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Mechanical, Corrosive, and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces

by

Patricia Jovičević-Klug

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Matic Jovičević-Klug

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László Tóth

Coatings 2022, 12(7), 886; https://doi.org/10.3390/coatings12070886 - 22 Jun 2022

Viewed by 822

Abstract

Mechanical, corrosive, and tribological degradation of metal and metal coatings is just one of the challenges faced by numerous industries [...] Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

Research

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Open AccessFeature PaperArticle

Steel Surface Doped with Nb via Modulated Electron-Beam Irradiation: Structure and Properties

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Maxim Sergeevich Vorobyov

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Elizaveta Alekseevna Petrikova

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Vladislav Igorevich Shin

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Pavel Vladimirovich Moskvin

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Yurii Fedorovich Ivanov

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Nikolay Nikolaevich Koval

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Tamara Vasil`evna Koval

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Nikita Andreevich Prokopenko

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Ruslan Aleksandrovich Kartavtsov

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Dmitry Alekseevich Shpanov

Coatings 2023, 13(6), 1131; https://doi.org/10.3390/coatings13061131 - 20 Jun 2023

Cited by 1 | Viewed by 477

Abstract

A niobium film on an AISI 5135 steel substrate was exposed to submillisecond pulsed electron-beam irradiation with controlled energy modulation within a pulse to increase the film–substrate adhesion. This modulated irradiation made it possible to dope the steel-surface layer with Nb through film [...] Read more.

A niobium film on an AISI 5135 steel substrate was exposed to submillisecond pulsed electron-beam irradiation with controlled energy modulation within a pulse to increase the film–substrate adhesion. This modulated irradiation made it possible to dope the steel-surface layer with Nb through film dissolution in the layer, for which optimum irradiation conditions were chosen from experiments and a mathematical simulation. The irradiated system was tested for surface hardness and wear, and its surface structure and elemental composition were analyzed. The results demonstrate that the microhardness of the irradiated system is much higher and that its wear rate is much lower compared to the initial state. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Development of an Improved YOLOv7-Based Model for Detecting Defects on Strip Steel Surfaces

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Coatings 2023, 13(3), 536; https://doi.org/10.3390/coatings13030536 - 01 Mar 2023

Cited by 1 | Viewed by 1899

Abstract

The detection of defects on the surface is of great importance for both the production and the application of strip steel. In order to detect the defects accurately, an improved YOLOv7-based model for detecting strip steel surface defects is developed. To enhances the [...] Read more.

The detection of defects on the surface is of great importance for both the production and the application of strip steel. In order to detect the defects accurately, an improved YOLOv7-based model for detecting strip steel surface defects is developed. To enhances the ability of the model to extract features and identify small features, the ConvNeXt module is introduced to the backbone network structure, and the attention mechanism is embedded in the pooling module. To reduce the size and improves the inference speed of the model, an improved C3 module was used to replace the ELAN module in the head. The experimental results show that, compared with the original models, the mAP of the proposed model reached 82.9% and improved by 6.6%. The proposed model can satisfy the need for accurate detection and identification of strip steel surface defects. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

High Temperature Oxidation of Enamel Coated Low-Alloyed Steel 16Mo3 in Water Vapor

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Coatings 2023, 13(2), 342; https://doi.org/10.3390/coatings13020342 - 02 Feb 2023

Cited by 1 | Viewed by 835

Abstract

New types of ceramic coatings based on SiO₂-Na₂O-B₂O₃-TiO₂ oxide phases were investigated as protection for boiler steel in power generation systems. Low-alloyed Cr-Mo 16Mo3 steel was coated with different compositions of enamel coatings to [...] Read more.

