Corrosion and Protection of Metallic Materials

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Materials materials	3.4	5.2	2008	13.9 Days	CHF 2600
Metals metals	2.9	4.4	2011	15 Days	CHF 2600
Coatings coatings	3.4	4.7	2011	13.8 Days	CHF 2600
Chemistry chemistry	2.1	2.5	2019	19.1 Days	CHF 1800
Corrosion and Materials Degradation cmd	-	-	2020	20.2 Days	CHF 1000

18 pages, 7800 KiB

Open AccessArticle

Controlled Delivery of 2-Mercapto 1-Methyl Imidazole by Metal–Organic Framework for Efficient Inhibition of Copper Corrosion in NaCl Solution

by Zhishun Zhu and Xiulan Zhang

Materials 2023, 16(20), 6712; https://doi.org/10.3390/ma16206712 - 16 Oct 2023

Viewed by 889

Abstract

In this paper, zeolitic imidazolate framework-8 was modified by N-(3-aminopropyl)-imidazole to obtain a novel MOF called AMOF. Subsequently, AMOF served as a carrier for the delivery of 2-mercapto-1-methyl imidazole (MMI) to inhibit the corrosion of Cu. Scanning electron microscopy, Fourier transform infrared spectroscopy, [...] Read more.

In this paper, zeolitic imidazolate framework-8 was modified by N-(3-aminopropyl)-imidazole to obtain a novel MOF called AMOF. Subsequently, AMOF served as a carrier for the delivery of 2-mercapto-1-methyl imidazole (MMI) to inhibit the corrosion of Cu. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction were applied to characterize the morphologies and structures of AMOF and AMOF@MMI. Ultraviolet-visible spectroscopy and thermogravimetric analysis were adopted to value the capacity of the load and release of the AMOF, respectively. The mass ratio of loaded MMI molecules was 18.15%. In addition, the inhibition behavior of AMOF@MMI for Cu was evaluated by polarization curves and electrochemical impedance spectroscopy. The results indicated that the AMOF loaded MMI successfully, and the released MMI could adsorb on the Cu surface and inhibit the Cu corrosion. The inhibition efficiency could reach 88.2%. The binding and interaction energies between the AMOF surface and the MMI were −16.41 kJ/mol and −20.27 kJ/mol. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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27 pages, 2056 KiB

Open AccessReview

Natural Polyphenols and the Corrosion Protection of Steel: Recent Advances and Future Perspectives for Green and Promising Strategies

by Rossella Sesia, Silvia Spriano, Marco Sangermano and Sara Ferraris

Metals 2023, 13(6), 1070; https://doi.org/10.3390/met13061070 - 03 Jun 2023

Cited by 2 | Viewed by 2310

Abstract

Corrosion is recognized as an unavoidable phenomenon and steel, particularly carbon steel, is strongly susceptible to corrosion. Corrosion damages cause serious material, energy, and economic losses as well as negative impacts on the environment. As a result, research interest has been focused on [...] Read more.

Corrosion is recognized as an unavoidable phenomenon and steel, particularly carbon steel, is strongly susceptible to corrosion. Corrosion damages cause serious material, energy, and economic losses as well as negative impacts on the environment. As a result, research interest has been focused on the development of effective corrosion prevention strategies. However, some of the most commonly used corrosion inhibitors, such as chromates and pyridines, are harmful to human and environmental health. Polyphenols are natural, non-toxic, and biodegradable compounds from plant sources or agricultural by-products. Polyphenols’ chelating capacity has been acknowledged since the 1990s, and tannins, in particular, have been widely exploited as green rust converters in phosphoric acid-based formulations to recover rusty steel. Polyphenolic compounds have recently been investigated as a method of corrosion prevention. This review overviews not only the polyphenolic rust converters, but also the application of green anticorrosive coatings containing polyphenols. Moreover, polyphenols were discussed as an active component in corrosion-inhibiting primers to also promote strong adhesion between the steel surface and the topcoat layer. Finally, an overview of the use of polyphenolic additives in coatings as sustainable systems to improve corrosion resistance is provided. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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20 pages, 15060 KiB

Open AccessArticle

Effect of Surface Roughness on Static Corrosion Behavior of J55 Carbon Steel in CO₂-Containing Geothermal Water at 65 °C

by Haitao Bai, Xing Cui, Rui Wang, Naixin Lv, Xupeng Yang, Ruixuan Li and Yun Ma

Coatings 2023, 13(5), 821; https://doi.org/10.3390/coatings13050821 - 23 Apr 2023

Cited by 1 | Viewed by 1146

Abstract

The influence of surface roughness on the static corrosion behavior of J55 carbon steel in CO₂-containing geothermal water environment was investigated with respect to average corrosion rate, morphology, chemical composition, corrosion depth, and the cross section of corrosion products. The influence [...] Read more.

