Deconvolution of the Partial Anodic and Cathodic Processes during the Corrosion of Carbon Steel in Concrete Pore Solution under Simulated Anoxic Conditions

Lü, Ping; Kursten, Bruno; Macdonald, Digby D.

doi:10.1016/j.electacta.2014.08.027

Cited by 43 publications

(39 citation statements)

References 23 publications

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“…Although the partial anodic current density is predicted to be independent of E app , there exists a competition between partial anodic and partial cathodic currents in determining the total (observed) current [21]. This observation has been made by other authors [21,28] and shows the importance of considering the cathodic current produced by hydrogen evolution due to the water reduction in deaerated condition when considering the electrochemistry of reactive metals, such as Al, Li, Mg, and Zn.…”

Section: Resultsmentioning

confidence: 62%

Studies on Pitting Corrosion of Al–Cu–Li Alloys Part III: Passivation Kinetics of AA2098–T851 Based on the Point Defect Model

et al. 2019

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In this paper, the passivation kinetics of AA2098–T851 was investigated by a fundamental theoretical interpretation of experimental results based on the mixed potential model (MPM). The steady state passive layer formed on the AA2098–T851 in NaHCO3 solution in a CO2 atmosphere upon potentiostatic stepping in the anodic direction followed by stepping in the opposite direction was explored. Potentials were selected in a way that both anodic passive dissolution of the metal and hydrogen evolution reaction (HER) occur, thereby requiring the MPM for interpretation. Optimization of the MPM on the experimental electrochemical impedance spectroscopy (EIS) data measured after each potentiostatic step revealed the important role of the migration of Al interstitials in determining the kinetics of passive layer formation and dissolution. More importantly, it is shown that the inequalities of the kinetics of formation and dissolution of the passive layer as observed in opposite potential stepping directions lead to the irreversibility of the passivation process. Finally, by considering the Butler–Volmer (B–V) equation for the cathodic reaction (HER) in the MPM, and assuming the quantum mechanical tunneling of the charge carriers across the barrier layer of the passive film, it was shown that the HER was primarily controlled by the slow electrochemical discharge of protons at the barrier layer/solution (outer layer) interface.

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Section: Resultsmentioning

confidence: 62%

Studies on Pitting Corrosion of Al–Cu–Li Alloys Part III: Passivation Kinetics of AA2098–T851 Based on the Point Defect Model

et al. 2019

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“…Based on the proposed equivalent electrical circuit, the total impedance of the interfacial system is written as: where Z cath and Z ol are the impedance of the cathodic-reaction branch and the outer-layer. The theory of the MPM, the detailed derivation of Z F , Z W , and the optimization procedure of the MPM and the PDM on impedance data have been elaborated elsewhere 29,60 and hence they will not be repeated here due to space limitations.…”

Section: Modelling and Optimization Of The Modelmentioning

confidence: 99%

“…The results obtained by this method match fairly well with those calculated from the optimization, despite some minor difference which possibly originates from the over-simplified "parallel plate capacitor" assumption for the film, or, alternatively, is a reflection of the existence of the outer-layer. 29 Point defect diffusivity.-The diffusivity of the point defects within the barrier layer can be evaluated via the PDM from the equation given below 78 :…”

Section: Modelling and Optimization Of The Modelmentioning

confidence: 99%

The Irreversibility of the Passive State of Carbon Steel in the Alkaline Concrete Pore Solution under Simulated Anoxic Conditions

