The effects of sulphate-reducing bacteria （SRB） on the 2205 duplex stainless steel in the sea water and oil industry environments were studied by electrochemical impedance spectroscopy （EIS）, potentiodynamic polar...The effects of sulphate-reducing bacteria （SRB） on the 2205 duplex stainless steel in the sea water and oil industry environments were studied by electrochemical impedance spectroscopy （EIS）, potentiodynamic polarization and microorganism analysis. The results showed that the detected SRB was the non-spore bacillus of about 0.8μm×（1.8--2.2）μm in size and the content of S was about 7. 59% in the corrosion products. SRB contributed to the corrosion evolution which caused the corrosion failure of 2205 duplex stainless steel pipe in the liquid hydrocarbon cooler. During the corrosion process, the produced H2S could significantly influence the anodic process and finally accelerate the corrosion. SEM observation indicated that the distribution of SRB on the surface of 2205 duplex stainless steel was nonuniform. X ray photoelectron spectroscopy analysis revealed that the surface film was composed of Cr2O3, MoO3 , FeS, FeS2, Fe（OH）2 and FeO after immersing the sample in the SRB medium for 14 d.展开更多
By using polarization resistance measurement and electrochemical impedance spectroscopy(EIS),in field corrosion electrochemical detections of Q235 carbon steel and Q235 ultrafine grained steel immersed samples in Zhou...By using polarization resistance measurement and electrochemical impedance spectroscopy(EIS),in field corrosion electrochemical detections of Q235 carbon steel and Q235 ultrafine grained steel immersed samples in Zhoushan Marine Corrosion Test Station were performed for 4 years.Dynamic corrosion data during exposure were obtained.Electrochemical detection results reflected not only the corrosion modalities and corrosion rates of the samples,but also the direct influence of marine environmental factors on the corrosion behavior.Seawater temperature was the major factor influencing the corrosion behaviors of carbon steels,and corrosion rates of these samples increased with increasing seawater temperature.The influence of seawater velocity and orientation of flow was less than that of temperature.展开更多
The corrosion behavior of nickel-based 718 alloy at seven partial pressures of H2 S(PH2 S)was investigated using electrochemical impedance spectroscopy(EIS)and polarization methods in 25 wt% NaCl solution at150℃ for ...The corrosion behavior of nickel-based 718 alloy at seven partial pressures of H2 S(PH2 S)was investigated using electrochemical impedance spectroscopy(EIS)and polarization methods in 25 wt% NaCl solution at150℃ for 168 h.The tested results show that anodic reactions are controlled alternately by the diffusion mostly,then both charge transfer and diffusion and finally charge transfer mainly with the increment of PH2 S.The corrosive products are composed of sulfides and oxides of Ni,Cr and Fe with double layers for PH2 S of 5.1 and 13.0 MPa and three layers for PH2 S of 10.4 MPa according to microstructures and compositions of corrosion products characterized by the scanning electron microscope(SEM)and electron probe microanalysis(EPMA)methods.The inner oxides layer plays a critical role in anti-corrosion in a wet H2 S environment at high temperature and pressure.展开更多
基金Item Sponsored by National Natural Science Foundation of China(21276036,51101025)
文摘The effects of sulphate-reducing bacteria （SRB） on the 2205 duplex stainless steel in the sea water and oil industry environments were studied by electrochemical impedance spectroscopy （EIS）, potentiodynamic polarization and microorganism analysis. The results showed that the detected SRB was the non-spore bacillus of about 0.8μm×（1.8--2.2）μm in size and the content of S was about 7. 59% in the corrosion products. SRB contributed to the corrosion evolution which caused the corrosion failure of 2205 duplex stainless steel pipe in the liquid hydrocarbon cooler. During the corrosion process, the produced H2S could significantly influence the anodic process and finally accelerate the corrosion. SEM observation indicated that the distribution of SRB on the surface of 2205 duplex stainless steel was nonuniform. X ray photoelectron spectroscopy analysis revealed that the surface film was composed of Cr2O3, MoO3 , FeS, FeS2, Fe（OH）2 and FeO after immersing the sample in the SRB medium for 14 d.
文摘By using polarization resistance measurement and electrochemical impedance spectroscopy(EIS),in field corrosion electrochemical detections of Q235 carbon steel and Q235 ultrafine grained steel immersed samples in Zhoushan Marine Corrosion Test Station were performed for 4 years.Dynamic corrosion data during exposure were obtained.Electrochemical detection results reflected not only the corrosion modalities and corrosion rates of the samples,but also the direct influence of marine environmental factors on the corrosion behavior.Seawater temperature was the major factor influencing the corrosion behaviors of carbon steels,and corrosion rates of these samples increased with increasing seawater temperature.The influence of seawater velocity and orientation of flow was less than that of temperature.
基金financially supported by the Science and Technology Open Cooperation Project of Henan Province (No. 172106000062)the Science and Technology Development Project of Henan Province (No. 182102310837)the HighSchool Science and Technology Innovation Team Support Plan of Henan Province (No. 18IRTSTHN005)
文摘The corrosion behavior of nickel-based 718 alloy at seven partial pressures of H2 S(PH2 S)was investigated using electrochemical impedance spectroscopy(EIS)and polarization methods in 25 wt% NaCl solution at150℃ for 168 h.The tested results show that anodic reactions are controlled alternately by the diffusion mostly,then both charge transfer and diffusion and finally charge transfer mainly with the increment of PH2 S.The corrosive products are composed of sulfides and oxides of Ni,Cr and Fe with double layers for PH2 S of 5.1 and 13.0 MPa and three layers for PH2 S of 10.4 MPa according to microstructures and compositions of corrosion products characterized by the scanning electron microscope(SEM)and electron probe microanalysis(EPMA)methods.The inner oxides layer plays a critical role in anti-corrosion in a wet H2 S environment at high temperature and pressure.
