Here,a novel real-time monitoring sensor that integrates the oxidation of peroxymonosulfate(PMS)and the in situ monitoring of the pollutant degradation process is proposed.Briefly,FeCo@carbon fiber(FeCo@CF)was utilize...Here,a novel real-time monitoring sensor that integrates the oxidation of peroxymonosulfate(PMS)and the in situ monitoring of the pollutant degradation process is proposed.Briefly,FeCo@carbon fiber(FeCo@CF)was utilized as the anode electrode,while graphite rods served as the cathode electrode in assembling the galvanic cell.The FeCo@CF electrode exhibited rapid reactivity with PMS,generating reactive oxygen species that efficiently degrade organic pollutants.The degradation experiments indicate that complete bisphenol A(BPA)degradation was achieved within 10 min under optimal conditions.The real-time electrochemical signal was measured in time during the catalytic reaction,and a linear relationship between BPA concentration and the real-time charge(Q)was confirmed by the equation ln(C0/C)=4.393Q(correlation coefficients,R^(2)=0.998).Furthermore,experiments conducted with aureomycin and tetracycline further validated the effectiveness of the monitoring sensor.First-principles investigation confirmed the superior adsorption energy and improved electron transfer in FeCo@CF.The integration of pollutant degradation with in situ monitoring of catalytic reactions offers promising prospects for expanding the scope of the monitoring of catalytic processes and making significant contributions to environmental purification.展开更多
The galvanic coupling formed in origin potential flotation systems of sulfide minerals can be divided （into） three types: sulfide mineral-sulfide mineral-water system; sulfide mineral-steel ball-water system; and su...The galvanic coupling formed in origin potential flotation systems of sulfide minerals can be divided （into） three types: sulfide mineral-sulfide mineral-water system; sulfide mineral-steel ball-water system; and sulfide mineral-sulfide mineral-collector system. In this paper, taking lead, zinc, iron sulfide mineral systems for examples, several models of galvanic coupling were proposed and the effects of galvanic coupling on flotation were discussed. A galvanic contact between galena （or sphalerite） and pyrite contributes to decreasing the content of zinc in lead concentrate, and enhances remarkably the absorption of collector on the galena surface. During grinding, due to galvanic interactions between minerals and steel medium, Fe（OH）3 formed covers on the cathodic mineral surface, affecting its floatability.展开更多
The capacitive deionization(CDI)performance of silver(Ag)electrodes is limited by electrochemical failure induced by volumetric expansion.While carbon encapsulation and Ag size control mitigate stress concentration an...The capacitive deionization(CDI)performance of silver(Ag)electrodes is limited by electrochemical failure induced by volumetric expansion.While carbon encapsulation and Ag size control mitigate stress concentration and pulverization,achieving precise size control,suppression of aggregation,and uniform dispersion of Ag nanoparticles remains challenging.Herein,the metal-organic frameworks(MOF)-assisted pyrolysis-galvanic replacement method was employed to construct ultrafine Ag particles uniformly anchored within a three-dimensional(3D)-ordered porous carbon skeleton composite(3D Ag@NC).By utilizing the potential difference between the elements,spontaneous replacement reactions occur,effectively preventing particle agglomeration usually caused by high-temperature reduction.The in situ constructed 3D porous carbon skeleton not only promotes electron transfer and electrolyte penetration but also mitigates the volume expansion of Ag particles during electrochemical cycling.Consequently,3D Ag@NC demonstrates outstanding dechlorination performance(105.29 mg g^(-1)),high charge efficiency(0.95),and exceptional cycling stability(84.12% after 100 cycles).This galvanic replacement strategy offers valuable insights into the fabrication of other small-sized,highly dispersed metal electrode materials.展开更多
The authors regret the author name was incorrectly published as“Piyush Updadhyay”and it has now been corrected to“Piyush Upadhyay”.The authors would like to apologise for any inconvenience caused.
