the long-term stable corrosion resistance of alloyed-steel rebar is ensured.The potential difference between carbon-steel rebar and alloyed-steel rebar is reduced to weaken the driving force of macro-cell corrosion.It is a useful way to inhibit the macro-cell corrosion of dissimilar steel rebar and ensure the high corrosion resistance and durability of marine reinforced concrete structures.展开更多
To effectively improve the corrosion resistance of aluminum alloys without affecting their strength, the effect of Ce content on the microstructure, stress corrosion, intergranular corrosion, and exfoliation corrosion...To effectively improve the corrosion resistance of aluminum alloys without affecting their strength, the effect of Ce content on the microstructure, stress corrosion, intergranular corrosion, and exfoliation corrosion resistances of Al−11.3Zn−3.1Mg−1.2Cu−0.2Zr−0.1Ti alloy was investigated. The results showed that the addition of Ce formed the (Zn,Al,Cu)_(22)Ce_(3) phase with a size of 100 nm, which enhanced the recrystallization resistance of the alloy, increased the number of low-angle grain boundaries and dislocation density, refined the grains, promoted the phase transition from GP zone to η' phase, and promoted the size and discontinuity of precipitates at grain boundaries. All Ce-added alloys exhibited the higher resistance to corrosion. The alloy with 0.15 wt.% Ce possessed the optimal corrosion resistance along with the strength and elongation at slow strain rate of 744.8 MPa and 4.6%, respectively, in 3.5 wt.% NaCl solution. The minimum depth of intergranular corrosion and exfoliation corrosion was achieved as well.展开更多
Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring...Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring a straightforward preparation method and the potential for manufacturing large-scale components,exhibit notable corrosion rates up to 29 mg cm^(-2)h^(-1)at 25℃ and 643 mg cm^(-2)h^(-1)at 93℃.The high corrosion rate is primary due to the Ni–containing second phases,which intensify the galvanic corrosion that overwhelms their corrosion barrier effect.Low-zinc rolled Mg-1.5Zn-0.2Ca-x Ni(0≤x≤5)series,characterizing excellent deformability with an elongation to failure of~26%,present accelerated corrosion rates up to 34 mg cm^(-2)h^(-1)at 25℃ and 942 mg cm^(-2)h^(-1)at 93℃.The elimination of corrosion barrier effect via deformation contributes to the further increase of corrosion rate compared to the T6 series.Additionally,Mg-Zn-Ca-xNi(0≤x≤5)alloys exhibit tunable ultimate tensile strengths ranging from~190 to~237 MPa,depending on their specific composition.The adjustable corrosion rate and mechanical properties render the Mg-Zn-Ca-x Ni(0≤x≤5)alloys suitable for fracturing materials.展开更多
Semiconductors and related fields today hold vast application prospects.The semiconductor wafer fabrication process involves steps such as substrate preparation and epitaxy,which occur in high-temperature corrosive en...Semiconductors and related fields today hold vast application prospects.The semiconductor wafer fabrication process involves steps such as substrate preparation and epitaxy,which occur in high-temperature corrosive environments.Consequently,components like crucibles,susceptors and wafer carriers require carbon-based materials such as graphite and carbon-carbon composites.However,traditional carbon materials underperform in these extreme conditions,failing to effectively address the challenges.This leads to issues including product contamination and shortened equipment lifespan.Therefore,effective protection of carbon materials is crucial.This paper reviews current research status on the preparation methods and properties of corrosion-resistant coatings within relevant domestic and international fields.Preparation methods include various techniques such as physical vapor deposition(PVD),chemical vapor deposition(CVD)and the sol-gel method.Furthermore,it offers perspectives on future research directions for corrosion-resistant coated components in semiconductor equipment.These include exploring novel coating materials,improving coating preparation processes,enhancing coating corrosion resistance,as well as further investigating the interfacial interactions between coatings and carbon substrates to achieve better adhesion and compatibility.展开更多
Ti(C,N)-Mo_(2)C-Ni cermet as alternative materials was explored for use in alkaline conditions,replacing the WC-Co cemented carbides,since Co is classified as a potentially carcinogenic substance and there is potentia...Ti(C,N)-Mo_(2)C-Ni cermet as alternative materials was explored for use in alkaline conditions,replacing the WC-Co cemented carbides,since Co is classified as a potentially carcinogenic substance and there is potential hazard of“hard metal disease”under the exposure to cobalt dust.The changes in microstructure,corrosion rate and volumetric loss rate of the two materials were compared under electrochemical corrosion and erosion-corrosion in alkaline environment.The results demonstrates that Ti(C,N)-Mo_(2)C-Ni cermet undergoes passivation when exposed to electrochemical corrosion of NaOH solution,resulting in a significant increase in oxygen content on the corroded surface.The corrosion rate of cermet is approximately one order of magnitude lower than that of the cemented carbide.Under the erosion-corrosion of an alkaline sand-water mixture,both the cermet and cemented carbide experience a gradual increase in volumetric loss rate with prolonging the erosion time.During erosion,the rim phase in cermet is fragile,so cracks easily penetrate it while the core phase remains intact.The medium-grained cemented carbide commonly demonstrates transgranular fracture mode,while in the fine-grained cemented carbide,cracks tend to propagate along phase boundaries.The erosive wear and damage caused by sand particles play a predominant role in the erosion-corrosion process of alkaline sand-water mixtures.This process represents an accelerated destructive phenomenon influenced and intensified by the combined effects of corrosion and erosion.It is confirmed that using cermet as an alternative anti-wear material to cemented carbides is feasible under alkaline conditions,and even better.展开更多
Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneit...Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneity due to the degradation of Mg on its corrosion behavior.The immersion experiments using pure Mg plates,which were placed vertically in a culture medium(Dulbecco’s Modified Eagle’s Medium(DEME)+10%fetal bovine serum(FBS))for 1,5,and 10 days,were conducted.Surface analyses for the corrosion product layers and the measurements of the pH values and concentrations of eluted ions in the immersion medium around the upper and lower areas of the Mg plate were performed.The significant effect of the macroscopic environmental heterogeneity derived from Mg degradation on the corrosion behavior was demonstrated by in vitro tests.Additionally,the in vivo tests were carried out by implanting the pure Mg plates in the femur of rabbits.The in vivo results exhibited macroscopically heterogeneous Mg degradation,with areas of more severe corrosion compared to the in vitro test;it is especially noticeable during the early stage of degradation,even though the average corrosion rate was lower.展开更多
Conventional nanoparticles incorporated into epoxy coatings suffer from poor compatibility and insufficient corrosion improvement,hindering their practical applications.A dual-strategy approach integrating in-situ hos...Conventional nanoparticles incorporated into epoxy coatings suffer from poor compatibility and insufficient corrosion improvement,hindering their practical applications.A dual-strategy approach integrating in-situ host–vip nanoconfinement and surface self-assembly was devised to fabricate 8HQ@ZIF-8/PDA smart nanocontainers.The vip 8-hydroxyquinoline(8HQ)was encapsulated within the zeolitic imidazolate framework-8(ZIF-8)host,leveraging nanoconfinement effects.A bioinspired polydopamine(PDA)layer was then self-assembled on the 8HQ@ZIF-8 surface through dopamine oxidative self-polymerization,resulting in a robust nanocontainer architecture.Density functional theory(DFT)calculations verify that the molecular interactions between the PDA and the ZIF-8 surface was the chemical adsorption.The resultant 8HQ@ZIF-8/PDA retained the rhombic dodecahedral morphology and crystallinity of ZIF-8,demonstrating controlled pH-responsive release behavior.When incorporated into an epoxy(EP)resin matrix on magnesium alloy,the 8HQ@ZIF-8/PDA/EP smart composite coatings exhibited outstanding interfacial compatibility and long-term stability,achieving a low-frequency impedance(|Z|_(n.n1Hz))of 2.49×10^(7)Ωcm^(2),a maximum phase angle of 82.8°,and a breakpoint frequency(f_(b))of 63.34 Hz after 50 days of immersion in a 3.5 wt%NaCl solution.These findings highlight the exceptional self-healing and corrosion-resistant properties of the 8HQ@ZIF-8/PDA/EP smart composite coatings,underscoring its potential for protecting magnesium alloys in aggressive environments.展开更多
Erosion-corrosion(EC)-induced damage is a primary contributor to premature failures in hydraulic transport structures involving sudden changes in flow patterns,especially the hydraulic pipeline(tee,reducer,pipe bend,e...Erosion-corrosion(EC)-induced damage is a primary contributor to premature failures in hydraulic transport structures involving sudden changes in flow patterns,especially the hydraulic pipeline(tee,reducer,pipe bend,etc.),pumps,and valves.A comprehensive exploration of EC behavior of steels subjected to high tensile stress was provided,as most engineering structures are operated under high stress.The stress-accelerated erosion(SAE)and stress-accelerated corrosion(SAC)behaviors of highly stressed steel and their synergistic effect were mainly focused.SAE,SAC,and their synergistic mechanisms,existing debate,and possible reasons,as well as available analytic models with their advantages and limitations,are thoroughly discussed.The multiphysics simulation methods for modeling EC interactions with both static and cyclic stresses are also summarized,and EC mitigation strategies,especially the bionics-based strategies,were also summarized in detail.展开更多
Implants are inevitably subjected to stress corrosion,bringing serious challenges to the controlled degradation of biomedical Mg alloys.It is worth studying the stress corrosion cracking(SCC)behavior of Mg alloy and e...Implants are inevitably subjected to stress corrosion,bringing serious challenges to the controlled degradation of biomedical Mg alloys.It is worth studying the stress corrosion cracking(SCC)behavior of Mg alloy and exploring Mg alloy with good SCC resistance for wide biomedical applications.In this work,the as-cast and as-extruded Mg-3Gd-1Zn-0.4Zr(GZ31K)alloys with uniform corrosion were used to investigate SCC behavior.The as-extruded GZ31K alloy exhibited better corrosion resistance and mechanical properties than the as-cast one mainly owing to grain refinement and uniformly distributed fine precipitates,and possessed superior SCC resistance.To clarify the SCC mechanism,the slow strain rate tests were assisted with applied constant potentials via an electrochemical workstation.Accelerated anodic dissolution at anodic polarization deteriorated SCC resistance due to the initiation of corrosion pits and micro-cracks.However,cathodic polarization had no obvious effects on SCC resistance,along with both retarded corrosion and accelerated hydrogen evolution.Stacking faults in GZ31K alloy were hydrogen capture containers to reduce the effect of hydrogen on SCC resistance during cathodic polarization.These findings provide new insights into the evaluation of SCC mechanism,and offer more opportunities to explore Mg alloys with good SCC resistance by regulating anodic dissolution.展开更多
The corrosion resistance and mechanical properties of peak-aged AlZnMgCu alloys containing Si and Er elements were investigated with hardness test,tensile test,intergranular corrosion test,exfoliation corrosion test a...The corrosion resistance and mechanical properties of peak-aged AlZnMgCu alloys containing Si and Er elements were investigated with hardness test,tensile test,intergranular corrosion test,exfoliation corrosion test and transmission electron microscopy.The results indicate that peak-aged AlZnMgCuSiEr alloy is strengthened by co-precipitation of η′phases and nano-sized GPB-Ⅱ zones.The yield strength of the AlZnMgCu alloy is increased by 38.5 MPa and the elongation is increased by 4.5%.At the same time,the corrosion resistance of the AlZnMgCuSiEr alloy is enhanced due to the synergistic effect of Er and Si.The maximum intergranular corrosion(IGC)depth decreases from 264.2 to 9.9μm.The fundamental reason is that the co-addition of Si and Er regulates the evolution of precipitated phases in grains and at grain boundaries.展开更多
