Microbial contamination and the resulting corrosion in aircraft fuel system pose a serious threat to flight safety.Revealing the corrosion behavior and mechanism of fuel-degrading microorganisms on tank materials is c...Microbial contamination and the resulting corrosion in aircraft fuel system pose a serious threat to flight safety.Revealing the corrosion behavior and mechanism of fuel-degrading microorganisms on tank materials is crucial for developing effective mitigation strategies.In this study,the corrosion mechanisms of two representative hydrocarbon-degrading bacteria,Alcanivorax dieselolei and Microbacterium oxydans,toward AA7075 aluminum alloy,were systematically investigated.A combination of biofilm characterization,electrochemical testing,and surface/corrosion product characterization was employed.Both strains markedly accelerated the corrosion of AA7075,as evidence by the progressive decrease in polarization resistance and the pronounced rightward shift of the potentiodynamic polarization curves.Moreover,the difference between the pitting potential(E_(pit))and the corrosion potential(E_(corr))(ΔE=E_(pit)‒E_(corr))decreased due to microbial activities,indicating a pronounced tendency toward accelerated pitting corrosion.Corrosion morphology analysis revealed that both microbes promoted localized pitting corrosion.Furthermore,analysis of aviation kerosene composition indicated that both bacteria accelerated the degradation of C8 and C9 alkanes.These findings highlight the multiple threats of microbial contamination,material degradation,and fuel quality deterioration in fuel systems and underscore the need for targeted protection strategies for marine aviation operations.展开更多
The authors regret that due to negligence,the picture was misplaced in the original manuscript,resulting in Fig.6d being incorrectly included.The correct version of Fig.6d is provided below for reference.This error do...The authors regret that due to negligence,the picture was misplaced in the original manuscript,resulting in Fig.6d being incorrectly included.The correct version of Fig.6d is provided below for reference.This error does not affect the conclusions of the study,and we apologize for any confusion it may have caused.展开更多
A new perspective was reported to design the self-densified plasma electrolytic oxidation(SDF-PEO)coat-ings on magnesium alloys based on the dissolution-ionization-diffusion-deposition(DIDD)model.The main consideratio...A new perspective was reported to design the self-densified plasma electrolytic oxidation(SDF-PEO)coat-ings on magnesium alloys based on the dissolution-ionization-diffusion-deposition(DIDD)model.The main considerations of the new PEO electrolyte include the establishment of a thermodynamics diagram,the construction of a liquid-solid sintering system and the regulation of plasma sparkling kinetics.The SDF-PEO coating exhibited a homogeneous and dense microstructure,superior corrosion resistance and good technological adaptability.This work offers a novel theory to design surface treatment solutions with superior corrosion resistance and promising application prospects.展开更多
Titanium alloys,usually known as non-corrodible material,are susceptible to microbiologically influenced corrosion(MIC)in marine environment.While titanium-zirconium(TiZr)alloys have been extensively studied in medica...Titanium alloys,usually known as non-corrodible material,are susceptible to microbiologically influenced corrosion(MIC)in marine environment.While titanium-zirconium(TiZr)alloys have been extensively studied in medical applications,the influence of microorganisms,especially marine microorganisms,on their corrosion behavior has not been explored.In this work,a TiZrCu alloy with a combination of excel-lent mechanical,anti-corrosion,and antibacterial properties was developed by optimizing the Cu content and grain refinement.Its MIC and antibacterial mechanisms against Pseudomonas aeruginosa,a represen-tative marine microorganism,were systematically investigated.5.5 wt%was determined as the optimal copper content.The fine-grained Ti-15Zr-5.5Cu(TZC-5.5FG)alloy maintained high MIC resistance,exhibit-ing a corrosion current of 5.7±0.1 nA/cm^(2) and an antibacterial rate of 91.8% against P.aeruginosa.The mechanism of improved corrosion resistance was attributed to the denser passive film with high TiO2 content and the lower surface potential differenceΔE.The release of Cu^(2+)ions,ΔE,and the generation of ROS are three major factors that contribute to the antibacterial performance of TiZrCu alloys.Com-pared to other available marine metals,TZC-5.5FG alloy exhibited superior comprehensive performance,including excellent mechanical properties and anti-MIC capacity,which make it a promising material for load-bearing applications in marine environment.展开更多
Zinc-based alloys are promising biodegradable materials for application in the intestinal environment due to their appropriate degradation rates and favorable biocompatibility.However,the corrosion and degradation of ...Zinc-based alloys are promising biodegradable materials for application in the intestinal environment due to their appropriate degradation rates and favorable biocompatibility.However,the corrosion and degradation of biodegradable zinc alloys in the presence of intestinal microorganisms are seldom investigated.In this study,binary Zn-Mn alloys with 0.4 and 0.8 wt.%Mn content were fabricated using the extrusion process.The corrosion behaviors of pure zinc and Zn-Mn alloys with the existence of Lactobacillus acidophilus,a representative microorganism in the intestinal tract,were systematically investigated.In comparison to pure zinc,both Zn-Mn alloys exhibited enhanced strength and ductility.L.acidophilus significantly accelerated the corrosion of both pure zinc and Zn-Mn alloys by generating acidic agents.The presence of L.acidophilus increased the icorr values for pure zinc,Zn-0.4Mn,and Zn-0.8Mn from 68.7±9.9,33.9±2.3 and 17.1±0.1µA cm^(-2) to 253.5±26.7,167.6±8.7 and 30.6±2.2µA cm^(-2),respectively.The addition of Mn mitigated corrosion by refining grains and reducing the local surface potential difference.Compared to pure zinc,the surface potential difference of Zn-0.8Mn decreased from 31.8±1.7 mV to 11.8±0.9 mV.This study points out the existence of microbiologically influenced corrosion in the intestinal environment and emphasizes its importance in the comprehensive design of biodegradable zinc alloys.展开更多