The detailed precipitation behavior and grain structure in different sub-regions of friction stir welding(FSW)AA6061-T6 joint after post-weld solution and aging treatments were explored.And the effects of microstructu...The detailed precipitation behavior and grain structure in different sub-regions of friction stir welding(FSW)AA6061-T6 joint after post-weld solution and aging treatments were explored.And the effects of microstructural evolution on mechanical properties,macro/micro electrochemical corrosion behavior and stress corrosion cracking behavior were investigated.The inherent microstructural gradients in FSW joint lead to dramatic degradation of mechanical properties and the presence of macro-galvanic effect,with the latter exacerbating anodic dissolution in heat-affected zone(HAZ)induced by micro-galvanic corro-sion and inhibiting pitting corrosion in stirred zone(SZ).Post-weld heat treatment(PWHT)causes the formation of matrix precipitates with similar densities in different sub-regions,resulting in optimized precipitate distribution,comprehensive hardness recovery,and diminished macro-galvanic effect.Grain boundary misorientation angle,grain size and pre-existing dislocations synergistically influence the evo-lution of grain boundary precipitates(GBPs)and precipitation-free zones(PFZs)during the PWHT.As a result,pitting corrosion is the dominant corrosion form in SZ due to the narrowest PFZ width and dis-persed GBPs,while intergranular corrosion is caused by continuous GBPs in other sub-regions.This study verified the dominant role of macro-galvanic effect and micro-galvanic effect in the corrosion process of FSW joint and FSW-PWHT joint,respectively.The maximum SCC susceptibility at HAZ in As-FSWed joint is dominated by enhanced anodic dissolution due to macro-galvanic effect.The SCC sensitivity of FSW-PWHT joint is higher than that of FSW joint due to high electrochemical activity and corrosion rate caused by the severe stress concentration between sub-grains and recrystallized grains at the thermome-chanical affected zone(TMAZ)/SZ interface.展开更多
The aluminum alloy-steel hybrid structures offer numerous advantages, including lightweight and flexibility. However, the contact between aluminum alloy and steel is prone to cause serious local corrosion. To further ...The aluminum alloy-steel hybrid structures offer numerous advantages, including lightweight and flexibility. However, the contact between aluminum alloy and steel is prone to cause serious local corrosion. To further reveal the corrosion mechanism at the contact region of aluminum alloy/steel, this paper investigates the crevice corrosion of QC-10 aluminum alloy and the crevice-galvanic coupling corrosion of QC-10 aluminum alloy/S50C steel, explores the synergistic effect of different crevice height, pH and Cl- concentration on the corrosion behavior of QC-10 aluminum alloy by electrochemical experiments, immersion corrosion experiments and microscopic morphology characterization. The results demonstrate that the crevice corrosion of aluminum alloy decreases with the increase of crevice height, and there exists a critical crevice height for the occurrence of crevice corrosion. In the aluminum alloy-steel hybrid structure, the galvanic effect accelerates the crevice corrosion of aluminum alloy, and the corrosion products of steel embedded in the aluminum alloy oxide film decrease the corrosion resistance of the aluminum alloy. Additionally, the corrosion products of steel alter the crevice solution compositions, while intensifying the crevice corrosion of aluminum alloy. It is concluded that reasonable control of the crevice height and the inhibition of the corrosion of steel are effective methods to improve the corrosion resistance of aluminum alloy-steel hybrid structures.展开更多
The corrosion behaviors of copper and copper/titanium galvanic couple （GC） in seawater were studied by electrochemical impedance spectroscopy （EIS） and electrochemical noise （EN） techniques in conjunction with s...The corrosion behaviors of copper and copper/titanium galvanic couple （GC） in seawater were studied by electrochemical impedance spectroscopy （EIS） and electrochemical noise （EN） techniques in conjunction with scanning electron microscopy （SEM） method. The results show that the corrosion process of copper in seawater can be divided into two stages, in which corrosion resistance and SE show the same evolution trend of initial increase and subsequent decrease, while SG changes oppositely. However, the ensemble corrosion process of copper/titanium GC in seawater includes three stages, in which corrosion resistance and SE show the evolution features of initial decrease with a subsequently increase, and the final decrease again;while SG changes oppositely. The potential difference between copper and titanium in their galvanic couple can accelerate the initiation of pitting corrosion of copper, and both the minimum and maximum corrosion potentials of copper/titanium GC are much more positive than those of pure copper.展开更多
The effects of galvanic interaction between galena and pyrite on their flotation and electrochemical characters were studied by electrochemical,adsorption,flotation and FTIR techniques,respectively.Electrochemical tes...The effects of galvanic interaction between galena and pyrite on their flotation and electrochemical characters were studied by electrochemical,adsorption,flotation and FTIR techniques,respectively.Electrochemical tests indicate that galena is electrochemically more active than pyrite and serves as an anode in galvanic combination with pyrite.The galvanic current density from a mixture of galena and pyrite is 4 times as high as the self corrosion current density of galena,which indicates that the corrosion rate of galena is accelerated.Adsorption tests show that the adsorption of butyl xanthate on galena surface is enhanced,and affected by a combination of pyrite-galena mixtures and conditioning time.Compared with individual mineral particles,galvanic interaction reduces the floatability difference between galena and pyrite.The flotation recovery of galena decreases while that of pyrite increases when two minerals are mixed together due to the influence of galvanic interaction on the formation of hydrophilic/hydrophobic product.The FTIR results show that the formation of dixanthogen on pyrite surface is depressed due to the galvanic interaction.展开更多