The influence of surface roughness on the static corrosion behavior of J55 carbon steel in CO₂-containing geothermal water environment was investigated with respect to average corrosion rate, morphology, chemical composition, corrosion depth, and the cross section of corrosion products. The influence of surface roughness on the CO₂ corrosion of J55 carbon steel was then proposed based on the understanding of corrosion at 65 °C. The results show that the static corrosion rate of J55 carbon steel in CO₂-containing geothermal water increases with increasing surface roughness. The surface roughness of J55 carbon steel increases 5.3-fold and the CO₂ corrosion rate increases by 1.4-fold under different exposure times. The static corrosion rate of J55 carbon steel in CO₂-containing geothermal water changes with exposure time. The corrosion rate of J55 carbon steel decreases with the increase in exposure time, and there is little change in the corrosion rate after immersion for 2 days. At the initial stage of corrosion, the corrosion rate of J55 carbon steel was mainly affected by surface roughness. The greater the roughness, the greater the corrosion driving force and the corrosion reaction surface area and therefore the greater the corrosion rate of J55 carbon steel. After immersion for 2 days, a continuous corrosion product layer was formed on the surface of J55 carbon steel and the corrosion rate was mainly affected by the corrosion product layer. The corrosion products of J55 carbon steel are not altered by surface roughness in a CO₂-containing geothermal water environment. The corrosion products of J55 carbon steel are FeCO₃ and a minute amount of CaCO₃. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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16 pages, 3017 KiB

Open AccessArticle

Synthesis and Characterisation of CeO₂ Coatings on the AZ31 Alloy for Corrosion Protection and In Vitro Biocompatibility of MC3T3-E1 Pre-Osteoblasts

by Sandra E. Benito-Santiago, Edgar Onofre-Bustamante and Rosa M. Lozano-Puerto

Metals 2023, 13(4), 653; https://doi.org/10.3390/met13040653 - 25 Mar 2023

Cited by 1 | Viewed by 1164

Abstract

The use of bioabsorbable metals as temporary medical implants has attracted considerable research interest as they do not require a second surgical operation for removal after the healing process is completed. However, magnesium (Mg) and its alloys have a degradation rate that is [...] Read more.

The use of bioabsorbable metals as temporary medical implants has attracted considerable research interest as they do not require a second surgical operation for removal after the healing process is completed. However, magnesium (Mg) and its alloys have a degradation rate that is too high in biological environments. Therefore, it must be controlled using various strategies. In this study, an AZ31-Mg-based alloy coated with CeO₂ is investigated to analyse the effect of the coating on its corrosion protection and biocompatibility. The AZ31 alloy is anodised with NaOH solution, before coating to stabilise the alloy surface. The CeO₂ coating is deposited on anodised AZ31 by chemical conversion treatment. The electrochemical properties of samples are evaluated using electrochemical impedance spectroscopy and cyclic polarisation curves using Hank’s solution. Structural and morphological characterisation of the samples are performed using X-ray diffraction and scanning electron microscopy–energy dispersive X-ray spectroscopy. Additionally, biocompatibility is determined by live/dead assay using MC3T3-E1 pre-osteoblasts. The preliminary results indicate that CeO₂ coatings exhibit higher electrochemical properties. Additionally, an increase in the ratio of live/dead cells of the AZ31OH-CeO₂ surface is detected, in contrast with AZ31, thus indicating improvement in biocompatibility upon CeO₂ coating. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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22 pages, 3232 KiB

Open AccessArticle

Preparation and Performance of a Self-Produced High-Molecular-Weight Waterborne Epoxy–Acrylic Emulsion

by Jianbao Liu, Yifu Zhang and Jianping Sun

Coatings 2023, 13(3), 595; https://doi.org/10.3390/coatings13030595 - 10 Mar 2023

Cited by 2 | Viewed by 1781

Abstract

To improve the stability of waterborne epoxy–acrylic emulsions and their comprehensive properties, such as the chemical resistance of coatings, a new research idea is proposed in this paper. First, a series of high-molecular-weight epoxy resins were synthesized with epoxy resin E-51 and bisphenol [...] Read more.

To improve the stability of waterborne epoxy–acrylic emulsions and their comprehensive properties, such as the chemical resistance of coatings, a new research idea is proposed in this paper. First, a series of high-molecular-weight epoxy resins were synthesized with epoxy resin E-51 and bisphenol A (BPA) using benzyl triphenyl phosphine bromide as the catalyst. Then, free-radical graft copolymerization was carried out between the epoxy resin and methacrylic acid (MAA), styrene (ST), and butyl acrylate (BA) using benzoyl peroxide (BPO) as the initiator. This method ensured that the epoxy groups were retained. Finally, the carboxylic acid groups were neutralized with N,N-dimethylethanolamine (DMEA), and a stable aqueous epoxy–acrylic emulsion was obtained by high-speed dispersion in deionized water. The effects of key factors such as temperature, time, the molecular weight and dosage of epoxy resin, the dosage of MAA, the dosage of BPO, and the neutralization degree of the synthesis of emulsions and coating film properties were mainly discussed. The molecular weight and molecular weight distribution of the epoxy resin were determined by gel permeation chromatography (GPC). The epoxy resin and its graft copolymer were analyzed and characterized by Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The particle size and distribution of the emulsions were tested by laser particle size analysis. The morphology of the emulsion particles was observed by transmission electron microscopy. The results showed that the acrylic monomers (MAA, ST, and BA) were grafted onto the epoxy resin. The graft copolymers showed higher glass transition temperatures compared with those of the pure epoxy resin. TGA showed that the graft copolymer started to decompose at a high temperature before the pure epoxy resin did, and the thermal stability was slightly reduced. The prepared emulsions with a particle size of 160 nm had a storage stability of more than one year and showed excellent dilution stability, mechanical stability, and freeze–thaw stability. The emulsions were coated and cured at 150 °C for 1 h with a pencil hardness of 5 H, an adhesion of grade 1, and a flexibility of 1 mm. The water resistance was >60 days, the salt water resistance was >30 days, the acid resistance was >10 days, and the alkali resistance was >5 days. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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14 pages, 2866 KiB

