A mechanistic study on thiosulfate-enhanced passivity degradation of Alloy 800 in chloride solutions

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

doi:10.1016/j.electacta.2013.08.030

Cited by 85 publications

(92 citation statements)

References 69 publications

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“…The pitting propagates on these active regions and causes the UNS N08800 failure. In addition, previous work found that S 2 O 3 2− can facilitate hydrogen entering into the passive layer, 13 therefore, S 2 O 3 2− also induces hydrogen embrittlement in some cases. 17 It has been reported that S 2 O 3 2− has two structures: structure A ( ) and structure B ( ).…”

Section: Chloride-to-thiosulfate Concentration Ratio (Ctcr)-ctcr Ismentioning

confidence: 99%

Factors Influencing Passivity Breakdown on UNS N08800 in Neutral Chloride and Thiosulfate Solutions

Wang

Shi

et al. 2017

J. Electrochem. Soc.

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In this work, the passivity degradation of UNS N08800 in solutions containing Cl − and S 2 O 3 2− is studied by using polarization curve, electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). Experimental results reveal that the passivity breakdown heavily depends on anodic potentials, concentration ratios of Cl − to S 2 O 3 2− , and the composition of materials. A combined effect between Cl − and S 2 O 3 2− on pitting corrosion is observed at high anodic potentials at which the passive film is broken down; in this situation, S 2 O 3 2− ions can enter into the pits by electromigration, and they are reduced to S ads and S 2− , stabilizing the metastable pits and accelerate the pit growth rate. However, there is no such combined effect at low anodic potentials when the passive film is intact, on the contrary, S 2 O 3 2− is beneficial to passivity in chloride solutions. At low anodic potentials, the interaction of S 2 O 3 2− with an intact passive layer is weak, and the adsorption of S 2 O 3 2− would mitigate the detrimental effect of Cl − ions.

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Section: Chloride-to-thiosulfate Concentration Ratio (Ctcr)-ctcr Ismentioning

confidence: 99%

Factors Influencing Passivity Breakdown on UNS N08800 in Neutral Chloride and Thiosulfate Solutions

Wang

Shi

et al. 2017

J. Electrochem. Soc.

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“…Duret-Thual, et al 18 also observed some surface adsorption of elemental sulfur S 0 , but this was limited to a weak adsorption on the external oxide surface rather than an accumulation within the oxide film. The combined effect with chloride has been reported to lower the pitting potentials of Alloy 690, 13 Type 304 stainless steel, 12,20 Alloy 800 6,12 and Alloy 600 12 in neutral chloride solutions. In addition, the detrimental effect of S x depends on the sulfur valence.…”

mentioning

confidence: 99%

“…Sulfate concentrations of up to 10 ppb (by weight) exist in the SG blowdown. 6 However, during reactor start-up the concentration of sulfate can be higher due to hideout return from SG crevices. Thermodynamically, hydrazine (N 2 H 4 ) can react with these species to produce compounds containing lower-valence sulfur, however this reaction is kinetically limited.…”

mentioning

confidence: 99%

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

Xia

Zhu

Behnamian

et al. 2014

J. Electrochem. Soc.

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The effects of pH on sulfur-induced passivity degradation of Alloy 800 in simulated crevice chemistries were evaluated using electrochemical impedance spectroscopy (EIS), secondary ion mass spectroscopy (SIMS), and Mott-Schottky analysis methods. Experimental results reveal that the detrimental effect of impurities containing sulfur at the reduced or intermediate oxidation level (S x ) on the passivity of Alloy 800 depends significantly on the solution pH. In neutral crevice (NC) chemistry containing chloride ions, the S x obstructs the healing process during repassivation, retards the dehydration reaction and also incorporates H, -OH and S into the passive film. However, the detrimental effect of S x is insignificant in an alkaline crevice (AKC) solution due to a change in surface adsorption and surface charge. Impurities containing sulfur at the reduced or intermediate oxidation level would cause Alloy 800 to lose its passivity and become active in an acidic crevice (AC) chemistry. Experimental evidence also indicates that the solution pH alters the semiconductor type of the surface film -from n-type in NC solution to p-type in AKC solution.

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“…6 In order to fully understand the hydrogen effect on the properties of passive film, various techniques are needed, including surface analysis methods like secondary ion mass spectroscopy (SIMS), 7,8 X-ray photoelectron spectroscopy (XPS), 7 as well as electrochemical methods like electrochemical impedance spectroscopy (EIS), 9,10 electrochemical noise. 11 Previous works mainly focused on hydrogen effects on the electrochemical behaviour and physicochemical property of the surface film, but limited investigations have been conducted focusing on the surface reactivity. In recent years, scanning electrochemical microscopy (SECM) has been developed for a wide range of applications in corrosion science.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen-enhanced Surface Reactivity of X80 Pipeline Steel observed by Scanning Electrochemical Microscopy

Xia

Zhu

et al. 2016

Electrochemistry

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Effect of hydrogen on the surface reactivity of X80 pipeline steel was studied by scanning electrochemical microscopy (SECM), electrochemical impedance spectroscopy (EIS) and secondary ion mass spectroscopy (SIMS). Hydrogen can enhance the reactivity of passive film formed on X80 pipeline steel, reduce the corrosion resistance and thickness of this passive layer, which is due to an increase in hydroxide in the passive layer.

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A mechanistic study on thiosulfate-enhanced passivity degradation of Alloy 800 in chloride solutions

Cited by 85 publications

References 69 publications

Factors Influencing Passivity Breakdown on UNS N08800 in Neutral Chloride and Thiosulfate Solutions

Factors Influencing Passivity Breakdown on UNS N08800 in Neutral Chloride and Thiosulfate Solutions

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

Hydrogen-enhanced Surface Reactivity of X80 Pipeline Steel observed by Scanning Electrochemical Microscopy

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