Mathematical models were proposed to clarify the effect of alloying on corrosion of magnesium alloys based on film-free and film-covered status. The models are applicable to explain the “barrier effect” by cathodes ...Mathematical models were proposed to clarify the effect of alloying on corrosion of magnesium alloys based on film-free and film-covered status. The models are applicable to explain the “barrier effect” by cathodes and the “analogous Hall-Petch relationship” between corrosion rates and grain size. The slope of corrosion rates versus alloying content is determined by the dissolution ability of film-free substrate and the hindering effects by corrosion product film. Designing strategy for corrosion-resistant Mg alloys is established.展开更多
A novel Mg-Al LDH film was in-situ prepared hydrothermally in an alkaline aqueous solution on an Al-alloyed AZ31 substrate.The structural,chemical and functional characteristics of the film were explored by means of s...A novel Mg-Al LDH film was in-situ prepared hydrothermally in an alkaline aqueous solution on an Al-alloyed AZ31 substrate.The structural,chemical and functional characteristics of the film were explored by means of scanning electron microscope(SEM),X-ray diffraction(XRD),energy dispersive spectrometer(EDS),polarization curve,AC impedance and salt immersion tests,respectively.The anti-corrosion results indicated that the Mg-Al LDH film on the Al-alloyed AZ31 surface could effectively protect the AZ31 from corrosion attack even after 90 days of immersion in 3.5 wt.%NaCl solution.The protection performance is surprisingly better than most of the reported coatings on Mg alloys.More interestingly,when the Mg-Al LDH film was scratched,the exposed Al-alloyed surface might gradually release metal ions and re-generate dense LDH nano-sheets in the corrosive environment to inhibit the further corrosion there,exhibiting a self-repairing behavior.The combination of the benign long-term protection and desirable self-repairing performance in this new process of surface-alloying and LDH-formation may significantly extend the practical application of magnesium alloys.展开更多
To clarify the anodic dissolution mechanism of Mg,the hydrogen evolution from pure Mg in acidic solutions under galvanostatic conditions were systematically measured.With increasing anodic current density,the cathodic...To clarify the anodic dissolution mechanism of Mg,the hydrogen evolution from pure Mg in acidic solutions under galvanostatic conditions were systematically measured.With increasing anodic current density,the cathodic hydrogen evolution rate decreased,and the anodic hydrogen evolution became faster while some surface area on the Mg was becoming dark under anodic polarization.Based on the surface analysis results and the generally accepted basic electrochemical equations,the evolution kinetics of hydrogen from Mg was deduced,and the most possible surface intermediate active species that could facilitate the anodic Mg dissolution and anodic hydrogen evolution were proposed.This paper further develops the model of incomplete film Mg^(+) dissolution,explains many reported experimental phenomena,and clarifies misunderstandings of current mechanism.展开更多
The anode activity can to a great degree limit the cathodic hydrogen evolution efficiency in an electrolyte cell.Thus,cost-efficient electrocatalysts with good water oxidation performance and stability are highly desi...The anode activity can to a great degree limit the cathodic hydrogen evolution efficiency in an electrolyte cell.Thus,cost-efficient electrocatalysts with good water oxidation performance and stability are highly desired in widespread implementation of the hydrogen production from water splitting.This paper proposes a facile corrosion-reconstruction strategy to transform Fe surface into a Fe-Co hydroxide layer to improve the oxygen evolution activity.The as-prepared catalyst was measured to have an over-potentential as low as 320 mV at 100 mA·cm^(−2),and its stability even exceeded 600 h.Surface and Raman spectroscopy analyses indicated that the catalyst experienced chemical changes from hydroxides to oxyhydroxides and Co^(2+)to Co^(3+)during oxygen evolution reaction(OER).The corrosion-reconstruction is not only an economical method to synthesize a highly efficient,stable and durable Fe-based catalysts,it also converses the detrimental corrosion into a beneficial catalyst fabrication process.展开更多
