Cathodic Reactions Involved in Corrosion Processes Occurring in Concentrated Nitric Acid at 100 °C

Balbaud, Fanny; Sanchez, Gérard; Santarini, G.; Picard, Gauthier

doi:10.1002/(sici)1099-0682(200004)2000:4<665::aid-ejic665>3.0.co;2-n

Cited by 55 publications

(25 citation statements)

References 5 publications

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“…While the high corrosion rates indicate the high rate of anodic (metal dissolution) reaction, the corresponding cathodic reactions are the reduction reactions of nitric acid 6 13 17 6,13,17,26. The autocatalytic mechanism increases the reduction rate of nitric acid.…”

Section: Resultsmentioning

confidence: 99%

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Methodology based on potential measurement for predicting corrosion behaviour of SS 304L in boiling nitric acid containing oxidising ions

Bhise

Kain

2012

Corrosion Engineering, Science and Technology

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Austenitic stainless steels like SS 304L are prone to intergranular corrosion (IGC) in boiling nitric acid media. A major cause is sensitisation induced in the heat affected zone of the weldments. Developments in sensitisation resistant materials have lead to the minimisation of degradation due to IGC. Corrosion in nitric acid medium is essentially controlled by oxidising potentials in the transpassive potential regime. The corrosion potential of stainless steel in nitric acid is a function of the concentration of acid, temperature and concentration of specific oxidising ions. In this work, a 'master curve' for the dependence of corrosion rates on the applied potentials was generated for type 304L stainless steel (nitric acid grade) in 6M nitric acid at near boiling (95uC) condition. The master curve was validated by measuring the corrosion rates at 48 h exposure in 6M near boiling nitric acid, in which various oxidising ions had been added. It was illustrated that there is a threshold potential (at transition to transpassivity) above which the non-sensitised stainless steel also undergoes IGC. A methodology for the prediction of corrosion rate has thus been proposed that can be applied to austenitic stainless steels at any given operating condition/component in operating plants where nitric acid media are used as process fluid. The effect of the temperature/ area ratio of stainless steel on corrosion has been illustrated.

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Section: Resultsmentioning

confidence: 99%

“…6,13,17,26 The autocatalytic mechanism increases the reduction rate of nitric acid. In the transpassive regime of potentials, water is not stable and oxidises to give oxygen and hydrogen ions.…”

Section: Susceptibility To Igc By Addition Of Oxidising Ionsmentioning

confidence: 99%

Methodology based on potential measurement for predicting corrosion behaviour of SS 304L in boiling nitric acid containing oxidising ions

Bhise

Kain

2012

Corrosion Engineering, Science and Technology

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“…In strongly acidic media, they may be oxidized at elevated temperatures as has been previously seen, ,, but this is unlikely at low acid concentrations. Only the presence of Fe 3+ could promote corrosion without requiring further oxidation, as it contributes to the autocatalytic reduction mechanism of nitric acid which has been extensively described. − However, it is clear from Figure that the effects of these species on the overall corrosion rate are minimal, suggesting that the extent of oxidation of these ions to higher oxidation states is very small.…”

Section: Discussionmentioning

confidence: 97%

Development of a Multi-technique Characterization Portfolio for Stainless Steels Exposed to Magnox Reprocessing Liquors

Barton,

Denman,

Grebennikova

et al. 2023

ACS Omega

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AISI Type 304 stainless steel coupons have been exposed to a simulant aqueous environment representative of the Magnox Reprocessing Plant (MRP) at Sellafield, UK. The experiments were performed for extended time periods (up to 420 days) at elevated temperatures to develop a comprehensive understanding of the extent, nature, and depth of contamination for pipework and vessels in Magnox spent nuclear fuel reprocessing environments. This will inform upcoming decommissioning work which represents a major post-operational challenge. Previous relevant literature has focused on developing fundamental understanding of contamination mechanisms of stainless steels in simplistic, single-element systems, which lack elements of industrial relevance. Contamination behavior is expected to be drastically different in these more complex environments. A characterization portfolio has been developed to enable detailed assessment of corrosion and contamination behavior in acidic reprocessing environments. Solution, surface, and depth analysis determined that uptake was dominated by the elements present in highest concentrations within the environment, namely, Mg, Nd, and Cs. Most contaminants were incorporated into a relatively thin surface oxide layer (<100 nm) in metal oxide form, although there were some exceptions (Cs and Sr). Grain boundary etching was present despite very low corrosion rates (3 μm year −1 ). As a result of this lack of corrosion, diffusion of contaminants beyond the immediate surface (10− 20 nm) did not occur, evidenced through depth profiling. As a result of these findings, surface-based decontamination techniques minimizing excess secondary waste generation can be further developed in order to reduce the environmental and economic burden associated with decommissioning activities.

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“…It has indeed been shown that other species than HNO 2 can form and that this is not HNO 3 (but other species with a lower oxidation degree) which directly exchanges the electrons with the steel [1] [2]. It has indeed been shown that other species than HNO 2 can form and that this is not HNO 3 (but other species with a lower oxidation degree) which directly exchanges the electrons with the steel [1] [2].…”

Section: Discussionmentioning

confidence: 99%

Corrosion behavior of martensitic/ferritic oxide dispersed strengthened steels in nitric media

et al. 2011

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The corrosion behavior of three martensitic/ferritic oxide dispersed strengthened (ODS) steels with different chromium contents (respectively 9, 14 and 18wt %) has been studied in hot and concentrated nitric acid. Immersion and electrochemical tests have been carried out in different experimental conditions (temperature and nitric acid concentration). In each case, the corrosion kinetics has been characterized by mass loss measurement of samples (immersion tests) and the electrochemical behavior by linear sweep voltammetry techniques. The dependency of the corrosion rate with the chromium content in the steel, the nitric acid concentration and the temperature, has been quantitatively established and qualitatively discussed.

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Cathodic Reactions Involved in Corrosion Processes Occurring in Concentrated Nitric Acid at 100 °C

Cited by 55 publications

References 5 publications

Methodology based on potential measurement for predicting corrosion behaviour of SS 304L in boiling nitric acid containing oxidising ions

Methodology based on potential measurement for predicting corrosion behaviour of SS 304L in boiling nitric acid containing oxidising ions

Development of a Multi-technique Characterization Portfolio for Stainless Steels Exposed to Magnox Reprocessing Liquors

Corrosion behavior of martensitic/ferritic oxide dispersed strengthened steels in nitric media

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