The atmospheric corrosion behavior of pure copper exposed for three years in Turpan, China, which is a typical hot and dry atmosphere environment, was investigated using mass-loss tests, morphology observations, com...The atmospheric corrosion behavior of pure copper exposed for three years in Turpan, China, which is a typical hot and dry atmosphere environment, was investigated using mass-loss tests, morphology observations, composition analyses, and electrochemical techniques. The results indicated that the annual corrosion rate of pure copper was approximately 2.90 μm/a. An uneven distribution of corrosion products was observed by scanning electron microscopy; this uneven distribution was attributed to the dehydration process during wet–dry and cold–hot cycles, and the compositions mainly consisted of cuprite （Cu2O） and atacamite （Cu2Cl（OH）3）. Electrochemical measurements showed that deposits on copper improved its resistance to corrosion and the protectiveness decreased with increasing temperature. On the other hand, results obtained using the scanning vibrating electrode technique showed that the porous and uneven structure of the deposit layer generated a spatial separation of cathodic and anodic reaction sites, which accelerated the corrosion process in wet and rainy weather.展开更多
The corrosion behavior of mild steel in a simulated coastal atmosphere environment has been investigated by the indoor accelerated wet/dry cyclic corrosion acceleration test(CCT),scanning electron microscopy(SEM),Rama...The corrosion behavior of mild steel in a simulated coastal atmosphere environment has been investigated by the indoor accelerated wet/dry cyclic corrosion acceleration test(CCT),scanning electron microscopy(SEM),Raman spectroscopy and electrochemical measurements.During the CCT test of 60 cycles,the evolution of logarithmic(corrosion rate)vs.logarithmic(CCT cycles)presents a turning point at the 5th cycle,presenting a tendency to increase first and then decrease to gradually stabilize as the CCT cycle prolonged.Before the 5th cycle,γ-FeOOH andβ-FeOOH and Fe_(3)O_(4)were detected,respectively.And then,α-FeOOH as a new chemical composition was detected in the subsequent corrosion cycles.It is found that,after long term corrosion,the rust separated into a relatively dense inner layer rich withα-FeOOH and a loose outer layer rich withγ-FeOOH,both of which have poor electrical conductivity.The rapid increase of corrosion rate in the early stage since reducible corrosion products are involved in the reduction process of the cathode which promotes the dissolution of the anodic metal substrate.Afterward,as the rust layer thickens,the resistance of the rust increases,and the aggressive ions diffusion is blocked,gradually suppressing the electrochemical corrosion process.At last,when the composition and distribution of the rust layer remain stable,the corrosion presents a fluctuating speed around a certain value during the cracking and self-repairing process of the rust layer.展开更多
The corrosion behavior of pure copper exposed to the atmosphere of Nansha Islands for 21 months was studied by mass loss method,composition analysis,morphology observation and electrochemical measurements.The results ...The corrosion behavior of pure copper exposed to the atmosphere of Nansha Islands for 21 months was studied by mass loss method,composition analysis,morphology observation and electrochemical measurements.The results showed that the average corrosion rate of copper exposed for one year was approximately 7.85μm/a,implying that Nansha Islands was classified as a corrosion category of CX.The structure and properties of the corrosion product layer generated on the front and back sides of the exposed sample differed significantly.The inner corrosion product layer(Cu2O)on the front side was relatively thick and dense,whereas the outer product layer(Cu2Cl(OH)3)was extremely thin.However,the outer product layer on the back side was thicker than the inner layer.Electrochemical measurements indicated that the protection afforded by the corrosion product layer on the front side was improved gradually,while that on the back side was deteriorated.展开更多
The corrosion and pitting behavior of pure aluminum 1060 exposed to Nansha Islands marine atmosphere for 34 months was investigated based on mass loss measurement,scanning electron microscopy(SEM),energy dispersive sp...The corrosion and pitting behavior of pure aluminum 1060 exposed to Nansha Islands marine atmosphere for 34 months was investigated based on mass loss measurement,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS),and electrochemical impedance spectroscopy(EIS).The results indicated that serious pitting corrosion occurred on the surfaces of pure aluminum.The corrosion rate after exposure for 13 months was approximately 1.28 g/(m^(2)·a).The XPS results showed that the corrosion products were Al_(2)O_(3),Al(OH)_(3),and AlCl_(3).Moreover,the corrosion product layer was more protective than the native oxide film,and the protectiveness first increased and then decreased.Finally,the shape of the pits was evaluated using statistical analysis.展开更多
The stable operation of electronic devices in marine atmospheric environment is affected by the corrosion deterioration of solder joints,and the effects by atmosphere temperature and chloride deposition are critical.I...The stable operation of electronic devices in marine atmospheric environment is affected by the corrosion deterioration of solder joints,and the effects by atmosphere temperature and chloride deposition are critical.In this work,NaCl deposition and temperature dependent corrosion of Pb-free SAC305 solder in simulated marine atmosphere has been investigated.The results indicate that higher NaCl deposition prolongs the surface wetting time and leads to the final thicker saturated electrolyte film for further corrosion.Higher temperature accelerates the evaporation and contributes to the final thinner saturated NaCl electrolyte film.Besides,the corrosion control process varies under the initially covered thicker NaCl electrolyte layer and under the final saturated much thinner NaCl electrolyte film as the evaporation proceeds.Moreover,the ready oxygen availability through the final thinner saturated NaCl electrolyte film facilitates the formation of corrosion product layer mainly of electrochemically stable SnO2,but higher temperature leads to the final corrosion product layer with smaller crystal size and large cracks.The findings clearly demonstrate the effects of NaCl deposition and temperature on corrosion evolution of SAC305 solder joints and are critical to the daily maintenance of electronic devices for longer service life in marine atmosphere.展开更多