A novel coating on the Mg1Mn alloy was produced by anodic polarization combined with hydrothermal treatment(AP+H)in 0.1 M Na2CO3 solution.The microstructure and protection of the coating were evaluated.The coating con...A novel coating on the Mg1Mn alloy was produced by anodic polarization combined with hydrothermal treatment(AP+H)in 0.1 M Na2CO3 solution.The microstructure and protection of the coating were evaluated.The coating consisted of MgCO3,Mg(OH)2 and MgO,and provided satisfactory protection in 3.5 wt%NaCl with a corrosion rate of 0.07 mm y−1 in 72 h.However,after that period,the corrosion rate of the specimen increased due to the damage of the coating.The failure of the coating was strongly related to the second phase particles(e.g.Zr particles)or impurities in the matrix.The AP+H coating is supposed to be used as a primer coating for Mg applications in kitchen ware,biomedical areas or industry.展开更多
In order to analyze the effect of scratch on the corrosion behaviour of a calcium phosphate conversion coating(CPCC)on AZ80,the electrochemical testing,scanning vibrating electrode technique(SVET),immersion test and h...In order to analyze the effect of scratch on the corrosion behaviour of a calcium phosphate conversion coating(CPCC)on AZ80,the electrochemical testing,scanning vibrating electrode technique(SVET),immersion test and hydrogen evolution experiment were performed to study the corrosion resistance of AZ80,AZ80 with CPCC and coated AZ80 with scratch.The results show that the coating improves the corrosion resistance of the AZ80 from a current density of(85±4)to(4±1)μA/cm^(2).When the coating was damaged,its protection on substrate would be reduced.The scratch with a length of around 12 mm on the coating reduced the corrosion resistance to a current density of(39±1)μA/cm^(2).In addition,the corrosion occurred initially in the scratch area and the corrosion site first occurred at the junction of the scratch and the coating.Besides,the micro corrosion mechanism of the specimen containing scratch was clarified.展开更多
The influence of heat treatment on the corrosion behavior of rolled Mg5 Gd alloys in 3.5 wt.% Na Cl solution saturated with Mg(OH)2 was characterized by immersion test, electrochemical test, scanning electrochemical m...The influence of heat treatment on the corrosion behavior of rolled Mg5 Gd alloys in 3.5 wt.% Na Cl solution saturated with Mg(OH)2 was characterized by immersion test, electrochemical test, scanning electrochemical microscopy(SECM) and corrosion morphology analysis in order to improve the corrosion resistance of Mg alloys. The results showed that solution treatment reduced the corrosion rate of the Mg5 Gd significantly, resulting in relatively uniform corrosion and shallow corrosion cavities due to the dissolution of Cd-containing particles. The following aging process could further decrease the corrosion rate. Precipitation of nano-sized Cd-containing particles did not cause apparent micro-galvanic corrosion, which could be attributed to the formation of a protective corrosion product film fully covering the particles.展开更多
The assemblages of unicellular microalgae and bacteria in phytoplankton communities can generally result in biodeterioration of metals in marine environment.In this study,the self-promoted biofouling mechanism underne...The assemblages of unicellular microalgae and bacteria in phytoplankton communities can generally result in biodeterioration of metals in marine environment.In this study,the self-promoted biofouling mechanism underneath red-tide alga Phaeodactylum tricornutum and its symbiotic bacterium Bacillus altitudinis was systematically revealed.The mutualistic interaction of the bacteria and algae quadrupled the corrosion rate in comparison to the individual effect of the bacterium or algal strain alone.Reversely,the corroded metal appeared to be an accelerator that can stimulate the activity of the P.tricornutum and aggravate the biological pollution based on the result of 62.3%up-regulation of the key photosynthesis genes.The corrosion-biofouling-accelerated corrosion-deteriorated biofouling formed a vicious cycle.展开更多
Hydrogen evolution is normally associated with the corrosion or dissolution of Mg alloys in aqueous solutions.This work studied the corrosion behavior of sputtered pure Mg,Mg82Zn18(at.%),Mg64Zn36(at.%),and pure Zn in ...Hydrogen evolution is normally associated with the corrosion or dissolution of Mg alloys in aqueous solutions.This work studied the corrosion behavior of sputtered pure Mg,Mg82Zn18(at.%),Mg64Zn36(at.%),and pure Zn in 3.5%Na Cl solution.Mg64Zn36had(ⅰ)an amorphous microstructure with some nano-scale grains,(ⅱ)a corrosion rate substantially lower than that of pure Mg,and(ⅲ)no hydrogen evolution during corrosion or anodic dissolution,because the positive corrosion potential retarded the cathodic hydrogen evolution.This is a new route to prevent hydrogen evolution during Mg corrosion,which has never previously been realized.展开更多
