Investigation of stone‐hard‐soil formation from AC corrosion of cathodically protected pipeline

Junker, Andreas; Belmonte, Louise Josefine; Kioupis, Nick; Nielsen, Lars Vendelbo; Møller, Per

doi:10.1002/maco.201709947

Cited by 13 publications

(13 citation statements)

References 19 publications

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“…[55] The pH of the WE during CP was estimated from corresponding data of pH at a current density of 0.5 A m −2 from the literature. [56][57][58][59][60][61][62][63][64][65][66] The black lines correspond to the equilibrium reactions of the iron species considering a soluble concentration of Fe 2+ in water of 10 −6 M. The dashed line corresponds to the reversible potential of the hydrogen evolution reaction (HER). [Color figure can be viewed at wileyonlinelibrary.com] alkaline conditions at the metal surface upon cathodic polarization has been widely provided in the literature, [55][56][57][58][59][61][62][63]67,68,71,72,75,76] limited experimental evidence is available that simultaneously and directly relates this raise in pH to passive film formation.…”

Section: Cathodic Potentiostatic Polarizationmentioning

confidence: 99%

Second‐harmonic generation technique for in situ study of passive film formation on carbon steel surfaces in aqueous solutions

Martinelli-Orlando

Dénervaud

Grange

et al. 2022

Materials & Corrosion

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The aim of this work was to revisit second-harmonic generation (SHG) as a technique for the in situ analysis of oxide film formation on steel samples immersed in aqueous solutions and during electrochemical experiments. The measurements were compared to active reflectance spectroscopy (ARS), which is a more established in situ spectroscopy technique. Carbon steel electrodes were subjected to polarization in pH neutral and mild-alkaline electrolytes to provoke the formation of passive films. In situ SHG measurements allowed monitoring of compositional changes in the formed film, as the SHG intensity increased in the domain of stability of Fe 3 O 4 and decreased in the domain of stability of Fe 2 O 3 during potentiodynamic polarization. ARS, on the other hand, is suitable to monitor film thickness. ARS absorption increased along with film growth when moving in the anodic direction during potentiodynamic polarization. During 30 min cathodic polarization at −0.9 V Ag/AgCl sat. KCl in initially pH neutral the combination of SHG and ARS revealed the presence of an oxide film that was primarily composed of Fe 3 O 4 and with a thickness up to 0.7 nm.

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Section: Cathodic Potentiostatic Polarizationmentioning

confidence: 99%

Second‐harmonic generation technique for in situ study of passive film formation on carbon steel surfaces in aqueous solutions

Martinelli-Orlando

Dénervaud

Grange

et al. 2022

Materials & Corrosion

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“…This causes a cyclic variation of spread resistance, current densities and corrosion rate. The detailed chemical investigation of stone hard soil formed on cathodically protected pipeline under AC interference is reported in [68]. The crucial role of soil chemical composition, pH and spread resistance was carefully investigated by Junker et al [62,[67][68][69].…”

Section: The Alkalization Mechanism and The Effect Of Spread Resistancementioning

confidence: 99%

“…The detailed chemical investigation of stone hard soil formed on cathodically protected pipeline under AC interference is reported in [68]. The crucial role of soil chemical composition, pH and spread resistance was carefully investigated by Junker et al [62,[67][68][69]. The spread resistance is identified as a key parameter, controlling the current densities, and is highly influenced by the formation of calcareous deposits or corrosion products.…”

Section: The Alkalization Mechanism and The Effect Of Spread Resistancementioning

confidence: 99%

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AC Corrosion of Carbon Steel under Cathodic Protection Condition: Assessment, Criteria and Mechanism. A Review

2020

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Cathodic protection (CP), in combination with an insulating coating, is a preventative system to control corrosion of buried carbon steel pipes. The corrosion protection of coating defects is achieved by means of a cathodic polarization below the protection potential, namely −0.85 V vs. CSE (CSE, copper-copper sulfate reference electrode) for carbon steel in aerated soil. The presence of alternating current (AC) interference, induced by high-voltage power lines (HVPL) or AC-electrified railways, may represent a corrosion threat for coated carbon steel structures, although the potential protection criterion is matched. Nowadays, the protection criteria in the presence of AC, as well as AC corrosion mechanisms in CP condition, are still controversial and discussed. This paper deals with a narrative literature review, which includes selected journal articles, conference proceedings and grey literature, on the assessment, acceptable criteria and corrosion mechanism of carbon steel structures in CP condition with AC interference. The study shows that the assessment of AC corrosion likelihood should be based on the measurement of AC and DC (direct current) related parameters, namely AC voltage, AC and DC densities and potential measurements. Threshold values of the mentioned parameters are discussed. Overprotection (EIR-free < −1.2 V vs. CSE) is the most dangerous condition in the presence of AC: the combination of strong alkalization close to the coating defect due to the high CP current density and the action of AC interference provokes localized corrosion of carbon steel.

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“…Anonymous [4] and Dang et al [5] introduced the application of cathodic protection systems for pipeline coating defects. Varela et al [6] and Junker et al [7] pointed out the effective methods of anticorrosive coating defects of buried pipelines or corrosion mitigation measures, and they studied the severity and condition of corrosion undercoating defects. Wu et al [8] showed that the improvement of the cathodic protection performance of the coating can be attributed to severe galvanic corrosion.…”

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confidence: 99%

Assessment of cathodic protection effect on long‐distance gas transportation pipelines based on buried steel specimens

Han

Liao

et al. 2020

Materials & Corrosion

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Different severe corrosions are found at the damaged point of anticorrosive coating on natural gas pipelines, even though the cathodic protection (CP) potential is between −0.85 and −1.15 V. Therefore, there are totally 168 buried steel specimens (BSSs) and 28 soil samples at 28 buried points that are taken out in situ and then analyzed in the lab to assess the CP effectiveness. First, the CP status is simulated by BSSs at the damaged points, and the corrosion products on BSSs are analyzed microscopically. Second, the corrosion rates of the testing BSSs are calculated by the weight‐loss method to perform the quantitative assessment. Third, the specific reasons for external corrosion are explored via analyzing the CP potential attenuation tendency and the corrosiveness of soil. The corrosion growth trend is also investigated by comparing the test results among three test cycles within 8 years. Finally, the control measures for external corrosion of pipelines are put forward. The study is beneficial to evaluate the CP system and determine the causes of external corrosion of pipelines, thereby formulating corresponding protective measures.

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Investigation of stone‐hard‐soil formation from AC corrosion of cathodically protected pipeline

Cited by 13 publications

References 19 publications

Second‐harmonic generation technique for in situ study of passive film formation on carbon steel surfaces in aqueous solutions

Second‐harmonic generation technique for in situ study of passive film formation on carbon steel surfaces in aqueous solutions

AC Corrosion of Carbon Steel under Cathodic Protection Condition: Assessment, Criteria and Mechanism. A Review

Assessment of cathodic protection effect on long‐distance gas transportation pipelines based on buried steel specimens

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