New types of ceramic coatings based on SiO₂-Na₂O-B₂O₃-TiO₂ oxide phases were investigated as protection for boiler steel in power generation systems. Low-alloyed Cr-Mo 16Mo3 steel was coated with different compositions of enamel coatings to assess the protective potential of these coatings under water vapor at high temperatures. Oxidation at 650 °C for 50 h in Ar + water vapor was performed in a TGA apparatus to investigate the oxidation kinetics. The results indicate that the ceramic coatings provided a high degree of protection for the steel exposed to such conditions compared to the uncoated 16Mo3 steel. Furthermore, despite the formation of cracks in the coatings, no spallation from the steel surface was observed. Interconnected porosity in the coatings is suspected to provoke interfacial degradation. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Effect of Voltage on the Microstructure and High-Temperature Oxidation Resistance of Micro-Arc Oxidation Coatings on AlTiCrVZr Refractory High-Entropy Alloy

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Coatings 2023, 13(1), 14; https://doi.org/10.3390/coatings13010014 - 22 Dec 2022

Cited by 5 | Viewed by 1058

Abstract

In order to improve the high-temperature oxidation resistance of refractory high-entropy alloys (RHEAs), we used micro-arc oxidation (MAO) technology to prepare ceramic coatings on AlTiCrVZr alloy, and the effects of voltage on the microstructure and high-temperature oxidation resistance of the coatings were studied. [...] Read more.

In order to improve the high-temperature oxidation resistance of refractory high-entropy alloys (RHEAs), we used micro-arc oxidation (MAO) technology to prepare ceramic coatings on AlTiCrVZr alloy, and the effects of voltage on the microstructure and high-temperature oxidation resistance of the coatings were studied. In this paper, the MAO voltage was adjusted to 360 V, 390 V, 420 V, and 450 V. The microstructure, elements distribution, chemical composition, and surface roughness of the coatings were studied by scanning electron microscopy (SEM), energy dispersive (EDS), X-ray photoelectron spectroscopy (XPS), and white-light interferometry. The matrix alloy and MAO-coated samples were oxidized at 800 °C for 5 h and 20 h to study their high-temperature oxidation resistance. The results showed that as the voltage increased, the MAO coating gradually became smooth and dense, the surface roughness decreased, and the coating thickness increased. The substrate elements and solute ions in the electrolyte participated in the coating formation reaction, and the coating composition was dominated by Al₂O₃, TiO₂, Cr₂O₃, V₂O₅, ZrO₂, and SiO₂. Compared with the substrate alloy, the high-temperature oxidation resistance of the MAO-coated samples prepared at different voltages was improved after oxidation at 800 °C, and the coating prepared at 420 V showed the best high-temperature oxidation resistance after oxidation for 20 h. In short, MAO coatings can prevent the diffusion of O elements into the substrate and the volatilization of V₂O₅, which improves the high-temperature oxidation resistance of AlTiCrVZr RHEAs. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Mechanical, Corrosion, and Wear Properties of TiZrTaNbSn Biomedical High-Entropy Alloys

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Coatings 2022, 12(12), 1795; https://doi.org/10.3390/coatings12121795 - 22 Nov 2022

Cited by 1 | Viewed by 763

Abstract

The phase composition, microstructure, mechanical, corrosion, and wear behaviors of the Ti15Zr35Ta10Nb10Sn30 (Sn30) and Ti15Zr30Ta10Nb10Sn35 (Sn35) biomedical high-entropy alloys (BHEAs) were studied. We found that the Ti–Zr–Ta–Nb–Sn BHEAs showed hyper-eutectic and eutectic structures with body-centered cubic (BCC) and face-centered cubic (FCC) solid-solution phases. [...] Read more.