The evolution of corrosion behavior of 316 L stainless steels exposed to salt lake atmosphere for 8 years was investigated.The results showed that the stainless steel in salt lake atmosphere had a greater corrosion ra...The evolution of corrosion behavior of 316 L stainless steels exposed to salt lake atmosphere for 8 years was investigated.The results showed that the stainless steel in salt lake atmosphere had a greater corrosion rate during the initial exposure time and relatively lower corrosion rate during the subsequent exposure time.Dust depositions accumulated on the downward surface caused severe local corrosion of stainless steel.As exposure time prolonged,the relative amount of Croxide and Feoxidein the corrosion products gradually increased,which may directly affect the corrosion rate of stainless steels.Moreover,the maximum pit depth followed a power function with respect to exposure time.展开更多
The electrochemical and Stress Corrosion Cracking(SCC)behaviors of 7085-T7651 aluminum alloy in different environments are studied by electrochemical and mechanical testing.The research shows that the type,concentrati...The electrochemical and Stress Corrosion Cracking(SCC)behaviors of 7085-T7651 aluminum alloy in different environments are studied by electrochemical and mechanical testing.The research shows that the type,concentration of the corrosive medium and electrolyte state affect the electrochemical and SCC controlling processes of aluminum alloys.The Thin Electrolyte Layer(TEL)state and the addition of HSO3–increase the corrosion rate and SCC susceptibility.The presence of HSO3–in a corrosive environment can significantly accelerate the corrosion rate and mechanical property degradation,and this effect increases with the increase of HSO3–concentration.Compared with the solution environment,the TEL environment will further aggravate corrosion and mechanical property degradation.With the increase of HSO3–concentration,the pH of the corrosive environment exhibits little change,while the SCC degradation is significantly promoted.This is attributed to the HSO3–induced buffer effect and film-assisted stress effect,yielding the overshadowing effect against solution pH.展开更多
In order to better understand why the corrosion behavior of carbon steel exposed in Nansha atmospheric environment is very serious, the effect of sodium, potassium and magnesium chlorides deposited on carbon steel sur...In order to better understand why the corrosion behavior of carbon steel exposed in Nansha atmospheric environment is very serious, the effect of sodium, potassium and magnesium chlorides deposited on carbon steel surface has been studied under atmosphere conditions by wet/dry accelerated test. The difference of corrosion behavior and surface structure in Na+, K+, and Mg2+ containing atmosphere has been investigated by thickness loss, scanning electron microscope, X-ray diffraction and electrochemical techniques. The results indicate that the thickness loss of carbon steel exposed in different metal cations containing atmospheric environment increases in the order of Na+, K+, Mg2+. The hard metal cation can promote the dissolution of the steel to a certain extent. In Mg2+ containing atmosphere, the relative content of β-FeOOH is rather higher and the protective ability index α */γ * decreases in the order of Na+, K+, Mg2+. The corrosion current density of both bare carbon steel and the rusted carbon steel increases in the order of Na+, K+, Mg2+. The polarization resistance and the charge transfer resistance decreases in the order of Na+, K+, Mg2+.展开更多
The corrosion behavior of copper exposed in a simulated coastal-industrial atmosphere has been investigated using weight loss measurement, scanning electron microscopy, X-ray diffraction, potentiodynamic polarization ...The corrosion behavior of copper exposed in a simulated coastal-industrial atmosphere has been investigated using weight loss measurement, scanning electron microscopy, X-ray diffraction, potentiodynamic polarization and in-situ electrochemical impedance spectroscopy（EIS） with micro-distance electrodes.The results show that corrosion kinetics follows the empirical equation D = Atn. The main corrosion products are composed of Cu_2O, Cu_2Cl（OH）_3 and Cu_4Cl_2（OH）_6. A two-layer structure comprising a loose outer layer and a compact inner layer forms the corrosion products during corrosion process. SO_2 has been found to promote the formation of Cu_4Cl_2（OH）_6.展开更多
The corrosion behavior of pure aluminum 1060 subjected to a wet-dry cyclic accelerated test in simulated Nansha marine atmosphere in the dark and under UV illumination has been investigated by means of scanning electr...The corrosion behavior of pure aluminum 1060 subjected to a wet-dry cyclic accelerated test in simulated Nansha marine atmosphere in the dark and under UV illumination has been investigated by means of scanning electron microscopy(SEM),electrochemical impedance spectroscopy(EIS),and Mott–Schottky measurements in this work.The results show that under the two conditions,the native oxide films are constantly destroyed and the thicknesses of the oxide films continuously decrease in the first 24 days of the corrosion test.In particular,UV illumination can diminish the pitting corrosion susceptibility of the native oxide films to an extent in terms of a photo-induced modifi cation of the native oxide film on the pure aluminum surfaces.Besides,UV illumination can also reduce the carrier concentration in the oxide films,thus reducing the conductivity and the corrosion rate.展开更多
The corrosion behavior of stainless steel exposed to a simulated salt lake atmosphere has been investigated by analyzing the evolution of surface morphologies and corrosion products, the initiation and development of ...The corrosion behavior of stainless steel exposed to a simulated salt lake atmosphere has been investigated by analyzing the evolution of surface morphologies and corrosion products, the initiation and development of pits, and the electrochemical characteristics. The results indicated that(Mg6Fe2(OH)16(CO3)(H2O)4.5)0.25, a layered double hydroxide, has been detected for the first time in the corrosion products formed on stainless steel exposed to a simulated salt lake atmosphere. The specimens exposed to MgCl2 deposit conditions were corroded more severely than those exposed to NaCl deposit conditions, which was attributed to the differences in the deliquescence relative humidity and efflorescence relative humidity values of MgCl2 and NaCl. In addition, a special corrosion morphology consisting of a concentric circle of yellowish material was observed on the specimens exposed to MgCl2 deposit conditions, which was attributed to the formation of Mg(OH)2, inhibiting the diffusion and migration of OH- ions to the anode region. The maximum pit depth followed a power function with respect to corrosion time. The corrosion mechanism of stainless steel exposed to a simulated salt lake atmosphere is also discussed.展开更多