Open AccessArticle

Photopolymerization of Coating Materials for Protection against Carbon Steel Corrosion

by Bo Li, Huibing Yang, Jinhang He, Siwu Yu, Rengui Xiao, Huanhu Luo, Yi Wen, Shengyan Peng, Xia Liao and Daning Yang

Materials 2023, 16(5), 2015; https://doi.org/10.3390/ma16052015 - 28 Feb 2023

Cited by 1 | Viewed by 1019

Abstract

This work demonstrated a workable approach for the synthesis of a re-healing polyaniline-modified epoxy resin coating material via photopolymerization. The prepared coating material exhibited low water absorption, allowing it to be used as an anti-corrosion protective layer for carbon steel. First, graphene oxide [...] Read more.

This work demonstrated a workable approach for the synthesis of a re-healing polyaniline-modified epoxy resin coating material via photopolymerization. The prepared coating material exhibited low water absorption, allowing it to be used as an anti-corrosion protective layer for carbon steel. First, graphene oxide (GO) was synthesized through the modified Hummers’ method. It was then mixed with TiO₂ to extend its light response range. The structural features of the coating material were identified using scanning electron microscopy (SEM), X ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT IR). The corrosion behavior of the coatings and the pure resin layer were tested by using electrochemical impedance spectroscopy (EIS) and the potentiodynamic polarization curve (Tafel). The presence of TiO₂ reduced the corrosion potential (E_corr) toward lower values in 3.5% NaCl at room temperature, which was due to the photocathode of titanium dioxide. The experimental results indicated that GO was successfully compounded with TiO₂ and that GO effectively improved the light utilization capacity of TiO₂. The experiments showed that the presence of local impurities or defects can reduce the band gap energy, resulting in a lower Eg for the 2GO:1TiO₂ composite (2.95 eV) compared to that of TiO₂ alone (3.37 eV). After applying visible light to the coating surface, the change in the Ecorr value of the V-composite coating was 993 mV and the value of I_corr decreased to 1.993 × 10⁻⁶ A/cm². The calculated results showed that the protection efficiency of the D-composite and V-composite coatings on composite substrates was approximately 73.5 and 83.3%, respectively. More analyses revealed that under visible light, the coating had better corrosion resistance. This coating material is expected to be a candidate for carbon steel corrosion protection. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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14 pages, 4414 KiB

Open AccessArticle

Textural, Microstructural and Chemical Characterization of Ferritic Stainless Steel Affected by the Gold Dust Defect

by Beatriz Amaya Dolores, Andrés Ruiz Flores, Andrés Núñez Galindo, José Juan Calvino Gámez, Juan F. Almagro and Luc Lajaunie

Materials 2023, 16(5), 1825; https://doi.org/10.3390/ma16051825 - 23 Feb 2023

Cited by 3 | Viewed by 1317

Abstract

The “gold dust defect” (GDD) appears at the surface of ferritic stainless steels (FSS) and degrades their appearance. Previous research showed that this defect might be related to intergranular corrosion and that the addition of aluminium improves surface quality. However, the nature and [...] Read more.

The “gold dust defect” (GDD) appears at the surface of ferritic stainless steels (FSS) and degrades their appearance. Previous research showed that this defect might be related to intergranular corrosion and that the addition of aluminium improves surface quality. However, the nature and origin of this defect are not properly understood yet. In this study, we performed detailed electron backscatter diffraction analyses and advanced monochromated electron energy-loss spectroscopy experiments combined with machine-learning analyses in order to extract a wealth of information on the GDD. Our results show that the GDD leads to strong textural, chemical, and microstructural heterogeneities. In particular, the surface of affected samples presents an α-fibre texture which is characteristic of poorly recrystallised FSS. It is associated with a specific microstructure in which elongated grains are separated from the matrix by cracks. The edges of the cracks are rich in chromium oxides and MnCr₂O₄ spinel. In addition, the surface of the affected samples presents a heterogeneous passive layer, in contrast with the surface of unaffected samples, which shows a thicker and continuous passive layer. The quality of the passive layer is improved with the addition of aluminium, explaining the better resistance to the GDD. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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13 pages, 4808 KiB

