Corrosion and Materials Degradation

22 pages, 19748 KiB

Open AccessArticle

Controlling Lateral Size and Thickness of Layered Double Hydroxide (LDH) Used as Conversion Layer for Corrosion Protection of AZ31 Mg Alloy

by Roya Malekkhouyan, Yoann Paint, Loïc Prince, Maurice Gonon and Marie-Georges Olivier

Corros. Mater. Degrad. 2023, 4(1), 174-195; https://doi.org/10.3390/cmd4010011 - 20 Mar 2023

Cited by 1 | Viewed by 2065

Abstract

In the present study, Mg-Al layered double hydroxide (Mg-Al/LDH) was synthesized on the surface of AZ31 Mg alloy substrate via in-situ hydrothermal treatment. Synthesis parameters were changed to determine their effect on the lateral size of LDH. For this purpose, etching in nitric [...] Read more.

In the present study, Mg-Al layered double hydroxide (Mg-Al/LDH) was synthesized on the surface of AZ31 Mg alloy substrate via in-situ hydrothermal treatment. Synthesis parameters were changed to determine their effect on the lateral size of LDH. For this purpose, etching in nitric acid and anodizing in sodium hydroxide solution were performed as surface pretreatments. Moreover, the influence of LDH solution pH (10 and 11) on the lateral size of LDH coating was investigated. Morphology, chemical composition, and crystalline structure were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The corrosion resistance of the coatings was investigated by H₂ measurements, salt spray, and electrochemical impedance spectroscopy (EIS). Moreover, the epoxy coating was applied on the best anti-corrosive LDH sample for assessing the compatibility and effectiveness of LDH on the corrosion properties of the substrate with the epoxy layer. At pH = 11, the lateral size of LDH was smaller than samples at pH = 10. In addition, small-sized LDH, as well as LDH/epoxy coating, revealed enhanced corrosion protection. Full article

(This article belongs to the Special Issue Advances in Corrosion Protection by Coatings)

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16 pages, 4527 KiB

Open AccessArticle

Scanning Kelvin Probe for Detection in Steel of Locations Enriched by Hydrogen and Prone to Cracking

by Andrei Nazarov, Varvara Helbert and Flavien Vucko

Corros. Mater. Degrad. 2023, 4(1), 158-173; https://doi.org/10.3390/cmd4010010 - 02 Mar 2023

Cited by 2 | Viewed by 1832

Abstract

Hydrogen, due to corrosion processes, can degrade high strength steels (HSS) through embrittlement and stress corrosion cracking mechanisms. Scanning Kelvin probe (SKP) mapping of surface potential was applied, to visualize the locations with an increased subsurface concentration of hydrogen in mild steel and [...] Read more.

Hydrogen, due to corrosion processes, can degrade high strength steels (HSS) through embrittlement and stress corrosion cracking mechanisms. Scanning Kelvin probe (SKP) mapping of surface potential was applied, to visualize the locations with an increased subsurface concentration of hydrogen in mild steel and martensitic HSS. This work can help to determine the reasons behind hydrogen localization in a steel microstructure, leading to embrittlement and hydrogen-assisted cracking. Cathodic charging was used to insert hydrogen, which decreased the steel potential. Hydrogen effusion in air passivates steel, increasing the potential of HSS and mild steel. The passivation of steels was monitored depending on different conditions of cathodic pre-charging and the amount of absorbed hydrogen. The SKP could determine the area of diffusible hydrogen and the area of cracks. In addition, low potential locations linked to the hydrogen trapped in the deformed HSS microstructure were also determined, which delayed the steel passivation. Mild steel showed a uniform potential distribution related to interstitial hydrogen, without potential extremes attributed to locally accumulated hydrogen. Thus, SKP sensing can detect locations containing increased concentrations of hydrogen and sensitive to steel cracking. Full article

