pH Effect on Sulfur-Induced Passivity Degradation of Alloy 800 in Simulated Crevice Chemistries

Xia, Da-Hai; Zhu, Renkang; Behnamian, Yashar; Shen, Chia; Luo, Jing‐Li; Lu, Yucheng; Klimas, Stan J.

doi:10.1149/2.063404jes

Cited by 39 publications

(32 citation statements)

References 67 publications

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“…1 and 2 with Figs. 3 and 4, it is concluded that the dissolution of metal ions is not remarkable in thiosulfate-free solution, whereas the dissolution of metal ions is significant in thiosulfate-containing solution, which is due to thiosulfate-enhanced anodic dissolution within the pits, and this is consistent with the previous experimental observations [19,23]. Moreover, the current in thiosulfate-containing solution is significantly higher than that in thiosulfate-free solution.…”

Section: Methodssupporting

confidence: 86%

Monitoring the Diffusion Layer During Passive Film Breakdown on Alloy 800 with Digital Holography

Xia

Luo

Gao

et al. 2015

Acta Metall. Sin. (Engl. Lett.)

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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.

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Section: Methodssupporting

confidence: 86%

Monitoring the Diffusion Layer During Passive Film Breakdown on Alloy 800 with Digital Holography

Xia

Luo

Gao

et al. 2015

Acta Metall. Sin. (Engl. Lett.)

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“…30 The initiation of SCC in sensitized Alloy 600 in aqueous Na 2 S 2 O 3 is much lower than that in Na 2 S 4 O 6 solutions, indication that S 2 O 3 2¹ is more detrimental to materials than S 4 O 6 2¹ . 6 Our previous work 31 found that the detrimental effect of impurities containing sulfur at the reduced or intermediate oxidation level on the passivity of Alloy 800 depends significantly on the solution pH.…”

Section: ¹mentioning

confidence: 99%

Pitting Corrosion Mechanism of Alloy 800 in Simulated Crevice Chemistries Containing Thiosulfate

Gao

Xia

et al. 2016

Electrochemistry

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Interaction of thiosulfate with Alloy 800 was systematically investigated to obtain the kinetics in a neutral simulated steam generator crevice solution. Cyclic polarization showed that the pitting potential in a thiosulfate-chloride solution was much lower than in either a chloride solution or a sulphate-chloride solution, and thiosulfate selectively and distinguishably degraded the oxide film on Alloy 800. The donor density of oxide film formed in a thiosulfatechloride solution was slightly higher than in either a chloride-only solution or a sulphate-chloride solution. Even in the passivity range the material was degraded due to the slow interaction with S 2 O 3 2− with oxide, especially when the applied potential was close to the pitting potential. The UV-visible absorption spectra showed that thiosulfate formed a stable complex with Cu 2+ , and their product was soluble in aqueous solution, which is possible evidence to indicate that thiosulfate assists Cu 2+ in dissolving from an oxide film into solution. Also, due to the complexity of the reaction, thiosulfate decreased the oxidation potential of Cu 0 to Cu 2+ . Since the Cu, an impurity in Alloy 800, normally accumulates at the grain boundary, especially at the triple points, thiosulfate induced corrosion is in the form of pitting or intergranular attack.

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“…Some electrochemical methods such as open circuit potential (OCP) measurement, linear polarization resistance, electrochemical noise (EN), electrochemical impedance spectroscopy (EIS) are widely used for the purpose mentioned above, because these techniques are based on the mechanism of corrosion, and the measurement system is relatively simple, and easy to operate. [1][2][3][4] Among these techniques, EN has gradually become a promising tool for corrosion measurement. 5 Spontaneous fluctuations of electrode potential and current in an electrochemical system are known as EN.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Noise Study on the Corrosion Behavior of 304NG Stainless Steel in High Temperature Water

Shi

Wang

et al. 2014

Electrochemistry

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This paper investigates the application of Electrochemical Noise (EN) to study the corrosion behavior of 304 nuclear-grade (NG) stainless steel (SS) in high purity water system at varying temperatures (105, 160, 190, 220, 250, 293°C) and pressures (0.6,7,9, 10.5,16, 19 MPa). An EN sensor has been developed and applied to the high temperature water system. The potential and coupling current noise were recorded simultaneously and a variety of analytical methods (such as wavelet transform, chaos theory, noise resistance (R n ), the spectral noise resistance (R sn ) and the direct current (DC) limit of the spectral noise resistance (R 0 sn )) have been used to obtain corrosion rate and corrosion form. EN analysis results demonstrated an increase in R n with increasing temperature and pressure, except for a peak value at 293°C, 19 MPa, which was possibly due to the change in the thickness of passive film; combined chaos analysis results with morphology analysis, we may infer that the corrosion form of 304NG SS under high purity water system at high temperature and high pressure is general corrosion.

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pH Effect on Sulfur-Induced Passivity Degradation of Alloy 800 in Simulated Crevice Chemistries

Cited by 39 publications

References 67 publications

Monitoring the Diffusion Layer During Passive Film Breakdown on Alloy 800 with Digital Holography

Monitoring the Diffusion Layer During Passive Film Breakdown on Alloy 800 with Digital Holography

Pitting Corrosion Mechanism of Alloy 800 in Simulated Crevice Chemistries Containing Thiosulfate

Electrochemical Noise Study on the Corrosion Behavior of 304NG Stainless Steel in High Temperature Water

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