The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties ...The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties of organic coatings.This study compared a bare epoxy coating with one containing zinc phosphate corrosion inhibitors,both applied on ACM sensors,to observe their corrosion protection properties over time.Coatings with artificial damage via scratches were exposed to immersion and alternating dry and wet environments,which allowed for monitoring galvanic corrosion currents in real-time.Throughout the corrosion tests,the ACM currents of the zinc phosphate/epoxy coating were considerably lower than those of the blank epoxy coating.The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis.This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings.Compared with the blank epoxy coating,the zinc phosphate/epoxy coating showed much-decreased ACM current values that confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating.展开更多
The corrosion behaviour of zinc–aluminium–magnesium-coated steel in a simulated polluted marine atmospheric environment was investigated.Therefore,an indoor ageing acceleration test was carefully designed by simulat...The corrosion behaviour of zinc–aluminium–magnesium-coated steel in a simulated polluted marine atmospheric environment was investigated.Therefore,an indoor ageing acceleration test was carefully designed by simulating a polluted marine environment.The objective was to in-depth investigate the corrosion mechanism of Zn–Al–Mg-coated steel exposed to a simulated polluted marine environment.The experiments were carried out by scanning electron microscopy for micro-morphological characterization,X-ray diffraction,electrochemical impedance spectroscopy and electrodynamic polarization curves for the aged samples.The analysis of the results obtained after an indoor accelerated ageing test shows that Zn–Al–Mg coatings generate insoluble Zn_(5)Cl_(2)(OH)_(8)·H_(2)O and Zn_(4)SO_(4)(OH)_(6)during the corrosion process,which hinders the diffusion of corrosive substances into the substrate,and the insoluble substances are structurally dense and thus inhibit further corrosion.Therefore,this effectively inhibits the occurrence of further corrosion,and thus,Zn–Al–Mg coating can significantly extend the service life of Zn–Al–Mg-coated steel.展开更多
Semiconductors and related fields today hold vast application prospects.The semiconductor wafer fabrication process involves steps such as substrate preparation and epitaxy,which occur in high-temperature corrosive en...Semiconductors and related fields today hold vast application prospects.The semiconductor wafer fabrication process involves steps such as substrate preparation and epitaxy,which occur in high-temperature corrosive environments.Consequently,components like crucibles,susceptors and wafer carriers require carbon-based materials such as graphite and carbon-carbon composites.However,traditional carbon materials underperform in these extreme conditions,failing to effectively address the challenges.This leads to issues including product contamination and shortened equipment lifespan.Therefore,effective protection of carbon materials is crucial.This paper reviews current research status on the preparation methods and properties of corrosion-resistant coatings within relevant domestic and international fields.Preparation methods include various techniques such as physical vapor deposition(PVD),chemical vapor deposition(CVD)and the sol-gel method.Furthermore,it offers perspectives on future research directions for corrosion-resistant coated components in semiconductor equipment.These include exploring novel coating materials,improving coating preparation processes,enhancing coating corrosion resistance,as well as further investigating the interfacial interactions between coatings and carbon substrates to achieve better adhesion and compatibility.展开更多
The corrosion degradation of organic coatings in tropical marine atmospheric environments results in substantial economic losses across various industries.The complexity of a dynamic environment,combined with high cos...The corrosion degradation of organic coatings in tropical marine atmospheric environments results in substantial economic losses across various industries.The complexity of a dynamic environment,combined with high costs,extended experimental periods,and limited data,places a limit on the comprehension of this process.This study addresses this challenge by investigating the corrosion de-gradation of damaged organic coatings in a tropical marine environment using an atmospheric corrosion monitoring sensor and a random forest(RF)model.For damage simulation,a polyurethane coating applied to a Fe/graphite corrosion sensor was intentionally scratched and exposed to the marine atmosphere for over one year.Pearson correlation analysis was performed for the collection and filtering of en-vironmental and corrosion current data.According to the RF model,the following specific conditions contributed to accelerated degrada-tion:relative humidity(RH)above 80%and temperatures below 22.5℃,with the risk increasing significantly when RH exceeded 90%.High RH and temperature exhibited a cumulative effect on coating degradation.A high risk of corrosion occurred in the nighttime.The RF model was also used to predict the coating degradation process using environmental data as input parameters,with the accuracy show-ing improvement when the duration of influential environmental ranges was considered.展开更多
Copper is widely used as conductive components in transmission lines,facing severe corrosion risks.The current passing through copper conductors will significantly affect its corrosion process,yet there is a lack of d...Copper is widely used as conductive components in transmission lines,facing severe corrosion risks.The current passing through copper conductors will significantly affect its corrosion process,yet there is a lack of detailed study on the corrosion mechanism under this specific condition.Thus,this study inves-tigated the effect of direct current current-carrying(DC C-C)conditions on the atmospheric corrosion behavior of copper conductors under thin electrolyte layer(TEL)through electrochemical measurements and corrosion exposure experiments.Results revealed that the presence of DC C-C significantly hastened the corrosion process of copper conductors in the TEL,leading to distinct corrosion patterns at the input and output ends.Furthermore,both the extent of corrosion acceleration and the unevenness of corrosion were positively correlation with the DC C-C level.The above phenomenon was attributed to the special motion of charged particles and paramagnetic substances in TEL under the self-generated magnetic field.展开更多