The phase composition, microstructure, mechanical, corrosion, and wear behaviors of the Ti15Zr35Ta10Nb10Sn30 (Sn30) and Ti15Zr30Ta10Nb10Sn35 (Sn35) biomedical high-entropy alloys (BHEAs) were studied. We found that the Ti–Zr–Ta–Nb–Sn BHEAs showed hyper-eutectic and eutectic structures with body-centered cubic (BCC) and face-centered cubic (FCC) solid-solution phases. The Sn30 BHEA exhibited a high Vickers hardness of approximately 501.2 HV, a compressive strength approaching 684.5 MPa, and plastic strain of over 46.6%. Furthermore, the Vickers hardness and compressive strength of Sn35 BHEA are 488.7 HV and 999.2 MPa, respectively, with a large plastic strain of over 49.9%. Moreover, the Sn30 and Sn 35 BHEA friction coefficients are 0.152 and 0.264, respectively. Sn30 BHEA has the smallest and shallowest furrow-groove width, and its wear rate is 0.86 (km/mm³); at the same time, we observed the delamination phenomenon. Sn35 BHEA has a wear rate value of 0.78 (km/mm³), and it displays wear debris and the largest–deepest furrow groove. Sn30 BHEA has the highest impedance value, and its corrosion current density I_corr is 1.261 × 10⁻⁷ (A/cm²), which is lower than that of Sn35 BHEA (1.265 × 10⁻⁶ (A/cm²)) by 88%, and the passivation current density I_pass of Sn30 BHEA and Sn35 BHEA is 4.44 × 10⁻⁴ (A/cm²) and 3.71 × 10⁻³ (A/cm²), respectively. Therefore, Sn30 BHEA preferentially produces passive film and has a small corrosion tendency, and its corrosion resistance is considerably better than that of the Sn35 BHEA alloy. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Discrimination of Steel Coatings with Different Degradation Levels by Near-Infrared (NIR) Spectroscopy and Deep Learning

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Mingyang Chen

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Guangming Lu

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Gang Wang

Coatings 2022, 12(11), 1721; https://doi.org/10.3390/coatings12111721 - 11 Nov 2022

Cited by 1 | Viewed by 875

Abstract

Assessing the current condition of protective organic coatings on steel structures is an important but challenging task, particularly when it comes to complex structures located in harsh environments. Near-infrared (NIR) spectroscopy is a rapid, low-cost, and nondestructive analytical technique with applications ranging from [...] Read more.

Assessing the current condition of protective organic coatings on steel structures is an important but challenging task, particularly when it comes to complex structures located in harsh environments. Near-infrared (NIR) spectroscopy is a rapid, low-cost, and nondestructive analytical technique with applications ranging from agriculture, food, and remote sensing to pharmaceuticals. In this study, an objective and reliable NIR-based technique is proposed for the accurate distinction between different coating conditions during their degradation process. In addition, a state-of-the-art deep learning method using a one-dimensional convolutional neural network (1-D CNN) is explored to automatically extract features from the spectrum. The characteristics of the spectrum show a downward trend over the entire wavenumber period, and two major absorption peaks were observed around 5250 and 4400 cm⁻¹. The experimental results indicate that the proposed deep network structure can powerfully extract the complex characteristics inside the spectrum, and the classification accuracy of the training and testing data was 99.84% and 95.23%, respectively, which suggests that NIR spectroscopy coupled with a deep learning algorithm could be used for the rapid and accurate inspection of steel coatings. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Study on Size Effect of Surface Roughness Based on the 3D Voronoi Model and Establishment of Roughness Prediction Model in Micro-Metal Forming

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Coatings 2022, 12(11), 1659; https://doi.org/10.3390/coatings12111659 - 01 Nov 2022

Cited by 2 | Viewed by 1094

Abstract

The primary purpose of this paper is to study the size effect of surface roughness and realize the quantitative description of the surface roughness in micro-forming process. This work is a continuation of the previous work by the authors. The effects of the [...] Read more.

The primary purpose of this paper is to study the size effect of surface roughness and realize the quantitative description of the surface roughness in micro-forming process. This work is a continuation of the previous work by the authors. The effects of the initial surface roughness of the specimen, the grain size, and grain orientations on the surface roughness of micro-upsetting products were investigated. The ratio of the number of grains of the surface layer to the total number of grains was adopted to characterize the size effect. The variation of the size effect on the contact normal pressure during the compression process was also analyzed. And the quantitative description of the evolution law of surface roughness for micro-formed parts was realized. The corresponding micro compression experiment was done in order to testify the prediction model. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Experimental Study on Fatigue Performance of Welded Hollow Spherical Joints Reinforced by CFRP

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Yutong Duan

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Honggang Lei

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Shihong Jin

Coatings 2022, 12(10), 1585; https://doi.org/10.3390/coatings12101585 - 20 Oct 2022

Viewed by 806

Abstract

The risk of fatigue failure of welded hollow spherical joints (WHSJs) under alternating loads increases due to the inherent defects, the disrepair, and the demand for tonnage upgrades, of suspension cranes. The finite element analysis results revealed that the ranking of the stress [...] Read more.