Open AccessArticle

Effect of Mo Content on Hydrogen Evolution Reaction of 1400 MPa-Grade High-Strength Bolt Steel

by Xilin Xiong, Keke Song, Jinxu Li and Yanjing Su

Materials 2023, 16(3), 1020; https://doi.org/10.3390/ma16031020 - 22 Jan 2023

Cited by 1 | Viewed by 1243

Abstract

The effect of Mo content of 1400 MPa-grade high-strength bolt steel on hydrogen diffusion behavior and the hydrogen evolution reaction were studied using a hydrogen permeation experiment, potentiodynamic polarization tests, thermal desorption spectroscopy, and the first-principle calculation. Two 1400 MPa-grade high-strength bolt steels [...] Read more.

The effect of Mo content of 1400 MPa-grade high-strength bolt steel on hydrogen diffusion behavior and the hydrogen evolution reaction were studied using a hydrogen permeation experiment, potentiodynamic polarization tests, thermal desorption spectroscopy, and the first-principle calculation. Two 1400 MPa-grade high-strength bolt steels with different Mo content were used. Based on the potentiodynamic polarization tests, both steels’ electrochemical behavior was similar in the test range. The hydrogen permeation experiment showed that the process of hydrogen adsorption and absorption was significantly promoted, and hydrogen desorption and recombination were slightly promoted, with the Mo content increasing from 0.70 to 1.09 wt%. The thermal desorption spectroscopy showed the overall reaction of hydrogen permeation and evolution. The increasing Mo content facilitated hydrogen entry behavior and increased the hydrogen content. According to the first-principle calculation and the density functional theory, this phenomenon is induced by the stronger bonding ability of Mo-H than Fe-H. This work could guide the design of 1400 MPa-grade high-strength bolt steel. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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14 pages, 27280 KiB

Open AccessFeature PaperArticle

Wear and Corrosion Resistance of CrYN Coating in Artificial Seawater

by Man Li, Yunjiang Yu, Changwei Zou, Canxin Tian, Zesong Wang and Yanxiong Xiang

Metals 2023, 13(2), 183; https://doi.org/10.3390/met13020183 - 17 Jan 2023

Cited by 4 | Viewed by 1136

Abstract

In this study, CrYN coatings were prepared using multi-arc ion plating at various substrate bias voltages (−50 V, −100 V, −150 V, and −200 V). X-ray diffractometry and scanning electron microscopy were used to characterize the composition and microstructure of the coatings. An [...] Read more.

In this study, CrYN coatings were prepared using multi-arc ion plating at various substrate bias voltages (−50 V, −100 V, −150 V, and −200 V). X-ray diffractometry and scanning electron microscopy were used to characterize the composition and microstructure of the coatings. An electrochemical workstation and a ball-on-disk tribometer were used to investigate their corrosion and friction behavior. The results show that grain refinement can be achieved through the addition of yttrium (Y) and that the surfaces of coatings prepared under different bias voltages have varying smoothness and compactness. It was shown that surfaces prepared under −100 V bias voltages were relatively smooth and dense in structure, corresponding to a Y content of 2.83 at.%; CrYN coatings at −100 V were shown to have the highest corrosion potential and a low self-corrosion current, equating to superior corrosion resistance. Additionally, the friction coefficients of deposited CrYN coatings under bias voltages of −100 V were less than 0.2. Therefore, the coatings under bias voltages of −100 V had the minimum wear rate due to its structure, corrosion resistance, and friction. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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14 pages, 4509 KiB

Open AccessArticle

The Effect of Temperatures on the Passivation Behavior of Q235 Steel in the Simulated Concrete Pore Solution

by Haosen Jiang, Zuquan Jin, Xiaoying Zhang, Lixing Qian and Zhaoliang Zhou

Materials 2023, 16(2), 588; https://doi.org/10.3390/ma16020588 - 07 Jan 2023

Viewed by 1409

Abstract

Concrete, especially mass concrete, releases a large amount of heat during the hydration process, resulting in the passivation of reinforcement at high temperatures. However, the passivation study of reinforced concrete is mostly conducted at room temperature, and the influence of temperature on passive [...] Read more.

Concrete, especially mass concrete, releases a large amount of heat during the hydration process, resulting in the passivation of reinforcement at high temperatures. However, the passivation study of reinforced concrete is mostly conducted at room temperature, and the influence of temperature on passive film behavior is not clear at present. The passivation film of reinforcing steel directly determines the corrosion resistance of reinforcing steel and affects the service life of reinforced concrete. Herein, the passivation of Q235 steel soaking in simulated concrete pore (SCP) solution at 20 °C, 40 °C, and 60 °C is explored. It is found that the passivation process is divided into two stages, with 24 h as the boundary; within 24 h the passivation was carried out rapidly, and the passive film is in a relatively stable state after 24 h. In addition, the higher the temperature, the faster the passivation. Moreover, under the condition of higher temperatures, more Fe³⁺ compounds are produced, and the semiconductor properties of passivated films are more stable. Based on experiments, the passivation mechanism affected by temperature was analyzed in detail. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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22 pages, 4602 KiB

