Corrosion and Materials Degradation

12 pages, 7729 KiB

Open AccessArticle

Self-Healing Coatings Consisting of an Outer Electrodeposited Epoxy Resin Layer and an Inner Porous Anodic Oxide Layer with Healing Agents for the Corrosion Protection of Al Alloys

by Rin Takada, Kota Hirasawa, Hideaki Takahashi and Makoto Chiba

Corros. Mater. Degrad. 2023, 4(3), 516-527; https://doi.org/10.3390/cmd4030027 - 18 Sep 2023

Viewed by 1182

Abstract

Recently, new surface treatments for the corrosion protection of Al alloys by forming self-healing layers have attracted the attention of many researchers. The authors of this paper have previously developed self-healing polyurethane coatings with micro-capsules containing healing agents and porous anodic oxide films [...] Read more.

Recently, new surface treatments for the corrosion protection of Al alloys by forming self-healing layers have attracted the attention of many researchers. The authors of this paper have previously developed self-healing polyurethane coatings with micro-capsules containing healing agents and porous anodic oxide films filled with healing agents. In this study, self-healing coatings consisting of an outer electrodeposited epoxy resin layer and an inner porous anodic oxide layer with healing agents were developed for the corrosion protection of Al alloys. The corrosion protection abilities of the self-healing coating were shown in Cu²⁺/Cl⁻ solutions after damaging with indenters and were affected by freezing treatments and the tip angles of the indenter. Full article

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13 pages, 3441 KiB

Open AccessArticle

The Effect of Microstructure on Local Corrosion Product Formation during Initial SO₂-Induced Atmospheric Corrosion of ZnAlMg Coating Studied by FTIR-ATR FPA Chemical Imaging

by Dan Persson, Dominique Thierry and Nathalie LeBozec

Corros. Mater. Degrad. 2023, 4(3), 503-515; https://doi.org/10.3390/cmd4030026 - 08 Sep 2023

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Abstract

The initial atmospheric corrosion of ZM (ZnAlMg)-coated steel in humid air (85% RH) and humid argon (85% RH) containing 320 ppb SO₂ was studied using in situ infrared reflection absorption spectroscopy (IRRAS), FTIR-ATR focal plane array (FPA) imaging and SEM-EDS. The corrosion [...] Read more.

The initial atmospheric corrosion of ZM (ZnAlMg)-coated steel in humid air (85% RH) and humid argon (85% RH) containing 320 ppb SO₂ was studied using in situ infrared reflection absorption spectroscopy (IRRAS), FTIR-ATR focal plane array (FPA) imaging and SEM-EDS. The corrosion products formed in humid air containing SO₂ are mainly composed of magnesium sulphites and sulphates, with sulphite-containing corrosion products formed initially while the contribution from sulphates increased with exposure time. The results from FTIR-FPA imaging and SEM-EDS showed that the magnesium sulphite and sulphate are formed mainly on eutectic phases with a higher quantity of corrosion products formed on the binary eutectic (Zn-MgZn₂) phases. This is due to presence of microgalvanic elements with the zinc-rich phases as the main sites for the cathodic oxygen reduction while the anodic reactions take place on the eutectic areas. Sulphate content is the highest on the binary eutectic phases, due to the microgalvanic effects and the production of oxidants by the cathodic reaction, which increases the oxidation of sulphite to sulphate. Full article

(This article belongs to the Special Issue Atmospheric Corrosion of Materials)

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15 pages, 3537 KiB

Open AccessFeature PaperArticle

Plasma Electrolytic Oxidation on Magnesium AZ31 with Sepiolite as Inhibitor Carrier for Improved Corrosion Protection

by Robert Sottor, Ricarda Gruen, Kerstin Kremmer, Stephan Lederer, Michael Schneider and Wolfram Fuerbeth

Corros. Mater. Degrad. 2023, 4(3), 488-502; https://doi.org/10.3390/cmd4030025 - 30 Aug 2023

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Abstract

Plasma electrolytic oxidation (PEO) in an alkaline silicate electrolyte containing nanosized sepiolite fibers was carried out on magnesium alloy AZ31. The mineral fibers were loaded with different corrosion inhibitors and incorporated in situ during the PEO treatment. The composition and microstructure of the [...] Read more.