The risk of fatigue failure of welded hollow spherical joints (WHSJs) under alternating loads increases due to the inherent defects, the disrepair, and the demand for tonnage upgrades, of suspension cranes. The finite element analysis results revealed that the ranking of the stress concentration factor at the WHSJ was as follows: weld toe in steel tube of tube–ball connection weld > weld toe in steel tube of tube–endplate connection weld > weld toe in sphere of tube–ball connection weld > weld toe in plate of tube–endplate connection weld. Moreover, the peak stress at the weld of the tube–sphere connection was reduced by 32.93% after CFRP bonding reinforcement, which was beneficial for improving the fatigue performance. In this study, 16 full-scale specimens of Q235B WHSJs were tested by an MTS fatigue testing machine to study the strengthening effect of CFRP on the fatigue performance. It was found that the fatigue fracture of WHSJs was transferred from the tube–sphere connection weld to the tube–endplate connection after CFRP reinforcement. According to the fitted S-N curves, the fatigue strength could be increased by 13.26%–18.19% when the cycle number increased from 10,000 to 5,000,000. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Highly Efficient CuInSe₂ Sensitized TiO₂ Nanotube Films for Photocathodic Protection of 316 Stainless Steel

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Coatings 2022, 12(10), 1448; https://doi.org/10.3390/coatings12101448 - 30 Sep 2022

Cited by 3 | Viewed by 766

Abstract

CuInSe₂ nanoparticles were successfully deposited on the surface of TiO₂ nanotube arrays (NTAs) by a solvothermal method for the photocathodic protection (PCP) of metals. Compared with TiO₂ NTAs, the CuInSe₂/TiO₂ composites exhibited stronger visible light absorption and [...] Read more.

CuInSe₂ nanoparticles were successfully deposited on the surface of TiO₂ nanotube arrays (NTAs) by a solvothermal method for the photocathodic protection (PCP) of metals. Compared with TiO₂ NTAs, the CuInSe₂/TiO₂ composites exhibited stronger visible light absorption and higher photoelectric conversion efficiency. After 316 Stainless Steel (SS) was coupled with CuInSe₂/TiO₂, the potential of 316 SS could drop to −0.90 V. The photocurrent density of CuInSe₂/TiO₂ connected to 316 SS reached 140 μA cm⁻², which was four times that of TiO₂ NTAs. The composites exhibited a protective effect in the dark state for more than 8 h after 4 h of visible light illumination. The above could be attributed to increased visible light absorption, the extended lifetime of photogenerated electrons, and generation of oxygen vacancies. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Corrosion Resistance of Mg/Al Vacuum Diffusion Layers

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Coatings 2022, 12(10), 1439; https://doi.org/10.3390/coatings12101439 - 30 Sep 2022

Viewed by 877

Abstract

This study used a vacuum diffusion welding process to weld magnesium (Mg1) and aluminum (Al1060). The diffusion layers, with different phase compositions, were separated and extracted by grinding. The diffusion layers’ microstructures and phase compositions were analyzed using scanning electron microscopy (SEM) and [...] Read more.