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

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16 pages, 13412 KiB

Open AccessArticle

Microstructural, Corrosion, and Mechanical Characterization of Friction Stir Welded Al 6022-to-ZEK100 Mg Joints

by Qingli Ding, Hrishikesh Das, Piyush Upadhyay, Bryer C. Sousa, Kubra Karayagiz, Adam Powell and Brajendra Mishra

Corros. Mater. Degrad. 2023, 4(1), 142-157; https://doi.org/10.3390/cmd4010009 - 23 Feb 2023

Cited by 1 | Viewed by 1695

Abstract

Friction stir welded (FSW) aluminum–magnesium lightweight vehicle joints have gained significant interest due to their high strength-to-weight ratio. In this work, the corrosion resistance of this material is analyzed through electrochemical tests, which include open circuit potential (OCP) inspection and potentiodynamic polarization (PD) [...] Read more.

Friction stir welded (FSW) aluminum–magnesium lightweight vehicle joints have gained significant interest due to their high strength-to-weight ratio. In this work, the corrosion resistance of this material is analyzed through electrochemical tests, which include open circuit potential (OCP) inspection and potentiodynamic polarization (PD) scanning. Weight loss measurements tested the corrosion rate of the FSW weld through cyclic corrosion testing (CCT) according to the standard SAEJ 2334. Mechanical properties were also investigated, including lap-shear strength, micro- and nano-hardness mapping, and true stress–strain curves as a function of local processing history. The electrochemical results indicate that the center weld zone’s corrosion property stays between the two base alloys. Indentation-based testing demonstrated that the weld zone behaves differently from base alloys. Lap shear strength surprisingly did not drop much even after eight weeks of cyclic corrosion tests, indicating that the joint did not allow any ingress of the electrolyte. Full article

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22 pages, 33061 KiB

Open AccessArticle

Erosion–Corrosion of Novel Electroless Ni-P-NiTi Composite Coating

by Rielle Jensen, Zoheir Farhat, Md. Aminul Islam and George Jarjoura

Corros. Mater. Degrad. 2023, 4(1), 120-141; https://doi.org/10.3390/cmd4010008 - 08 Feb 2023

Cited by 1 | Viewed by 2107

Abstract

The lifespan of low-carbon steel petroleum pipelines can often be shortened by the erosion–corrosion damage caused by their service conditions. Applying electroless Ni-P coating is a promising option to protect the steel from the environment due to its high hardness and corrosion resistance. [...] Read more.

The lifespan of low-carbon steel petroleum pipelines can often be shortened by the erosion–corrosion damage caused by their service conditions. Applying electroless Ni-P coating is a promising option to protect the steel from the environment due to its high hardness and corrosion resistance. However, electroless Ni-P has a low toughness but can be increased by the addition of NiTi ductile particles. This work produced electroless Ni-P and Ni-P-NiTi coatings of different thicknesses on AISI 1018 substrates and compared their erosion, corrosion, and erosion–corrosion behaviors. The methodology involved conducting slurry pot erosion–corrosion tests on AISI 1018 steel substrate, the monolithic Ni-P coatings, and the composite Ni-P-NiTi coatings. Erosion resistance was highly influenced by coating thickness, presumably because of the relationship between the erosion-induced compressive stresses and the coating’s as-plated internal stresses. The NiTi nanoparticle addition was highly effective at improving the erosion–corrosion resistance of the coating. Pitting corrosion and cracking were present after erosion–corrosion on the monolithic Ni-P coatings. However, the Ni-P-NiTi composite coating had a relatively uniform material loss. Overall, the AISI 1018 steel substrate had the worst erosion–corrosion resistance and 25 μm thick Ni-P-NiTi coating had the best. Full article

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16 pages, 3599 KiB

Open AccessArticle

Development of an In Situ Micro-Corrosion Cell for the Investigation of Pitting Corrosion on Austenitic and Ferritic Stainless Steels

by Sinan Kiremit, Julian Cremer, Yannic Stallmeier, Adrian Sonntag, Michaela Klöcker, Dario Anselmetti, Andreas Hütten and Thomas Kordisch