Zirconium-based conversion coatings have emerged as an environmentally friendly alternative to traditional phosphate coatings in the automotive industry,offering excellent corrosion resistance and effective protection...Zirconium-based conversion coatings have emerged as an environmentally friendly alternative to traditional phosphate coatings in the automotive industry,offering excellent corrosion resistance and effective protection for metal substrates.However,due to their relatively recent use in industrial applications,process control during zirconium conversion coating remains underdeveloped.In this study,the reaction kinetics of galvanized steel during the zirconium conversion coating were investigated systematically.The findings reveal an optimal coating time,after which the corrosion resistance of galvanized steel decreases.This decline results from the formation of corrosion cavities that cause discontinuities in the protective zirconium layer.These insights provide guidance for optimizing zirconium conversion coating processes in industrial manufacturing.展开更多
Galvanic corrosion of tri-metallic couples is more complicated than that of bi-metallic couples. In this study, the effect of the pH of corrosive media on the galvanic corrosion of 2024 A1 alloy/Q235 mild steel/304 st...Galvanic corrosion of tri-metallic couples is more complicated than that of bi-metallic couples. In this study, the effect of the pH of corrosive media on the galvanic corrosion of 2024 A1 alloy/Q235 mild steel/304 stainless steel tri-metallic couples was investigated using potentiodynamic polarization, scanning electron microscopy, scanning vibrating electrode technique and a multi-channel galvanic corrosion meter. The results show that 2024 always acts as the only anode in 3.5 wt% NaCl at pH 5.56,9.72 and 12.0, while both Q235 and 2024 act as anodes at pH 2.39 in the initial stage and then the role of Q235 changes at longer coupling time, which can be attributed to the effect of pH on the surface film of 2024. It is also found that the galvanic current density of a tri-metallic couple is the superposition of two bi-metallic couples when cathodic reactions are controlled by the diffusion of oxygen, otherwise it is smaller than that of the sum of two bi-metallic couples. The localized corrosion instead of uniform corrosion of anodic metal is accelerated by galvanic corrosion.展开更多
In this study,the corrosion behavior of the CuAl-NiC abradable seal coating system in chloride solution was investigated to systematically research the effect of porosity,multiphase,and multilayer structure on the cor...In this study,the corrosion behavior of the CuAl-NiC abradable seal coating system in chloride solution was investigated to systematically research the effect of porosity,multiphase,and multilayer structure on the corrosion failure.Through the composition and structure analysis,the corrosion process of the system was predicted and then verified with mercury intrusion porosimetry,cross-section SEM/EDS analysis,and electrochemical measurements.The results demonstrated that the interphase selective corrosion caused the porosity of the top layer to decrease first and then increase during the corrosion development.The interlayer galvanic corrosion,determined by the pore connectivity,is crucial for corrosion failure.展开更多
The galvanic corrosion behaviour of aluminium 3004 and copper with different area ratios were studied in the tropical marine atmosphere at Tuticorin harbour over a period of 426 days. The area ratios OfAAI： Acu, stud...The galvanic corrosion behaviour of aluminium 3004 and copper with different area ratios were studied in the tropical marine atmosphere at Tuticorin harbour over a period of 426 days. The area ratios OfAAI： Acu, studied were l：l, 1：2, l：4, 1：8, 2：1, 4：1 ＆ 8：1. The galvanic corrosion behaviour of metals was studied in terms of relative increase in the corrosion rate of aluminium due to galvanic coupling with copper, relative decrease in the corrosion rate of copper due to galvanic coupling with aluminium, and the susceptibility of aluminium to pitting owing to galvanic coupling with copper, The galvanic potential and galvanic current of the system were monitored. Pits of different dimensions ranging from mild etchings to perforations were experienced on the borders and the surfaces of the interface of aluminium in contact with copper. The weathering parameters and the environmental pollutants which have a major role in influencing the galvanic corrosion of metals were also monitored. The corrosion products resulting from galvanic corrosion were analysed using XRD and the pitting on aluminium resulting from galvanic corrosion has been highlighted in terms of pit depth, size and density of pit, using a high resolution microscope.展开更多
Galvanic deposition method was used to prepare the Pd/Ni-Al2O3-GD catalyst for the combustion of methane under lean conditions. The new catalyst and compared catalysts （Pd/Al2O3-IW, Pd-Ni/Al2O3-IW, Pd/Ni-Al2O3-IW） p...Galvanic deposition method was used to prepare the Pd/Ni-Al2O3-GD catalyst for the combustion of methane under lean conditions. The new catalyst and compared catalysts （Pd/Al2O3-IW, Pd-Ni/Al2O3-IW, Pd/Ni-Al2O3-IW） prepared by incipient wetness impregnation were characterized by N2-physisorption, XRD and TEM to clarify particle size and size distribution of palladium species. Combined O2-TPD and XPS results with the catalytic data, it shows that the surface palladium species with low valence exhibits better combustion performance due to their stronger interaction with support. The results indicate that the galvanic deposition method is an effective route to prepare efficient catalyst for methane combustion, and it also provides useful information for improving the present commercial catalyst.展开更多
The galvanic corrosion of the Q-phase/Al couple in 0.1 M NaCl solutions has been studied using the scanning vibrating electrode technique (SVET)f the scanning ion-selective electrode technique (SIET) and energy disper...The galvanic corrosion of the Q-phase/Al couple in 0.1 M NaCl solutions has been studied using the scanning vibrating electrode technique (SVET)f the scanning ion-selective electrode technique (SIET) and energy dispersive X-ray spectroscopy (EDX). The galvanic corrosion of the Q-phase/Al couple was found to be dependent on pH and immersion time. Current density maps obtained by SVET shows that the anodic oxidation processes emerge from Al in a localized manner in pH 2 and 6 solutions but is initiated in a uniform manner in pH 13 solution, whereas, the cathodic processes are more homogeneously distributed over the Q-phase at pH 2.6 and 13. It is seen that the Q-phase remains cathodic in the Q-phase/Al couple in acidic, neutral and alkaline solutions indicating that the galvanic polarity of the Q-phase is independent of pH. The effect of the galvanic corrosion was largest at pH 2 and 13 compared to pH 6. The pH map obtained by SIET indicates that the galvanic activity of the Q-phase/Al couple proceeds via heavy alkalization of the Q-phase surface with the generation of appreciable amounts of OH~ ions. The enrichment of Cu indicated by EDX is responsible for the observed cathodic activity of the Q-phase in the Q-phase/Al couple.展开更多