This study used a vacuum diffusion welding process to weld magnesium (Mg1) and aluminum (Al1060). The diffusion layers, with different phase compositions, were separated and extracted by grinding. The diffusion layers’ microstructures and phase compositions were analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Furthermore, the corrosion resistance of each diffusion layer and the substrates were investigated and compared by performing corrosion immersion tests and linear polarization measurements in a 3.5 wt.% NaCl solution. The results showed that diffusion layers consisting of Mg₂Al₃, Mg₁₇Al₁₂, and Mg₁₇Al₁₂/Mg-based solid solutions were formed at the interface of the Mg1/Al1060 vacuum diffusion joint. Furthermore, each diffusion layer’s structure and morphology were of good quality, and the surfaces were free from defects. This result was obtained for a welding temperature of 440 °C and a holding time of 180 min. The corrosion current density of Mg1 was 2.199 × 10⁻³ A/cm², while that of the Al1060, Mg₂Al₃, Mg₁₇Al_12, and Mg₁₇Al₁₂/Mg-based solid solutions increased by order of magnitude, reaching 1.483 × 10⁻⁴ A/cm², 1.419 × 10⁻⁴ A/cm², 1.346 × 10⁻⁴ A/cm^2, and 3.320 × 10⁻⁴ A/cm², respectively. The order of corrosion rate was Mg1 > Mg₁₇Al₁₂ and Mg-based solid solution > Mg₂Al₃ > Mg₁₇Al₁₂ > Al1060. Moreover, all diffusion layers exhibited an improved corrosion resistance compared to Mg1. This was especially the situation for the Mg₂Al₃ layer and Mg₁₇Al₁₂ layer, whose corrosion resistances were comparable to that of Al1060. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessEditor’s ChoiceArticle

Comparison of K340 Steel Microstructure and Mechanical Properties Using Shallow and Deep Cryogenic Treatment

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Patricia Jovičević-Klug

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László Tóth

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Bojan Podgornik

Coatings 2022, 12(9), 1296; https://doi.org/10.3390/coatings12091296 - 02 Sep 2022

Cited by 5 | Viewed by 1496

Abstract

In this research, Böhler K340 cold work tool steel was subjected to three different heat treatment protocols, conventional heat treatment (CHT), shallow cryogenic treatment (SCT), and deep cryogenic treatment (DCT). The study compares the effect of SCT and DCT on the microstructure and [...] Read more.

In this research, Böhler K340 cold work tool steel was subjected to three different heat treatment protocols, conventional heat treatment (CHT), shallow cryogenic treatment (SCT), and deep cryogenic treatment (DCT). The study compares the effect of SCT and DCT on the microstructure and consequently on the selected mechanical properties (micro- and macroscale hardness and impact toughness). The study shows no significant difference in macroscale hardness after the different heat treatments. However, the microhardness values indicate a slightly lower hardness in the case of SCT and DCT. Microstructure analysis with light (LM) and scanning electron microscopy (SEM) indicated a finer and more homogenous microstructure with smaller lath size and preferential orientation of the martensitic matrix in SCT and DCT samples compared to CHT. In addition, the uniform precipitation of more spherical and finer carbides is determined for both cryogenic treatments. Moreover, the precipitation of small dispersed secondary carbides is observed in SCT and DCT, whereas in the CHT counterparts, these carbide types were not detected. X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) confirms that SCT and DCT are very effective in minimizing the amount of retained austenite down to 1.8 vol.% for SCT and even below 1 vol.% for the DCT variant. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Mathematical Model of Surface Topography of Corroded Steel Foundation in Submarine Soil Environment

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Coatings 2022, 12(8), 1078; https://doi.org/10.3390/coatings12081078 - 30 Jul 2022

Viewed by 923

Abstract

For the corrosion risk of steel structures in the marine environment, the topography characteristics of corroded steel surfaces were paid little attention to, which has a significant effect on the mechanical properties of the interface between steel foundation and soil medium. An effective [...] Read more.