Surface-adhering biofilms contribute significantly to irreversible biofouling and corrosion,presenting a multi-trillion-dollar annual problem in public health and industry.Strategies employing antibacterial elements a...Surface-adhering biofilms contribute significantly to irreversible biofouling and corrosion,presenting a multi-trillion-dollar annual problem in public health and industry.Strategies employing antibacterial elements are emerging to fabricate multifunctional coatings that effectively combat such microbially produced damage.However,rapid,reliable,and robust surface engineering remains challenging due to stability limitations and intricate anti-biofilm additive dynamics.Herein,a silver-capsule-conjugated polyurethane coating with high stability and antimicrobial efficacy in a cooperative manner is developed through controlled supramolecular self-assembly.Polyvinylpyrrolidone(PVP)-mediated molecule entanglement breaks through the incompatibility between polymeric components and nanomaterials,strengthening the dispersion and fixation of encapsulated silver nanoparticles.The facilitation and control of the nanoscale interfacial binding significantly suppresses the aggregation of inorganic nanoparticles and consequent microcracks development,giving rise to mechanical robustness and thermal stability of the hybrid coating under extreme conditions.A synergistic combination of exposed residues,electrostatic,and coordination interactions could readily integrate the resultant coating on virtually arbitrary material sur-faces.This composite coating exhibits broad-spectrum and high bactericidal efficiencies of 99.99% against Staphylococcus aureus and Escherichia coli,as well as excellent biofilm formation suppression.Moreover,our coating has robust resistance to microbial-influenced corrosion(MIC)and can even endure 720 h of salt spray.This study deciphers a general code for creating stable and durable nanohybrid coatings to mitigate microbially related risks.展开更多
Nickel-based alloys applied in marine environments often face multiple challenges of stress,corrosion and wear.In this work,heterostructured NiCrTi alloy was prepared by spark plasma sintering coarse Ni20Cr and ultraf...Nickel-based alloys applied in marine environments often face multiple challenges of stress,corrosion and wear.In this work,heterostructured NiCrTi alloy was prepared by spark plasma sintering coarse Ni20Cr and ultrafine Ti powders.Apart that some are dissolved into the nickel alloy,Ti powders react in situ with Ni20Cr during sintering to form hard intermetallic Ni_(3)Ti.It builds up a typical heterostructure that endows NiCrTi alloy with well-balanced mechanical strength and plasticity,e.g.high yield strength of 1321 MPa,compressive strength of 2470 MPa,and compressive strain of 20%.On tribocorrosion,the hard shell enriched with Ti transforms to connected protrusion and form in situ surface texture.Oxides or wear debris are trapped at the textured surface and compacted to form a stable tribofilm.Thus negative synergy between corrosion and wear is observed for NiCrTi and high tribocorrosion resistance is achieved.At a potential of+0.3 V,the tribocorrosion rate of NiCrTi is reduced by an order of magnitude to 1.87×10^(-5)mm^(3)/(Nm)in comparison to the alloy Ni20Cr.展开更多
In order to obtain a more protective phosphate conversion coating with a denser architecture,the nucleation kinetics of phosphate chemical conversion coating on Mg-Gd-Y-Zr magnesium alloy was tuned in this work.A pret...In order to obtain a more protective phosphate conversion coating with a denser architecture,the nucleation kinetics of phosphate chemical conversion coating on Mg-Gd-Y-Zr magnesium alloy was tuned in this work.A pretreatment process was proposed and organic additives were incorporated,which aims at increasing the ionic produce(J_(sp))at the interface for increasingσ,and decreasing the critical ionic product(J_(C,sp)),respectively.Results prove that the pretreatment of bare alloys in a phosphate bath could increase the ion products of MgHPO_(4)/MnHPO_(4).The addition of benzalkonium chloride could neutralize the charges of crystals,and in turn promote the nucleation kinetics.A denser and more protective conversion coating could consequently be obtained.展开更多
Self-catalytic reactions have consistently been implicated in the high-temperature corrosion mechanism of NiAl-phase coatings in NaCl-or Na_(2)SO_(4)-containing mediums,with little discussion concerning the adsorption...Self-catalytic reactions have consistently been implicated in the high-temperature corrosion mechanism of NiAl-phase coatings in NaCl-or Na_(2)SO_(4)-containing mediums,with little discussion concerning the adsorption and competitive behavior of complex environmental molecules.This study investigated the adsorption and dissociation behavior of a series of gas-phase molecules(O_(2),H_(2)O,SO_(3),S_(2),H_(2)S,Cl_(2)and HCl)on the NiAl(110)surface using first-principles calculations.The findings reveal a mechanism of competitive adsorption and dissociation,with two distinct adsorption dissociation behaviors observed upon the introduction of Pt or Hf elements.Pt-doping inhibits the surface adsorption behavior of self-catalytic molecules,while Hf significantly enhances the adsorption and dissociation of oxygen-carrying molecules.By preparing three types of NiAl-phase coatings(β-NiAl,(Ni,Pt)Al,and Hf-(Ni,Pt)Al)and conducting corrosion tests in the presence of NaCl or Na_(2)SO_(4),it is determined that the excellent corrosion resistance of Hf-(Ni,Pt)Al can be attributed to the combined effects of Pt in delaying corrosion reactions and Hf in promoting the formation of a protective oxide scale.A comprehensive analysis,combining first-principles calculations and experimental observations,was conducted to elucidate the corrosion mechanisms of three coatings in different corrosion mediums.展开更多
A principle was proposed for designing a method to seal anodized aluminum used in semiconductor processing apparatuses.Thermodynamic calculations and Fick’s second law were used to reveal trends in the metal ion depo...A principle was proposed for designing a method to seal anodized aluminum used in semiconductor processing apparatuses.Thermodynamic calculations and Fick’s second law were used to reveal trends in the metal ion deposition,deposition product stability,vapor pressures of halides for selected metal ions,the holding temperature,and time.Interactions between ion concentrations and the sealing temperature were also revealed.According to the design principles,anodized aluminum dipped in 1 mM Cr^(3+)ion solution and steam-sealed for 18 h exhibited the highest corrosion resistance when exposed to 5 wt.%HCl solution and HCl gas,verifying the designed results.展开更多