Hot corrosion in molten salt is a complex process,involving both chemical corrosion and electrochemical corrosion.Interfacial reactions and oxide dissolution can also impact the corrosion results.Compared with single ...Hot corrosion in molten salt is a complex process,involving both chemical corrosion and electrochemical corrosion.Interfacial reactions and oxide dissolution can also impact the corrosion results.Compared with single component/type salt,multicomponent/type hot corrosion leads to more severe degradation,while the multi-component alloys offer potential chances for developing anti-corrosion metallic materials.In this study,we aim to elucidate the hot corrosion behavior and gain a better understanding of the corrosion mechanism of the multi-component alloys under multi-component/type NaCl-KCl-Na_(2)SO_(4)salt.The corrosion behavior of dual-phaseNi_(36)Fe_(34)Al_(17)Cr_(10)Mo_(1)Ti_(2)(HEA-1)and Ni_(34)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)(HEA-2)alloys was studied within NaCl-KCl-Na_(2)SO_(4)molten salt with mass ratios of 5:5:1 and 5:5:2.After exposure to the salt at 650°C for 168 h,it was found that the Ni_(34)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)exhibited better corrosion resistance thanNi_(36)Fe_(34)Al_(17)Cr_(10)Mo_(1)Ti_(2).The improved performance of Ni_(30)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)alloy was attributed to the Co element,which facilitated the formation of dense oxides scale and enhanced scale adhesion.Alkali chlorides with stronger penetration ability dominated the corrosion process and alkali sulfate further aggravated the corrosion.The primary corrosion mechanisms involved in this process were identified as“electrochemical mechanism”attacking the body-centered cubic structure in the alloys and“active oxidation”causing dissolution of the alloy elements.展开更多
The influence mechanism of trace Nb on the corrosion resistance of surface corrosion products of high-strength anti-seismic rebar in the simulated marine environment was studied by combining first-principles calculati...The influence mechanism of trace Nb on the corrosion resistance of surface corrosion products of high-strength anti-seismic rebar in the simulated marine environment was studied by combining first-principles calculations with corrosion mass loss method,surface analysis,cross-sectional analysis,quantitative analysis,and electrochemical test.The results demonstrated that the addition of trace Nb effectively improved the compactness and stability of surface corrosion layer of rebar,and the corrosion resistance of corrosion layer increased with the increase in Nb content.The beneficial effect of Nb content on the corrosion layer summarized two important key points.Firstly,the addition of Nb was beneficial to promoting the improvement in the structural stability of α-FeOOH,and α-FeOOH structure of solid solution Nb atoms was beneficial to strengthening the fixation of Cl atoms,thus increasing α/(β+γ)ratio,total impedance value,and corrosion potential.Secondly,the formation of Nb oxides can not only repair the corrosion layer,but also play a role in the fixation Cl atoms,resulting in the improvement in corrosion resistance of corrosion layer.展开更多
In our previous work,die cast LA42(Mg-4La-2.5Al-0.3Mn,wt.%)alloy with an excellent combination of thermal-conducting performance and mechanical properties was developed.This study,taking commercial die cast AZ91(Mg-9A...In our previous work,die cast LA42(Mg-4La-2.5Al-0.3Mn,wt.%)alloy with an excellent combination of thermal-conducting performance and mechanical properties was developed.This study,taking commercial die cast AZ91(Mg-9Al-1 Zn,wt.%)alloy as a comparison,investigates the microstructure and corrosion behavior of the LA42 alloy in chloride-containing environment.The findings revealed that the microstructure of die cast LA42 alloy displays an Al-depletedα-Mg dendrite and a network shape eutectic phase comprising of eutecticα-Mg and lamellar Al11La3.The LA42 alloy exhibited slightly inferior corrosion resistance and deeper corrosion pits than the AZ91 alloy,which were related to the interphase attack and the presence of a layer of corrosion products containing more magnesium hydroxide of the LA42alloy.The corrosion behavior of the LA42 alloy was characterized by an interphase attack on the periphery of Al-depletedα-Mg dendrite adjacent to Al_(11)La_(3),which primarily ascribed to the relatively lower potential of the Al-depletedα-Mg phase and the interfacial reactivity between it and the adjacent Al_(11)La_(3),whereas the AZ91 alloy showed a trait of preferential corrosion of the interior ofα-Mg dendrite for its lowest potential among different phases.This comprehensive research can provide a guidance for future alloy design of Mg-Al-La alloys and their industrial applications.展开更多
The corrosion behavior of Ti–6Al–2Zr–1Mo–1V(TA15)alloy fabricated through selective laser melting(SLM)technology and traditional wrought technology in hydrochloric acid solutions was investigated using electrochem...The corrosion behavior of Ti–6Al–2Zr–1Mo–1V(TA15)alloy fabricated through selective laser melting(SLM)technology and traditional wrought technology in hydrochloric acid solutions was investigated using electrochemical testing and surface characterizations,including electron backscattered diffraction,scanning electron microscopy,and X-ray photoelectron spectroscopy analyses.The results showed that both types of TA15 alloy underwent spontaneous passivation reactions in HCl solution,and with the increase in HCl concentration,the surface of SLM-TA15 sample exhibited larger and deeper pits.In comparison to SLM-TA15 sample,the pits on the wrought-TA15 sample were shallower and the surface was more uniform.Analysis of the passive current density,breakdown potential,and electrochemical impedance revealed that the corrosion resistance of both alloys decreased as the concentration of HCl increased,and SLM sample exhibited poorer corrosion resistance compared with the wrought sample.Analysis of Mott–Schottky test curves and calculation of passive film thickness indicated that the passive film of wrought-TA15 sample was superior to that of SLM-TA15 sample.展开更多