Controllable and scalable preparation of electrocatalyst materials holds significant importance for their practical application.Magnetron sputtering is a highly effective synthesis method,known for its producing unifo...Controllable and scalable preparation of electrocatalyst materials holds significant importance for their practical application.Magnetron sputtering is a highly effective synthesis method,known for its producing uniform films and allowing easy control of component compositions.In this paper,we propose an in-situ synthesis method for layered double hydroxide(LDH)electrocatalysts through sacrificing magnetron sputtered films.The resulting FeCo-LDH catalyst demonstrated a low overpotential of only 300 mV at 10 mA·cm^(-2).Furthermore,we conducted spectroscopic analysis to investigate the surface changes of the catalysts during the oxygen evolution reaction(OER)process.Our findings indicated that the formation of Co oxyhydroxides plays a beneficial role in enhancing the catalytical performance of the FeCo-LDH for OER reaction.This restructuring strategy of converting a magnetron-sputtered sacrificial film into a catalytical LDH introduces a new avenue to the synthesis of transition metal-based electrocatalysts.展开更多
The galvanic corrosion behavior of carbon fiber reinforced polymers （CFRPs） GM-CFRP and Tepex-CFRP in contact with a Zn-coated DP590 steel in solution containing 0.9 wt% NaCl＋ 0.1 wt% CaCl2 ＋ 0.075 wt% NaHCO3 was ...The galvanic corrosion behavior of carbon fiber reinforced polymers （CFRPs） GM-CFRP and Tepex-CFRP in contact with a Zn-coated DP590 steel in solution containing 0.9 wt% NaCl＋ 0.1 wt% CaCl2 ＋ 0.075 wt% NaHCO3 was investigated. The results showed that the GM-CFRP/steel couple was initially more resistant to galvanic corrosion, but its galvanic corrosion activity gradually became higher than the Tepex-CFRP/steel couple. The different galvanic behaviors of these two couples were discussed based on the electrochemical performance of GM-CFRP, Tepex-CFRP and DP590 coupons in the testing solution.展开更多
The corrosion behavior of pure Magnesium(Mg)in a Mg(OH)2-saturated solution containing different individual constituents of PM2.5 in haze were studied by hydrogen evolution,weight loss and electrochemical experiments....The corrosion behavior of pure Magnesium(Mg)in a Mg(OH)2-saturated solution containing different individual constituents of PM2.5 in haze were studied by hydrogen evolution,weight loss and electrochemical experiments.The results indicated that the corrosivity of these constituents to pure Mg decreased in the following order:(NH4)2SO4>Haze-contaminated-solution>NH4NO3>NH4Cl>NaCl≈KCl≈Na2SO4≈MgCl2≈CaSO4>Mg(OH)2(basic solution)>Ca(NO3)2.Possible mechanisms behind the different corrosion behaviors of Mg in response to these constituents were also briefly discussed in this paper.展开更多
Layered double hydroxides(LDHs),a class of two-dimensional(2D)brucite-like layers,have been effectively applied in diverse fields.However,the current synthesis methods restrict the in situ scaling-up and tunable produ...Layered double hydroxides(LDHs),a class of two-dimensional(2D)brucite-like layers,have been effectively applied in diverse fields.However,the current synthesis methods restrict the in situ scaling-up and tunable production of LDH-based materials.Inspired by the growing characteristic of“Bryophyllum pinnatum”,a sacrificial co-sputtered Zn-Al transition layer was introduced for the first time to in situ grow a scalable-manufactured and thickness-controllable LDH film on arbitrary substrate materials with flexible shapes through“partial dissolution”and“solution infiltration”processes.Diverse LDH films could be tailored by the creative regulation of the component,structure and surface state of the transition layer.Results showed that the as-prepared LDH film had strong mechanical robustness under harsh abrasion conditions due to its large thickness and multi-level microstructure.Moreover,a series of galvanic couple model experiments based on Zn/Al single-metal transition layers were designed to solve the real-time monitoring issue in the complex hydrothermal solution.This work not only develops a new strategy to design and grow in situ LDH films with multifaceted features,but also reveals sophisticated LDH formation mechanisms.Hence,the findings of this study may broaden the practical application of LDH-based materials toward advanced and smart devices.展开更多