Objectives: The aim of our study is to examine vestibular-evoked myogenic potentials(VEMPs) elicited by the galvanic vestibular stimulation in the sternocleidomastoid muscle(SCM) in healthy subjects for clinical appli...Objectives: The aim of our study is to examine vestibular-evoked myogenic potentials(VEMPs) elicited by the galvanic vestibular stimulation in the sternocleidomastoid muscle(SCM) in healthy subjects for clinical applications of auditory neuropathy or vestibular neuropathy in the future.Methods: We enrolled sixteen healthy subjects to record the average responses of SCM to galvanic vestibular stimulation(GVS) [current 3 mA;duration 1 ms] by electromyography(EMG). SPSS 18.0 software was used to analyze the obtained data for mean and standard deviation.Results: In all healthy subjects mastoid-forehead galvanic vestibular stimulation produced a positive-negative biphasic EMG responses on SCM ipsilateral to the cathodal electrode. The latency of p13 was 11.7 ± 3.0 ms. The latency of n23 was 17.8 ± 3.4 ms. The amplitude of p13-n23 was147.0 ± 69.0 μV. The interaural asymmetry ratio(AR) of p13, n23 latency and the amplitude was respectively 0.12 ± 0.09, 0.08 ± 0.08 and0.16 ± 0.10.Discussions: Galvanic vestibular stimulation could elicit biphasic EMG responses from SCM via the vestibular nerve but not from the otolith organs. Galvanic stimulation together with air conducted sound(ACS) or bone conducted vibration(BCV) can elicit VEMPs and may enable the differentiation of retrolabyrinthine lesions from labyrinthine lesions in vestibular system.展开更多
Motivated by the increasing use of Sn-3.0 Ag-0.5 Cu(SAC305)solder in electronics worked in marine atmospheric environment and the uneven distribution of Ag3Sn and Cu6Sn5 intermetallic compounds(IMCs)inβ-Sn matrix,com...Motivated by the increasing use of Sn-3.0 Ag-0.5 Cu(SAC305)solder in electronics worked in marine atmospheric environment and the uneven distribution of Ag3Sn and Cu6Sn5 intermetallic compounds(IMCs)inβ-Sn matrix,comb-like electrodes have been designed for in-situ EIS measurements to study the microstructure induced galvanic corrosion evolution of SAC305 solder in simulated marine atmosphere with high-temperature and high-humidity.Results indicate that in-situ EIS measurement by comb-like electrodes is an effective method for corrosion evolution behavior study of SAC305 solder.Besides,the galvanic effect between Ag3Sn IMCs andβ-Sn matrix can aggravate the corrosion of both as-received and furnace-cooled SAC305 solder as the exposure time proceeds in spite of the presence of corrosion product layer.Pitting corrosion can be preferentially found on furnace-cooled SAC305 with larger Ag3Sn grain size.Moreover,the generated inner stress during phases transformation process with Sn3O(OH)2Cl2 as an intermediate and the possible hydrogen evolution at local acidified sites are supposed to be responsible for the loose,porous,cracked,and non-adherent corrosion product layer.These findings clearly demonstrate the corrosion acceleration behavior and mechanism of SAC305 solder,and provide potential guidelines on maintenance of microelectronic devices for safe operation and longer in-service duration.展开更多
Galvanic, compatibility between graphite epoxy composite materials (GECM) and LY12CZ aluminum alloy was evaluated in different atmospheric corrosion environments and by laboratory electrochemical measurements. Open ci...Galvanic, compatibility between graphite epoxy composite materials (GECM) and LY12CZ aluminum alloy was evaluated in different atmospheric corrosion environments and by laboratory electrochemical measurements. Open circuit potential electrochemical measurements showed a relatively large potential difference about 1 volt between the GECM and LY12CZ aluminum alloy, and this difference provided the driving force for galvanic corrosion of the LY12CZ aluminum alloy as an anode. Having been exposed for 1, 3 or 5 years in Beijing, Tuandao and Wanning station, GECM/LY12CZ couples showed significant losses of strength and elongation. Protective coatings and non-conductive barriers breaking the galvanic corrosion circuit were evaluated under the same atmospheric corrosive conditions. Epoxy primer paint, glass cloth barriers and LY12CZ anodizing were effective in galvanic corrosion control for GECM/LY12CZ couples.展开更多
The synergistic effects of area ratio and microstructure on the galvanic corrosion of A508/309 L/308 L dissimilar metals weld(DMW)are studied by a multi-analytical approach.It was demonstrated that decreasing the anod...The synergistic effects of area ratio and microstructure on the galvanic corrosion of A508/309 L/308 L dissimilar metals weld(DMW)are studied by a multi-analytical approach.It was demonstrated that decreasing the anode/cathode surface area ratio obviously enhances the corrosion rate of A508,both locally and globally.Deeper analyses of the AFM results enabled quantitative comparison of the corrosion behaviour of the different surface constituents.It was revealed that in the galvanic interaction of the DMW,the grain refined region corrodes most,followed by the partial grain refined region and base metal matrix of the A508,respectively.The electrochemical localization index(LI)estimation method and AFM analysis both confirmed the presence of a mixed(localized and uniform)corrosion phenomenon occurring on the surface of the A508 anode metal in the galvanic interaction of the dissimilar metals.Finally,the degree of synergism equation was utilized to describe the synergistic effects of anode/cathode area ratio and the microstructure of the samples on the galvanic corrosion of LAS A508/309 L/308 L SS DMW.展开更多
The influence of pH and metallographic structure on the corrosion behavior of copper-drawn steel is studied with the simulated system.The effect of pH on the corrosion behavior of copper-drawn steel has been investiga...The influence of pH and metallographic structure on the corrosion behavior of copper-drawn steel is studied with the simulated system.The effect of pH on the corrosion behavior of copper-drawn steel has been investigated using open-circuit potential,potentiodynamic polarization,galvanic current measurement,scanning electron microscopy and scanning vibrating electrode technique techniques.The steel is corroded as anode,while the corrosion of copper plate is protected as cathode.All the results revealed that pH and metallographic structure had a significant influence on the corrosion behavior of copper-drawn steel.With the decrease in pH value from 6 to 2.4,the corrosion rate of copper-drawn steel galvanic couple(Cu-Fe GC)obviously increased in the simulated solution of acidic red soil.The electric field formed by the Cu-Fe GC changes the direction of ion migration between the copper and drawn steel electrodes,which impacts the composition and microstructure of corrosion products formed on the electrode surface.展开更多
基金supported by the National Natural Science Foundation of China(No.22306076)the Natural Science Foundation of Jiangsu Province(No.BK20230676)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.22KJB610011).