The corrosion resistance of aluminum(Al)cable-copper(Cu)terminal joints fabricated by magnetic pulse crimping(MPC)and hydraulic clamp crimping(HCC)was compared.Performance degradation was evaluated by mechanical and e...The corrosion resistance of aluminum(Al)cable-copper(Cu)terminal joints fabricated by magnetic pulse crimping(MPC)and hydraulic clamp crimping(HCC)was compared.Performance degradation was evaluated by mechanical and electrical properties.Additionally,corrosion behavior was analyzed by electrochemical testing.Microscopic characterization was performed by scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).Results show that the tensile strength of the corroded joints is reduced.However,due to the advantages of high-speed forming and contact tightness unique to MPC,the contact resistance of the corroded joints still maintains excellent.Electrochemical tests demonstrate that the MPC joints have higher corrosion potentials and smaller corrosion currents,providing better corrosion resistance.The formation of a primary battery between Al and Cu at the lap joint leads to the formation of severer corrosion pits.展开更多
Purpose-Weathering steel has excellent resistance to atmospheric corrosion,but still faces complex environmental corrosion problems during long-term operation.This paper mainly studies the corrosion problem of weather...Purpose-Weathering steel has excellent resistance to atmospheric corrosion,but still faces complex environmental corrosion problems during long-term operation.This paper mainly studies the corrosion problem of weather resistant steel materials for railway freight car bodies with a load capacity of 70 tons.Design/methodology/approach-The paper analyzes the corrosion characteristics of weather resistant steel materials for truck bodies through macroscopic and microscopic methods including metallographic microscopy,scanning electron microscopy,energy dispersive spectroscopy and X-ray diffraction.Electrochemical analysis shows that the rust layer on the surface of weathering steel changes the surface state of the material,and also proves that weathering steel used in trucks undergoes electrochemical corrosion under atmospheric corrosion.At the same time,ion chromatography technology is used to study the corrosive ions mainly present in the residual liquid and foam solution inside the vehicle body.Findings-The corrosion of truck body materials is mainly electrochemical corrosion,and the corrosion of door materials is more obvious than that of other parts.The corrosion products are mainly Fe oxides and hydroxides.There are high concentrations of Cl-and SO42-ions in the residual liquid and foam solution at the bottom of the freight car,which are the main factors causing corrosion of the railway freight car body.Originality/value-The foam adhesive around the door panel is in a moist state for a long time,and corrosive ions will accelerate the electrochemical corrosion of the weather resistant steel material of the door panel.Therefore,the corrosion of the cargo door panel is more severe than other components.展开更多
基金sponsored by the National Key R&D Program of China(No.2022YFC2806200)the National Natural Science Foundation of China(No.52001055)the Open Foundation of State Key Laboratory of Structural Analysis for Industrial Equipment(GZ22118).
文摘Corrosion poses a major threat to the safety of transportation pipelines.Therefore,it is crucial to have an in-depth understanding of corrosion mechanisms in pipeline steels for the effective management of pipeline integrity.Conducting research on corrosion mechanisms relies on the use of efficient and reliable corrosion monitoring and analysis techniques.The advancements in corrosion monitoring techniques specifically designed for the localized corrosion monitoring were aimed to be introduced,and a comprehensive overview of recent progress in understanding the localized corrosion mechanisms in pipeline steels was provided.Based on the different corrosive environments encountered,the localized corrosion issues inside pipelines are classified into two categories:localized corrosion primarily influenced by electrochemical processes and localized corrosion controlled by both electrochemical and mechanical factors.Additionally,a thorough analysis of the synergistic effects between micro-cell and macro-cell currents,as well as the interplay of mechanics and electrochemistry is presented.Finally,recommendations for future research on the mechanisms of internal localized corrosion in pipelines are provided.
基金financially supported by the National Natural Science Foundation of China(No.52371049)the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(YESS,No.2020QNRC001)the National Science and Technology Resources Investigation Program of China(Nos.2021FY100603 and 2019FY101404)。
文摘The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties of organic coatings.This study compared a bare epoxy coating with one containing zinc phosphate corrosion inhibitors,both applied on ACM sensors,to observe their corrosion protection properties over time.Coatings with artificial damage via scratches were exposed to immersion and alternating dry and wet environments,which allowed for monitoring galvanic corrosion currents in real-time.Throughout the corrosion tests,the ACM currents of the zinc phosphate/epoxy coating were considerably lower than those of the blank epoxy coating.The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis.This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings.Compared with the blank epoxy coating,the zinc phosphate/epoxy coating showed much-decreased ACM current values that confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating.
基金supported by the National Natural Science Foundation of China(No.52171063).
文摘The rust layer is a critical factor in determining the corrosion resistance performance of weathering bridge steel.Understanding the evolution mechanism of this rust layer is fundamental for the design and optimization of such steel.This study investigates the evolu-tion of the rust layer on high-Cr-content weathering bridge steel,using an atmospheric corrosion monitoring(ACM)sensor and big data mining techniques in a simulated tropical marine atmosphere.Results reveal that the protective properties of the rust layer follow a peri-odic pattern of“ascending–constant”rather than a continuous ascending.Correlation analysis indicates that this phenomenon is attributed to the introduction of Cr,which promotes the formation of FeCr_(2)O_(4) in the rust layer.FeCr_(2)O_(4) helps prevent chloride ions from penetrating the rust layer,exerting a protective effect.These findings provide a strong scientific foundation for the design and improvement of new high-Cr-content weathering bridge steels.
基金supported by Guangdong Basic and Applied Basic Research Foundation,China(No.2023A1515012146)the National Natural Science Foundation of China(No.52271083).
