The Specific Effects of Chloride and Sulfate Ions on Oxide Covered Aluminum

Heine, Martha; Keir, David; Pryor, M. J.

doi:10.1149/1.2423459

Cited by 112 publications

(56 citation statements)

References 9 publications

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“…As for carbonation-induced corrosion, there still is a lack in the physical understanding of the depassivation mechanism of steel exposed to chloride ions [92,187]. Two models are generally proposed: the ion exchange model [189] and the point defect model [190]. In the first one, depassivation is the result of the adsorption and ingress of Clthrough the outer film layer and the progressive thinning of the inner film until dissolution.…”

Section: Depassivation and Corrosion Mechanismsmentioning

confidence: 99%

Reinforced concrete structures: A review of corrosion mechanisms and advances in electrical methods for corrosion monitoring

Rodrigues

Gaboreau

Gance

et al. 2021

Construction and Building Materials

202

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Steel corrosion is the main cause of deterioration of reinforced concrete (RC) structures. We provide an up-to-date review on corrosion mechanisms and recent advances in electrical methods for corrosion monitoring. When assessing corrosion mechanism, the inherent heterogeneity of RC structures and the significant effect of environmental factors remain major issues in data interpretations. The steel surface condition and local inhomogeneities at the steel-concrete interface appear to have an important effect on corrosion initiation. Considering uniform corrosion in atmospherically exposed reinforced concrete, the two main influencing factors of the corrosion process are the water content and the pore structure at the steel-concrete interface. However, irrespective of the depassivation mechanism, i.e. carbonation or chloride-induced corrosion, nonuniform corrosion is expected to be the main process for RC structures due to local variations in environmental exposure or the presence of interconnected rebars with different properties. Future studies may then be focused on their effect on macrocell corrosion to gain further insights in the corrosion mechanisms of RC structures. Concerning corrosion monitoring using electrical methods, the half-cell potential technique with potential mapping is accurate for locating areas with a high corrosion risk. Recent developments in the measurement of concrete resistivity have shown that the use of electrical resistivity tomography allows to consider appropriately the inherent heterogeneity of concrete and provides more insights on transport phenomena (e.g. water and salts ingress) in the material. Nevertheless, during the corrosion propagation stage, the polarization resistance remains the most important parameter to be determined as it provides quantitative information of the corrosion rate. If conventional three-electrode configuration methods can supply an accurate determination in the case of uniform corrosion, they often fail in the case of macrocell corrosion in field experiments. Recent advances have shown that a four-electrode configuration without any connection to the rebar can rather be used for the non-destructive testing and evaluation of corrosion. If studies are still required to quantify the corrosion rate, this method appears sensitive to localized corrosion and thus more suitable to field investigations. Finally, the coupling of numerical simulations with complementary electrical and other non-destructive testing methods is essential for consolidating the results to provide a better diagnosis of the service life of RC structures.

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Section: Depassivation and Corrosion Mechanismsmentioning

confidence: 99%

Reinforced concrete structures: A review of corrosion mechanisms and advances in electrical methods for corrosion monitoring

Rodrigues

Gaboreau

Gance

et al. 2021

Construction and Building Materials

202

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“…The adsorption and penetration of Cl − on the passive film surface were achieved by means of oxygen vacancies. Heine et al [62] proposed the iron exchange model, which suggested that the ion penetration of oxide films was capable through an ion exchange process or through cation vacancies. The oxide layers on the metal surface contain defects and are porous in nature; thus, through these pores, aggressive ions can directly reach the metal/film interface to disturb passivity [63].…”

Section: Penetration and Film Breakdown Mechanismmentioning

confidence: 99%

A review of passivity breakdown on metal surfaces: influence of chloride- and sulfide-ion concentrations, temperature, and pH

2021

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Metals, including austenitic steels and alloys, have been extensively applied in industrial and engineering applications. Passive films on metal surfaces are very important for corrosion protection. However, localized attack, such as passive film breakdown and the initiation of pits, is found upon exposure of such metals to aggressive ion-containing environments, leading to material failure and prominent adverse economic and safety concerns. For several decades, the mechanism of passivity breakdown and pit nucleation during pitting corrosion has been widely studied. The present article provides a detailed review of passive film breakdown on metal surfaces and the effects of complicated conditions, such as chloride- and sulfide-ion concentrations, temperature, and solution pH, on passivity breakdown. The possible mechanism for passivity breakdown is reviewed and discussed. The composition, structure, and electronic properties of passive layers are of conclusive importance to understand the leading corrosion mechanism, and they have been investigated with different techniques. Furthermore, we aim to present the structure, chemical composition, and electronic properties of passive films on metal surfaces by using X-ray photoelectron spectroscopy and energy-dispersive spectroscopy. Additionally, the surface morphology of passive films is analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) techniques. Finally, the effect of chloride- and sulfide-ion concentrations, pH, and temperature on passivity breakdown is discussed in detail.

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“…In these models, the penetrated chlorides cause the dissolution of the passive film from within and/or increase the iron oxidation rate of the metal substrate such that the passive film breaks down due to excessive generation of oxides. Among these models, the ion exchange model 21 suggests a penetration of chloride ions into the oxide film through an ion exchange process (e.g., Cl − for lattice O 2− ). On the other hand, the pore models 22,23 are based on the fact that typical oxide layers contain flaws and are porous in nature; therefore, chlorides can pass through the pores and reach metal/film interface to disturb passivity.…”

Section: Depassivation Mechanismmentioning

confidence: 99%

“…Some of the depassivation models suggest that chlorides penetrate into the passive film through ion exchange processes or simple diffusion. [21][22][23] However, other models hypothesize that chlorides only act as a catalyst, without penetrating into the film, to form iron vacancies that eventually diffuse to the metal/film interface to initiate the depassivation process. 24,25 The debate between these different models is ongoing.…”

Section: Introductionmentioning

confidence: 99%

Investigation of chloride-induced depassivation of iron in alkaline media by reactive force field molecular dynamics

et al. 2019

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The passivity of iron in alkaline media enables the use of carbon steel as reinforcement in concrete, which makes up the majority of modern infrastructure. However, chlorides, mainly from deicing chemicals or marine salts, can break down the iron passive film and cause active corrosion. Despite recent advances in nanoscale characterization of iron passivity, significant gaps exist in our understanding of the dynamic processes that lead to the chloride-induced breakdown of passive films. In this study, chlorideinduced depassivation of iron in pH 13.5 NaOH solution is studied using reactive force field molecular dynamics. The depassivation process initiates by local acidification of the electrolyte near the film surface, followed by iron dissolution into the electrolyte, and iron vacancy formation in the passive film. Chlorides do not penetrate the passive film, but mainly act as a catalyst for the formation of iron vacancies, which diffuse toward the metal/oxide interface, suggesting a depassivation mechanism consistent with the pointdefect model.

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The Specific Effects of Chloride and Sulfate Ions on Oxide Covered Aluminum

Cited by 112 publications

References 9 publications

Reinforced concrete structures: A review of corrosion mechanisms and advances in electrical methods for corrosion monitoring

Reinforced concrete structures: A review of corrosion mechanisms and advances in electrical methods for corrosion monitoring

A review of passivity breakdown on metal surfaces: influence of chloride- and sulfide-ion concentrations, temperature, and pH

Investigation of chloride-induced depassivation of iron in alkaline media by reactive force field molecular dynamics

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