Corros. Mater. Degrad. 2023, 4(1), 104-119; https://doi.org/10.3390/cmd4010007 - 31 Jan 2023

Cited by 1 | Viewed by 1821

Abstract

In order to investigate the electrochemical pitting corrosion in more detail, a micro-corrosion cell was developed, allowing real-time in situ optical observations of steel surfaces in direct correlation with electrochemical measurement results. In this study, the austenitic 1.4301–X5CrNi18-10 and the ferritic 1.4016–X6Cr17 stainless [...] Read more.

In order to investigate the electrochemical pitting corrosion in more detail, a micro-corrosion cell was developed, allowing real-time in situ optical observations of steel surfaces in direct correlation with electrochemical measurement results. In this study, the austenitic 1.4301–X5CrNi18-10 and the ferritic 1.4016–X6Cr17 stainless steel grades were examined in electrolytes containing chloride ions. The micro-corrosion cell revealed a stable pitting corrosion of the ferritic 1.4016 and metastable pitting corrosion of the austenitic 1.4301. The pits were characterized by means of scanning electron microscopy (SEM) and atomic force microscopy (AFM) in detail. A clear correlation between current peaks in the current density-potential curve and the growth of many small pits on the test surface was established and was identified as metastable pit growth. In general, the pitting corrosion potential increased as the diameter of the test surface decreased for both stainless steels. In contrast to the complex precipitates of 1.4301, chromium precipitates with a significantly higher amount was detected on the entire surface of the 1.4016. The corrosion initiation was identified at the interface between the precipitates and the base material for both stainless steels. By comparing both materials, the ferritic 1.4016 had a lower pitting corrosion potential than the austenitic 1.4301 under all test conditions. Full article

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14 pages, 70119 KiB

Open AccessArticle

Long-Exposure Air and Steam Oxidation Characteristics of IN 617 Alloys

by Rishikesh Karthikeyan, Satyanaryanan Seshadri, V Subramanya Sarma and M Kamaraj

Corros. Mater. Degrad. 2023, 4(1), 90-103; https://doi.org/10.3390/cmd4010006 - 31 Jan 2023

Cited by 1 | Viewed by 1646

Abstract

India’s growing power demands and emission norms require more efficient coal-based power plants. The shifting of power plants from subcritical to ultra-supercritical (USC) steam conditions could improve efficiency by 12% and reduce CO

_{2}

emissions by 35%. There is a need to develop [...] Read more.

India’s growing power demands and emission norms require more efficient coal-based power plants. The shifting of power plants from subcritical to ultra-supercritical (USC) steam conditions could improve efficiency by 12% and reduce CO

_{2}

emissions by 35%. There is a need to develop and qualify materials under ultra-supercritical steam conditions with high temperatures and high pressures in laboratory scale. The sample materials were exposed to high temperatures of 700 °C under air and high pressure steam at 700 °C/243 bars for 1000 h in as-received and grain-boundary-enhanced conditions. Grain boundary enhancement included optimization of a thermo-mechanical process involving cold rolling and annealing of samples. The effect of air and steam oxidation on IN 617, a nickel-based candidate superalloy, was analysed. Steam oxidation was performed on a custom-built PARR 4650 series autoclave, and the oxidized samples were characterised under scanning electron microscopy, to evaluate the oxide scales. The grain-boundary-engineered material performed better than the as-received samples. IN 617 overall fared better under both air and steam conditions, with far less weight gains. Full article

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36 pages, 10268 KiB

Open AccessArticle

Investigation via Electron Microscopy and Electrochemical Impedance Spectroscopy of the Effect of Aqueous Zinc Ions on Passivity and the Surface Films of Alloy 600 in PWR PW at 320 °C

by Yifan Jiang, Karen C. Bustillo and Thomas M. Devine

Corros. Mater. Degrad. 2023, 4(1), 54-89; https://doi.org/10.3390/cmd4010005 - 19 Jan 2023

Viewed by 1899

Abstract

Aqueous zinc ions lower the corrosion rate of Alloy 600, which helps lower the radiation dose rate in pressurized water reactors (PWRs). The influence of zinc on the electrochemical behavior of Alloy 600 in PWR primary water (PW) at 320 °C was investigated [...] Read more.