文摘The corrosion behavior of deposit-covered aluminum alloy 7075(AA7075)caused by fungus Aspergillus terreus(A.terreus)was thoroughly investigated in artificial seawater aiming to offer some new insights into the under-deposit corrosion mechanism of aluminum alloys in marine environments containing fungi.Electrochemical impedance spectroscopy,polarization curves,wire beam electrodes,and surface analysis were performed.Results indicate that A.terreus can survive beneath the deposit but the counts of sessile spores decline as the increase of deposit thickness,suggesting a poor biological activity of A.terreus beneath the deposit.Both the uniform corrosion and pitting corrosion are accelerated by A.terreus,while the pitting corrosion of AA7075 alloys beneath the deposit derives from a galvanic cell with a small anode and a large cathode.Deposits have a corrosion inhibition effect on AA7075.However,the galvanic effect caused by the bare and deposit-covered AA specimens is obviously enhanced by A.terreus.
基金the financial support from National Natural Science Foundation of China(Grant Nos.52278255 and 51878246)Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX24_0195).
文摘A new type of corrosion-resistant alloyed-steel rebar,Cr10MoV,was researched using techniques such as corrosion electrochemistry,X-ray computed tomography,and zero resistance ammeter to systematically study the macro-cell corrosion behavior and corrosion resistance of alloyed-steel rebar in mortar and concrete samples induced by chloride ion concentration in the marine environment.The macro-cell corrosion characteristics and development patterns induced by chloride ion concentration in alloyed-steel rebar were preliminarily revealed.In the macro-cell corrosion system of rebar mortar samples induced by 29 times chloride ion concentration,the corrosion current density of the alloyed-steel rebar combination stabilizes at 1.6–2.4μA/cm^(2),which is only one-third of that of the carbon-steel rebar combination,while the dissimilar steel rebar combination stabilizes at 0–0.4μA/cm^(2).Alloyed-steel rebar and carbon-steel rebar are configured in high concentration and low concentration chlorine salt areas,respectively.With the help of high corrosion resistance,the long-term stable corrosion resistance of alloyed-steel rebar is ensured.The potential difference between carbon-steel rebar and alloyed-steel rebar is reduced to weaken the driving force of macro-cell corrosion.It is a useful way to inhibit the macro-cell corrosion of dissimilar steel rebar and ensure the high corrosion resistance and durability of marine reinforced concrete structures.
基金financially supported from the Key Project of Equipment Pre-research Foundation of the Ministry of Equipment Development of the Central Military Commission of China(No.6140922010201)the Key Project of Research and Development of Zhenjiang Province,China(No.GY2018021)。
文摘To effectively improve the corrosion resistance of aluminum alloys without affecting their strength, the effect of Ce content on the microstructure, stress corrosion, intergranular corrosion, and exfoliation corrosion resistances of Al−11.3Zn−3.1Mg−1.2Cu−0.2Zr−0.1Ti alloy was investigated. The results showed that the addition of Ce formed the (Zn,Al,Cu)_(22)Ce_(3) phase with a size of 100 nm, which enhanced the recrystallization resistance of the alloy, increased the number of low-angle grain boundaries and dislocation density, refined the grains, promoted the phase transition from GP zone to η' phase, and promoted the size and discontinuity of precipitates at grain boundaries. All Ce-added alloys exhibited the higher resistance to corrosion. The alloy with 0.15 wt.% Ce possessed the optimal corrosion resistance along with the strength and elongation at slow strain rate of 744.8 MPa and 4.6%, respectively, in 3.5 wt.% NaCl solution. The minimum depth of intergranular corrosion and exfoliation corrosion was achieved as well.
基金supported by the National Key Research and Development Program(No.2022YFE0122000)National Natural Science Foundation of China under Grant Nos.52234009,52274383,52222409,and 52201113。
文摘Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring a straightforward preparation method and the potential for manufacturing large-scale components,exhibit notable corrosion rates up to 29 mg cm^(-2)h^(-1)at 25℃ and 643 mg cm^(-2)h^(-1)at 93℃.The high corrosion rate is primary due to the Ni–containing second phases,which intensify the galvanic corrosion that overwhelms their corrosion barrier effect.Low-zinc rolled Mg-1.5Zn-0.2Ca-x Ni(0≤x≤5)series,characterizing excellent deformability with an elongation to failure of~26%,present accelerated corrosion rates up to 34 mg cm^(-2)h^(-1)at 25℃ and 942 mg cm^(-2)h^(-1)at 93℃.The elimination of corrosion barrier effect via deformation contributes to the further increase of corrosion rate compared to the T6 series.Additionally,Mg-Zn-Ca-xNi(0≤x≤5)alloys exhibit tunable ultimate tensile strengths ranging from~190 to~237 MPa,depending on their specific composition.The adjustable corrosion rate and mechanical properties render the Mg-Zn-Ca-x Ni(0≤x≤5)alloys suitable for fracturing materials.
基金National Natural Science Foundation of China(12002196,12102140)。
文摘Semiconductors and related fields today hold vast application prospects.The semiconductor wafer fabrication process involves steps such as substrate preparation and epitaxy,which occur in high-temperature corrosive environments.Consequently,components like crucibles,susceptors and wafer carriers require carbon-based materials such as graphite and carbon-carbon composites.However,traditional carbon materials underperform in these extreme conditions,failing to effectively address the challenges.This leads to issues including product contamination and shortened equipment lifespan.Therefore,effective protection of carbon materials is crucial.This paper reviews current research status on the preparation methods and properties of corrosion-resistant coatings within relevant domestic and international fields.Preparation methods include various techniques such as physical vapor deposition(PVD),chemical vapor deposition(CVD)and the sol-gel method.Furthermore,it offers perspectives on future research directions for corrosion-resistant coated components in semiconductor equipment.These include exploring novel coating materials,improving coating preparation processes,enhancing coating corrosion resistance,as well as further investigating the interfacial interactions between coatings and carbon substrates to achieve better adhesion and compatibility.