The Zn0.6Cu wires are fabricated into stents for the potential biodegradable application of nasal wound healing.The degradation behavior of Zn0.6Cu stents in 0.9 wt%NaCl at 36.5℃ is evaluated.It shows that the untrea...The Zn0.6Cu wires are fabricated into stents for the potential biodegradable application of nasal wound healing.The degradation behavior of Zn0.6Cu stents in 0.9 wt%NaCl at 36.5℃ is evaluated.It shows that the untreated Zn0.6Cu stent experiences severe crevice corrosion with acceleration and autocatalytic effects within the micro-cracks and ruptures at 4.67±1.15 d,with the average corrosion rate of 0.28 mm y^(-1).Fortunately,the anodic polarization(AP)+hydrothermal(H)conversion coating,consisting of ZnCO_(3),Zn(OH)_(2) and ZnO,could inhibit the crevice corrosion significantly by reducing the cathode/anode ratio,extending the rupture time up to 16.50±2.95 d,with the average corrosion rate of 0.14 mm y^(-1).This research indicates that the biodegradable Zn-based stent has some potential applications in nasal wound recovery area.展开更多
Mg atmospheric corrosion is induced by a thin surface aqueous layer. Controlling factors are microgalvanic acceleration between different phases, protection by a continuous second phase distribution, protection by cor...Mg atmospheric corrosion is induced by a thin surface aqueous layer. Controlling factors are microgalvanic acceleration between different phases, protection by a continuous second phase distribution, protection by corrosion products, and degradation of protective layers by aggressive species such as chloride ions. The Mg atmospheric corrosion rate increases with relative humidity (RH) and concentrations of aggressive species. Temperature increases the corrosion rate unless a protective film causes a decrease.O2, SO2 and NO2 accelerate the atmospheric corrosion rate, whereas the corrosion rate is decreased by CO2. The traditional gravimetric method can evaluate effectively the corrosion behavior of Mg alloys.展开更多
Algae are reported to be corrosive,while little is known about the role of the algae associated bacteria in the corrosion process.In the present study,Halomonas titanicae was isolated from a culture of an alga strain,...Algae are reported to be corrosive,while little is known about the role of the algae associated bacteria in the corrosion process.In the present study,Halomonas titanicae was isolated from a culture of an alga strain,Spirulina platensis,and identified through 16 S rRNA gene analysis.Corrosion behavior of 304L stainless steel(SS)coupons in the presence and absence of H.titanicae was characterized by using electrochemical measurements and surface analysis.The results showed that H.titanicae significantly accelerated the corrosion rate and decreased the pitting potential of 304L SS in the biotic medium.After removal of the corrosion products and biofilms,severe pitting corrosion caused by H.titanicae was observed.The largest pit depth after 14 d reached 6.6μm,which was 5.5 times higher than that of the sterile control(1.2μm).This is the first report revealing that an alga associated bacterium can induce microbiologically influenced corrosion(MIC),and a further concern is raised that whether algae play a role in the MIC process.展开更多
Stainless steel(SS)has unsatisfied corrosion resistance in many aggressive environments,particularly under a low p H condition in the bioleaching industry.In this study,through surface analyses and electrochemical mea...Stainless steel(SS)has unsatisfied corrosion resistance in many aggressive environments,particularly under a low p H condition in the bioleaching industry.In this study,through surface analyses and electrochemical measurements,the corrosion resistance of a novel Cu-bearing 316L SS was evaluated in the presence of an acid-producing bacterium,Acidithiobacillus caldus SM-1 that was able to create an extremely acidic corrosive environment.The significantly enhanced anti-microbiologically-inducedcorrosion performance could be explained by the intracellular reactive oxygen species(ROS)and Fenton reaction on the Cu-bearing 316L SS.展开更多
Several mechanisms have been proposed to interpret the widely reported phenomenon of Mg corrosion that the hydrogen evolution rate increases with increasing anodic potential or anodic current density. This paper criti...Several mechanisms have been proposed to interpret the widely reported phenomenon of Mg corrosion that the hydrogen evolution rate increases with increasing anodic potential or anodic current density. This paper critically analyzed the two main mechanisms,(1) "the incomplete film univalent Mg+ion mechanism" and(2) "the enhanced catalytic activity mechanism", aiming to clarify the current understanding of the Mg corrosion mechanism and to provide a profound insight into the Mg characteristic electrochemical behavior, anodic polarization accelerating both hydrogen evolution and Mg dissolution. It is expected that the deepened fundamental understanding from this comprehensive mechanistic review will provide a basis of practical applications for Mg alloys and open up a new way to the control of corrosion of Mg alloys in practice.展开更多
