The effects of an applied magnetic field on the corrosion process of beryllium copper in NaCl solution have been investigated by electrochemical measurements,scanning electron microscopy(SEM)and energy dispersive spec...The effects of an applied magnetic field on the corrosion process of beryllium copper in NaCl solution have been investigated by electrochemical measurements,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).The results showed that a horizontal magnetic field with 0.4 T barely shifted the open circuit potentials(Ecorr)of beryllium copper in NaCl solution with different concentrations.However,the horizontal magnetic field increased the limiting current density of beryllium copper in NaCl solution with low concentration,while decreased the limiting current density of beryllium copper in NaCl solution with high concentration.It was found that magnetic field accelerated the diffusion of CuCl2-away from the electrode surface and delayed the formation of Cu2O.The results of SEM and EDS showed that the inffuence of magnetic field over the elements distribution of the corrosion products differed from the different concentration of the immersion solution.展开更多
Microbiologically influenced corrosion （MIC） is a major cause of corrosion damages, facility failures, and financial losses, making MIC an important research topic. Due to complex microbiological activities and a la...Microbiologically influenced corrosion （MIC） is a major cause of corrosion damages, facility failures, and financial losses, making MIC an important research topic. Due to complex microbiological activities and a lack of deep understanding of the interactions between biofilms and metal surfaces, MIC occurrences and mechanisms are difficult to predict and interpret. Many theories and mechanisms have been pro- posed to explain MIC. In this review, the mechanisms of MIC are discussed using hioenergetics, microbial respiration types, and biofilm extracellular electron transfer （EET）. Two main MIC types, namely EET-MIC and metabolite MIC （M-ME）, are discussed. This brief review provides a state of the art insight into MIC mechanisms and it helps the diagnosis and prediction of occurrences of MIC under anaerobic conditions in the oil and gas industry.展开更多
Sulfate reducing bacteria(SRB)are widely present in oil and gas industry,causing pitting corrosion on pipeline steel.Stress corrosion cracking(SCC)often occurs in the presence of mechanical stress before pit-ting perf...Sulfate reducing bacteria(SRB)are widely present in oil and gas industry,causing pitting corrosion on pipeline steel.Stress corrosion cracking(SCC)often occurs in the presence of mechanical stress before pit-ting perforation failure,leading to economic losses and even catastrophic accidents.In this study,stress distribution simulation using the finite element method(FEM),corrosion analysis techniques and elec-trochemical corrosion measurements were employed to investigate the SCC mechanism of X80 pipeline steel caused by Desulfovibrio vulgaris,which is a common SRB strain used in microbiologically influenced corrosion(MIC)studies.It was found that D.vulgaris MIC caused sharp microcracks on an X80 U-bend coupon after only 2 weeks of immersion at 37℃in the deoxygenated ATCC 1249 culture medium inocu-lated with D.vulgaris.The X80 U-bend coupon’s weight loss-based uniform corrosion rate for the 12 cm^(2)surface was 60%of that for the unstressed flat square coupon(2.3 mg cm^(−2)vs.3.8 mg cm^(−2)).This was likely because the square coupon had wide MIC pits,providing a larger effective surface area for more sessile cells(4.2×10^(8)cells cm^(−2)on square coupon vs.2.4×10^(8)cells cm^(−2)on U-bend coupon)to attach and harvest more electrons.An SCC failure occurred on an X80 U-bend pre-cracked at the outer bottom after a 6-week immersion in the D.vulgaris broth.Apart from MIC damage,this could also be because D.vulgaris metabolism increased the availability hydrogen atoms on the steel surface,and promoted the diffusion of hydrogen atoms into the metal lattice,thus increasing the brittleness of the steel.展开更多
基金supported by the National Natural Science Foundation of China(No.50771020)
文摘The effects of an applied magnetic field on the corrosion process of beryllium copper in NaCl solution have been investigated by electrochemical measurements,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).The results showed that a horizontal magnetic field with 0.4 T barely shifted the open circuit potentials(Ecorr)of beryllium copper in NaCl solution with different concentrations.However,the horizontal magnetic field increased the limiting current density of beryllium copper in NaCl solution with low concentration,while decreased the limiting current density of beryllium copper in NaCl solution with high concentration.It was found that magnetic field accelerated the diffusion of CuCl2-away from the electrode surface and delayed the formation of Cu2O.The results of SEM and EDS showed that the inffuence of magnetic field over the elements distribution of the corrosion products differed from the different concentration of the immersion solution.
基金supported by Science Foundation of China University of Petroleum,Beijing(Nos.2462017YJRC038 and 2462018BJC005)supported by the National Natural Science Foundation of China(Grant U1660118)+1 种基金the National Basic Research Program of China(973 Program,No.2014CB643300)the National Environmental Corrosion Platform(NECP)
文摘Microbiologically influenced corrosion （MIC） is a major cause of corrosion damages, facility failures, and financial losses, making MIC an important research topic. Due to complex microbiological activities and a lack of deep understanding of the interactions between biofilms and metal surfaces, MIC occurrences and mechanisms are difficult to predict and interpret. Many theories and mechanisms have been pro- posed to explain MIC. In this review, the mechanisms of MIC are discussed using hioenergetics, microbial respiration types, and biofilm extracellular electron transfer （EET）. Two main MIC types, namely EET-MIC and metabolite MIC （M-ME）, are discussed. This brief review provides a state of the art insight into MIC mechanisms and it helps the diagnosis and prediction of occurrences of MIC under anaerobic conditions in the oil and gas industry.
基金supported by National Natural Science Foundation of China(No.U2106206)Institute of Marine Science and Technology,Shandong Univer-sity,China.
文摘Sulfate reducing bacteria(SRB)are widely present in oil and gas industry,causing pitting corrosion on pipeline steel.Stress corrosion cracking(SCC)often occurs in the presence of mechanical stress before pit-ting perforation failure,leading to economic losses and even catastrophic accidents.In this study,stress distribution simulation using the finite element method(FEM),corrosion analysis techniques and elec-trochemical corrosion measurements were employed to investigate the SCC mechanism of X80 pipeline steel caused by Desulfovibrio vulgaris,which is a common SRB strain used in microbiologically influenced corrosion(MIC)studies.It was found that D.vulgaris MIC caused sharp microcracks on an X80 U-bend coupon after only 2 weeks of immersion at 37℃in the deoxygenated ATCC 1249 culture medium inocu-lated with D.vulgaris.The X80 U-bend coupon’s weight loss-based uniform corrosion rate for the 12 cm^(2)surface was 60%of that for the unstressed flat square coupon(2.3 mg cm^(−2)vs.3.8 mg cm^(−2)).This was likely because the square coupon had wide MIC pits,providing a larger effective surface area for more sessile cells(4.2×10^(8)cells cm^(−2)on square coupon vs.2.4×10^(8)cells cm^(−2)on U-bend coupon)to attach and harvest more electrons.An SCC failure occurred on an X80 U-bend pre-cracked at the outer bottom after a 6-week immersion in the D.vulgaris broth.Apart from MIC damage,this could also be because D.vulgaris metabolism increased the availability hydrogen atoms on the steel surface,and promoted the diffusion of hydrogen atoms into the metal lattice,thus increasing the brittleness of the steel.