基金Chongqing Light Alloy Materials and Processing Engineering Technology Research Center Open Fund Project(GCZX201903)Yunnan Province Major Science and Technology Special Project Plan(202302AA310038)Sichuan University-Suining Municipal-University Cooperation Project(2023CDSN-12)。
文摘Ti(C,N)-Mo_(2)C-Ni cermet as alternative materials was explored for use in alkaline conditions,replacing the WC-Co cemented carbides,since Co is classified as a potentially carcinogenic substance and there is potential hazard of“hard metal disease”under the exposure to cobalt dust.The changes in microstructure,corrosion rate and volumetric loss rate of the two materials were compared under electrochemical corrosion and erosion-corrosion in alkaline environment.The results demonstrates that Ti(C,N)-Mo_(2)C-Ni cermet undergoes passivation when exposed to electrochemical corrosion of NaOH solution,resulting in a significant increase in oxygen content on the corroded surface.The corrosion rate of cermet is approximately one order of magnitude lower than that of the cemented carbide.Under the erosion-corrosion of an alkaline sand-water mixture,both the cermet and cemented carbide experience a gradual increase in volumetric loss rate with prolonging the erosion time.During erosion,the rim phase in cermet is fragile,so cracks easily penetrate it while the core phase remains intact.The medium-grained cemented carbide commonly demonstrates transgranular fracture mode,while in the fine-grained cemented carbide,cracks tend to propagate along phase boundaries.The erosive wear and damage caused by sand particles play a predominant role in the erosion-corrosion process of alkaline sand-water mixtures.This process represents an accelerated destructive phenomenon influenced and intensified by the combined effects of corrosion and erosion.It is confirmed that using cermet as an alternative anti-wear material to cemented carbides is feasible under alkaline conditions,and even better.
基金supported by JSPS KAKENHI Grant Number 22K12903.
文摘Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneity due to the degradation of Mg on its corrosion behavior.The immersion experiments using pure Mg plates,which were placed vertically in a culture medium(Dulbecco’s Modified Eagle’s Medium(DEME)+10%fetal bovine serum(FBS))for 1,5,and 10 days,were conducted.Surface analyses for the corrosion product layers and the measurements of the pH values and concentrations of eluted ions in the immersion medium around the upper and lower areas of the Mg plate were performed.The significant effect of the macroscopic environmental heterogeneity derived from Mg degradation on the corrosion behavior was demonstrated by in vitro tests.Additionally,the in vivo tests were carried out by implanting the pure Mg plates in the femur of rabbits.The in vivo results exhibited macroscopically heterogeneous Mg degradation,with areas of more severe corrosion compared to the in vitro test;it is especially noticeable during the early stage of degradation,even though the average corrosion rate was lower.
基金the Natural Science Foundation of Hunan Province(2024JJ6364)the National Natural Science Foundation of China(52271073)+1 种基金the Sichuan Science and Technology Program(2024NSFJQ0034)the Innovation Team Funds of China West Normal University(KCXTD2024-1).
文摘Conventional nanoparticles incorporated into epoxy coatings suffer from poor compatibility and insufficient corrosion improvement,hindering their practical applications.A dual-strategy approach integrating in-situ host–vip nanoconfinement and surface self-assembly was devised to fabricate 8HQ@ZIF-8/PDA smart nanocontainers.The vip 8-hydroxyquinoline(8HQ)was encapsulated within the zeolitic imidazolate framework-8(ZIF-8)host,leveraging nanoconfinement effects.A bioinspired polydopamine(PDA)layer was then self-assembled on the 8HQ@ZIF-8 surface through dopamine oxidative self-polymerization,resulting in a robust nanocontainer architecture.Density functional theory(DFT)calculations verify that the molecular interactions between the PDA and the ZIF-8 surface was the chemical adsorption.The resultant 8HQ@ZIF-8/PDA retained the rhombic dodecahedral morphology and crystallinity of ZIF-8,demonstrating controlled pH-responsive release behavior.When incorporated into an epoxy(EP)resin matrix on magnesium alloy,the 8HQ@ZIF-8/PDA/EP smart composite coatings exhibited outstanding interfacial compatibility and long-term stability,achieving a low-frequency impedance(|Z|_(n.n1Hz))of 2.49×10^(7)Ωcm^(2),a maximum phase angle of 82.8°,and a breakpoint frequency(f_(b))of 63.34 Hz after 50 days of immersion in a 3.5 wt%NaCl solution.These findings highlight the exceptional self-healing and corrosion-resistant properties of the 8HQ@ZIF-8/PDA/EP smart composite coatings,underscoring its potential for protecting magnesium alloys in aggressive environments.
基金This project was supported by National Natural Science Foundation of China(Nos.52301339 and U2005216)the Natural Science Foundation of Fujian Province(Nos.2021J05004 and 2020J01010)+1 种基金State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation opening Fund(HESS-2402)the Fundamental Research Funds for the Central Universities(20720240038).
文摘Erosion-corrosion(EC)-induced damage is a primary contributor to premature failures in hydraulic transport structures involving sudden changes in flow patterns,especially the hydraulic pipeline(tee,reducer,pipe bend,etc.),pumps,and valves.A comprehensive exploration of EC behavior of steels subjected to high tensile stress was provided,as most engineering structures are operated under high stress.The stress-accelerated erosion(SAE)and stress-accelerated corrosion(SAC)behaviors of highly stressed steel and their synergistic effect were mainly focused.SAE,SAC,and their synergistic mechanisms,existing debate,and possible reasons,as well as available analytic models with their advantages and limitations,are thoroughly discussed.The multiphysics simulation methods for modeling EC interactions with both static and cyclic stresses are also summarized,and EC mitigation strategies,especially the bionics-based strategies,were also summarized in detail.