To enhance the corrosion resistance of Mg-Li alloy,a composite coating system integrating plasma electrolytic oxidation(PEO)with solgel sealing treatment is developed.Two functionalized sepiolite microcontainers(sepio...To enhance the corrosion resistance of Mg-Li alloy,a composite coating system integrating plasma electrolytic oxidation(PEO)with solgel sealing treatment is developed.Two functionalized sepiolite microcontainers(sepiolite-Ce and sepiolite-BA)are constructed by loading cerium ions(Ce3+)via ion exchange and encapsulating barbituric acid(BA)through low-pressure impregnation.The microcontainers are subsequently incorporated into the coating surface through controlled sol-gel deposition process.UV-Vis and ICP-OES analyses reveal that both functionalized sepiolite microcontainers exhibited pH-responsive release characteristics under alkaline conditions.Electrochemical impedance spectroscopy(EIS)tests demonstrate that the inhibitor-containing composite coating has excellent long-term corrosion resistance and self-healing performance.After 240 h of immersion in a 0.5 wt.%NaCl solution,the low-frequency impedance modulus of the composite coating is four orders of magnitude higher than that of the pristine coating.展开更多
In-situ growth of layered double hydroxide(LDH)has been considered a feasible method to further improve the corrosion protection of PEO coated Mg alloys,but the process is basically carried out in an autoclave.In this...In-situ growth of layered double hydroxide(LDH)has been considered a feasible method to further improve the corrosion protection of PEO coated Mg alloys,but the process is basically carried out in an autoclave.In this study,LDH was in-situ synthesized on PEO treated AM50 Mg by hydrothermal treatment at ambient pressure in the presence of chelating agents.Results indicated that the synergistic effect of sulfosalicylic acid(SSA)and ethylenediaminetetraacetic acid tetrasodium salt(EDTA)chelating agents is appropriate for Mg-Al LDH formation due to the sufficient quantity of highly stable Mg and Al complexes in the treatment bath.An appropriate hydrothermal treatment time was also revealed in this work,which can efficiently seal the pores and defects of PEO coating with a uniform LDH film.As a result,the corrosion protection of the coating was improved dramatically.The prolonged hydrothermal treatment is detrimental to the integrity of PEO layers.The influence of chelating agents on the LDH formation processes is supported by thermodynamic calculation of the equilibrium composition,and the formation mechanism of LDH film is discussed in depth.展开更多
Hot corrosion of the sputtered nanocrystalline coating and its(Al+Y)-modified coating on N5 with and without different preoxidation treatments under 75 wt.%Na_(2)SO_(4)+25 wt.%NaCl molten salts at 900℃was investigate...Hot corrosion of the sputtered nanocrystalline coating and its(Al+Y)-modified coating on N5 with and without different preoxidation treatments under 75 wt.%Na_(2)SO_(4)+25 wt.%NaCl molten salts at 900℃was investigated.The results showed both the nanocrystalline coatings without preoxidation suffered from severe corrosion.No intact protective scale could form on the surface due to the fast penetration of the corrosive media through massive grain boundaries in the coating.The effect of different preoxidation treatments on the corrosion varied for the two coatings.The original nanocrystalline coatings with simi-lar compositions to the substrate N5 after preoxidation showed a low corrosion resistance,with a loose defective oxide scale on the surface and severe internal corrosion in the coating.Ta oxide segregation ru-ined the stability of the preoxide scale and thus accelerated the subsequent corrosion.In comparison,the AlY-modified coating after preoxidation at 1000℃exhibited the best corrosion resistance.Its oxide con-sisted exclusively of the Al_(2)O_(3) scale,and the least internal corrosion occurred in the coating.Co-addition of Al and Y retarded the diffusion of Ta,improved the stability of the scale,and provided a sufficient Al supplement to reform the Al_(2)O_(3) scale in the corrosion process,postponing corrosion destruction of the scale.The AIY-modified coating after preoxidation at 1100℃performed worse than that at 1000℃.The inferior corrosion resistance could be attributed to the more defective preoxide scale caused by higher thermal stress concentration during preoxidation.展开更多
Novel neutral electrolytes were designed to substantially decrease porosity and increase barrier property of plasma electrolytic oxidation(PEO)coating on AM50 Mg surface.Presence of additives was effective in tuning c...Novel neutral electrolytes were designed to substantially decrease porosity and increase barrier property of plasma electrolytic oxidation(PEO)coating on AM50 Mg surface.Presence of additives was effective in tuning coating microstructure and composition,leading to significantly enhanced corrosion and wear properties.50%improvement in fatigue limit was detected for the optimized coating compared to conventional PEO coating.The low-porosity coating remained uncorroded after performing salt spray test for 1 month,and exposure 1 year in harsh South China Sea environment.This can be new strategy to evaluate coating lifespan and promote wide range of applications for Mg alloy.展开更多
The effect of intermetallic particles on the corrosion of 6061 aluminum alloy and its coating used in semiconductor processing systems was systematically studied via liquid and gas experiments and micromorphology char...The effect of intermetallic particles on the corrosion of 6061 aluminum alloy and its coating used in semiconductor processing systems was systematically studied via liquid and gas experiments and micromorphology characterization.The results revealed that a huge difference of corrosion resistance between imported and domestic 6061 aluminum alloys in HCl solution and gas acid mist experiments mainly was attributed to the different size and amount of Al_(15)(Fe,Mn)_(3)Si_(2).The corrosion resistance of domestic 6061 alloy in dry/wet semiconductor electronic special gas environments was worse than that of imported aluminum alloy,and there are great differences in the corrosion mechanism of 6061 alloy caused by the second phase in the two dry/wet environments.And the corrosion resistance of the hard anodized alumina film was closely related to the microscopic morphology of holes.The vertical and elongatedα-Al_(15)(Mn,Fe)_(3)Si_(2) phase was formed in the rolled aluminum alloy that has been rolled perpendicular to the surface of the substrate.Compared to the horizontal long hole,the longitudinal long holes generated by the verticalα-Al_(15)(Mn,Fe)_(3)Si_(2) phase will enable the corrosive medium to reach the substrate rapidly,which significantly weakens the corrosion resistance of the hard anodized film.展开更多