Plasma electrolytic oxidation (PEO) in an alkaline silicate electrolyte containing nanosized sepiolite fibers was carried out on magnesium alloy AZ31. The mineral fibers were loaded with different corrosion inhibitors and incorporated in situ during the PEO treatment. The composition and microstructure of the PEO coatings were investigated by SEM. It was shown that the fibers are located on the surface as well as inside the “weak spots” of the coating, i.e., pores and discharge channels. The fixation of the particles is caused by sintering due to the heat developed during the PEO treatment. Investigations using electrochemical impedance spectroscopy and linear sweep voltammetry in 0.01 M NaCl solution confirmed an improvement of the corrosion protection. The use of the inhibitors shifts the critical pitting potential in the anodic direction. Regarding efficiency, cerium-loaded sepiolite showed the best behavior by shifting the pitting potential by +0.9 V. Full article

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22 pages, 3187 KiB

Open AccessFeature PaperReview

Improved and Innovative Accident-Tolerant Nuclear Fuel Materials Considered for Retrofitting Light Water Reactors—A Review

by Raul B. Rebak

Corros. Mater. Degrad. 2023, 4(3), 466-487; https://doi.org/10.3390/cmd4030024 - 24 Aug 2023

Cited by 1 | Viewed by 1827

Abstract

Since 2011, there has been an international effort to evaluate the behavior of newer fuel rod materials for the retrofitting of existing light water reactors (LWR). These materials include concepts for the cladding of the fuel and for the fuel itself. The materials [...] Read more.

Since 2011, there has been an international effort to evaluate the behavior of newer fuel rod materials for the retrofitting of existing light water reactors (LWR). These materials include concepts for the cladding of the fuel and for the fuel itself. The materials can be broadly categorized into evolutionary or improved existing materials and revolutionary or innovative materials. The purpose of the newer materials or accident-tolerant fuels (ATF) is to make the LWRs more resistant to loss-of-coolant accidents and thus increase their operation safety. The benefits and detriments of the three main concepts for the cladding are discussed. These include (i) coatings for existing zirconium alloys; (ii) monolithic iron–chromium–aluminum alloys; and (iii) composites based on silicon carbide. The use of ATF materials may help extend the life of currently operating LWRs, while also being a link to material development for future commercial reactors. Full article

(This article belongs to the Special Issue Mechanism and Predictive/Deterministic Aspects of Corrosion)

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21 pages, 7795 KiB

Open AccessArticle

Corrosion of Silica-Based Optical Fibers in Various Environments

by Amanda Leong, Steven Derek Rountree and Jinsuo Zhang

Corros. Mater. Degrad. 2023, 4(3), 445-465; https://doi.org/10.3390/cmd4030023 - 08 Aug 2023

Viewed by 1455

Abstract

This research article explores the potential of optical fibers as sensors, highlighting their ability to measure various parameters such as temperature, pressure, stress, and radiation dose. The study focuses on investigating the material compatibility of optical fibers in challenging sensing environments like Gen [...] Read more.

This research article explores the potential of optical fibers as sensors, highlighting their ability to measure various parameters such as temperature, pressure, stress, and radiation dose. The study focuses on investigating the material compatibility of optical fibers in challenging sensing environments like Gen II/II+ and advance nuclear reactors, as well as concentrated solar power (CSP) plants. Material compatibility tests were conducted to determine the feasibility of using fluorine and germanium optical fiber sensors in these environments. The study found that raw fibers were corrosion-resistant to lead bismuth eutectic at 600 °C, regardless of the coating. In molten salt environments, raw fibers were incompatible with FLiNaK but showed corrosion resistance to MgCl₂-NaCl-KCl. However, the survivability of raw fiber optics improved with a gold coating in FLiNaK. Raw fiber optics were found to be incompatible in high-temperature steam at 1200 °C and in a pressurized water reactor (PWR) at 300 °C. Full article

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17 pages, 6726 KiB

Open AccessReview

Concrete Alkali–Aggregate-Reactivity-Induced Steel Reinforcement Corrosion

by Robert E. Melchers and Henry Humphrey

Corros. Mater. Degrad. 2023, 4(3), 428-444; https://doi.org/10.3390/cmd4030022 - 21 Jul 2023

Cited by 1 | Viewed by 1204

Abstract

The alkali–aggregate reactivity (AAR) of concrete, long known for mass concrete, can also induce corrosion of steel in reinforced concrete structures. Several examples are given for which the origin of observed reinforcement corrosion and loss of concrete cover originally was attributed to chloride-induced [...] Read more.