Open AccessArticle

Evaluation in Real Conditions of New Anticorrosive Formulations Based on Polyphenols from Natural Sources and Encapsulated Nanoparticles

by Jesús Ramírez, Andrés Díaz-Gómez, Luis Felipe Montoya, Saireddy Shiva Samhitha, David Rojas, Ángelo Oñate, Andrés Felipe Jaramillo and Manuel Francisco Melendrez

Coatings 2023, 13(1), 8; https://doi.org/10.3390/coatings13010008 - 21 Dec 2022

Cited by 2 | Viewed by 1347

Abstract

The objective of this study was to examine the combined protection effect of a two-layer system consisting of organic corrosion inhibitors (tannins derived from the bark of radiata pine) and anodic protection by means of the incorporation of zinc oxide nanoparticles modified superficially [...] Read more.

The objective of this study was to examine the combined protection effect of a two-layer system consisting of organic corrosion inhibitors (tannins derived from the bark of radiata pine) and anodic protection by means of the incorporation of zinc oxide nanoparticles modified superficially by chemical methods to improve the protection of metallic structures against corrosion. Film evaluations are performed in accordance with ISO and ASTM standards. This study also took into account the evaluation of the performance of two commercial coatings according to the scheme suggested by the supplier, in addition to the electrochemical impedance spectroscopy (EIS) characterizations at 0 h, 720 h of accelerated exposure, and 4 months of atmospheric exposure in a corrosive environment of classification C3. The results obtained indicated that the combination of tannins derived from pine bark and encapsulated zinc oxide nanoparticles is a viable alternative to commercial coatings with a higher concentration of synthetic compounds. Although the film properties decrease slightly, performance tests at different exposure times show that they can still be classified as high-performance coatings. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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17 pages, 4767 KiB

Open AccessArticle

Corrosion Activity of Carbon Steel B450C and Stainless Steel SS430 Exposed to Extract Solution of a Supersulfated Cement

by David Bonfil, Lucien Veleva, Sebastian Feliu, Jr. and José Iván Escalante-García

Materials 2022, 15(24), 8782; https://doi.org/10.3390/ma15248782 - 08 Dec 2022

Cited by 1 | Viewed by 1262

Abstract

Carbon steel B450C and low-chromium stainless steel SS430 were exposed for 30 days to supersulfated “SS1” cement extract solution, considered as a “green” alternative for partial replacement of the Portland cement clinker. The initial pH of 12.38 dropped since the first day to [...] Read more.

Carbon steel B450C and low-chromium stainless steel SS430 were exposed for 30 days to supersulfated “SS1” cement extract solution, considered as a “green” alternative for partial replacement of the Portland cement clinker. The initial pH of 12.38 dropped since the first day to 7.84, accompanied by a displacement to more negative values of the free corrosion potential (OCP) of the carbon steel up to ≈−480.74 mV, giving the formation of γ-FeOOH, α-FeOOH and Fe₂O₃, as suggested by XRD and XPS analysis. In the meantime, the OCP of the SS430 tended towards more positive values (+182.50 mV), although at lower pH, and XPS analysis revealed the presence of Cr(OH)₃ and FeO as corrosion products, as well the crystals of CaCO₃, NaCl and KCl. On both surfaces, a localized corrosion attack was observed in the vicinity of local cathodes (Cu, Mn-carbides, Cr-nitrides, among others), influenced by the presence of Cl⁻ ions in the “SS1” extract solution, originating from the pumice. Two equivalent circuits were proposed for the quantitative analysis of EIS Nyquist and Bode diagrams, whose data were correlated with the OCP values and pH change in time of the “SS1” extract solution. The thickness of the corrosion layer formed on the SS430 surface was ≈0.8 nm, while that on the B450C layer was ≈0.3 nm. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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13 pages, 6806 KiB

Open AccessArticle

The Failure Mechanism of the 316 SS Heat Exchanger Tube in the Geothermal Water Environment

by Jike Yang, Chan Li, Yue Pan and Hui Huang

Materials 2022, 15(22), 8103; https://doi.org/10.3390/ma15228103 - 16 Nov 2022

Cited by 3 | Viewed by 1147

Abstract

In this work, the intrinsic reason for the premature failure of a 316 stainless steel heat exchanger tube in geothermal water environment is disclosed. The chemical composition of the tube was tested, and the microstructure was examined for material inspection. Fracture morphology and [...] Read more.