Carbide dispersion reinforcing has been demonstrated to be an effective way of strengthening metal matrix composites.However,plagued by the nerve-wracking fact that the carbide particles tend to aggregate at the grain...Carbide dispersion reinforcing has been demonstrated to be an effective way of strengthening metal matrix composites.However,plagued by the nerve-wracking fact that the carbide particles tend to aggregate at the grain boundary of the metal matrix,grow up,and form an incoherent interface with it,their improvement in mechanical strength tends to be limited.In this study,spark plasma sintering(SPS)was used to prepare the bulk alloy Ni20Cr and its composites with different carbides including TiC,SiC,and Ti_(3)SiC_(2).Plasma leads to discharge and elevates temperature at the interface to melt the Ni20Cr alloy particles locally.When cooled down,the alloy is heterogeneously solidified on the surface of the carbide and builds up a coherent interface with it.Owing to the decomposition of Ti_(3)SiC_(2) during sintering,it completely transformed into nanosized TiC particles,which are engulfed by the outer melted layer of Ni20Cr and well dispersed within the alloy grains.In comparison to the Ni20Cr alloy,the composite with merely 4 wt%Ti_(3)SiC_(2) gains over three times enhancement in yield strength to 879 MPa,while keeping a moderate high elongation of 17.8%.Finite element analysis demonstrated that the combination of SPS and precursor MAX phase of Ti_(3)SiC_(2),which results in the in-situ precipitation of coherent ultrafine TiC particles in alloy grains,plays the key role in getting a good balance between mechanical strength and ductility for the Ni20Cr matrix composites.展开更多
Microbiologically influenced corrosion （MIC） is a major cause of corrosion damages, facility failures, and financial losses, making MIC an important research topic. Due to complex microbiological activities and a la...Microbiologically influenced corrosion （MIC） is a major cause of corrosion damages, facility failures, and financial losses, making MIC an important research topic. Due to complex microbiological activities and a lack of deep understanding of the interactions between biofilms and metal surfaces, MIC occurrences and mechanisms are difficult to predict and interpret. Many theories and mechanisms have been pro- posed to explain MIC. In this review, the mechanisms of MIC are discussed using hioenergetics, microbial respiration types, and biofilm extracellular electron transfer （EET）. Two main MIC types, namely EET-MIC and metabolite MIC （M-ME）, are discussed. This brief review provides a state of the art insight into MIC mechanisms and it helps the diagnosis and prediction of occurrences of MIC under anaerobic conditions in the oil and gas industry.展开更多
The corrosion behavior of 2 A02 Al alloy under simulated marine atmospheric environment has been studied using mass-gain, scanning electron microscope/energy dispersive spectroscopy(SEM/EDS), laser scanning confocal m...The corrosion behavior of 2 A02 Al alloy under simulated marine atmospheric environment has been studied using mass-gain, scanning electron microscope/energy dispersive spectroscopy(SEM/EDS), laser scanning confocal microscopy, X-ray diffraction spectroscopy and localized electrochemical methods. The results demonstrate that the relationship between the corrosion induced mass-gain and the corrosion time is in accordance with the power rule. The mass-gain increases gradually during the corrosion time,while the corrosion rate decreases. With ongoing of the corrosion, corrosion products film changed from a porous to a compact structure. The various spectroscopic data show that the corrosion products films composed mainly of Al(OH)_3, Al_2O_3 and AlCl_3. The electrochemical corrosion behavior of the 2 A02 Al alloy was studied by electrochemical impedance spectroscopy(EIS).展开更多
The effects of heat-treatment on corrosion behavior of Mg-15Gd-2Zn-0.39Zr alloys were investigated through microstructure characterization, corrosion tests, and scanning Kelvin probe force microscope(SKPFM) analysis. ...The effects of heat-treatment on corrosion behavior of Mg-15Gd-2Zn-0.39Zr alloys were investigated through microstructure characterization, corrosion tests, and scanning Kelvin probe force microscope(SKPFM) analysis. In long-term corrosion experiments, the corrosion rates of Mg-Gd-Zn-Zr alloys were mainly determined by the effects of micro-galvanic corrosion. During heat-treatment, the β-(Mg,Zn)3Gd eutectic phase in as-cast alloys transformed into a long-period stacking ordered(LPSO) phase, coupled with the precipitation of small precipitates. As heat-treatment proceeded, the local potential and the volume fraction of the LPSO phases reduced gradually compared with the eutectic phase, which resulted in a remarkable decrease of the micro-galvanic effect between the second phase and Mg matrix. As a result, the corrosion resistance of heat-treated alloys improved significantly.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 52371056)the Liaoning Provincial Youth Science Fund Project, China (Category B, No. 2025JH6/101000010)+1 种基金the Guangdong Basic and Applied Basic Research Foundation, China (No. 2024A1515240055)funding from the China Scholarship Council
文摘Microbial contamination and the resulting corrosion in aircraft fuel system pose a serious threat to flight safety.Revealing the corrosion behavior and mechanism of fuel-degrading microorganisms on tank materials is crucial for developing effective mitigation strategies.In this study,the corrosion mechanisms of two representative hydrocarbon-degrading bacteria,Alcanivorax dieselolei and Microbacterium oxydans,toward AA7075 aluminum alloy,were systematically investigated.A combination of biofilm characterization,electrochemical testing,and surface/corrosion product characterization was employed.Both strains markedly accelerated the corrosion of AA7075,as evidence by the progressive decrease in polarization resistance and the pronounced rightward shift of the potentiodynamic polarization curves.Moreover,the difference between the pitting potential(E_(pit))and the corrosion potential(E_(corr))(ΔE=E_(pit)‒E_(corr))decreased due to microbial activities,indicating a pronounced tendency toward accelerated pitting corrosion.Corrosion morphology analysis revealed that both microbes promoted localized pitting corrosion.Furthermore,analysis of aviation kerosene composition indicated that both bacteria accelerated the degradation of C8 and C9 alkanes.These findings highlight the multiple threats of microbial contamination,material degradation,and fuel quality deterioration in fuel systems and underscore the need for targeted protection strategies for marine aviation operations.
