Mechanisms of localized corrosion of carbon steel associated with magnetite/mackinawite layers in a cement grout

2020 ◽  
Vol 72 (1-2) ◽  
pp. 194-210
Author(s):  
Mathieu Robineau ◽  
René Sabot ◽  
Marc Jeannin ◽  
Valérie Deydier ◽  
Didier Crusset ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Cement Grout ◽  
Localized Corrosion

scholarly journals Formation of Iron Sulfides on Carbon Steel in a Specific Cement Grout Designed for Radioactive Waste Repository and Associated Corrosion Mechanisms

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3563
Author(s):  
Mathieu Robineau ◽  
Valérie Deydier ◽  
Didier Crusset ◽  
Alexandre Bellefleur ◽  
Delphine Neff ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Radioactive Waste ◽  
Corrosion Product ◽  
Product Layer ◽  
Cement Grout ◽  
Radioactive Waste Disposal ◽  
Sulfide Concentration ◽  
Iron Sulfides ◽  
Corrosion Mechanisms ◽  
A Minor

Carbon steel coupons were buried in a specific low-pH cement grout designed for radioactive waste disposal and left 6 months in anoxic conditions at 80 °C. The corrosion product layers were analyzed by µ-Raman spectroscopy, XRD, and SEM. They proved to be mainly composed of iron sulfides, with magnetite as a minor phase, mixed with components of the grout. Average corrosion rates were estimated by weight loss measurements between 3 and 6 µm yr−1. Corrosion profiles revealed local degradations with a depth up to 10 µm. It is assumed that the heterogeneity of the corrosion product layer, mainly composed of conductive compounds (FeS, Fe3S4, and Fe3O4), promotes the persistence of corrosion cells that may lead to locally aggravated degradations of the metal. New cement grouts, characterized by a slightly higher pH and a lower sulfide concentration, should then be designed for the considered application.

scholarly journals In-Situ Monitoring and Analysis of the Pitting Corrosion of Carbon Steel by Acoustic Emission

2019 ◽  
Vol 9 (4) ◽  
pp. 706 ◽  
Author(s):  
Junlei Tang ◽  
Junyang Li ◽  
Hu Wang ◽  
Yingying Wang ◽  
Geng Chen
Keyword(s):  
Acoustic Emission ◽  
Carbon Steel ◽  
Pitting Corrosion ◽  
Optical Microscope ◽  
Open Circuit ◽  
In Situ Monitoring ◽  
Localized Corrosion ◽  
Uniform Corrosion ◽  
Corrosion Morphology

The acoustic emission (AE) technique was applied to monitor the pitting corrosion of carbon steel in NaHCO3 + NaCl solutions. The open circuit potential (OCP) measurement and corrosion morphology in-situ capturing using an optical microscope were conducted during AE monitoring. The corrosion micromorphology was characterized with a scanning electron microscope (SEM). The propagation behavior and AE features of natural pitting on carbon steel were investigated. After completion of the signal processing, including pre-treatment, shape preserving interpolation, and denoising, for raw AE waveforms, three types of AE signals were classified in the correlation diagrams of the new waveform parameters. Finally, a 2D pattern recognition method was established to calculate the similarity of different continuous AE graphics, which is quite effective to distinguish the localized corrosion from uniform corrosion.

Localized corrosion of carbon steel in seawater: Processes occurring in cathodic zones

2019 ◽  
Vol 70 (6) ◽  
pp. 973-984
Author(s):  
Julien Duboscq ◽  
René Sabot ◽  
Marc Jeannin ◽  
Philippe Refait
Keyword(s):  
Carbon Steel ◽  
Localized Corrosion

Multi-Physics Coupling Analysis on the Time-Dependent Localized Corrosion Behavior of Carbon Steel in CO2-H2O Environment

2019 ◽  
Vol 167 (1) ◽  
pp. 013505 ◽  
Author(s):  
Kai Wang ◽  
Chenpei Li ◽  
Yanhui Li ◽  
Jinling Lu ◽  
Yueshe Wang ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Corrosion Behavior ◽  
Time Dependent ◽  
Localized Corrosion ◽  
Coupling Analysis

scholarly journals Corrosion of Carbon Steel in Artificial Geothermal Brine: Influence of Carbon Dioxide at 70 °C and 150 °C