基金supported by the National Natural Science Foundation of China(52071175,52301304)the Natural Science Foundation of Jiangsu Province(BK20230704)+3 种基金the China Postdoctoral Science Foundation Funded Project(2023M731742)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(23KJB430019)the Research Fund of Nanjing Institute of Technology(YKJ202402)the Open Research Fund of Jiangsu Key Laboratory for Light Metal Alloys(LMA202401).
文摘Implants are inevitably subjected to stress corrosion,bringing serious challenges to the controlled degradation of biomedical Mg alloys.It is worth studying the stress corrosion cracking(SCC)behavior of Mg alloy and exploring Mg alloy with good SCC resistance for wide biomedical applications.In this work,the as-cast and as-extruded Mg-3Gd-1Zn-0.4Zr(GZ31K)alloys with uniform corrosion were used to investigate SCC behavior.The as-extruded GZ31K alloy exhibited better corrosion resistance and mechanical properties than the as-cast one mainly owing to grain refinement and uniformly distributed fine precipitates,and possessed superior SCC resistance.To clarify the SCC mechanism,the slow strain rate tests were assisted with applied constant potentials via an electrochemical workstation.Accelerated anodic dissolution at anodic polarization deteriorated SCC resistance due to the initiation of corrosion pits and micro-cracks.However,cathodic polarization had no obvious effects on SCC resistance,along with both retarded corrosion and accelerated hydrogen evolution.Stacking faults in GZ31K alloy were hydrogen capture containers to reduce the effect of hydrogen on SCC resistance during cathodic polarization.These findings provide new insights into the evaluation of SCC mechanism,and offer more opportunities to explore Mg alloys with good SCC resistance by regulating anodic dissolution.
基金funded by the National Key Research and Development Program of China(Nos.2021YFB3700902,2021YFB3704204,and 2021YFB3704205)the Beijing Lab Project for Modern Transportation Metallic Materials and Processing Technology,China,the Jiangsu Key Laboratory for Clad Materials,China(No.BM2014006)+4 种基金the Doctor Funds of Taiyuan University of Science and Technology,China(No.20222063)the Fundamental Research Program of Shanxi Province,China(No.202303021212216)the Award Fund for Outstanding Doctors in Shanxi Province,China(No.20232045)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province,China(Nos.2022L289,and 2022L280)the Special Project for Transformation of Scientific Achievements,China(No.202204021301025)。
文摘The corrosion resistance and mechanical properties of peak-aged AlZnMgCu alloys containing Si and Er elements were investigated with hardness test,tensile test,intergranular corrosion test,exfoliation corrosion test and transmission electron microscopy.The results indicate that peak-aged AlZnMgCuSiEr alloy is strengthened by co-precipitation of η′phases and nano-sized GPB-Ⅱ zones.The yield strength of the AlZnMgCu alloy is increased by 38.5 MPa and the elongation is increased by 4.5%.At the same time,the corrosion resistance of the AlZnMgCuSiEr alloy is enhanced due to the synergistic effect of Er and Si.The maximum intergranular corrosion(IGC)depth decreases from 264.2 to 9.9μm.The fundamental reason is that the co-addition of Si and Er regulates the evolution of precipitated phases in grains and at grain boundaries.
基金supported by the National Natural Science Foundation of China(No.51874245)the Natural Science Basic Research Program of Shaanxi(Program No.2022JC-28).
文摘Hot corrosion in molten salt is a complex process,involving both chemical corrosion and electrochemical corrosion.Interfacial reactions and oxide dissolution can also impact the corrosion results.Compared with single component/type salt,multicomponent/type hot corrosion leads to more severe degradation,while the multi-component alloys offer potential chances for developing anti-corrosion metallic materials.In this study,we aim to elucidate the hot corrosion behavior and gain a better understanding of the corrosion mechanism of the multi-component alloys under multi-component/type NaCl-KCl-Na_(2)SO_(4)salt.The corrosion behavior of dual-phaseNi_(36)Fe_(34)Al_(17)Cr_(10)Mo_(1)Ti_(2)(HEA-1)and Ni_(34)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)(HEA-2)alloys was studied within NaCl-KCl-Na_(2)SO_(4)molten salt with mass ratios of 5:5:1 and 5:5:2.After exposure to the salt at 650°C for 168 h,it was found that the Ni_(34)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)exhibited better corrosion resistance thanNi_(36)Fe_(34)Al_(17)Cr_(10)Mo_(1)Ti_(2).The improved performance of Ni_(30)Co_(25)Fe_(12)Al_(15)Cr_(12)W_(2)alloy was attributed to the Co element,which facilitated the formation of dense oxides scale and enhanced scale adhesion.Alkali chlorides with stronger penetration ability dominated the corrosion process and alkali sulfate further aggravated the corrosion.The primary corrosion mechanisms involved in this process were identified as“electrochemical mechanism”attacking the body-centered cubic structure in the alloys and“active oxidation”causing dissolution of the alloy elements.
基金supported by National Natural Science Foundation of China(Grant No.52074095)Guizhou Provincial Basic Research Program(Natural Science)(Grant No.QKHJC-ZK[2023]YB072)+2 种基金Guizhou Provincial Key Technology R&D Program(Grant No.QKHZC[2023]YB404)Guizhou Provincial Key Technology R&D Program(Grant No.QKHZC[2022]YB053)The numerical calculation of the first-principles was supported and assisted by the High-Performance Computing Center of Guizhou University.