基金supported by Shanghai Science and Technology Committee (No.18511109300)Science and Technology Commission of the CMC (2019JCJQZD27300)+1 种基金Foundation from Shanghai Jiao Tong University (AF0500132,AF0500149)Funding from Center of Hydrogen Science of Shanghai Jiao Tong University。
文摘Mathematical models were proposed to clarify the effect of alloying on corrosion of magnesium alloys based on film-free and film-covered status. The models are applicable to explain the “barrier effect” by cathodes and the “analogous Hall-Petch relationship” between corrosion rates and grain size. The slope of corrosion rates versus alloying content is determined by the dissolution ability of film-free substrate and the hindering effects by corrosion product film. Designing strategy for corrosion-resistant Mg alloys is established.
基金The research is supported by the National Science Foundation of China(key project grant No.51731008 and general project grant No.51671163).
文摘A novel Mg-Al LDH film was in-situ prepared hydrothermally in an alkaline aqueous solution on an Al-alloyed AZ31 substrate.The structural,chemical and functional characteristics of the film were explored by means of scanning electron microscope(SEM),X-ray diffraction(XRD),energy dispersive spectrometer(EDS),polarization curve,AC impedance and salt immersion tests,respectively.The anti-corrosion results indicated that the Mg-Al LDH film on the Al-alloyed AZ31 surface could effectively protect the AZ31 from corrosion attack even after 90 days of immersion in 3.5 wt.%NaCl solution.The protection performance is surprisingly better than most of the reported coatings on Mg alloys.More interestingly,when the Mg-Al LDH film was scratched,the exposed Al-alloyed surface might gradually release metal ions and re-generate dense LDH nano-sheets in the corrosive environment to inhibit the further corrosion there,exhibiting a self-repairing behavior.The combination of the benign long-term protection and desirable self-repairing performance in this new process of surface-alloying and LDH-formation may significantly extend the practical application of magnesium alloys.
基金supported by the National Science Foundation of China(key project grant No.51731008 and general project grant No.51671163).
文摘To clarify the anodic dissolution mechanism of Mg,the hydrogen evolution from pure Mg in acidic solutions under galvanostatic conditions were systematically measured.With increasing anodic current density,the cathodic hydrogen evolution rate decreased,and the anodic hydrogen evolution became faster while some surface area on the Mg was becoming dark under anodic polarization.Based on the surface analysis results and the generally accepted basic electrochemical equations,the evolution kinetics of hydrogen from Mg was deduced,and the most possible surface intermediate active species that could facilitate the anodic Mg dissolution and anodic hydrogen evolution were proposed.This paper further develops the model of incomplete film Mg^(+) dissolution,explains many reported experimental phenomena,and clarifies misunderstandings of current mechanism.
基金support from the National Natural Science Foundation of China(key project Grant No.51731008 and general project Grant No.51671163).
文摘The anode activity can to a great degree limit the cathodic hydrogen evolution efficiency in an electrolyte cell.Thus,cost-efficient electrocatalysts with good water oxidation performance and stability are highly desired in widespread implementation of the hydrogen production from water splitting.This paper proposes a facile corrosion-reconstruction strategy to transform Fe surface into a Fe-Co hydroxide layer to improve the oxygen evolution activity.The as-prepared catalyst was measured to have an over-potentential as low as 320 mV at 100 mA·cm^(−2),and its stability even exceeded 600 h.Surface and Raman spectroscopy analyses indicated that the catalyst experienced chemical changes from hydroxides to oxyhydroxides and Co^(2+)to Co^(3+)during oxygen evolution reaction(OER).The corrosion-reconstruction is not only an economical method to synthesize a highly efficient,stable and durable Fe-based catalysts,it also converses the detrimental corrosion into a beneficial catalyst fabrication process.