文摘Here,a novel real-time monitoring sensor that integrates the oxidation of peroxymonosulfate(PMS)and the in situ monitoring of the pollutant degradation process is proposed.Briefly,FeCo@carbon fiber(FeCo@CF)was utilized as the anode electrode,while graphite rods served as the cathode electrode in assembling the galvanic cell.The FeCo@CF electrode exhibited rapid reactivity with PMS,generating reactive oxygen species that efficiently degrade organic pollutants.The degradation experiments indicate that complete bisphenol A(BPA)degradation was achieved within 10 min under optimal conditions.The real-time electrochemical signal was measured in time during the catalytic reaction,and a linear relationship between BPA concentration and the real-time charge(Q)was confirmed by the equation ln(C0/C)=4.393Q(correlation coefficients,R^(2)=0.998).Furthermore,experiments conducted with aureomycin and tetracycline further validated the effectiveness of the monitoring sensor.First-principles investigation confirmed the superior adsorption energy and improved electron transfer in FeCo@CF.The integration of pollutant degradation with in situ monitoring of catalytic reactions offers promising prospects for expanding the scope of the monitoring of catalytic processes and making significant contributions to environmental purification.
文摘The galvanic coupling formed in origin potential flotation systems of sulfide minerals can be divided （into） three types: sulfide mineral-sulfide mineral-water system; sulfide mineral-steel ball-water system; and sulfide mineral-sulfide mineral-collector system. In this paper, taking lead, zinc, iron sulfide mineral systems for examples, several models of galvanic coupling were proposed and the effects of galvanic coupling on flotation were discussed. A galvanic contact between galena （or sphalerite） and pyrite contributes to decreasing the content of zinc in lead concentrate, and enhances remarkably the absorption of collector on the galena surface. During grinding, due to galvanic interactions between minerals and steel medium, Fe（OH）3 formed covers on the cathodic mineral surface, affecting its floatability.
基金financially supported by the Innovative Research Groups of the National Natural Science Foundation of China(No.52121004)the National Natural Science Foundation of China(52374423)+1 种基金the Major Science and Technology Programs of Yunnan Province(202302AB080016)the Hunan Provincial Natural Science Youth Fund(2024JJ6726)。
文摘The capacitive deionization(CDI)performance of silver(Ag)electrodes is limited by electrochemical failure induced by volumetric expansion.While carbon encapsulation and Ag size control mitigate stress concentration and pulverization,achieving precise size control,suppression of aggregation,and uniform dispersion of Ag nanoparticles remains challenging.Herein,the metal-organic frameworks(MOF)-assisted pyrolysis-galvanic replacement method was employed to construct ultrafine Ag particles uniformly anchored within a three-dimensional(3D)-ordered porous carbon skeleton composite(3D Ag@NC).By utilizing the potential difference between the elements,spontaneous replacement reactions occur,effectively preventing particle agglomeration usually caused by high-temperature reduction.The in situ constructed 3D porous carbon skeleton not only promotes electron transfer and electrolyte penetration but also mitigates the volume expansion of Ag particles during electrochemical cycling.Consequently,3D Ag@NC demonstrates outstanding dechlorination performance(105.29 mg g^(-1)),high charge efficiency(0.95),and exceptional cycling stability(84.12% after 100 cycles).This galvanic replacement strategy offers valuable insights into the fabrication of other small-sized,highly dispersed metal electrode materials.
文摘The authors regret the author name was incorrectly published as“Piyush Updadhyay”and it has now been corrected to“Piyush Upadhyay”.The authors would like to apologise for any inconvenience caused.
基金supported by the National Key R&D Program of China(No.2022YFB3705801)the National Natural Science Foundation of China(No.52271065).
文摘The detailed precipitation behavior and grain structure in different sub-regions of friction stir welding(FSW)AA6061-T6 joint after post-weld solution and aging treatments were explored.And the effects of microstructural evolution on mechanical properties,macro/micro electrochemical corrosion behavior and stress corrosion cracking behavior were investigated.The inherent microstructural gradients in FSW joint lead to dramatic degradation of mechanical properties and the presence of macro-galvanic effect,with the latter exacerbating anodic dissolution in heat-affected zone(HAZ)induced by micro-galvanic corro-sion and inhibiting pitting corrosion in stirred zone(SZ).Post-weld heat treatment(PWHT)causes the formation of matrix precipitates with similar densities in different sub-regions,resulting in optimized precipitate distribution,comprehensive hardness recovery,and diminished macro-galvanic effect.Grain boundary misorientation angle,grain size and pre-existing dislocations synergistically influence the evo-lution of grain boundary precipitates(GBPs)and precipitation-free zones(PFZs)during the PWHT.As a result,pitting corrosion is the dominant corrosion form in SZ due to the narrowest PFZ width and dis-persed GBPs,while intergranular corrosion is caused by continuous GBPs in other sub-regions.This study verified the dominant role of macro-galvanic effect and micro-galvanic effect in the corrosion process of FSW joint and FSW-PWHT joint,respectively.The maximum SCC susceptibility at HAZ in As-FSWed joint is dominated by enhanced anodic dissolution due to macro-galvanic effect.The SCC sensitivity of FSW-PWHT joint is higher than that of FSW joint due to high electrochemical activity and corrosion rate caused by the severe stress concentration between sub-grains and recrystallized grains at the thermome-chanical affected zone(TMAZ)/SZ interface.