文摘The authors regret that due to negligence,the picture was misplaced in the original manuscript,resulting in Fig.6d being incorrectly included.The correct version of Fig.6d is provided below for reference.This error does not affect the conclusions of the study,and we apologize for any confusion it may have caused.
基金supported by the National Natural Sci-ence Foundation of China(Nos.U21A2045 and 52201066)the Liaoning Revitalization Talents Program(No.XLYC2002071).
文摘A new perspective was reported to design the self-densified plasma electrolytic oxidation(SDF-PEO)coat-ings on magnesium alloys based on the dissolution-ionization-diffusion-deposition(DIDD)model.The main considerations of the new PEO electrolyte include the establishment of a thermodynamics diagram,the construction of a liquid-solid sintering system and the regulation of plasma sparkling kinetics.The SDF-PEO coating exhibited a homogeneous and dense microstructure,superior corrosion resistance and good technological adaptability.This work offers a novel theory to design surface treatment solutions with superior corrosion resistance and promising application prospects.
基金supported by the National Key Research and Development Program of China(No.2022YFB3808800)the National Natural Science Foundation of China(No.52425112 and 52401178)+1 种基金the IMR Innovation Fund(No.2024-PY06)the CAS-WEGO Research and Development Plan Project.
文摘Titanium alloys,usually known as non-corrodible material,are susceptible to microbiologically influenced corrosion(MIC)in marine environment.While titanium-zirconium(TiZr)alloys have been extensively studied in medical applications,the influence of microorganisms,especially marine microorganisms,on their corrosion behavior has not been explored.In this work,a TiZrCu alloy with a combination of excel-lent mechanical,anti-corrosion,and antibacterial properties was developed by optimizing the Cu content and grain refinement.Its MIC and antibacterial mechanisms against Pseudomonas aeruginosa,a represen-tative marine microorganism,were systematically investigated.5.5 wt%was determined as the optimal copper content.The fine-grained Ti-15Zr-5.5Cu(TZC-5.5FG)alloy maintained high MIC resistance,exhibit-ing a corrosion current of 5.7±0.1 nA/cm^(2) and an antibacterial rate of 91.8% against P.aeruginosa.The mechanism of improved corrosion resistance was attributed to the denser passive film with high TiO2 content and the lower surface potential differenceΔE.The release of Cu^(2+)ions,ΔE,and the generation of ROS are three major factors that contribute to the antibacterial performance of TiZrCu alloys.Com-pared to other available marine metals,TZC-5.5FG alloy exhibited superior comprehensive performance,including excellent mechanical properties and anti-MIC capacity,which make it a promising material for load-bearing applications in marine environment.
基金financially supported by the National Natural Science Foundation of China(No.52231010).
文摘Zinc-based alloys are promising biodegradable materials for application in the intestinal environment due to their appropriate degradation rates and favorable biocompatibility.However,the corrosion and degradation of biodegradable zinc alloys in the presence of intestinal microorganisms are seldom investigated.In this study,binary Zn-Mn alloys with 0.4 and 0.8 wt.%Mn content were fabricated using the extrusion process.The corrosion behaviors of pure zinc and Zn-Mn alloys with the existence of Lactobacillus acidophilus,a representative microorganism in the intestinal tract,were systematically investigated.In comparison to pure zinc,both Zn-Mn alloys exhibited enhanced strength and ductility.L.acidophilus significantly accelerated the corrosion of both pure zinc and Zn-Mn alloys by generating acidic agents.The presence of L.acidophilus increased the icorr values for pure zinc,Zn-0.4Mn,and Zn-0.8Mn from 68.7±9.9,33.9±2.3 and 17.1±0.1µA cm^(-2) to 253.5±26.7,167.6±8.7 and 30.6±2.2µA cm^(-2),respectively.The addition of Mn mitigated corrosion by refining grains and reducing the local surface potential difference.Compared to pure zinc,the surface potential difference of Zn-0.8Mn decreased from 31.8±1.7 mV to 11.8±0.9 mV.This study points out the existence of microbiologically influenced corrosion in the intestinal environment and emphasizes its importance in the comprehensive design of biodegradable zinc alloys.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB3808800,Dake Xu)the National Natural Science Foundation of China(Grant Nos.U2006219(Dake Xu),52301081(Xiangyu Li))+4 种基金the National Postdoctoral Program for Innovative Talents(Grant No.BX20220059,Xiangyu Li)the China Postdoctoral Science Foundation(Grant No.2022M720677,Xiangyu Li)the Liaoning Provincial Natural Science Foundation of China(Grant No.2023-BS-052,Xiangyu Li)the Fundamental Research Funds for the Central Universities(Grant No.N2302015,Xiangyu Li)the State Key Laboratory of Marine Coatings Funded Project(Grant No.2024020800027,Xiangyu Li).