The alkali–aggregate reactivity (AAR) of concrete, long known for mass concrete, can also induce corrosion of steel in reinforced concrete structures. Several examples are given for which the origin of observed reinforcement corrosion and loss of concrete cover originally was attributed to chloride-induced or to carbonation-induced reinforcement corrosion. Critical reviews of these cases, using available information, suggest that, more likely, the observed crack patterns and concrete deterioration are the result of long-term AAR-induced concrete matrix expansion and loss of concrete strength and that these effects occurred prior to the eventual initiation of reinforcement corrosion. This proposition is supported by finite element and other stress analyses of various concrete–steel ensembles. They show that concrete expansion produces tensile stresses localised at and near exterior concrete surfaces or relative to the reinforcement. The locations of high-stress and -strain zones so produced correlate with field observations of long-term concrete cracking and delamination. The present interpretations highlight that AAR may be a significant contributor to initiation and subsequent long-term development of reinforcement corrosion in structurally reinforced concretes. Full article

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30 pages, 3485 KiB

Open AccessFeature PaperArticle

Passive Oxide Destruction by Dense Low-Energy Radionuclide i-Analyzed by Voltammetry ii-Analyzed by Chaos

by Gilbert Bellanger

Corros. Mater. Degrad. 2023, 4(3), 398-427; https://doi.org/10.3390/cmd4030021 - 15 Jul 2023

Viewed by 962

Abstract

The destruction of the passive oxide can be caused by the action of a radionuclide, which collides with the surface of the oxide. In this case, the

β^{-}

nuclear particle produced by the decay of tritiated water is considered for corrosion, and [...] Read more.

The destruction of the passive oxide can be caused by the action of a radionuclide, which collides with the surface of the oxide. In this case, the

β^{-}

nuclear particle produced by the decay of tritiated water is considered for corrosion, and it follows that the

β^{-}

energy is absorbed first into the oxide. The penetration depth is sufficient for all the passive oxides to be destabilized. Destabilization was examined by voltammetry and by the electrochemical circuit in the passive potential. The corresponding pathway leads to the destruction of oxide. Tests carried out using a chaos data analyzer are an aid for expertise. Different behavior may occur depending on the passive potential and the

β^{-}

density. The synchronization of phase space spectra and tests realized sector by sector make possible the interpretation of divergence leading to unstable oxide and oxide destruction at different passive potentials and for different

β^{-}

particle densities. Full article

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16 pages, 1913 KiB

Open AccessFeature PaperArticle

Microbial Communities Associated with Alternative Fuels in Model Seawater-Compensated Fuel Ballast Tanks

by Lina E. Dominici, Kathleen E. Duncan, Mark A. Nanny, Irene A. Davidova, Brian H. Harriman and Joseph M. Suflita

Corros. Mater. Degrad. 2023, 4(3), 382-397; https://doi.org/10.3390/cmd4030020 - 03 Jul 2023

Cited by 2 | Viewed by 1276

Abstract

The biocorrosion of carbon steel poses a risk for ships combining seawater and fuel in metal ballast tanks. Ballast tanks were simulated by duplicate reactors containing carbon steel coupons and either petroleum F76 (petro-F76), Fischer–Tropsch F76 (FT-F76), or a 1:1 mix of both [...] Read more.