In this work, the intrinsic reason for the premature failure of a 316 stainless steel heat exchanger tube in geothermal water environment is disclosed. The chemical composition of the tube was tested, and the microstructure was examined for material inspection. Fracture morphology and secondary cracks were analyzed, and electron backscattered diffraction was applied to explore the crack propagation mode. The corrosion morphology was observed. The electrochemical behavior was studied with cyclic polarization and double-loop electrochemical potentiokinetic reactivation. It is found that the main failure cause was stress corrosion cracking (SCC). Attacked by chloride ions, the tube is susceptible to SCC under the residual stress as a result of the substandard Mo and Ni content. The SCC mechanism is localized anodic dissolution, and the propagation mode is a mixture of transgranular SCC and intergranular SCC. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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19 pages, 22356 KiB

Open AccessArticle

Durability and Corrosion Properties of Waterborne Coating Systems on Mild Steel Dried under Atmospheric Conditions and by Infrared Radiation

by Ivan Stojanović, Ivan Cindrić, Lovro Turkalj, Marin Kurtela and Daniela Rakela-Ristevski

Materials 2022, 15(22), 8001; https://doi.org/10.3390/ma15228001 - 12 Nov 2022

Cited by 4 | Viewed by 1417

Abstract

Increasing attention is given to waterborne coatings for corrosion protection due to the lower ecological impact on the environment. It has been found that by using waterborne coatings, the emission of harmful volatile organic compounds (VOCs) is reduced by more than 50 g/L. [...] Read more.

Increasing attention is given to waterborne coatings for corrosion protection due to the lower ecological impact on the environment. It has been found that by using waterborne coatings, the emission of harmful volatile organic compounds (VOCs) is reduced by more than 50 g/L. However, they require longer drying time, their anti-corrosion performance is not as good as solvent-borne coatings and they still have not been developed for all corrosion environments. Another way to reduce VOCs is by using infrared (IR) drying technology. With catalytic infrared radiation, it is possible to cure all surfaces at notably reduced costs compared to traditional systems and in total respect for the environment, thanks to significant energy savings and minimal CO₂ emissions. The aim of this paper was to evaluate corrosion protective properties of waterborne coatings which were dried with traditional and accelerated drying techniques, i.e., under atmospheric conditions and by using IR technology. Two different coating systems were applied, with and without Zn in the primer. To achieve this goal, the test samples were subjected to electrochemical, corrosion, and physical tests. It was shown that infrared technology does not affect the quality of the coating and it drastically reduces the intercoating interval. A coating system with zinc in the primer showed better overall protection properties after being subjected to impedance and salt spray testing, but generally, solvent-borne coatings still have higher durability than waterborne in extreme marine conditions according to recent research. Microstructure and porosity remained intact and the atomic force microscope confirmed that the flash-off was conducted correctly since there were no pinholes and blisters detected on the coating’s surface. This study can serve as a foundation for further investigations of IC-dried waterborne coatings because there are not many at the moment. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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14 pages, 2566 KiB

Open AccessArticle

A Novel Simple Fabrication Method for Mechanically Robust Superhydrophobic 2024 Aluminum Alloy Surfaces

by Li-Mei Shan, Guo-Biao Liu, Hua Tang, Zhi-Hong Li and Ju-Ying Wu

Coatings 2022, 12(11), 1717; https://doi.org/10.3390/coatings12111717 - 10 Nov 2022

Cited by 1 | Viewed by 1412

Abstract

The mechanical durability of a superhydrophobic aluminum alloy surface is an important indicator of its practical use. Herein, we propose a strategy to prepare a superhydrophobic 2024 aluminum alloy surface with highly enhanced mechanical durability by using a two-step chemical etching method, using [...] Read more.

The mechanical durability of a superhydrophobic aluminum alloy surface is an important indicator of its practical use. Herein, we propose a strategy to prepare a superhydrophobic 2024 aluminum alloy surface with highly enhanced mechanical durability by using a two-step chemical etching method, using a NaOH solution as the etchant in step one and a Na₂CO₃ solution as the etchant in step two. Robust mechanical durability was studied by static contact angle tests before and after an abrasion test, potentiodynamic polarization measurements after an abrasion test and electrochemical impedance spectroscopy tests after an abrasion test. Furthermore, the mechanism for enhanced mechanical durability was investigated through scanning of electron microscopy images, energy-dispersive X-ray spectra, Fourier transform infrared spectra and X-ray photoelectron spectra. The testing results indicate that a hierarchical rough surface consisting of regular micro-scale dents and some nano-scale fibers in the micro-scale dents, obtained with the two-step chemical etching method, contributes to highly enhanced mechanical durability. Meanwhile, the as-prepared superhydrophobic 2024 aluminum alloy surface retained a silvery color instead of the black shown on the superhydrophobic 2024 aluminum alloy surface prepared by a conventional one-step chemical etching method using NaOH solution as the etchant. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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19 pages, 8128 KiB

Open AccessArticle

Manufacture and Characterization of Geopolymer Coatings Deposited from Suspensions on Aluminium Substrates

by Jan Novotný, Martin Jaskevič, Filip Mamoń, Jakub Mareš, Roman Horký and Pavel Houška

Coatings 2022, 12(11), 1695; https://doi.org/10.3390/coatings12111695 - 07 Nov 2022

Cited by 5 | Viewed by 1546

Abstract

Geopolymers compete with a number of conventional coatings and a few of them have already been replaced. The aim of this work was the analysis of alkali-activated metakaolin-based geopolymers and their use as brush-applied coatings, which were chosen due to their simplicity and [...] Read more.