For the corrosion risk of steel structures in the marine environment, the topography characteristics of corroded steel surfaces were paid little attention to, which has a significant effect on the mechanical properties of the interface between steel foundation and soil medium. An effective mathematical model for reconstructing the topography of corroded steel surface is very helpful for numerically or experimentally studying the soil-corroded steel interaction properties. In this study, an electrolytic accelerated corrosion experiment is conducted first to obtain corroded steel samples, which are exposed to submarine soil and suffer different corrosion degrees. Then, the surface height data of these corroded steel samples are scanned and analyzed. It is found that the height of surface two-dimensional contour curves under different corrosion degrees obeys the Gaussian distribution. Based on the spectral representation method, a mathematical model is developed for the profile height of the corroded steel surface. By comparing the standard deviation, arithmetic mean height and maximum height of reconstructed samples with those of experimental samples, the reliability of the developed mathematical model is proved. The proposed mathematical model can be adapted to reconstruct the surface topography of steel with different corrosion degrees for the following research on the shearing behavior of soil-corroded steel interface. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Influence of Contact Interface Friction on Plastic Deformation of Stretch-Bend Forming

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Coatings 2022, 12(8), 1043; https://doi.org/10.3390/coatings12081043 - 23 Jul 2022

Viewed by 981

Abstract

The contact interface friction between the specimen and the mold during the stretch-bend is a complex interactive process. Friction causes the uneven distribution of tensile stress on the specimen, which affects the plastic flow of the forming material and the spring-back after forming. [...] Read more.

The contact interface friction between the specimen and the mold during the stretch-bend is a complex interactive process. Friction causes the uneven distribution of tensile stress on the specimen, which affects the plastic flow of the forming material and the spring-back after forming. In this paper, the analytical model of frictional shear stress and tensile stress distribution in the contact mold segment of the stretch and bend synchronous loading stage was established. The influence law of friction coefficient and contact mold angle on the stress–strain distribution of the specimen contact mold segment was discussed. The effect of key factors affecting the friction state of the contact interface (mold surface roughness and contact mold angle) on the shrinkage deformation of the cross-section and the tensile deformation gradient of the specimen was analyzed by equivalent stretch-bend forming experiments. The results showed that the smaller the surface roughness of the mold was, the better the friction state of the contact interface was, the plastic deformation of the specimen was more uniform, and the difference between the section shrinkage and elongation of the contact mold segment and the suspension segment was smaller. Reducing the contact mold angle of the stretch-bend can bring down the tensile stress difference at both ends of the contact mold segment of the specimen so that the section shrinkage and tensile elongation of the contact mold segment and the suspension segment tend to be consistent. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Effects of Sodium Carbonate and Calcium Oxide on Roasting Denitrification of Recycled Aluminum Dross with High Nitrogen Content

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Coatings 2022, 12(7), 922; https://doi.org/10.3390/coatings12070922 - 29 Jun 2022

Cited by 1 | Viewed by 1076

Abstract

Aluminum dross is solid waste produced by the aluminum industry. It has certain toxicity and needs to be treated innocuously. The effect of sodium carbonate and calcium oxide on the denitrification efficiency of high nitrogen aluminum dross roasting was studied in this paper. [...] Read more.

Aluminum dross is solid waste produced by the aluminum industry. It has certain toxicity and needs to be treated innocuously. The effect of sodium carbonate and calcium oxide on the denitrification efficiency of high nitrogen aluminum dross roasting was studied in this paper. By means of XRD, SEM and other characterization methods, the optimum technological parameters for calcination denitrification of the two additives were explored. The test results show that both additives can effectively improve the efficiency of aluminum dross roasting denitrification, and the effect of sodium carbonate is better. When the mass ratio of sodium carbonate to aluminum dross is 0.6, the roasting temperature is 1000 °C and the roasting time is 4 h, the denitrification rate can reach 91.32%. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Improving the Surface Friction and Corrosion Resistance of Magnesium Alloy AZ31 by Ion Implantation and Ultrasonic Rolling

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Coatings 2022, 12(7), 899; https://doi.org/10.3390/coatings12070899 - 25 Jun 2022

Cited by 4 | Viewed by 1215

Abstract

The use of the magnesium alloy AZ31 is common in aviation and biomedicine; however, this alloy has poor friction and corrosion resistance. Here, mechanical grinding, ultrasonic rolling, and ultrasonic rolling + ion implantation were performed on the magnesium alloy surface to study the [...] Read more.

