Passivity degradation of Alloy 800 in simulated crevice chemistries was systematically investigated using cyclic polarization curve, electrochemical impedance spectroscopy(EIS), Mott-Schottky analysis, Auger electron ...Passivity degradation of Alloy 800 in simulated crevice chemistries was systematically investigated using cyclic polarization curve, electrochemical impedance spectroscopy(EIS), Mott-Schottky analysis, Auger electron spectroscopy(AES)and atomic absorption spectrometry(AAS). Cyclic polarization showed that the pitting potential in a thiosulfate solution was much lower than in either a chloride solution or a sulfate-chloride solution. Mott-Schottky results revealed that passive films showed n-type semiconductivity, and the presence of thiosulfate in chloride solution led to an increased donor density in the passive film. EIS spectra indicated that thiosulfate enhanced the film dissolution rate in chloride solutions. Moreover, thiosulfate enhanced the pitting propagation rate in chloride solution by stabilizing the metastable pits and forming sulfide within the pits.展开更多
The effects of chloride and thiosulfate ions on localized corrosion of alloy 800 are investigated through dynamical observation of the change in phase image of the diffusion layer during passive film breakdown using d...The effects of chloride and thiosulfate ions on localized corrosion of alloy 800 are investigated through dynamical observation of the change in phase image of the diffusion layer during passive film breakdown using digital holography. The results indicate that solution chemistry has a significant effect on film breakdown and diffusion layer. The phase distribution changes at different applied potentials show that in the process of film breakdown, dissolution of metal ions from pitting is not remarkable in chloride-only solution, whereas dissolution of metal ions is significantly high in thiosulfate and chloride solution. Thiosulfate has a combined effect with chloride ions in passive film degradation.展开更多
基金Supported by the Atomic Energy of Canada Limited(AECL)and National Natural Science Foundation of China(No.51371124)
文摘Passivity degradation of Alloy 800 in simulated crevice chemistries was systematically investigated using cyclic polarization curve, electrochemical impedance spectroscopy(EIS), Mott-Schottky analysis, Auger electron spectroscopy(AES)and atomic absorption spectrometry(AAS). Cyclic polarization showed that the pitting potential in a thiosulfate solution was much lower than in either a chloride solution or a sulfate-chloride solution. Mott-Schottky results revealed that passive films showed n-type semiconductivity, and the presence of thiosulfate in chloride solution led to an increased donor density in the passive film. EIS spectra indicated that thiosulfate enhanced the film dissolution rate in chloride solutions. Moreover, thiosulfate enhanced the pitting propagation rate in chloride solution by stabilizing the metastable pits and forming sulfide within the pits.
基金supported by Natural Sciences and Engineering Research Council of Canada Discovery GrantNational Natural Science Foundation of China (No. 51371124)
文摘The effects of chloride and thiosulfate ions on localized corrosion of alloy 800 are investigated through dynamical observation of the change in phase image of the diffusion layer during passive film breakdown using digital holography. The results indicate that solution chemistry has a significant effect on film breakdown and diffusion layer. The phase distribution changes at different applied potentials show that in the process of film breakdown, dissolution of metal ions from pitting is not remarkable in chloride-only solution, whereas dissolution of metal ions is significantly high in thiosulfate and chloride solution. Thiosulfate has a combined effect with chloride ions in passive film degradation.