Geopolymers compete with a number of conventional coatings and a few of them have already been replaced. The aim of this work was the analysis of alkali-activated metakaolin-based geopolymers and their use as brush-applied coatings, which were chosen due to their simplicity and cost-effectiveness. Eight coatings were prepared and the AlMgSi aluminum alloy underlying the substrate was also studied. The main characterizations of the prepared coatings were the microscopy analysis, which showed that manual painting with a brush on the coatings we prepared could achieve a high-quality geopolymer layer, and that if microscopic cracks are visible on the surface, they are uniform and do not affect the resulting cohesiveness of the coating. The thicknesses of these coatings are different, ranging from 1.5 to 11 μm, with no visible anomalies. For the evaluation of the properties of the coatings, we determined the analysis of adhesion to the adjacent substrate, microhardness and thermal expansion determined using the so-called dilatometric analysis as important criteria. For these analyses, the results vary by geopolymer type and are discussed in the following chapters. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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13 pages, 2477 KiB

Open AccessArticle

Low-Melting Phosphate Glass Coatings for Structural Parts Composed of Depleted Uranium

by Volodymyr Lobaz, Magdalena Konefał, Nikolay Kotov, Miroslava Lukešová, Jiřina Hromádková, Miroslav Šlouf, Jiří Pánek, Martin Hrubý, Tomáš Chmela and Pavel Krupička

Coatings 2022, 12(10), 1540; https://doi.org/10.3390/coatings12101540 - 13 Oct 2022

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Abstract

The applications of depleted uranium in mechanical engineering are limited by its high susceptibility to corrosion. Among various methods of corrosion protection, painting is usually considered a fast and cost-efficient method; however, organic polymer paints are sensitive to ionizing radiation, which is a [...] Read more.

The applications of depleted uranium in mechanical engineering are limited by its high susceptibility to corrosion. Among various methods of corrosion protection, painting is usually considered a fast and cost-efficient method; however, organic polymer paints are sensitive to ionizing radiation, which is a limiting factor, e.g., for the fabrication of shielding containers or structural parts. The solution presented in this work is the creation of a glassy inorganic layer on top of the depleted uranium surface. Zinc lead phosphate low-melting glass was investigated for this purpose. Glass frit was obtained as an amorphous solid, as confirmed by differential scanning calorimetry and X-ray diffraction. The frit was easily ground in liquid media down to sizes suitable for spraying onto the surface of depleted uranium. When the glass powder is sprayed onto the surface of a substrate and fired at 440 °C, a partially crystallized continuous film with a complex morphology is formed, which significantly inhibits corrosion. The coating material shows resistance against high doses of γ-irradiation. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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16 pages, 3878 KiB

Open AccessArticle

Corrosion and Electrochemical Properties of Laser-Shock-Peening-Treated Stainless Steel AISI 304L in VVER Primary Water Environment

by Xavier Arnoult, Mariana Arnoult-Růžičková, Jan Maňák, Alberto Viani, Jan Brajer, Michel Arrigoni, Radek Kolman and Jan Macák

Metals 2022, 12(10), 1702; https://doi.org/10.3390/met12101702 - 12 Oct 2022

Cited by 3 | Viewed by 1620

Abstract

Laser Shock Peening (LSP) is a surface treatment technique for metallic materials. It induces plastic deformation at the surface of up to around 1 mm in depth. This process introduces residual stresses that lead to strain hardening, and potentially improvements in fatigue, stress [...] Read more.

Laser Shock Peening (LSP) is a surface treatment technique for metallic materials. It induces plastic deformation at the surface of up to around 1 mm in depth. This process introduces residual stresses that lead to strain hardening, and potentially improvements in fatigue, stress corrosion cracking (SCC) and general corrosion behaviour in many, but not all, corrosive media. In this paper, two specimens made of AISI 304L stainless steel, one LSP-treated and one un-treated, were tested at 280 °C and 8 MPa in VVER (or PWR) primary circuit water chemistry using in situ Electrochemical Impedance Spectroscopy (EIS). This experiment serves to qualify the influence of LSP on the changes in corrosion behaviour in high-temperature, high-density water. The residual stress (RS) measurement of the surface showed a compression RS. Before LSP treatment, RS at the surface was 52.2 MPa in the rolling direction 0°RD and 10.42 MPa in the transverse rolling direction 90°RD. After the treatment, surface RS was −175.27 MPa and −183.51 MPa for Scan and TScan directions, respectively. The effect of compressive RS at the surface was studied and showed an increase in corrosion rate. The analysis of oxide layer by SEM revealed differences between LSP-treated and untreated AISI 304L specimens and their connection to corrosion rates. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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18 pages, 5789 KiB

Open AccessArticle

Influence of 40% Cold Working and Annealing on Precipitation in AISI 316L Austenitic Stainless Steel

by Katarína Bártová, Mária Dománková, Jozef Bárta and Peter Pastier

Materials 2022, 15(18), 6484; https://doi.org/10.3390/ma15186484 - 19 Sep 2022

Cited by 1 | Viewed by 1659

Abstract

Intergranular corrosion is one of the most important processes affecting the behaviour of austenitic stainless steels. Factors such as steel chemical composition, the degree of prior deformation and the exposure temperature affect the degree of sensitisation. AISI 316L (0% CW) steel was annealed [...] Read more.