Although hydrogen evolution reaction(HER)is considered to be the main cathodic reaction of Mg corro-sion,oxygen reduction reaction(ORR)has been recently confirmed to be a secondary cathodic reaction.The factors affect...Although hydrogen evolution reaction(HER)is considered to be the main cathodic reaction of Mg corro-sion,oxygen reduction reaction(ORR)has been recently confirmed to be a secondary cathodic reaction.The factors affecting ORR of magnesium(Mg)alloys are still unclear,especially in cases under thin elec-trolyte layers(TEL).In this work,the influence of the corrosion product films on the cathodic reactions of Mg alloys under TEL and in a bulk solution was investigated.ORR does not influence the hydrogen evolution rates in the corrosion of Mg alloys.Therefore,with the existence of oxygen,corrosion rates of Mg alloys measured by hydrogen evolution tests are not accurate under TEL.And weight loss test is a more accurate method to evaluate Mg corrosion rates under TEL.ORR was confirmed to participate in the corrosion of Mg-4Nd-0.4Zr,Mg-4Nd and Mg-0.4Zr alloys under TEL.In 100-μm TEL,the highest con-tribution of ORR in cathodic reactions for the corrosion of Mg-4Nd-0.4Zr,Mg-4Nd and Mg-0.4Zr alloys are 28.6%,39.1%,and 35.8%,respectively.The more protective film on Mg-4Nd-0.4Zr alloy provides a stronger inhibition effect against the diffusion of oxygen,leading to decreased ORR contribution in ca-thodic reactions.In addition,it is suggested that the preparation of Mg alloys with protective corrosion product films can inhibit the corrosion induced by ORR in the atmosphere.This work emphasizes the effects of corrosion product films on ORR in Mg corrosion,especially under TEL.展开更多
The atmospheric corrosion behavior of bronze under thin electrolyte layer （TEL） with different thicknesses was monitored using cathodic polarization curves, open circuit potential （OCP） and electrochemical impedan...The atmospheric corrosion behavior of bronze under thin electrolyte layer （TEL） with different thicknesses was monitored using cathodic polarization curves, open circuit potential （OCP） and electrochemical impedance spectroscopy （EIS）. Cathodic polarization result indicates that the cathodic limiting current density increases with decreasing the TEL thickness. EIS result shows that the corrosion rate increases with decreasing the TEL thickness at the initial stage because the corrosion is dominated by the cathodic process, whereas after long immersion time, the corrosion degree with the TEL thickness is in the sequence of 150 μm 〉 310 μm〉 10μm ≈ bulk solution 〉 57 μm. The measurements of OCP and EIS present in-situ electrochemical corrosion information and their results are in good agreement with that of physical characterizations.展开更多
Atmospheric corrosion of aluminum alloy 2024 （AA2024） with salt lake water was simulated through a laboratory- accelerated test of cyclic wet-dry and electrochemical techniques. Effects of the soluble magnesium salt...Atmospheric corrosion of aluminum alloy 2024 （AA2024） with salt lake water was simulated through a laboratory- accelerated test of cyclic wet-dry and electrochemical techniques. Effects of the soluble magnesium salt contained in the salt water were investigated by scanning electron microscope （SEM）, transmission electron microscope （TEM）, energy dispersive spectrometer （EDS）, electron probe micro analyzer （EPMA）, X-ray diffraction （XRD）, infrared transmission spectroscope （IR）, and atmospheric corrosion monitor （ACM）. The results showed that, with the deposition, atmospheric corrosion of AA2024 could occur when the relative humidity （RH） was lower than 30%. A main crystalline component of corrosion products, layered double hydroxides （LDH）, [Mg1-xAlx（OH）2]^x＋ Clx-·mH2O （LDH-C1）, was determined, which meant that magnesium ion played an important role in the corrosion process. It not only facilitated the corrosion as a result of deliquescence, but also was involved in the corrosion process as a reactant.展开更多
In this work,we studied the effect of Cr element on the corrosion resistance evolution of weathering steel based on corrosion big data technology.It suggested that corrosion big data technology is suitable for evaluat...In this work,we studied the effect of Cr element on the corrosion resistance evolution of weathering steel based on corrosion big data technology.It suggested that corrosion big data technology is suitable for evaluation of the effect of microalloying Cr element on the corrosion evolution behavior of weathering steel.New understandings prove that the effect of Cr on the corrosion process is dynamic rather than static,the processes is affected by both of the environmental factors and the electrochemical or chemical reactions in the rust layer.Besides,Cr element has both beneficial effect and detrimental effect on the corrosion resistance of weathering steel.The beneficial effect is that the general corrosion resistance of Cr-additional steel is better than that of Cr-free steel,while the detrimental effect is that localized corrosion is intensified as the increase of Cr content in the Cr-additional steel.展开更多
基金Project(51222106)supported by the National Natural Science Foundation of ChinaProject(FRF-TP-14-011C1)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2014CB643300)supported by the National Basic Research Program of China
文摘The atmospheric corrosion behavior of pure copper exposed for three years in Turpan, China, which is a typical hot and dry atmosphere environment, was investigated using mass-loss tests, morphology observations, composition analyses, and electrochemical techniques. The results indicated that the annual corrosion rate of pure copper was approximately 2.90 μm/a. An uneven distribution of corrosion products was observed by scanning electron microscopy; this uneven distribution was attributed to the dehydration process during wet–dry and cold–hot cycles, and the compositions mainly consisted of cuprite （Cu2O） and atacamite （Cu2Cl（OH）3）. Electrochemical measurements showed that deposits on copper improved its resistance to corrosion and the protectiveness decreased with increasing temperature. On the other hand, results obtained using the scanning vibrating electrode technique showed that the porous and uneven structure of the deposit layer generated a spatial separation of cathodic and anodic reaction sites, which accelerated the corrosion process in wet and rainy weather.