Lü

Sharifi‐Asl

Kursten

et al. 2015

J. Electrochem. Soc.

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The commonly observed irreversibility of the passive state on carbon steel in alkaline solutions was examined in simulated concrete pore solution under anoxic conditions replicated by applying relatively negative film formation potentials, at which the cathodic process dominates the passive system. The fundamental source of this irreversibility was investigated by describing the kinetics of the passive system via a previously developed mixed potential model that combines the point defect model accounting for the anodic process and the Butler-Volmer equation accounting for the cathodic process. Electrochemical impedance spectroscopy, Mott-Schottky analysis and model optimization were performed at each potential when the potential was first stepped in the anodic direction and then in the cathodic direction. The experiment and optimization results demonstrate that the irreversibility of the passive state is closely associated with the discrepancy in the defect structure of the passive film upon opposite stepping directions of the film formation potential, and is essentially caused by the slower film formation and slower film dissolution during the cathodic potential stepping than those during the anodic potential stepping.The deep geological repositories for the storage of high level nuclear waste in Belgium have been proposed to adopt the "supercontainer" concept. 1-3 Corrosion of the carbon steel overpack in concrete pore water (pH of 13.5 at 25 • C 4 ) and under anoxic conditions characterized by very negative corrosion potential due to continuous oxygen consumption and following hydrogen buildup 5 has been determined to be the main threat to the integrity of the supercontainer structure. A huge amount of work 6-27 has been done on the corrosion of iron and steels in highly alkaline environment, including concrete pore solution, where the phenomenon of passivity breakdown that is usually induced by chloride, carbonate, and/or sulfide ions, et al. [6][7][8][9][10][11][12][13][14][15] and the kinetics and composition of the formed passive film 16-27 are the subjects being primarily focused on. However, very few studies employed sufficiently negative potentials that are comparable to the corrosion potential inside the supercontainer, which could reach down to −0.8 V SHE . 28 At such negative potentials, the cathodic reaction dominates the corrosion system and thus the information regarding to the partial anodic process which is required to study the passivity electrochemically, such as the anodic corrosion current density and the impedance associated with the anodic reactions, cannot be obtained directly, a difficulty that, however, has been solved previously by using a mixed potential model proposed by the authors. 29 Additionally, the passive carbon steel also exhibits apparent corrosion irreversibility when the film formation potential shifts in opposite anodic and cathodic directions; specifically, a strong resistance to cathodic potential reduction of the passive state is evident if a pre-exiting passive film h...

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“…In the potential range of around -0.3 to 0.0 V SCE , the slopes of the curves are positive, suggesting an n-type semiconductor behavior. According to the point defect model [7,8], the lowered slope and the enlarged carrier density with the increasing temperature indicates the lowered ability of corrosion resistance. In contrast, the slope of the curve is increased by Al addition into the exposed solution with the same exposure temperature.…”

Section: Resultsmentioning

confidence: 99%

Effects of Aluminum Addition on the Corrosion of 316 Stainless Steel in the Simulated Primary Circuit Water of PWR

Song¹,

Khalil²,

Zhang³

et al. 2017

dteees

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Abstract. The effect of Al addition on the corrosion of 316 SS exposed to simulated primary circuit of PWR has been investigated by potentiodynamic polarization, Mott-Schottky plots and corrosion kinetics. After Al addition, the weight loss of 316 SS was reduced, the semiconductor properties of the oxide film formed on the surface on 316 SS were optimized. The kinetic study indicates that corrosion process is well fitted by the pseudo-first order model. The presence of Al increases the corrosion activation energy resulting in the slowdown of the corrosion of 316 SS. Al additions may impedes the transport of the metal ion in the micropore of the 316 SS. The research may give a good solution for material corrosion in the primary circuit water of PWR.

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Deconvolution of the Partial Anodic and Cathodic Processes during the Corrosion of Carbon Steel in Concrete Pore Solution under Simulated Anoxic Conditions

Cited by 43 publications

References 23 publications

Studies on Pitting Corrosion of Al–Cu–Li Alloys Part III: Passivation Kinetics of AA2098–T851 Based on the Point Defect Model

Studies on Pitting Corrosion of Al–Cu–Li Alloys Part III: Passivation Kinetics of AA2098–T851 Based on the Point Defect Model

The Irreversibility of the Passive State of Carbon Steel in the Alkaline Concrete Pore Solution under Simulated Anoxic Conditions

Effects of Aluminum Addition on the Corrosion of 316 Stainless Steel in the Simulated Primary Circuit Water of PWR

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