The use of the magnesium alloy AZ31 is common in aviation and biomedicine; however, this alloy has poor friction and corrosion resistance. Here, mechanical grinding, ultrasonic rolling, and ultrasonic rolling + ion implantation were performed on the magnesium alloy surface to study the effect of the treatment process on the friction and corrosion resistance of the magnesium alloy surface. The results show that the surface roughness of the magnesium alloy treated by ultrasonic rolling + ion injection is reduced more than mechanical grinding and ultrasonic rolling. The friction coefficient is the lowest, the wear resistance is the best, and new phase nitrogen compounds appear on the surface. The results of SBF (simulated body fluid) solution immersion showed that the sample treated via this composite process had the lowest corrosion rate, which was 62.45% and 58.47% lower than that of the mechanically ground samples. The surface was relatively intact after the corrosion test, and the corrosion resistance was the best. These results can provide a new strategy for magnesium alloy surface protection. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Electrochemical Deposition of Fe–Co–Ni Samples with Different Co Contents and Characterization of Their Microstructural and Magnetic Properties

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Van Cao Long

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Umut Saraç

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Mevlana Celalettin Baykul

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Luong Duong Trong

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Ştefan Ţălu

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Dung Nguyen Trong

Coatings 2022, 12(3), 346; https://doi.org/10.3390/coatings12030346 - 06 Mar 2022

Cited by 11 | Viewed by 2172

Abstract

In this study, to explore the effect of Co contents on the electroplated Fe–Co–Ni samples, three different Fe–Co₃₃–Ni₆₂, Fe–Co₄₃–Ni₅₃, and Fe–Co₆₁–Ni₃₆ samples were electrochemically grown from Plating Solutions (PSs) containing different amounts [...] Read more.

In this study, to explore the effect of Co contents on the electroplated Fe–Co–Ni samples, three different Fe–Co₃₃–Ni₆₂, Fe–Co₄₃–Ni₅₃, and Fe–Co₆₁–Ni₃₆ samples were electrochemically grown from Plating Solutions (PSs) containing different amounts of Co ions on indium tin oxide substrates. Compositional analysis showed that an increase in the Co ion concentration in the PS gives rise to an increment in the weight fraction of Co in the sample. In all samples, the co–deposition characteristic was described as anomalous. The samples exhibited a predominant reflection from the (111) plane of the face–centered cubic structure. However, the Fe–Co₆₁–Ni₃₆ sample also had a weak reflection from the (100) plane of the hexagonal close–packed structure of Co. An enhancement in the Co contents caused a strong decrement in the crystallinity, resulting in a decrease in the size of the crystallites. The Fe–Co₃₃–Ni₆₂ sample exhibited a more compact surface structure comprising only cauliflower–like agglomerates, while the Fe–Co₄₃–Ni₅₃ and Fe–Co_61–Ni₃₆ samples had a surface structure consisting of both pyramidal particles and cauliflower–like agglomerates. The results also revealed that different Co contents play an important role in the surface roughness parameters. From the magnetic analysis of the samples, it was understood that the Fe–Co₆₁–Ni₃₆ sample has a higher coercive field and magnetic squareness ratio than the Fe–Co₄₃–Ni₅₃ and Fe–Co₃₃–Ni₆₂ samples. The differences observed in the magnetic characteristics of the samples were attributed to the changes revealed in their phase structure and surface roughness parameters. The obtained results are the basis for the fabrication of future magnetic devices. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Open AccessArticle

Unravelling the Role of Nitrogen in Surface Chemistry and Oxidation Evolution of Deep Cryogenic Treated High-Alloyed Ferrous Alloy

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Patricia Jovičević-Klug

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Matic Jovičević-Klug

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Bojan Podgornik

Coatings 2022, 12(2), 213; https://doi.org/10.3390/coatings12020213 - 06 Feb 2022

Cited by 5 | Viewed by 1223

Abstract

The role of nitrogen, introduced by deep cryogenic treatment (DCT), has been investigated and unraveled in relation to induced surface chemistry changes and improved corrosion resistance of high-alloyed ferrous alloy AISI M35. The assumptions and observations of the role of nitrogen were investigated [...] Read more.