基金financially the Natural Science Foundation of Liaoning Province,China(No.2019JH3/30100037)the National Natural Science Foundation of China(No.51671200)the State Key Laboratory of Metal Material for Marine Equipment and Application(No.SKLMEA-K201907)。
文摘The corrosion behavior of mild steel in a simulated coastal atmosphere environment has been investigated by the indoor accelerated wet/dry cyclic corrosion acceleration test(CCT),scanning electron microscopy(SEM),Raman spectroscopy and electrochemical measurements.During the CCT test of 60 cycles,the evolution of logarithmic(corrosion rate)vs.logarithmic(CCT cycles)presents a turning point at the 5th cycle,presenting a tendency to increase first and then decrease to gradually stabilize as the CCT cycle prolonged.Before the 5th cycle,γ-FeOOH andβ-FeOOH and Fe_(3)O_(4)were detected,respectively.And then,α-FeOOH as a new chemical composition was detected in the subsequent corrosion cycles.It is found that,after long term corrosion,the rust separated into a relatively dense inner layer rich withα-FeOOH and a loose outer layer rich withγ-FeOOH,both of which have poor electrical conductivity.The rapid increase of corrosion rate in the early stage since reducible corrosion products are involved in the reduction process of the cathode which promotes the dissolution of the anodic metal substrate.Afterward,as the rust layer thickens,the resistance of the rust increases,and the aggressive ions diffusion is blocked,gradually suppressing the electrochemical corrosion process.At last,when the composition and distribution of the rust layer remain stable,the corrosion presents a fluctuating speed around a certain value during the cracking and self-repairing process of the rust layer.
基金The authors are grateful for the financial supports from National Natural Science Foundation of China(51671197)Strategic Priority Research Program of Chinese Academy of Sciences(13040502).
文摘The corrosion behavior of pure copper exposed to the atmosphere of Nansha Islands for 21 months was studied by mass loss method,composition analysis,morphology observation and electrochemical measurements.The results showed that the average corrosion rate of copper exposed for one year was approximately 7.85μm/a,implying that Nansha Islands was classified as a corrosion category of CX.The structure and properties of the corrosion product layer generated on the front and back sides of the exposed sample differed significantly.The inner corrosion product layer(Cu2O)on the front side was relatively thick and dense,whereas the outer product layer(Cu2Cl(OH)3)was extremely thin.However,the outer product layer on the back side was thicker than the inner layer.Electrochemical measurements indicated that the protection afforded by the corrosion product layer on the front side was improved gradually,while that on the back side was deteriorated.
基金the National Natural Science Foundation of China(No.51671197)Special Project of Chinese Academy of Sciences(No.XDA130040502).
文摘The corrosion and pitting behavior of pure aluminum 1060 exposed to Nansha Islands marine atmosphere for 34 months was investigated based on mass loss measurement,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS),and electrochemical impedance spectroscopy(EIS).The results indicated that serious pitting corrosion occurred on the surfaces of pure aluminum.The corrosion rate after exposure for 13 months was approximately 1.28 g/(m^(2)·a).The XPS results showed that the corrosion products were Al_(2)O_(3),Al(OH)_(3),and AlCl_(3).Moreover,the corrosion product layer was more protective than the native oxide film,and the protectiveness first increased and then decreased.Finally,the shape of the pits was evaluated using statistical analysis.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51601057 and 51701038)and the Marine Science Special Project of Hebei Normal University of Science&Technology(No.2018HY004),and the authors acknowledge the assistance.
文摘The stable operation of electronic devices in marine atmospheric environment is affected by the corrosion deterioration of solder joints,and the effects by atmosphere temperature and chloride deposition are critical.In this work,NaCl deposition and temperature dependent corrosion of Pb-free SAC305 solder in simulated marine atmosphere has been investigated.The results indicate that higher NaCl deposition prolongs the surface wetting time and leads to the final thicker saturated electrolyte film for further corrosion.Higher temperature accelerates the evaporation and contributes to the final thinner saturated NaCl electrolyte film.Besides,the corrosion control process varies under the initially covered thicker NaCl electrolyte layer and under the final saturated much thinner NaCl electrolyte film as the evaporation proceeds.Moreover,the ready oxygen availability through the final thinner saturated NaCl electrolyte film facilitates the formation of corrosion product layer mainly of electrochemically stable SnO2,but higher temperature leads to the final corrosion product layer with smaller crystal size and large cracks.The findings clearly demonstrate the effects of NaCl deposition and temperature on corrosion evolution of SAC305 solder joints and are critical to the daily maintenance of electronic devices for longer service life in marine atmosphere.