The biocorrosion of carbon steel poses a risk for ships combining seawater and fuel in metal ballast tanks. Ballast tanks were simulated by duplicate reactors containing carbon steel coupons and either petroleum F76 (petro-F76), Fischer–Tropsch F76 (FT-F76), or a 1:1 mix of both fuels, to investigate whether the alternative fuel FT-F76 influenced this risk. The polycarbonate reactors were inoculated with seawater, and the control reactors did not receive fuel. The reactors were monitored for 400 days, and they all reached a pH and open circuit potential where elemental iron was oxidized, indicating corrosion. The reactors containing petro-76 or fuel mix had higher levels of dissolved iron; one of each replicate had lower concentrations of sulfate than the original seawater, while the sulfate concentration did not decrease in the other incubations. The high sulfate reactors, but not the low sulfate reactors, had a high relative abundance of microaerophilic sulfide-oxidizing bacteria. The FT-F76 and the no-fuel reactors had a high relative abundance of iron-sequestering Magnetovibrio. Although dissolved iron and loss of sulfate under anoxic conditions are associated with biocorrosion, our results suggest that in our reactors these indicators were altered by iron-sequestering and sulfide-oxidizing microbes, which is consistent with the slow diffusion of oxygen across the polycarbonate reactors. Full article

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18 pages, 7324 KiB

Open AccessArticle

Investigation of the Effect Chloride Ions on Carbon Steel in Closed Environments at Different Temperatures

by Saleh Ahmed, Yang Hou, Katerina Lepkova and Thunyaluk Pojtanabuntoeng

Corros. Mater. Degrad. 2023, 4(3), 364-381; https://doi.org/10.3390/cmd4030019 - 27 Jun 2023

Cited by 1 | Viewed by 1642

Abstract

This paper investigated carbon steel corrosion in an enclosed environment, where one set of steel was immersed in 3.5 wt.% NaCl solution and another exposed to humid (condensation) conditions. The study employed electrochemical noise and electrochemical impedance spectroscopy techniques to monitor real time [...] Read more.

This paper investigated carbon steel corrosion in an enclosed environment, where one set of steel was immersed in 3.5 wt.% NaCl solution and another exposed to humid (condensation) conditions. The study employed electrochemical noise and electrochemical impedance spectroscopy techniques to monitor real time corrosion behaviour. The samples were evaluated with surface characterisation techniques including optical light microscope, scanning electron microscope with energy dispersive X-ray spectroscopy, and Raman spectroscopy. The results showed that carbon steel immersed in the liquid phase at a constant temperature exhibited the highest weight loss. However, the carbon steel exposed to water condensation (gas phase) at 80 °C manifested extensive localised corrosion. EN results agreed with the microscopy findings. Full article

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19 pages, 7690 KiB

Open AccessArticle

Carbonation-Induced Corrosion of Reinforced Concrete Elements according to Their Positions in the Buildings

by Pascual Saura Gómez, Javier Sánchez Montero, Julio Emilio Torres Martín, Servando Chinchón-Payá, Nuria Rebolledo Ramos and Óscar Galao Malo

Corros. Mater. Degrad. 2023, 4(3), 345-363; https://doi.org/10.3390/cmd4030018 - 21 Jun 2023

Cited by 2 | Viewed by 2038

Abstract

Most regulations on the manufacturing of concrete for reinforced concrete structures rest on durability models that consider the corrosion of reinforcements. Those models are based on factors such as humidity, frost, presence of chlorides, and internal characteristics of the concrete itself, like resistance, [...] Read more.

Most regulations on the manufacturing of concrete for reinforced concrete structures rest on durability models that consider the corrosion of reinforcements. Those models are based on factors such as humidity, frost, presence of chlorides, and internal characteristics of the concrete itself, like resistance, porosity, type of cement, water/cement ratio, etc. No regulations, however, adopt a purely constructive perspective when evaluating the risk of corrosion, i.e., the relative position of the reinforced concrete in buildings. The present work focuses on the relationship between the position of the damaged element and the building envelope. A total of 84 elements (columns and reinforced concrete beams) across twenty buildings were analysed in the provinces of Alicante and Murcia (Spain). The reinforcement concrete of these elements underwent carbonation-induced corrosion according to their positions in the buildings: (A) façade columns in contact with the ground; (B) interior columns in contact with the ground; (C) columns of walls in contact with the ground; (D) columns and external beams protected from rain; (E) columns and external beams exposed to rain; (F) columns and beams in air chambers under sanitary slabs; and (G), columns and interior beams. Of all types, elements (E) and (F) suffered carbonation-induced corrosion faster than the models used in the regulations, and type (G) underwent slower carbonation. Full article

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Corros. Mater. Degrad., Volume 4, Issue 3 (September 2023) – 10 articles

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