基金supported by the National Natural Science Foundation of China(No.51801168).
文摘A novel coating on the Mg1Mn alloy was produced by anodic polarization combined with hydrothermal treatment(AP+H)in 0.1 M Na2CO3 solution.The microstructure and protection of the coating were evaluated.The coating consisted of MgCO3,Mg(OH)2 and MgO,and provided satisfactory protection in 3.5 wt%NaCl with a corrosion rate of 0.07 mm y−1 in 72 h.However,after that period,the corrosion rate of the specimen increased due to the damage of the coating.The failure of the coating was strongly related to the second phase particles(e.g.Zr particles)or impurities in the matrix.The AP+H coating is supposed to be used as a primer coating for Mg applications in kitchen ware,biomedical areas or industry.
基金financially supported by the National Natural Science Foundation of China(Nos.52071036,51701027)the Fundamental Research Funds for the Central Universities,China(Nos.2020CDJQY-A002,2021CDJCGJ009)the National Key Research and Development Program of China(Nos.2016YFB0301100,2016YFB0101700)。
文摘In order to analyze the effect of scratch on the corrosion behaviour of a calcium phosphate conversion coating(CPCC)on AZ80,the electrochemical testing,scanning vibrating electrode technique(SVET),immersion test and hydrogen evolution experiment were performed to study the corrosion resistance of AZ80,AZ80 with CPCC and coated AZ80 with scratch.The results show that the coating improves the corrosion resistance of the AZ80 from a current density of(85±4)to(4±1)μA/cm^(2).When the coating was damaged,its protection on substrate would be reduced.The scratch with a length of around 12 mm on the coating reduced the corrosion resistance to a current density of(39±1)μA/cm^(2).In addition,the corrosion occurred initially in the scratch area and the corrosion site first occurred at the junction of the scratch and the coating.Besides,the micro corrosion mechanism of the specimen containing scratch was clarified.
基金financial supports from the National Natural Science Foundation of China (51801168,51731008)Natural Science Foundation of Fujian Province (2018J05093),ChinaNational Environmental Corrosion Platform of China。
文摘The influence of heat treatment on the corrosion behavior of rolled Mg5 Gd alloys in 3.5 wt.% Na Cl solution saturated with Mg(OH)2 was characterized by immersion test, electrochemical test, scanning electrochemical microscopy(SECM) and corrosion morphology analysis in order to improve the corrosion resistance of Mg alloys. The results showed that solution treatment reduced the corrosion rate of the Mg5 Gd significantly, resulting in relatively uniform corrosion and shallow corrosion cavities due to the dissolution of Cd-containing particles. The following aging process could further decrease the corrosion rate. Precipitation of nano-sized Cd-containing particles did not cause apparent micro-galvanic corrosion, which could be attributed to the formation of a protective corrosion product film fully covering the particles.
基金The support of the National Key Research and Development Program of China(No.2017YFB0702100)the National Natural Science Foundation of China(key project No.51731008,general project Nos.51671163,51901198)。
文摘The assemblages of unicellular microalgae and bacteria in phytoplankton communities can generally result in biodeterioration of metals in marine environment.In this study,the self-promoted biofouling mechanism underneath red-tide alga Phaeodactylum tricornutum and its symbiotic bacterium Bacillus altitudinis was systematically revealed.The mutualistic interaction of the bacteria and algae quadrupled the corrosion rate in comparison to the individual effect of the bacterium or algal strain alone.Reversely,the corroded metal appeared to be an accelerator that can stimulate the activity of the P.tricornutum and aggravate the biological pollution based on the result of 62.3%up-regulation of the key photosynthesis genes.The corrosion-biofouling-accelerated corrosion-deteriorated biofouling formed a vicious cycle.
基金supported by National Natural Science Foundation of China No.51801168 and No.51731008Natural Science Foundation of Fujian Province No.2018J05093。
文摘Hydrogen evolution is normally associated with the corrosion or dissolution of Mg alloys in aqueous solutions.This work studied the corrosion behavior of sputtered pure Mg,Mg82Zn18(at.%),Mg64Zn36(at.%),and pure Zn in 3.5%Na Cl solution.Mg64Zn36had(ⅰ)an amorphous microstructure with some nano-scale grains,(ⅱ)a corrosion rate substantially lower than that of pure Mg,and(ⅲ)no hydrogen evolution during corrosion or anodic dissolution,because the positive corrosion potential retarded the cathodic hydrogen evolution.This is a new route to prevent hydrogen evolution during Mg corrosion,which has never previously been realized.