基金supported by the Key Research and Development Program of Shandong Province(No.2021ZLGX01).
文摘The aluminum alloy-steel hybrid structures offer numerous advantages, including lightweight and flexibility. However, the contact between aluminum alloy and steel is prone to cause serious local corrosion. To further reveal the corrosion mechanism at the contact region of aluminum alloy/steel, this paper investigates the crevice corrosion of QC-10 aluminum alloy and the crevice-galvanic coupling corrosion of QC-10 aluminum alloy/S50C steel, explores the synergistic effect of different crevice height, pH and Cl- concentration on the corrosion behavior of QC-10 aluminum alloy by electrochemical experiments, immersion corrosion experiments and microscopic morphology characterization. The results demonstrate that the crevice corrosion of aluminum alloy decreases with the increase of crevice height, and there exists a critical crevice height for the occurrence of crevice corrosion. In the aluminum alloy-steel hybrid structure, the galvanic effect accelerates the crevice corrosion of aluminum alloy, and the corrosion products of steel embedded in the aluminum alloy oxide film decrease the corrosion resistance of the aluminum alloy. Additionally, the corrosion products of steel alter the crevice solution compositions, while intensifying the crevice corrosion of aluminum alloy. It is concluded that reasonable control of the crevice height and the inhibition of the corrosion of steel are effective methods to improve the corrosion resistance of aluminum alloy-steel hybrid structures.
基金Projects(21073162,51131005)supported by the National Natural Science Foundation of ChinaProject(Y4100206)supported by the Science and Technology Bureau of Jiaxing Municipality and Zhejiang Provincial Natural Science Foundation of China
文摘The corrosion behaviors of copper and copper/titanium galvanic couple （GC） in seawater were studied by electrochemical impedance spectroscopy （EIS） and electrochemical noise （EN） techniques in conjunction with scanning electron microscopy （SEM） method. The results show that the corrosion process of copper in seawater can be divided into two stages, in which corrosion resistance and SE show the same evolution trend of initial increase and subsequent decrease, while SG changes oppositely. However, the ensemble corrosion process of copper/titanium GC in seawater includes three stages, in which corrosion resistance and SE show the evolution features of initial decrease with a subsequently increase, and the final decrease again;while SG changes oppositely. The potential difference between copper and titanium in their galvanic couple can accelerate the initiation of pitting corrosion of copper, and both the minimum and maximum corrosion potentials of copper/titanium GC are much more positive than those of pure copper.
基金Project(51274255)supported by the National Natural Science Foundation of ChinaProject supported by the Co-innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources,China
文摘The effects of galvanic interaction between galena and pyrite on their flotation and electrochemical characters were studied by electrochemical,adsorption,flotation and FTIR techniques,respectively.Electrochemical tests indicate that galena is electrochemically more active than pyrite and serves as an anode in galvanic combination with pyrite.The galvanic current density from a mixture of galena and pyrite is 4 times as high as the self corrosion current density of galena,which indicates that the corrosion rate of galena is accelerated.Adsorption tests show that the adsorption of butyl xanthate on galena surface is enhanced,and affected by a combination of pyrite-galena mixtures and conditioning time.Compared with individual mineral particles,galvanic interaction reduces the floatability difference between galena and pyrite.The flotation recovery of galena decreases while that of pyrite increases when two minerals are mixed together due to the influence of galvanic interaction on the formation of hydrophilic/hydrophobic product.The FTIR results show that the formation of dixanthogen on pyrite surface is depressed due to the galvanic interaction.
基金express their sincere gratitude to the Jiangsu Key Laboratory of Advanced Metallic Materials of Southeast University for providing the complete laboratory facilities required for this research project.
文摘Zirconium-based conversion coatings have emerged as an environmentally friendly alternative to traditional phosphate coatings in the automotive industry,offering excellent corrosion resistance and effective protection for metal substrates.However,due to their relatively recent use in industrial applications,process control during zirconium conversion coating remains underdeveloped.In this study,the reaction kinetics of galvanized steel during the zirconium conversion coating were investigated systematically.The findings reveal an optimal coating time,after which the corrosion resistance of galvanized steel decreases.This decline results from the formation of corrosion cavities that cause discontinuities in the protective zirconium layer.These insights provide guidance for optimizing zirconium conversion coating processes in industrial manufacturing.