The role of nitrogen, introduced by deep cryogenic treatment (DCT), has been investigated and unraveled in relation to induced surface chemistry changes and improved corrosion resistance of high-alloyed ferrous alloy AISI M35. The assumptions and observations of the role of nitrogen were investigated and confirmed by using a multitude of complementary investigation techniques with a strong emphasis on ToF-SIMS. DCT samples display modified thickness, composition and layering structure of the corrosion products and passive film compared to a conventionally heat-treated sample under the same environmental conditions. The changes in the passive film composition of a DCT sample is correlated to the presence of the so-called ghost layer, which has higher concentration of nitrogen. This layer acts as a precursor for the formation of green rust on which magnetite is formed. This specific layer combination acts as an effective protective barrier against material degradation. The dynamics of oxide layer build-up is also changed by DCT, which is elucidated by the detection of different metallic ions and their modified distribution over surface thickness compared to its CHT counterpart. Newly observed passive film induced by DCT successfully overcomes the testing conditions in more extreme environments such as high temperature and vibrations, which additionally confirms the improved corrosion resistance of DCT treated high-alloyed ferrous alloys. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Electrochemical Synthesis of Functional Coatings and Nanomaterials in Molten Salts and Their Application

by

,

,

and

Coatings 2023, 13(2), 352; https://doi.org/10.3390/coatings13020352 - 03 Feb 2023

Cited by 1 | Viewed by 1359

Abstract

Nanomaterials are widely used in modern technologies due to their unique properties. Developing methods for their production is one of the most important scientific problems. In this review, the advantages of electrochemical methods for synthesis in molten salts of nanostructured coatings and nanomaterials [...] Read more.

Nanomaterials are widely used in modern technologies due to their unique properties. Developing methods for their production is one of the most important scientific problems. In this review, the advantages of electrochemical methods for synthesis in molten salts of nanostructured coatings and nanomaterials for different applications were discussed. It was determined that the nanostructured Mo₂C coatings on a molybdenum substrate obtained by galvanostatic electrolysis have a superior catalytic activity for the water-gas shift reaction. The corrosion-resistant and wear-resistant coatings of refractory metal carbides on steels were synthesized by the method of currentless transfer. This method also was used for the production of composite carbon fiber/refractory metal carbide materials, which are efficient electrocatalysts for the decomposition of hydrogen peroxide. The possibility to synthesize GdB₆ nanorods and Si and TaO nanoneedles by potentiostatic electrolysis was shown. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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Influence of Laser Modification on the Surface Character of Biomaterials: Titanium and Its Alloys—A Review

by

Joanna Sypniewska

and

Marek Szkodo

Coatings 2022, 12(10), 1371; https://doi.org/10.3390/coatings12101371 - 20 Sep 2022

Viewed by 1282

Abstract

Laser surface modification is a widely available and simple technique that can be applied to different types of materials. It has been shown that by using a laser heat source, reproducible surfaces can be obtained, which is particularly important when developing materials for [...] Read more.

Laser surface modification is a widely available and simple technique that can be applied to different types of materials. It has been shown that by using a laser heat source, reproducible surfaces can be obtained, which is particularly important when developing materials for medical applications. The laser modification of titanium and its alloys is advantageous due to the possibility of controlling selected parameters and properties of the material, which offers the prospect of obtaining a material with the characteristics required for biomedical applications. This paper analyzes the effect of laser modification without material growth on titanium and its alloys. It addresses issues related to the surface roughness parameters, wettability, and corrosion resistance, and discusses how laser modification changes the hardness and wear resistance of materials. A thorough review of the literature on the subject provides a basis for the scientific community to develop further experiments based on the already investigated relationships between the effects of the laser beam and the surface at the macro, micro, and nano level. Full article

(This article belongs to the Special Issue Mechanical, Corrosive and Tribological Degradation of Metal Coatings and Modified Metallic Surfaces)

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