Intergranular corrosion is one of the most important processes affecting the behaviour of austenitic stainless steels. Factors such as steel chemical composition, the degree of prior deformation and the exposure temperature affect the degree of sensitisation. AISI 316L (0% CW) steel was annealed at 650 °C for 5, 10, 30, 100, 300 and 1000 h to analyse the influence of isothermal annealing on the precipitation of secondary phases. AISI 316L steel after 40% cold working and subsequent annealing at 650 °C for 1, 1.5, 2, 5 and 10 h was investigated. Time–temperature sensitisation (TTS) diagrams were created based on corrosion test (ASTM A 262, practice A) results. In the case of AISI 316L (0% CW), M₂₃C₆, chi and sigma phases precipitated at grain boundaries, and the Laves phase was mainly inside of the grains. In the case of AISI 316L (40% CW), sigma, chi, Laves and M₂₃C₆ were identified and precipitated mainly along the grain boundaries as well as on the shear bands within different annealing times. It was confirmed that the increase in the annealing time caused an increase in the amounts of secondary phases. Secondary phases in the equilibrium state were calculated using Thermo-Calc software. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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17 pages, 10933 KiB

Open AccessArticle

A Comparative Study of the Corrosion Behavior of 30CrMnSiNi2A in Artificial Seawater and Salt Spray Environments

by Lianhong Zhao, Weiping He, Yingqin Wang, Han Li and Zhongyu Cui

Metals 2022, 12(9), 1443; https://doi.org/10.3390/met12091443 - 29 Aug 2022

Cited by 2 | Viewed by 1636

Abstract

In this work, the corrosion behavior of 30CrMnSiNi2A in a simulated marine environment was studied. The electrochemical behavior was studied by changing the temperature and pH of the solution environment. Detailed information about the rust layer was obtained by scanning electron microscopy, energy-dispersive [...] Read more.

In this work, the corrosion behavior of 30CrMnSiNi2A in a simulated marine environment was studied. The electrochemical behavior was studied by changing the temperature and pH of the solution environment. Detailed information about the rust layer was obtained by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. The stress corrosion cracking (SCC) behavior of the steel in artificial seawater was studied through a slow strain rate tensile test (SSRT). The experimental results showed that the corrosion products were mainly composed of α-FeOOH, γ-FeOOH, and Fe₃O₄, while the content of Fe₃O₄ in the rust layer formed in the salt spray environment was much higher. The steel in the salt spray test showed a much higher corrosion rate than that observed when it underwent a full-immersion test. The decrease in the pH value mainly accelerated the cathodic reaction, and the temperature simultaneously promoted anodic dissolution and cathodic reductions. The decrease in the elongation during SCC test was minimal, while the index for the reduction-in-area showed a slight SCC susceptibility in the seawater environment, suggesting that anodic dissolution is the dominant mechanism of SCC degradation. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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15 pages, 8362 KiB

Open AccessArticle

Study on the Aging Behavior of an Ultra-High Molecular Weight Polyethylene Fiber Barrier Net in a Marine Environment

by Wangxuan Zhang, Xiaofei Jing, Yanqiang Bai, Xiaoming Shan, Xiaoyu Qi, Maoxin Yan and Zhongyu Cui

Materials 2022, 15(16), 5599; https://doi.org/10.3390/ma15165599 - 15 Aug 2022

Viewed by 1489

Abstract

In the present work, the performance of ultra-high molecular weight polyethylene (UHMWPE) barrier nets in marine environments is investigated by Fourier transform infrared spectroscopy, thermogravimetry, scanning electron microscopy, and tensile experiments. The chemical, morphological, thermal stability, and strength changes after aging in salt [...] Read more.

In the present work, the performance of ultra-high molecular weight polyethylene (UHMWPE) barrier nets in marine environments is investigated by Fourier transform infrared spectroscopy, thermogravimetry, scanning electron microscopy, and tensile experiments. The chemical, morphological, thermal stability, and strength changes after aging in salt spray, hygrothermal, and ultraviolet (UV) environments are characterized. An environmental spectrum is designed to simulate a real service environment and predict the service life of UHMWPE. The results show that UV energy can activate UHMWPE molecules and lead to chain breaking, which lowers the breaking strength more efficiently than salt spray. In a hygrothermal environment, the UHMPE fibers bond into clumps, which causes a slight increase in breaking strength after the initial rapid decrease with aging time. The acceleration ratio of the environmental spectrum increases with increasing aging time, which may be caused by the cross-linking and degradation of macromolecular chains in the material. The environmental spectrum given by this work can be used to evaluate performance and predict the service life of UHMWPE barrier nets in marine environments. Full article

(This article belongs to the Topic Corrosion and Protection of Metallic Materials)

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