基金supported by the National Natural Science Foundation of China(Nos.51601199 and 51671197)。
文摘The evolution of corrosion behavior of 316 L stainless steels exposed to salt lake atmosphere for 8 years was investigated.The results showed that the stainless steel in salt lake atmosphere had a greater corrosion rate during the initial exposure time and relatively lower corrosion rate during the subsequent exposure time.Dust depositions accumulated on the downward surface caused severe local corrosion of stainless steel.As exposure time prolonged,the relative amount of Croxide and Feoxidein the corrosion products gradually increased,which may directly affect the corrosion rate of stainless steels.Moreover,the maximum pit depth followed a power function with respect to exposure time.
基金support of the Ministry of Industry and Information Technology Project,China(No.MJ-2017-J-99)the National Science Foundation of China(No.51701102)the National Science and Technology Resources Investigation Program of China(No.2019FY101400).
文摘The electrochemical and Stress Corrosion Cracking(SCC)behaviors of 7085-T7651 aluminum alloy in different environments are studied by electrochemical and mechanical testing.The research shows that the type,concentration of the corrosive medium and electrolyte state affect the electrochemical and SCC controlling processes of aluminum alloys.The Thin Electrolyte Layer(TEL)state and the addition of HSO3–increase the corrosion rate and SCC susceptibility.The presence of HSO3–in a corrosive environment can significantly accelerate the corrosion rate and mechanical property degradation,and this effect increases with the increase of HSO3–concentration.Compared with the solution environment,the TEL environment will further aggravate corrosion and mechanical property degradation.With the increase of HSO3–concentration,the pH of the corrosive environment exhibits little change,while the SCC degradation is significantly promoted.This is attributed to the HSO3–induced buffer effect and film-assisted stress effect,yielding the overshadowing effect against solution pH.
基金the National Natural Science Foundation of China(No.51671197)the Strategic Priority Research Program of the Chinese Academy of Sciences XDA(No.13040502)。
文摘In order to better understand why the corrosion behavior of carbon steel exposed in Nansha atmospheric environment is very serious, the effect of sodium, potassium and magnesium chlorides deposited on carbon steel surface has been studied under atmosphere conditions by wet/dry accelerated test. The difference of corrosion behavior and surface structure in Na+, K+, and Mg2+ containing atmosphere has been investigated by thickness loss, scanning electron microscope, X-ray diffraction and electrochemical techniques. The results indicate that the thickness loss of carbon steel exposed in different metal cations containing atmospheric environment increases in the order of Na+, K+, Mg2+. The hard metal cation can promote the dissolution of the steel to a certain extent. In Mg2+ containing atmosphere, the relative content of β-FeOOH is rather higher and the protective ability index α */γ * decreases in the order of Na+, K+, Mg2+. The corrosion current density of both bare carbon steel and the rusted carbon steel increases in the order of Na+, K+, Mg2+. The polarization resistance and the charge transfer resistance decreases in the order of Na+, K+, Mg2+.
基金financially supported by the Technology Projects from China Southern Power Grid (K-GD2014-0532)the National Natural Science Foundation of China (Nos. 51131007 and 51401222)
文摘The corrosion behavior of copper exposed in a simulated coastal-industrial atmosphere has been investigated using weight loss measurement, scanning electron microscopy, X-ray diffraction, potentiodynamic polarization and in-situ electrochemical impedance spectroscopy（EIS） with micro-distance electrodes.The results show that corrosion kinetics follows the empirical equation D = Atn. The main corrosion products are composed of Cu_2O, Cu_2Cl（OH）_3 and Cu_4Cl_2（OH）_6. A two-layer structure comprising a loose outer layer and a compact inner layer forms the corrosion products during corrosion process. SO_2 has been found to promote the formation of Cu_4Cl_2（OH）_6.
基金supported by the National Natural Science Foundation of China(No.51671197)the Special Project of the Chinese Academy of Sciences(No.XDA130040502)。
文摘The corrosion behavior of pure aluminum 1060 subjected to a wet-dry cyclic accelerated test in simulated Nansha marine atmosphere in the dark and under UV illumination has been investigated by means of scanning electron microscopy(SEM),electrochemical impedance spectroscopy(EIS),and Mott–Schottky measurements in this work.The results show that under the two conditions,the native oxide films are constantly destroyed and the thicknesses of the oxide films continuously decrease in the first 24 days of the corrosion test.In particular,UV illumination can diminish the pitting corrosion susceptibility of the native oxide films to an extent in terms of a photo-induced modifi cation of the native oxide film on the pure aluminum surfaces.Besides,UV illumination can also reduce the carrier concentration in the oxide films,thus reducing the conductivity and the corrosion rate.