基金support from the National Natural Science Foundation of China(Nos.52250710159,51731008,51671163)。
文摘Controllable and scalable preparation of electrocatalyst materials holds significant importance for their practical application.Magnetron sputtering is a highly effective synthesis method,known for its producing uniform films and allowing easy control of component compositions.In this paper,we propose an in-situ synthesis method for layered double hydroxide(LDH)electrocatalysts through sacrificing magnetron sputtered films.The resulting FeCo-LDH catalyst demonstrated a low overpotential of only 300 mV at 10 mA·cm^(-2).Furthermore,we conducted spectroscopic analysis to investigate the surface changes of the catalysts during the oxygen evolution reaction(OER)process.Our findings indicated that the formation of Co oxyhydroxides plays a beneficial role in enhancing the catalytical performance of the FeCo-LDH for OER reaction.This restructuring strategy of converting a magnetron-sputtered sacrificial film into a catalytical LDH introduces a new avenue to the synthesis of transition metal-based electrocatalysts.
文摘The galvanic corrosion behavior of carbon fiber reinforced polymers （CFRPs） GM-CFRP and Tepex-CFRP in contact with a Zn-coated DP590 steel in solution containing 0.9 wt% NaCl＋ 0.1 wt% CaCl2 ＋ 0.075 wt% NaHCO3 was investigated. The results showed that the GM-CFRP/steel couple was initially more resistant to galvanic corrosion, but its galvanic corrosion activity gradually became higher than the Tepex-CFRP/steel couple. The different galvanic behaviors of these two couples were discussed based on the electrochemical performance of GM-CFRP, Tepex-CFRP and DP590 coupons in the testing solution.
基金This research was supported by National Natural Science Foundation of China(No.51731008)National Environment Corrosion Platform of China.
文摘The corrosion behavior of pure Magnesium(Mg)in a Mg(OH)2-saturated solution containing different individual constituents of PM2.5 in haze were studied by hydrogen evolution,weight loss and electrochemical experiments.The results indicated that the corrosivity of these constituents to pure Mg decreased in the following order:(NH4)2SO4>Haze-contaminated-solution>NH4NO3>NH4Cl>NaCl≈KCl≈Na2SO4≈MgCl2≈CaSO4>Mg(OH)2(basic solution)>Ca(NO3)2.Possible mechanisms behind the different corrosion behaviors of Mg in response to these constituents were also briefly discussed in this paper.
基金supported by the National Natural Science Foundation of China(51731008 and 51671163)China Scholarship Council for providing support(202006310139)。
文摘Layered double hydroxides(LDHs),a class of two-dimensional(2D)brucite-like layers,have been effectively applied in diverse fields.However,the current synthesis methods restrict the in situ scaling-up and tunable production of LDH-based materials.Inspired by the growing characteristic of“Bryophyllum pinnatum”,a sacrificial co-sputtered Zn-Al transition layer was introduced for the first time to in situ grow a scalable-manufactured and thickness-controllable LDH film on arbitrary substrate materials with flexible shapes through“partial dissolution”and“solution infiltration”processes.Diverse LDH films could be tailored by the creative regulation of the component,structure and surface state of the transition layer.Results showed that the as-prepared LDH film had strong mechanical robustness under harsh abrasion conditions due to its large thickness and multi-level microstructure.Moreover,a series of galvanic couple model experiments based on Zn/Al single-metal transition layers were designed to solve the real-time monitoring issue in the complex hydrothermal solution.This work not only develops a new strategy to design and grow in situ LDH films with multifaceted features,but also reveals sophisticated LDH formation mechanisms.Hence,the findings of this study may broaden the practical application of LDH-based materials toward advanced and smart devices.
基金supported by the National Natural Science Foundation of China(No.51975592).