Aqueous zinc ions lower the corrosion rate of Alloy 600, which helps lower the radiation dose rate in pressurized water reactors (PWRs). The influence of zinc on the electrochemical behavior of Alloy 600 in PWR primary water (PW) at 320 °C was investigated using a combination of electron microscopy and electrochemical impedance spectroscopy (EIS). Secondary electron microscopy (SEM) and scanning transmission electron microscopy (STEM)/energy-dispersive X-ray spectroscopy (EDS) indicated duplex surface films were formed on the Alloy 600 in PWR PW with and without 100 ppb of zinc. There was no effect of zinc on the chromium-rich inner layer (IL) (of Cr₂O₃ and/or CrOOH). Zinc had a significant effect on the outer layer (OL). In the absence of zinc, a highly porous OL formed that was mostly composed of nickel oxide whiskers. In the presence of zinc, a zinc-containing, denser OL of oxide was formed. The EIS data were acquired in laboratory simulated PWR PW at 320 °C with and without 100 ppb zinc. The spectra were measured at nine different values of potential that spanned a 500 mV-wide range. The EIS indicated there was no effect of zinc on the oxidation rate of metals at the alloy/IL interface nor on the transport of ions through the IL. Zinc lowered the corrosion rate because the dense OL inhibited the release of nickel ions from the IL into the solution. Full article

(This article belongs to the Special Issue Corrosion and Materials Degradation under Irradiation: From Understanding to Mitigation…)

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21 pages, 16767 KiB

Open AccessReview

Avant-Garde Polymer/Graphene Nanocomposites for Corrosion Protection: Design, Features, and Performance

by Ayesha Kausar, Ishaq Ahmad, M. H. Eisa and Malik Maaza

Corros. Mater. Degrad. 2023, 4(1), 33-53; https://doi.org/10.3390/cmd4010004 - 17 Jan 2023

Cited by 3 | Viewed by 2165

Abstract

Polymeric coatings have been widely selected for the corrosion resistance of metallic surfaces. Both the conducting and non-conducting polymers have been applied for corrosion confrontation. The conducting polymers usually possess high electrical conductivity and corrosion resistance features. On the other hand, non-conducting hydrophobic [...] Read more.

Polymeric coatings have been widely selected for the corrosion resistance of metallic surfaces. Both the conducting and non-conducting polymers have been applied for corrosion confrontation. The conducting polymers usually possess high electrical conductivity and corrosion resistance features. On the other hand, non-conducting hydrophobic polymers have also been used to avert the metal erosion. To improve the corrosion inhibition performance of the polymer coatings, nanocarbon nanofillers have been used as reinforcement. Graphene, especially, has gained an important position in the research on the corrosion-protecting nanocomposite coatings. Here, graphene dispersion and matrix–nanofiller interactions may significantly improve the anti-corrosion performance to protect the underlying metals. The graphene nanofiller may form an interconnecting percolation network in the polymers to support their electrical conductivity and thus their corrosion confrontation characteristics. Further research on the polymer/graphene nanocomposite and its anti-corrosion mechanism may lead to great advancements in this field. Full article

(This article belongs to the Special Issue Corrosion Barrier Coatings)

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2 pages, 177 KiB

Open AccessEditorial

Acknowledgment to the Reviewers of Corrosion and Materials Degradation in 2022

by CMD Editorial Office

Corros. Mater. Degrad. 2023, 4(1), 31-32; https://doi.org/10.3390/cmd4010003 - 17 Jan 2023

Viewed by 1113

Abstract

High-quality academic publishing is built on rigorous peer review [...] Full article