基金supported financially by the National Key Research and Development Program of China (No. 2017YFB0702100)the Natural Science Foundation of Liaoning Province (No. 20170540666)
文摘Galvanic corrosion of tri-metallic couples is more complicated than that of bi-metallic couples. In this study, the effect of the pH of corrosive media on the galvanic corrosion of 2024 A1 alloy/Q235 mild steel/304 stainless steel tri-metallic couples was investigated using potentiodynamic polarization, scanning electron microscopy, scanning vibrating electrode technique and a multi-channel galvanic corrosion meter. The results show that 2024 always acts as the only anode in 3.5 wt% NaCl at pH 5.56,9.72 and 12.0, while both Q235 and 2024 act as anodes at pH 2.39 in the initial stage and then the role of Q235 changes at longer coupling time, which can be attributed to the effect of pH on the surface film of 2024. It is also found that the galvanic current density of a tri-metallic couple is the superposition of two bi-metallic couples when cathodic reactions are controlled by the diffusion of oxygen, otherwise it is smaller than that of the sum of two bi-metallic couples. The localized corrosion instead of uniform corrosion of anodic metal is accelerated by galvanic corrosion.
基金financially supported by the National Natural Science Foundation of China(No.51671198)。
文摘In this study,the corrosion behavior of the CuAl-NiC abradable seal coating system in chloride solution was investigated to systematically research the effect of porosity,multiphase,and multilayer structure on the corrosion failure.Through the composition and structure analysis,the corrosion process of the system was predicted and then verified with mercury intrusion porosimetry,cross-section SEM/EDS analysis,and electrochemical measurements.The results demonstrated that the interphase selective corrosion caused the porosity of the top layer to decrease first and then increase during the corrosion development.The interlayer galvanic corrosion,determined by the pore connectivity,is crucial for corrosion failure.
基金the CSIR-CECRI for the financial support (Project No. MLP 0008)
文摘The galvanic corrosion behaviour of aluminium 3004 and copper with different area ratios were studied in the tropical marine atmosphere at Tuticorin harbour over a period of 426 days. The area ratios OfAAI： Acu, studied were l：l, 1：2, l：4, 1：8, 2：1, 4：1 ＆ 8：1. The galvanic corrosion behaviour of metals was studied in terms of relative increase in the corrosion rate of aluminium due to galvanic coupling with copper, relative decrease in the corrosion rate of copper due to galvanic coupling with aluminium, and the susceptibility of aluminium to pitting owing to galvanic coupling with copper, The galvanic potential and galvanic current of the system were monitored. Pits of different dimensions ranging from mild etchings to perforations were experienced on the borders and the surfaces of the interface of aluminium in contact with copper. The weathering parameters and the environmental pollutants which have a major role in influencing the galvanic corrosion of metals were also monitored. The corrosion products resulting from galvanic corrosion were analysed using XRD and the pitting on aluminium resulting from galvanic corrosion has been highlighted in terms of pit depth, size and density of pit, using a high resolution microscope.
基金supported by the National Natural Science Foundation of China (21273221)the National High Technology Research and Development Program of China (863 Program, 2011AA03A406)
文摘Galvanic deposition method was used to prepare the Pd/Ni-Al2O3-GD catalyst for the combustion of methane under lean conditions. The new catalyst and compared catalysts （Pd/Al2O3-IW, Pd-Ni/Al2O3-IW, Pd/Ni-Al2O3-IW） prepared by incipient wetness impregnation were characterized by N2-physisorption, XRD and TEM to clarify particle size and size distribution of palladium species. Combined O2-TPD and XPS results with the catalytic data, it shows that the surface palladium species with low valence exhibits better combustion performance due to their stronger interaction with support. The results indicate that the galvanic deposition method is an effective route to prepare efficient catalyst for methane combustion, and it also provides useful information for improving the present commercial catalyst.
基金financially supported by the National Natural Science Foundation of China (Grant No. 51571201)
文摘The galvanic corrosion of the Q-phase/Al couple in 0.1 M NaCl solutions has been studied using the scanning vibrating electrode technique (SVET)f the scanning ion-selective electrode technique (SIET) and energy dispersive X-ray spectroscopy (EDX). The galvanic corrosion of the Q-phase/Al couple was found to be dependent on pH and immersion time. Current density maps obtained by SVET shows that the anodic oxidation processes emerge from Al in a localized manner in pH 2 and 6 solutions but is initiated in a uniform manner in pH 13 solution, whereas, the cathodic processes are more homogeneously distributed over the Q-phase at pH 2.6 and 13. It is seen that the Q-phase remains cathodic in the Q-phase/Al couple in acidic, neutral and alkaline solutions indicating that the galvanic polarity of the Q-phase is independent of pH. The effect of the galvanic corrosion was largest at pH 2 and 13 compared to pH 6. The pH map obtained by SIET indicates that the galvanic activity of the Q-phase/Al couple proceeds via heavy alkalization of the Q-phase surface with the generation of appreciable amounts of OH~ ions. The enrichment of Cu indicated by EDX is responsible for the observed cathodic activity of the Q-phase in the Q-phase/Al couple.