文摘Surface-adhering biofilms contribute significantly to irreversible biofouling and corrosion,presenting a multi-trillion-dollar annual problem in public health and industry.Strategies employing antibacterial elements are emerging to fabricate multifunctional coatings that effectively combat such microbially produced damage.However,rapid,reliable,and robust surface engineering remains challenging due to stability limitations and intricate anti-biofilm additive dynamics.Herein,a silver-capsule-conjugated polyurethane coating with high stability and antimicrobial efficacy in a cooperative manner is developed through controlled supramolecular self-assembly.Polyvinylpyrrolidone(PVP)-mediated molecule entanglement breaks through the incompatibility between polymeric components and nanomaterials,strengthening the dispersion and fixation of encapsulated silver nanoparticles.The facilitation and control of the nanoscale interfacial binding significantly suppresses the aggregation of inorganic nanoparticles and consequent microcracks development,giving rise to mechanical robustness and thermal stability of the hybrid coating under extreme conditions.A synergistic combination of exposed residues,electrostatic,and coordination interactions could readily integrate the resultant coating on virtually arbitrary material sur-faces.This composite coating exhibits broad-spectrum and high bactericidal efficiencies of 99.99% against Staphylococcus aureus and Escherichia coli,as well as excellent biofilm formation suppression.Moreover,our coating has robust resistance to microbial-influenced corrosion(MIC)and can even endure 720 h of salt spray.This study deciphers a general code for creating stable and durable nanohybrid coatings to mitigate microbially related risks.
基金financially supported by the Liaoning Revitalization Talents Program(No.XLYC2203133)the Fundamental Research Funds for the Central Universities(No.N2302018)the Ningbo Yuyao City Science and Technology Plan Project(No.2023J03010010).
文摘Nickel-based alloys applied in marine environments often face multiple challenges of stress,corrosion and wear.In this work,heterostructured NiCrTi alloy was prepared by spark plasma sintering coarse Ni20Cr and ultrafine Ti powders.Apart that some are dissolved into the nickel alloy,Ti powders react in situ with Ni20Cr during sintering to form hard intermetallic Ni_(3)Ti.It builds up a typical heterostructure that endows NiCrTi alloy with well-balanced mechanical strength and plasticity,e.g.high yield strength of 1321 MPa,compressive strength of 2470 MPa,and compressive strain of 20%.On tribocorrosion,the hard shell enriched with Ti transforms to connected protrusion and form in situ surface texture.Oxides or wear debris are trapped at the textured surface and compacted to form a stable tribofilm.Thus negative synergy between corrosion and wear is observed for NiCrTi and high tribocorrosion resistance is achieved.At a potential of+0.3 V,the tribocorrosion rate of NiCrTi is reduced by an order of magnitude to 1.87×10^(-5)mm^(3)/(Nm)in comparison to the alloy Ni20Cr.
基金the National Natural Science Foundation of China(No.52201066 and No.U21A2045)LiaoNing Revitalization Talents Program(NO.XLYC2002071)+2 种基金Gratitude is also expressed to the support from the Shanghai Aerospace Science and Technology Innovation Fund(SAST2020-046)the Fundamental Research Funds for the Central Universities(N2224002-21)the Natural Science Foundation of Shanghai(20ZR1424200).
文摘In order to obtain a more protective phosphate conversion coating with a denser architecture,the nucleation kinetics of phosphate chemical conversion coating on Mg-Gd-Y-Zr magnesium alloy was tuned in this work.A pretreatment process was proposed and organic additives were incorporated,which aims at increasing the ionic produce(J_(sp))at the interface for increasingσ,and decreasing the critical ionic product(J_(C,sp)),respectively.Results prove that the pretreatment of bare alloys in a phosphate bath could increase the ion products of MgHPO_(4)/MnHPO_(4).The addition of benzalkonium chloride could neutralize the charges of crystals,and in turn promote the nucleation kinetics.A denser and more protective conversion coating could consequently be obtained.
基金the sponsorship by the National Natural Science Foundation of China(Nos.51671202 and 52301116)the Fundamental Science Center for Aviation and Gas Turbine Engines(No.P2021-A-IV-002-001)+1 种基金supported by the National Science and Technology Major Project(No.J2019-IV-0006-0074)the Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2021-2-2).
文摘Self-catalytic reactions have consistently been implicated in the high-temperature corrosion mechanism of NiAl-phase coatings in NaCl-or Na_(2)SO_(4)-containing mediums,with little discussion concerning the adsorption and competitive behavior of complex environmental molecules.This study investigated the adsorption and dissociation behavior of a series of gas-phase molecules(O_(2),H_(2)O,SO_(3),S_(2),H_(2)S,Cl_(2)and HCl)on the NiAl(110)surface using first-principles calculations.The findings reveal a mechanism of competitive adsorption and dissociation,with two distinct adsorption dissociation behaviors observed upon the introduction of Pt or Hf elements.Pt-doping inhibits the surface adsorption behavior of self-catalytic molecules,while Hf significantly enhances the adsorption and dissociation of oxygen-carrying molecules.By preparing three types of NiAl-phase coatings(β-NiAl,(Ni,Pt)Al,and Hf-(Ni,Pt)Al)and conducting corrosion tests in the presence of NaCl or Na_(2)SO_(4),it is determined that the excellent corrosion resistance of Hf-(Ni,Pt)Al can be attributed to the combined effects of Pt in delaying corrosion reactions and Hf in promoting the formation of a protective oxide scale.A comprehensive analysis,combining first-principles calculations and experimental observations,was conducted to elucidate the corrosion mechanisms of three coatings in different corrosion mediums.
基金supported by the Program of the National Natural Science Foundation of China(Grant No.52371055)the Young Elite Scientist Sponsorship Program Cast(Grant No.YESS20200139)+1 种基金the Basic Scientific Research Project of Liaoning Provincial Department of Education(Grant No.JYTMS20230618)Special thanks are due to the instrumental analysis from the Analytical and Testing Centre,Northeastern University.
文摘A principle was proposed for designing a method to seal anodized aluminum used in semiconductor processing apparatuses.Thermodynamic calculations and Fick’s second law were used to reveal trends in the metal ion deposition,deposition product stability,vapor pressures of halides for selected metal ions,the holding temperature,and time.Interactions between ion concentrations and the sealing temperature were also revealed.According to the design principles,anodized aluminum dipped in 1 mM Cr^(3+)ion solution and steam-sealed for 18 h exhibited the highest corrosion resistance when exposed to 5 wt.%HCl solution and HCl gas,verifying the designed results.