文摘The influence mechanism of trace Nb on the corrosion resistance of surface corrosion products of high-strength anti-seismic rebar in the simulated marine environment was studied by combining first-principles calculations with corrosion mass loss method,surface analysis,cross-sectional analysis,quantitative analysis,and electrochemical test.The results demonstrated that the addition of trace Nb effectively improved the compactness and stability of surface corrosion layer of rebar,and the corrosion resistance of corrosion layer increased with the increase in Nb content.The beneficial effect of Nb content on the corrosion layer summarized two important key points.Firstly,the addition of Nb was beneficial to promoting the improvement in the structural stability of α-FeOOH,and α-FeOOH structure of solid solution Nb atoms was beneficial to strengthening the fixation of Cl atoms,thus increasing α/(β+γ)ratio,total impedance value,and corrosion potential.Secondly,the formation of Nb oxides can not only repair the corrosion layer,but also play a role in the fixation Cl atoms,resulting in the improvement in corrosion resistance of corrosion layer.
基金supports from the collaboration research item between Shanghai Jiao Tong University and Hitachi(China)Ltdsupported by Qinghai Salt Lake Industry Co.Ltd financially by via of the Science and Technology Project(21-ZC0609-0003)the National Natural Science Foundation of China(No.51825101)。
文摘In our previous work,die cast LA42(Mg-4La-2.5Al-0.3Mn,wt.%)alloy with an excellent combination of thermal-conducting performance and mechanical properties was developed.This study,taking commercial die cast AZ91(Mg-9Al-1 Zn,wt.%)alloy as a comparison,investigates the microstructure and corrosion behavior of the LA42 alloy in chloride-containing environment.The findings revealed that the microstructure of die cast LA42 alloy displays an Al-depletedα-Mg dendrite and a network shape eutectic phase comprising of eutecticα-Mg and lamellar Al11La3.The LA42 alloy exhibited slightly inferior corrosion resistance and deeper corrosion pits than the AZ91 alloy,which were related to the interphase attack and the presence of a layer of corrosion products containing more magnesium hydroxide of the LA42alloy.The corrosion behavior of the LA42 alloy was characterized by an interphase attack on the periphery of Al-depletedα-Mg dendrite adjacent to Al_(11)La_(3),which primarily ascribed to the relatively lower potential of the Al-depletedα-Mg phase and the interfacial reactivity between it and the adjacent Al_(11)La_(3),whereas the AZ91 alloy showed a trait of preferential corrosion of the interior ofα-Mg dendrite for its lowest potential among different phases.This comprehensive research can provide a guidance for future alloy design of Mg-Al-La alloys and their industrial applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.51971067 and 52001080)Beijing Natural Science Foundation(Grant No.3232005).
文摘The corrosion behavior of Ti–6Al–2Zr–1Mo–1V(TA15)alloy fabricated through selective laser melting(SLM)technology and traditional wrought technology in hydrochloric acid solutions was investigated using electrochemical testing and surface characterizations,including electron backscattered diffraction,scanning electron microscopy,and X-ray photoelectron spectroscopy analyses.The results showed that both types of TA15 alloy underwent spontaneous passivation reactions in HCl solution,and with the increase in HCl concentration,the surface of SLM-TA15 sample exhibited larger and deeper pits.In comparison to SLM-TA15 sample,the pits on the wrought-TA15 sample were shallower and the surface was more uniform.Analysis of the passive current density,breakdown potential,and electrochemical impedance revealed that the corrosion resistance of both alloys decreased as the concentration of HCl increased,and SLM sample exhibited poorer corrosion resistance compared with the wrought sample.Analysis of Mott–Schottky test curves and calculation of passive film thickness indicated that the passive film of wrought-TA15 sample was superior to that of SLM-TA15 sample.
基金supported by the National Natural Science Foundation of China (No.52175315)the Shenzhen Science and Technology Program,China (No.KQTD20200820113110016)the Hunan Provincial Postgraduate Research Innovation Program,China (No.CX20220404)。
文摘The corrosion resistance of aluminum(Al)cable-copper(Cu)terminal joints fabricated by magnetic pulse crimping(MPC)and hydraulic clamp crimping(HCC)was compared.Performance degradation was evaluated by mechanical and electrical properties.Additionally,corrosion behavior was analyzed by electrochemical testing.Microscopic characterization was performed by scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).Results show that the tensile strength of the corroded joints is reduced.However,due to the advantages of high-speed forming and contact tightness unique to MPC,the contact resistance of the corroded joints still maintains excellent.Electrochemical tests demonstrate that the MPC joints have higher corrosion potentials and smaller corrosion currents,providing better corrosion resistance.The formation of a primary battery between Al and Cu at the lap joint leads to the formation of severer corrosion pits.
基金supported by Research and Development Plan of China Railway Group(N2023J065).
文摘Purpose-Weathering steel has excellent resistance to atmospheric corrosion,but still faces complex environmental corrosion problems during long-term operation.This paper mainly studies the corrosion problem of weather resistant steel materials for railway freight car bodies with a load capacity of 70 tons.Design/methodology/approach-The paper analyzes the corrosion characteristics of weather resistant steel materials for truck bodies through macroscopic and microscopic methods including metallographic microscopy,scanning electron microscopy,energy dispersive spectroscopy and X-ray diffraction.Electrochemical analysis shows that the rust layer on the surface of weathering steel changes the surface state of the material,and also proves that weathering steel used in trucks undergoes electrochemical corrosion under atmospheric corrosion.At the same time,ion chromatography technology is used to study the corrosive ions mainly present in the residual liquid and foam solution inside the vehicle body.Findings-The corrosion of truck body materials is mainly electrochemical corrosion,and the corrosion of door materials is more obvious than that of other parts.The corrosion products are mainly Fe oxides and hydroxides.There are high concentrations of Cl-and SO42-ions in the residual liquid and foam solution at the bottom of the freight car,which are the main factors causing corrosion of the railway freight car body.Originality/value-The foam adhesive around the door panel is in a moist state for a long time,and corrosive ions will accelerate the electrochemical corrosion of the weather resistant steel material of the door panel.Therefore,the corrosion of the cargo door panel is more severe than other components.