基金supported by Japan China Sasakawa Medical Fellowship 2016(YL)
文摘Objectives: The aim of our study is to examine vestibular-evoked myogenic potentials(VEMPs) elicited by the galvanic vestibular stimulation in the sternocleidomastoid muscle(SCM) in healthy subjects for clinical applications of auditory neuropathy or vestibular neuropathy in the future.Methods: We enrolled sixteen healthy subjects to record the average responses of SCM to galvanic vestibular stimulation(GVS) [current 3 mA;duration 1 ms] by electromyography(EMG). SPSS 18.0 software was used to analyze the obtained data for mean and standard deviation.Results: In all healthy subjects mastoid-forehead galvanic vestibular stimulation produced a positive-negative biphasic EMG responses on SCM ipsilateral to the cathodal electrode. The latency of p13 was 11.7 ± 3.0 ms. The latency of n23 was 17.8 ± 3.4 ms. The amplitude of p13-n23 was147.0 ± 69.0 μV. The interaural asymmetry ratio(AR) of p13, n23 latency and the amplitude was respectively 0.12 ± 0.09, 0.08 ± 0.08 and0.16 ± 0.10.Discussions: Galvanic vestibular stimulation could elicit biphasic EMG responses from SCM via the vestibular nerve but not from the otolith organs. Galvanic stimulation together with air conducted sound(ACS) or bone conducted vibration(BCV) can elicit VEMPs and may enable the differentiation of retrolabyrinthine lesions from labyrinthine lesions in vestibular system.
基金financially supported by the National Natural Science Foundation of China(No.51601057)。
文摘Motivated by the increasing use of Sn-3.0 Ag-0.5 Cu(SAC305)solder in electronics worked in marine atmospheric environment and the uneven distribution of Ag3Sn and Cu6Sn5 intermetallic compounds(IMCs)inβ-Sn matrix,comb-like electrodes have been designed for in-situ EIS measurements to study the microstructure induced galvanic corrosion evolution of SAC305 solder in simulated marine atmosphere with high-temperature and high-humidity.Results indicate that in-situ EIS measurement by comb-like electrodes is an effective method for corrosion evolution behavior study of SAC305 solder.Besides,the galvanic effect between Ag3Sn IMCs andβ-Sn matrix can aggravate the corrosion of both as-received and furnace-cooled SAC305 solder as the exposure time proceeds in spite of the presence of corrosion product layer.Pitting corrosion can be preferentially found on furnace-cooled SAC305 with larger Ag3Sn grain size.Moreover,the generated inner stress during phases transformation process with Sn3O(OH)2Cl2 as an intermediate and the possible hydrogen evolution at local acidified sites are supposed to be responsible for the loose,porous,cracked,and non-adherent corrosion product layer.These findings clearly demonstrate the corrosion acceleration behavior and mechanism of SAC305 solder,and provide potential guidelines on maintenance of microelectronic devices for safe operation and longer in-service duration.
基金The authors gratefully acknowledge the financial support from National Key Basic Research and Development Programme of China (No. G1999065004).
文摘Galvanic, compatibility between graphite epoxy composite materials (GECM) and LY12CZ aluminum alloy was evaluated in different atmospheric corrosion environments and by laboratory electrochemical measurements. Open circuit potential electrochemical measurements showed a relatively large potential difference about 1 volt between the GECM and LY12CZ aluminum alloy, and this difference provided the driving force for galvanic corrosion of the LY12CZ aluminum alloy as an anode. Having been exposed for 1, 3 or 5 years in Beijing, Tuandao and Wanning station, GECM/LY12CZ couples showed significant losses of strength and elongation. Protective coatings and non-conductive barriers breaking the galvanic corrosion circuit were evaluated under the same atmospheric corrosive conditions. Epoxy primer paint, glass cloth barriers and LY12CZ anodizing were effective in galvanic corrosion control for GECM/LY12CZ couples.
基金the National Natural Science Foundation of China(No.51771211)Key Research Program of Frontier Sciences,CAS(QYZDY-SSW-JSC012)the Key Program of the Chinese Academy of Sciences(ZDRW-CN-2017-1)。
文摘The synergistic effects of area ratio and microstructure on the galvanic corrosion of A508/309 L/308 L dissimilar metals weld(DMW)are studied by a multi-analytical approach.It was demonstrated that decreasing the anode/cathode surface area ratio obviously enhances the corrosion rate of A508,both locally and globally.Deeper analyses of the AFM results enabled quantitative comparison of the corrosion behaviour of the different surface constituents.It was revealed that in the galvanic interaction of the DMW,the grain refined region corrodes most,followed by the partial grain refined region and base metal matrix of the A508,respectively.The electrochemical localization index(LI)estimation method and AFM analysis both confirmed the presence of a mixed(localized and uniform)corrosion phenomenon occurring on the surface of the A508 anode metal in the galvanic interaction of the dissimilar metals.Finally,the degree of synergism equation was utilized to describe the synergistic effects of anode/cathode area ratio and the microstructure of the samples on the galvanic corrosion of LAS A508/309 L/308 L SS DMW.
基金financially supported by the Science and Technology Commission of Shanghai Municipality(No.19DZ2271100)。
文摘The influence of pH and metallographic structure on the corrosion behavior of copper-drawn steel is studied with the simulated system.The effect of pH on the corrosion behavior of copper-drawn steel has been investigated using open-circuit potential,potentiodynamic polarization,galvanic current measurement,scanning electron microscopy and scanning vibrating electrode technique techniques.The steel is corroded as anode,while the corrosion of copper plate is protected as cathode.All the results revealed that pH and metallographic structure had a significant influence on the corrosion behavior of copper-drawn steel.With the decrease in pH value from 6 to 2.4,the corrosion rate of copper-drawn steel galvanic couple(Cu-Fe GC)obviously increased in the simulated solution of acidic red soil.The electric field formed by the Cu-Fe GC changes the direction of ion migration between the copper and drawn steel electrodes,which impacts the composition and microstructure of corrosion products formed on the electrode surface.