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3801 ◽  
Author(s):  
Gabriela Aristia ◽  
Le Quynh Hoa ◽  
Ralph Bäßler
Keyword(s):  
Carbon Dioxide ◽  
Carbon Steel ◽  
Temperature Effect ◽  
Electrochemical Impedance ◽  
Corrosion Products ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
Sem Images ◽  
Geothermal Brine ◽  
Corrosive Effect

This study focuses on the corrosion mechanism of carbon steel exposed to an artificial geothermal brine influenced by carbon dioxide (CO2) gas. The tested brine simulates a geothermal source in Sibayak, Indonesia, containing 1500 mg/L of Cl−, 20 mg/L of SO42−, and 15 mg/L of HCO3− with pH 4. To reveal the temperature effect on the corrosion behavior of carbon steel, exposure and electrochemical tests were carried out at 70 °C and 150 °C. Surface analysis of corroded specimens showed localized corrosion at both temperatures, despite the formation of corrosion products on the surface. After 7 days at 150 °C, SEM images showed the formation of an adherent, dense, and crystalline FeCO3 layer. Whereas at 70 °C, the corrosion products consisted of chukanovite (Fe2(OH)2CO3) and siderite (FeCO3), which are less dense and less protective than that at 150 °C. Control experiments under Ar-environment were used to investigate the corrosive effect of CO2. Free corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS) confirm that at both temperatures, the corrosive effect of CO2 was more significant compared to that measured in the Ar-containing solution. In terms of temperature effect, carbon steel remained active at 70 °C, while at 150 °C, it became passive due to the FeCO3 formation. These results suggest that carbon steel is more susceptible to corrosion at the near ground surface of a geothermal well, whereas at a deeper well with a higher temperature, there is a possible risk of scaling (FeCO3 layer). A longer exposure test at 150 °C with a stagnant solution for 28 days, however, showed the unstable FeCO3 layer and therefore a deeper localized corrosion compared to that of seven-day exposed specimens.

scholarly journals Thin Benzotriazole Films for Inhibition of Carbon Steel Corrosion in Neutral Electrolytes

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 362 ◽  
Author(s):  
Maxim Petrunin ◽  
Liudmila Maksaeva ◽  
Natalia Gladkikh ◽  
Yuriy Makarychev ◽  
Marina Maleeva ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Photoelectron Spectroscopy ◽  
Steel Surface ◽  
Steel Corrosion ◽  
Chloride Ions ◽  
Localized Corrosion ◽  
Polymeric Coatings ◽  
Carbon Steel Surface ◽  
Corrosion Of Steel ◽  
Anticorrosion Properties

This article investigates the modification of a carbon steel surface by benzotriazole (BTA), and the structure and properties of the formed layers. Adsorption was studied by surface analytical methods such as X-ray photoelectron spectroscopy (XPS) and reflecting infrared microscopy (FTIR). It has been established that a polymer-like film containing iron-azole complexes that are 2 nm thick and strongly bonded to the metal is formed on the surface as a result of the azole interacting with a steel surface. This film is capable to inhibit uniform and localized corrosion of steel in neutral aqueous electrolytes containing chloride ions. It is shown that the iron-azole layer located at the interface acts as a promotor of adhesion, increasing the interaction of polymeric coatings with the steel surface. Taking into account these properties, the steel pretreatments can be used for improving the anticorrosion properties of polymeric coatings applied for the protection of steel constructions.

Studies on CUI of Carbon Steel in Simulation Environment Containing Chloride and Sulfur at 80°C

2012 ◽  
Vol 509 ◽  
pp. 166-170
Author(s):  
Jian Qun Tang ◽  
Jian Ming Gong ◽  
Ying Jie Jiang
Keyword(s):  
Carbon Steel ◽  
Metal Surface ◽  
Localized Corrosion ◽  
Experimental Simulation ◽  
Simulation Environment ◽  
Nacl Concentration ◽  
Corrosion Behaviors ◽  
Small Cracks ◽  
Testing Solution ◽  
Corrosion Under Insulation

Corrosion under insulation (CUI) is a localized corrosion occurring at the interface of a metal surface and the insulation on the metal surface. In order to explore the mechanism of CUI, some tests were conducted on 20 # carbon steel under insulation dripping different testing solution at 80°C in an experimental simulation device for CUI. Corrosion behaviors were analyzed by weight loss methods and other methods. The results showed that CUI rate of 20# carbon steel increased with NaCl concentration. The addition of sulfur and the decrease of pH promoted corrosion. The pits and small cracks were found on the corroded metal and the bonding between products and matrix was strong.

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