基金financially supported by LiaoNing Revitalization Talents Program(XLYC2403026)Shenyang Young and Middle-aged Science and Technology Innovation Talent Support Program(RC231178)the Fundamental Research Funds for the Central Universities(N25GFY002).
文摘To enhance the corrosion resistance of Mg-Li alloy,a composite coating system integrating plasma electrolytic oxidation(PEO)with solgel sealing treatment is developed.Two functionalized sepiolite microcontainers(sepiolite-Ce and sepiolite-BA)are constructed by loading cerium ions(Ce3+)via ion exchange and encapsulating barbituric acid(BA)through low-pressure impregnation.The microcontainers are subsequently incorporated into the coating surface through controlled sol-gel deposition process.UV-Vis and ICP-OES analyses reveal that both functionalized sepiolite microcontainers exhibited pH-responsive release characteristics under alkaline conditions.Electrochemical impedance spectroscopy(EIS)tests demonstrate that the inhibitor-containing composite coating has excellent long-term corrosion resistance and self-healing performance.After 240 h of immersion in a 0.5 wt.%NaCl solution,the low-frequency impedance modulus of the composite coating is four orders of magnitude higher than that of the pristine coating.
基金the financial support from National Natural Science Foundation of China(No.52071067)Mobility Programme of the Sino-German Center(M-0056)+3 种基金Shenyang Young and Middle-aged Science and Technology Innovation Talent Support Program(RC231178)Natural Science Foundation Project of Liaoning Province(2022-YGJC-16)the Fundamental Research Funds for the Central Universities(N2302019)Qianqian Chen would like to acknowledge China Scholarship Council for the award of fellowship(NO.202206080011).
文摘In-situ growth of layered double hydroxide(LDH)has been considered a feasible method to further improve the corrosion protection of PEO coated Mg alloys,but the process is basically carried out in an autoclave.In this study,LDH was in-situ synthesized on PEO treated AM50 Mg by hydrothermal treatment at ambient pressure in the presence of chelating agents.Results indicated that the synergistic effect of sulfosalicylic acid(SSA)and ethylenediaminetetraacetic acid tetrasodium salt(EDTA)chelating agents is appropriate for Mg-Al LDH formation due to the sufficient quantity of highly stable Mg and Al complexes in the treatment bath.An appropriate hydrothermal treatment time was also revealed in this work,which can efficiently seal the pores and defects of PEO coating with a uniform LDH film.As a result,the corrosion protection of the coating was improved dramatically.The prolonged hydrothermal treatment is detrimental to the integrity of PEO layers.The influence of chelating agents on the LDH formation processes is supported by thermodynamic calculation of the equilibrium composition,and the formation mechanism of LDH film is discussed in depth.
基金supported by the National Natural Science Foundation of China under Grant(Nos.51671053 and 51801021)the Fundamental Research Funds for the Central Uni-versities(No.N2302007)the Ministry of Industry and Infor-mation Technology Project(No.MJ-2017-J-99).
文摘Hot corrosion of the sputtered nanocrystalline coating and its(Al+Y)-modified coating on N5 with and without different preoxidation treatments under 75 wt.%Na_(2)SO_(4)+25 wt.%NaCl molten salts at 900℃was investigated.The results showed both the nanocrystalline coatings without preoxidation suffered from severe corrosion.No intact protective scale could form on the surface due to the fast penetration of the corrosive media through massive grain boundaries in the coating.The effect of different preoxidation treatments on the corrosion varied for the two coatings.The original nanocrystalline coatings with simi-lar compositions to the substrate N5 after preoxidation showed a low corrosion resistance,with a loose defective oxide scale on the surface and severe internal corrosion in the coating.Ta oxide segregation ru-ined the stability of the preoxide scale and thus accelerated the subsequent corrosion.In comparison,the AlY-modified coating after preoxidation at 1000℃exhibited the best corrosion resistance.Its oxide con-sisted exclusively of the Al_(2)O_(3) scale,and the least internal corrosion occurred in the coating.Co-addition of Al and Y retarded the diffusion of Ta,improved the stability of the scale,and provided a sufficient Al supplement to reform the Al_(2)O_(3) scale in the corrosion process,postponing corrosion destruction of the scale.The AIY-modified coating after preoxidation at 1100℃performed worse than that at 1000℃.The inferior corrosion resistance could be attributed to the more defective preoxide scale caused by higher thermal stress concentration during preoxidation.
基金supported by LiaoNing Revitalization Talents Program(XLYC2403026)Shenyang Young and Middle-aged Science and Technology Innovation Talent Support Program(No.RC231178)the Fundamental Research Funds for the Central Universities(No.N2302019).
文摘Novel neutral electrolytes were designed to substantially decrease porosity and increase barrier property of plasma electrolytic oxidation(PEO)coating on AM50 Mg surface.Presence of additives was effective in tuning coating microstructure and composition,leading to significantly enhanced corrosion and wear properties.50%improvement in fatigue limit was detected for the optimized coating compared to conventional PEO coating.The low-porosity coating remained uncorroded after performing salt spray test for 1 month,and exposure 1 year in harsh South China Sea environment.This can be new strategy to evaluate coating lifespan and promote wide range of applications for Mg alloy.