13 pages, 16631 KiB

Open AccessArticle

Development of Photocatalytically Active Anodized Layers by a Modified Phosphoric Acid Anodizing Process for Air Purification

by Stephan Lederer, Sigrid Benfer, Jonathan Bloh, Rezan Javed, Aneta Pashkova and Wolfram Fuerbeth

Corros. Mater. Degrad. 2023, 4(1), 18-30; https://doi.org/10.3390/cmd4010002 - 31 Dec 2022

Viewed by 1947

Abstract

One of the key urban air quality issues is pollution by nitrogen oxides (NO

_{x}

). To reduce NO

_{x}

, facade cladding could be provided with photocatalytic properties by incorporating titanium dioxide nanoparticles. For this purpose, a modified phosphoric acid anodizing process [...] Read more.

One of the key urban air quality issues is pollution by nitrogen oxides (NO

_{x}

). To reduce NO

_{x}

, facade cladding could be provided with photocatalytic properties by incorporating titanium dioxide nanoparticles. For this purpose, a modified phosphoric acid anodizing process (MPAA) was developed for the facade alloy EN AW-5005, in which highly ordered anodized structures with a low degree of arborization and tortuosity were produced. Pore widths between 70 nm and 150 nm and layer thicknesses of about 2–3

μ

m were obtained. The subsequent impregnation was carried out by dip coating from water-based systems. Depending on the dip-coating parameters and the suspension used, the pores can be filled up to 60% with the TiO

_{2}

nanoparticles. Photocatalytic tests according to ISO 22197-1 certify a high photocatalytic activity was obtained with rPCE values > 8 and with rPCE > 2, achieving “photocatalytically active for air purification”. Tests on the corrosion resistance of the anodized coatings with a commercially available aluminum and facade cleaner confirm a protective effect of the anodized coatings when compared with nonanodized aluminum material, as well as with compacted anodized layers. Full article

(This article belongs to the Special Issue Advances in Corrosion Protection by Coatings)

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17 pages, 8186 KiB

Open AccessArticle

Experimental Design Considerations for Assessing Atmospheric Corrosion in a Marine Environment: Surrogate C1010 Steel

by Christine E. Sanders and Raymond J. Santucci, Jr.

Corros. Mater. Degrad. 2023, 4(1), 1-17; https://doi.org/10.3390/cmd4010001 - 31 Dec 2022

Cited by 1 | Viewed by 1753

Abstract

A rigorous assessment of marine atmospheric corrosion at a controlled NRL test site in Key West Florida was conducted. Certain factors which have been previously implicated in the literature as influencing the corrosion of engineering materials in atmospheric exposure were isolated and explored. [...] Read more.

A rigorous assessment of marine atmospheric corrosion at a controlled NRL test site in Key West Florida was conducted. Certain factors which have been previously implicated in the literature as influencing the corrosion of engineering materials in atmospheric exposure were isolated and explored. In particular, the effect of sample size and orientation was explored. Low carbon steel (C1010) witness coupons were exposed in vertical non-sheltered, vertical sheltered, and tilted non-sheltered conditions. The effect of surface area on measured steel mass loss was also explored to identify the veracity of the so-called “edge effect”. Efforts were made to correlate meteorological atmospheric conditions (temperature, relative humidity, wind speed, wind direction, etc.) to the monthly assessment of corrosion damage. Results were assessed in terms of steel mass loss. Additive composite monthly corrosion damage tended to significantly overshoot the observed cumulative corrosion damage for samples exposed over the same period. This observation, among others presented herein, suggests that exposure of samples for less than 6 months is not an adequate predictor of long-term, natural exposure. Additionally, a smaller sample had a larger area-normalized mass loss than a larger sample. The influence of the sample edge (especially the bottom edge) was implicated in causing this difference. Full article

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

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Corros. Mater. Degrad., Volume 4, Issue 1 (March 2023) – 11 articles

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