基金the National Natural Science Foundation of China(Nos.51601199 and 51671197)the Guangzhou Industry-university-research Collaborative Innovation Alliance Special Project(201604046014)。
文摘The corrosion behavior of stainless steel exposed to a simulated salt lake atmosphere has been investigated by analyzing the evolution of surface morphologies and corrosion products, the initiation and development of pits, and the electrochemical characteristics. The results indicated that(Mg6Fe2(OH)16(CO3)(H2O)4.5)0.25, a layered double hydroxide, has been detected for the first time in the corrosion products formed on stainless steel exposed to a simulated salt lake atmosphere. The specimens exposed to MgCl2 deposit conditions were corroded more severely than those exposed to NaCl deposit conditions, which was attributed to the differences in the deliquescence relative humidity and efflorescence relative humidity values of MgCl2 and NaCl. In addition, a special corrosion morphology consisting of a concentric circle of yellowish material was observed on the specimens exposed to MgCl2 deposit conditions, which was attributed to the formation of Mg(OH)2, inhibiting the diffusion and migration of OH- ions to the anode region. The maximum pit depth followed a power function with respect to corrosion time. The corrosion mechanism of stainless steel exposed to a simulated salt lake atmosphere is also discussed.
基金financially supported by the National Natural Science Foundation of China(No.52371049)the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(YESS,No.2020QNRC001)the National Science and Technology Resources Investigation Program of China(Nos.2021FY100603 and 2019FY101404)。
文摘The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties of organic coatings.This study compared a bare epoxy coating with one containing zinc phosphate corrosion inhibitors,both applied on ACM sensors,to observe their corrosion protection properties over time.Coatings with artificial damage via scratches were exposed to immersion and alternating dry and wet environments,which allowed for monitoring galvanic corrosion currents in real-time.Throughout the corrosion tests,the ACM currents of the zinc phosphate/epoxy coating were considerably lower than those of the blank epoxy coating.The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis.This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings.Compared with the blank epoxy coating,the zinc phosphate/epoxy coating showed much-decreased ACM current values that confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFB0304602)the National Natural Science Foundation of China(Nos.51771029)the National Environmental Corrosion Platform(NECP,2005DKA10400).
文摘The corrosion behaviour of zinc–aluminium–magnesium-coated steel in a simulated polluted marine atmospheric environment was investigated.Therefore,an indoor ageing acceleration test was carefully designed by simulating a polluted marine environment.The objective was to in-depth investigate the corrosion mechanism of Zn–Al–Mg-coated steel exposed to a simulated polluted marine environment.The experiments were carried out by scanning electron microscopy for micro-morphological characterization,X-ray diffraction,electrochemical impedance spectroscopy and electrodynamic polarization curves for the aged samples.The analysis of the results obtained after an indoor accelerated ageing test shows that Zn–Al–Mg coatings generate insoluble Zn_(5)Cl_(2)(OH)_(8)·H_(2)O and Zn_(4)SO_(4)(OH)_(6)during the corrosion process,which hinders the diffusion of corrosive substances into the substrate,and the insoluble substances are structurally dense and thus inhibit further corrosion.Therefore,this effectively inhibits the occurrence of further corrosion,and thus,Zn–Al–Mg coating can significantly extend the service life of Zn–Al–Mg-coated steel.
基金National Natural Science Foundation of China(12002196,12102140)。
文摘Semiconductors and related fields today hold vast application prospects.The semiconductor wafer fabrication process involves steps such as substrate preparation and epitaxy,which occur in high-temperature corrosive environments.Consequently,components like crucibles,susceptors and wafer carriers require carbon-based materials such as graphite and carbon-carbon composites.However,traditional carbon materials underperform in these extreme conditions,failing to effectively address the challenges.This leads to issues including product contamination and shortened equipment lifespan.Therefore,effective protection of carbon materials is crucial.This paper reviews current research status on the preparation methods and properties of corrosion-resistant coatings within relevant domestic and international fields.Preparation methods include various techniques such as physical vapor deposition(PVD),chemical vapor deposition(CVD)and the sol-gel method.Furthermore,it offers perspectives on future research directions for corrosion-resistant coated components in semiconductor equipment.These include exploring novel coating materials,improving coating preparation processes,enhancing coating corrosion resistance,as well as further investigating the interfacial interactions between coatings and carbon substrates to achieve better adhesion and compatibility.
基金supported by the National Key R&D Program of China(No.2022YFB3808803)the National Natural Science Foundation of China(No.52371049)the National Science and Technology Resources Investigation Program of China(No.2021FY100603).
文摘The corrosion degradation of organic coatings in tropical marine atmospheric environments results in substantial economic losses across various industries.The complexity of a dynamic environment,combined with high costs,extended experimental periods,and limited data,places a limit on the comprehension of this process.This study addresses this challenge by investigating the corrosion de-gradation of damaged organic coatings in a tropical marine environment using an atmospheric corrosion monitoring sensor and a random forest(RF)model.For damage simulation,a polyurethane coating applied to a Fe/graphite corrosion sensor was intentionally scratched and exposed to the marine atmosphere for over one year.Pearson correlation analysis was performed for the collection and filtering of en-vironmental and corrosion current data.According to the RF model,the following specific conditions contributed to accelerated degrada-tion:relative humidity(RH)above 80%and temperatures below 22.5℃,with the risk increasing significantly when RH exceeded 90%.High RH and temperature exhibited a cumulative effect on coating degradation.A high risk of corrosion occurred in the nighttime.The RF model was also used to predict the coating degradation process using environmental data as input parameters,with the accuracy show-ing improvement when the duration of influential environmental ranges was considered.
基金supported by the National Natu-ral Science Foundation of China(Nos.52171074 and 52471084)the Young Elite Scientists Sponsorship Program by CAST(No.YESS20220137)the Science and Technology Commission of Shanghai Municipality(No.19DZ2271100).