文摘The Zn0.6Cu wires are fabricated into stents for the potential biodegradable application of nasal wound healing.The degradation behavior of Zn0.6Cu stents in 0.9 wt%NaCl at 36.5℃ is evaluated.It shows that the untreated Zn0.6Cu stent experiences severe crevice corrosion with acceleration and autocatalytic effects within the micro-cracks and ruptures at 4.67±1.15 d,with the average corrosion rate of 0.28 mm y^(-1).Fortunately,the anodic polarization(AP)+hydrothermal(H)conversion coating,consisting of ZnCO_(3),Zn(OH)_(2) and ZnO,could inhibit the crevice corrosion significantly by reducing the cathode/anode ratio,extending the rupture time up to 16.50±2.95 d,with the average corrosion rate of 0.14 mm y^(-1).This research indicates that the biodegradable Zn-based stent has some potential applications in nasal wound recovery area.
基金supported by the National Natural Science Foundation of China (No. 51731008)the National Environmental Corrosion Platform of China
文摘Mg atmospheric corrosion is induced by a thin surface aqueous layer. Controlling factors are microgalvanic acceleration between different phases, protection by a continuous second phase distribution, protection by corrosion products, and degradation of protective layers by aggressive species such as chloride ions. The Mg atmospheric corrosion rate increases with relative humidity (RH) and concentrations of aggressive species. Temperature increases the corrosion rate unless a protective film causes a decrease.O2, SO2 and NO2 accelerate the atmospheric corrosion rate, whereas the corrosion rate is decreased by CO2. The traditional gravimetric method can evaluate effectively the corrosion behavior of Mg alloys.
基金supported financially by the National Natural Science Foundation of China(Nos.U1660118 and 51871050)the National Environmental Corrosion Platform(NECP)of Chinathe Fundamental Research Funds for the Central Universities of Ministry of Education of China(No.N180205021).
文摘Algae are reported to be corrosive,while little is known about the role of the algae associated bacteria in the corrosion process.In the present study,Halomonas titanicae was isolated from a culture of an alga strain,Spirulina platensis,and identified through 16 S rRNA gene analysis.Corrosion behavior of 304L stainless steel(SS)coupons in the presence and absence of H.titanicae was characterized by using electrochemical measurements and surface analysis.The results showed that H.titanicae significantly accelerated the corrosion rate and decreased the pitting potential of 304L SS in the biotic medium.After removal of the corrosion products and biofilms,severe pitting corrosion caused by H.titanicae was observed.The largest pit depth after 14 d reached 6.6μm,which was 5.5 times higher than that of the sterile control(1.2μm).This is the first report revealing that an alga associated bacterium can induce microbiologically influenced corrosion(MIC),and a further concern is raised that whether algae play a role in the MIC process.
基金financially supported by the National Natural Science Foundation of China(Nos.51871050 and U1660118)the Fundamental Research Funds for the Central Universities(Nos.N180205021,N180203019,and N2002019)the Liaoning Revitalization Talents Program(No.XLYC1907158)。
文摘Stainless steel(SS)has unsatisfied corrosion resistance in many aggressive environments,particularly under a low p H condition in the bioleaching industry.In this study,through surface analyses and electrochemical measurements,the corrosion resistance of a novel Cu-bearing 316L SS was evaluated in the presence of an acid-producing bacterium,Acidithiobacillus caldus SM-1 that was able to create an extremely acidic corrosive environment.The significantly enhanced anti-microbiologically-inducedcorrosion performance could be explained by the intracellular reactive oxygen species(ROS)and Fenton reaction on the Cu-bearing 316L SS.
基金financially supported by the National Science Foundation of China (Nos. 51731008 and 51671163)。
文摘Several mechanisms have been proposed to interpret the widely reported phenomenon of Mg corrosion that the hydrogen evolution rate increases with increasing anodic potential or anodic current density. This paper critically analyzed the two main mechanisms,(1) "the incomplete film univalent Mg+ion mechanism" and(2) "the enhanced catalytic activity mechanism", aiming to clarify the current understanding of the Mg corrosion mechanism and to provide a profound insight into the Mg characteristic electrochemical behavior, anodic polarization accelerating both hydrogen evolution and Mg dissolution. It is expected that the deepened fundamental understanding from this comprehensive mechanistic review will provide a basis of practical applications for Mg alloys and open up a new way to the control of corrosion of Mg alloys in practice.
