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Investigation of the corrosion of a low alloyed steel in confined aqueous environments containing dissolved CO2

Abstract : The annulus of flexible pipelines is a space confined between two polymer sheaths which contains CO2. It exhibits a V/S ratio between the electrolyte volume and the exposed steel surface typically ranged between 0.01 and 0.06 mL.cm-2. In such confined environments, pH is rather high and corrosion rates are very low in comparison with bulk conditions. In order to investigate this confinement effect, an adapted thin layer cell including a gas supply system and a positioning control device was developed. Then, ohmic drop effects were modeled using a transmission line to calculate the impedance measured in this cell. Thanks to this model, impedance diagrams obtained during the corrosion of a low alloy steel covered by thin electrolyte films containing dissolved CO2 were analyzed. The decrease of the corrosion rates in confined environments was ascribed to an active surface coverage induced by the precipitation of an insulating siderite film. A corrosion model taking into account this surface coverage and the buffering effect induced by the presence of dissolved CO2 was developed. Model predictions are in fair agreement with experimental observations at steady state.
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https://pastel.archives-ouvertes.fr/pastel-00004934
Contributor : Ecole Chimie Paristech <>
Submitted on : Tuesday, March 24, 2009 - 8:00:00 AM
Last modification on : Thursday, March 21, 2019 - 2:16:53 PM

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  • HAL Id : pastel-00004934, version 1

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Elias Remita. Investigation of the corrosion of a low alloyed steel in confined aqueous environments containing dissolved CO2 . Chemical Sciences. Chimie ParisTech, 2007. English. ⟨pastel-00004934⟩

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