基金financially supported by the Program of the National Natural Science Foundation of China(Grant No.52371055)the Young Elite Scientist Sponsorship Program Cast(Grant No.YESS20200139)the Basic Scientific Research Project of Liaoning Provincial Department of Education(Grant No.JYTMS20230618)。
文摘The effect of intermetallic particles on the corrosion of 6061 aluminum alloy and its coating used in semiconductor processing systems was systematically studied via liquid and gas experiments and micromorphology characterization.The results revealed that a huge difference of corrosion resistance between imported and domestic 6061 aluminum alloys in HCl solution and gas acid mist experiments mainly was attributed to the different size and amount of Al_(15)(Fe,Mn)_(3)Si_(2).The corrosion resistance of domestic 6061 alloy in dry/wet semiconductor electronic special gas environments was worse than that of imported aluminum alloy,and there are great differences in the corrosion mechanism of 6061 alloy caused by the second phase in the two dry/wet environments.And the corrosion resistance of the hard anodized alumina film was closely related to the microscopic morphology of holes.The vertical and elongatedα-Al_(15)(Mn,Fe)_(3)Si_(2) phase was formed in the rolled aluminum alloy that has been rolled perpendicular to the surface of the substrate.Compared to the horizontal long hole,the longitudinal long holes generated by the verticalα-Al_(15)(Mn,Fe)_(3)Si_(2) phase will enable the corrosive medium to reach the substrate rapidly,which significantly weakens the corrosion resistance of the hard anodized film.
基金financially supported by the Liaoning Revitalization Talents Program(No.XLYC2203133)the Fundamental Research Funds for the Central Universities(No.N2302018)+1 种基金the Ningbo Yuyao City Science and Technology Plan Project(No.2023J03010010)the Fourth Batch of Ningxia Youth Talents Supporting Program(No.TJGC2019028).
文摘Carbide dispersion reinforcing has been demonstrated to be an effective way of strengthening metal matrix composites.However,plagued by the nerve-wracking fact that the carbide particles tend to aggregate at the grain boundary of the metal matrix,grow up,and form an incoherent interface with it,their improvement in mechanical strength tends to be limited.In this study,spark plasma sintering(SPS)was used to prepare the bulk alloy Ni20Cr and its composites with different carbides including TiC,SiC,and Ti_(3)SiC_(2).Plasma leads to discharge and elevates temperature at the interface to melt the Ni20Cr alloy particles locally.When cooled down,the alloy is heterogeneously solidified on the surface of the carbide and builds up a coherent interface with it.Owing to the decomposition of Ti_(3)SiC_(2) during sintering,it completely transformed into nanosized TiC particles,which are engulfed by the outer melted layer of Ni20Cr and well dispersed within the alloy grains.In comparison to the Ni20Cr alloy,the composite with merely 4 wt%Ti_(3)SiC_(2) gains over three times enhancement in yield strength to 879 MPa,while keeping a moderate high elongation of 17.8%.Finite element analysis demonstrated that the combination of SPS and precursor MAX phase of Ti_(3)SiC_(2),which results in the in-situ precipitation of coherent ultrafine TiC particles in alloy grains,plays the key role in getting a good balance between mechanical strength and ductility for the Ni20Cr matrix composites.
基金supported by Science Foundation of China University of Petroleum,Beijing(Nos.2462017YJRC038 and 2462018BJC005)supported by the National Natural Science Foundation of China(Grant U1660118)+1 种基金the National Basic Research Program of China(973 Program,No.2014CB643300)the National Environmental Corrosion Platform(NECP)
文摘Microbiologically influenced corrosion （MIC） is a major cause of corrosion damages, facility failures, and financial losses, making MIC an important research topic. Due to complex microbiological activities and a lack of deep understanding of the interactions between biofilms and metal surfaces, MIC occurrences and mechanisms are difficult to predict and interpret. Many theories and mechanisms have been pro- posed to explain MIC. In this review, the mechanisms of MIC are discussed using hioenergetics, microbial respiration types, and biofilm extracellular electron transfer （EET）. Two main MIC types, namely EET-MIC and metabolite MIC （M-ME）, are discussed. This brief review provides a state of the art insight into MIC mechanisms and it helps the diagnosis and prediction of occurrences of MIC under anaerobic conditions in the oil and gas industry.
基金supported by the National Natural Science Fund of China (Nos.51622106 and 5167010950)the National Key Basic Research and Development Plan of China (No.2014CB643303)the International S&T Cooperation Program of China (ISTCP) (No.2014DFR50560)
文摘The corrosion behavior of 2 A02 Al alloy under simulated marine atmospheric environment has been studied using mass-gain, scanning electron microscope/energy dispersive spectroscopy(SEM/EDS), laser scanning confocal microscopy, X-ray diffraction spectroscopy and localized electrochemical methods. The results demonstrate that the relationship between the corrosion induced mass-gain and the corrosion time is in accordance with the power rule. The mass-gain increases gradually during the corrosion time,while the corrosion rate decreases. With ongoing of the corrosion, corrosion products film changed from a porous to a compact structure. The various spectroscopic data show that the corrosion products films composed mainly of Al(OH)_3, Al_2O_3 and AlCl_3. The electrochemical corrosion behavior of the 2 A02 Al alloy was studied by electrochemical impedance spectroscopy(EIS).
基金financial support from the National Natural Science Foundation of China (Nos. 51531007 and 51771050)the National program for the Young Top-notch Professionalsthe Fundamental Research Funds for the Central Universities (N170205002)
文摘The effects of heat-treatment on corrosion behavior of Mg-15Gd-2Zn-0.39Zr alloys were investigated through microstructure characterization, corrosion tests, and scanning Kelvin probe force microscope(SKPFM) analysis. In long-term corrosion experiments, the corrosion rates of Mg-Gd-Zn-Zr alloys were mainly determined by the effects of micro-galvanic corrosion. During heat-treatment, the β-(Mg,Zn)3Gd eutectic phase in as-cast alloys transformed into a long-period stacking ordered(LPSO) phase, coupled with the precipitation of small precipitates. As heat-treatment proceeded, the local potential and the volume fraction of the LPSO phases reduced gradually compared with the eutectic phase, which resulted in a remarkable decrease of the micro-galvanic effect between the second phase and Mg matrix. As a result, the corrosion resistance of heat-treated alloys improved significantly.