文摘Copper is widely used as conductive components in transmission lines,facing severe corrosion risks.The current passing through copper conductors will significantly affect its corrosion process,yet there is a lack of detailed study on the corrosion mechanism under this specific condition.Thus,this study inves-tigated the effect of direct current current-carrying(DC C-C)conditions on the atmospheric corrosion behavior of copper conductors under thin electrolyte layer(TEL)through electrochemical measurements and corrosion exposure experiments.Results revealed that the presence of DC C-C significantly hastened the corrosion process of copper conductors in the TEL,leading to distinct corrosion patterns at the input and output ends.Furthermore,both the extent of corrosion acceleration and the unevenness of corrosion were positively correlation with the DC C-C level.The above phenomenon was attributed to the special motion of charged particles and paramagnetic substances in TEL under the self-generated magnetic field.
基金supported by the National Natu-ral Science Foundation of China(Nos.U23A20555 and 52271008)the Young Elite Scientists Sponsorship Program by CAST(No.2023QNRC001)the Joint Research Fund of Advanced Technology by Shanghai Aerospace(No.USCAST2023-15).
文摘Although hydrogen evolution reaction(HER)is considered to be the main cathodic reaction of Mg corro-sion,oxygen reduction reaction(ORR)has been recently confirmed to be a secondary cathodic reaction.The factors affecting ORR of magnesium(Mg)alloys are still unclear,especially in cases under thin elec-trolyte layers(TEL).In this work,the influence of the corrosion product films on the cathodic reactions of Mg alloys under TEL and in a bulk solution was investigated.ORR does not influence the hydrogen evolution rates in the corrosion of Mg alloys.Therefore,with the existence of oxygen,corrosion rates of Mg alloys measured by hydrogen evolution tests are not accurate under TEL.And weight loss test is a more accurate method to evaluate Mg corrosion rates under TEL.ORR was confirmed to participate in the corrosion of Mg-4Nd-0.4Zr,Mg-4Nd and Mg-0.4Zr alloys under TEL.In 100-μm TEL,the highest con-tribution of ORR in cathodic reactions for the corrosion of Mg-4Nd-0.4Zr,Mg-4Nd and Mg-0.4Zr alloys are 28.6%,39.1%,and 35.8%,respectively.The more protective film on Mg-4Nd-0.4Zr alloy provides a stronger inhibition effect against the diffusion of oxygen,leading to decreased ORR contribution in ca-thodic reactions.In addition,it is suggested that the preparation of Mg alloys with protective corrosion product films can inhibit the corrosion induced by ORR in the atmosphere.This work emphasizes the effects of corrosion product films on ORR in Mg corrosion,especially under TEL.
基金Projects (51131005, 51171172, 50801056) supported by the National Natural Science Foundation of ChinaProject (Y4110074) supported by Natural Science Foundation of Zhejiang Province, China
文摘The atmospheric corrosion behavior of bronze under thin electrolyte layer （TEL） with different thicknesses was monitored using cathodic polarization curves, open circuit potential （OCP） and electrochemical impedance spectroscopy （EIS）. Cathodic polarization result indicates that the cathodic limiting current density increases with decreasing the TEL thickness. EIS result shows that the corrosion rate increases with decreasing the TEL thickness at the initial stage because the corrosion is dominated by the cathodic process, whereas after long immersion time, the corrosion degree with the TEL thickness is in the sequence of 150 μm 〉 310 μm〉 10μm ≈ bulk solution 〉 57 μm. The measurements of OCP and EIS present in-situ electrochemical corrosion information and their results are in good agreement with that of physical characterizations.
基金Project(51131007) supported by the National Natural Science Foundation of China
文摘Atmospheric corrosion of aluminum alloy 2024 （AA2024） with salt lake water was simulated through a laboratory- accelerated test of cyclic wet-dry and electrochemical techniques. Effects of the soluble magnesium salt contained in the salt water were investigated by scanning electron microscope （SEM）, transmission electron microscope （TEM）, energy dispersive spectrometer （EDS）, electron probe micro analyzer （EPMA）, X-ray diffraction （XRD）, infrared transmission spectroscope （IR）, and atmospheric corrosion monitor （ACM）. The results showed that, with the deposition, atmospheric corrosion of AA2024 could occur when the relative humidity （RH） was lower than 30%. A main crystalline component of corrosion products, layered double hydroxides （LDH）, [Mg1-xAlx（OH）2]^x＋ Clx-·mH2O （LDH-C1）, was determined, which meant that magnesium ion played an important role in the corrosion process. It not only facilitated the corrosion as a result of deliquescence, but also was involved in the corrosion process as a reactant.
基金financially supported by the National Natural Science Foundation of China(No.52171063)the Fundamental Research Funds for the Central Universities(No.FRF-IP-19-005)。
文摘In this work,we studied the effect of Cr element on the corrosion resistance evolution of weathering steel based on corrosion big data technology.It suggested that corrosion big data technology is suitable for evaluation of the effect of microalloying Cr element on the corrosion evolution behavior of weathering steel.New understandings prove that the effect of Cr on the corrosion process is dynamic rather than static,the processes is affected by both of the environmental factors and the electrochemical or chemical reactions in the rust layer.Besides,Cr element has both beneficial effect and detrimental effect on the corrosion resistance of weathering steel.The beneficial effect is that the general corrosion resistance of Cr-additional steel is better than that of Cr-free steel,while the detrimental effect is that localized corrosion is intensified as the increase of Cr content in the Cr-additional steel.
