Journal Description
Coatings
Coatings
is an international, peer-reviewed, open access journal on coatings and surface engineering published monthly online by MDPI. The Korean Tribology Society (KTS) is affiliated with Coatings and its members receive discounts on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Inspec, CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q2 (Materials Science, Coatings & Films) / CiteScore - Q2 (Surfaces and Interfaces)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 13.8 days after submission; acceptance to publication is undertaken in 2.8 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Sections: published in 14 topical sections.
- Testimonials: See what our editors and authors say about Coatings.
Impact Factor:
3.4 (2022);
5-Year Impact Factor:
3.4 (2022)
Latest Articles
Non-Metal Doping as a First-Principles Study for Promoting the Hydrogen Evolution of Two-Dimensional Electride Y2C Electrocatalysts
Coatings 2024, 14(6), 657; https://doi.org/10.3390/coatings14060657 (registering DOI) - 22 May 2024
Abstract
The two-dimensional electrochemical Y2C’s low work function and strong charge transfer qualities limit its applicability in catalysis due to its poor catalytic activity. In this paper, based on density functional theory calculations, we use two techniques to increase the HER catalytic
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The two-dimensional electrochemical Y2C’s low work function and strong charge transfer qualities limit its applicability in catalysis due to its poor catalytic activity. In this paper, based on density functional theory calculations, we use two techniques to increase the HER catalytic activity of the Y2C monolayer: substitution doping (XC) and adsorption doping (XT) of non-metal (X = N, P, O, S, and F). The results showed that the absolute values of hydrogen free energies (ΔGH*) of the substitutional dopants of PC, SC and adsorptive dopants of NT, OT, ST, and PT had increased catalytic activity compared with those of the pristine Y2C monolayer (−0.673 eV). It was highlighted that the adsorption doping of PT can further reduce the adsorption free energy of the pristine Y2C monolayer to −0.19 eV, which is close to the optimal zero value, and the binding energy of the hydrogen atoms on the Y2C surface significantly increased from −0.913 to −0.438 eV, which is more favorable for the desorption of hydrogen atoms. These results demonstrate that the doping of non-metals activates the adsorption of hydrogen atoms on monolayer Y2C and provides a feasible method for hydrogen generation.
Full article
(This article belongs to the Section Surface Engineering for Energy Harvesting, Conversion, and Storage)
Open AccessArticle
Corrosion Resistance of Atomically Thin Graphene Coatings on Single Crystal Copper
by
Md Mahmudul Hasan, Ramesh Devadig, Pawan Sigdel, Alexey Lipatov, Recep Avci, Bharat K. Jasthi and Venkataramana Gadhamshetty
Coatings 2024, 14(6), 656; https://doi.org/10.3390/coatings14060656 - 22 May 2024
Abstract
Designing minimally invasive, defect-free coatings based on conformal graphene layers to shield metals from both abiotic and biotic forms of corrosion is a persistent challenge. Single-layer graphene (SLG) grown on polycrystalline copper (PC-Cu) surfaces often have inherent defects, particularly at Cu grain boundaries,
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Designing minimally invasive, defect-free coatings based on conformal graphene layers to shield metals from both abiotic and biotic forms of corrosion is a persistent challenge. Single-layer graphene (SLG) grown on polycrystalline copper (PC-Cu) surfaces often have inherent defects, particularly at Cu grain boundaries, which weaken their barrier properties and worsen corrosion through grain-dependent mechanisms. Here, we report that an SLG grown via chemical vapor deposition (CVD) on Cu (111) single crystal serves as a high-performance coating to lower corrosion by nearly 4–6 times (lower than bare Cu (111)) in abiotic (sulfuric acid) and microbiologically influenced corrosion (MIC) environments. For example, the charge transfer resistance for SLG/Cu (111) (3.95 kΩ cm2) was 2.5-fold higher than for bare Cu (111) (1.71 kΩ cm2). Tafel analysis corroborated a reduced corrosion current (42 ± 3 µA cm−2) for SLG/Cu (111) compared to bare Cu (111) (115 ± 7 µA cm−2). These findings are consistent with the results based on biofilm measurements. The SLG/Cu (111) reduced biofilm formation by 3-fold compared to bare Cu (111), increasing corrosion resistance, and effectively mitigating pitting corrosion. The average depths of the pits (3.4 ± 0.6 µm) for SLG/Cu (111) were notably shallower than those of bare Cu (111) (6.5 ± 1.2 µm). Surface analysis of the corrosion products corroborated these findings, with copper sulfide identified as a major component across both surfaces. The absence of grain boundaries in Cu (111) resulted in high-quality SLG manifesting higher barrier properties compared to SLG on PC-Cu. Our findings show promise for using the presented strategy for developing durable graphene coatings against diverse forms of corrosion.
Full article
(This article belongs to the Special Issue Wear-Resistance and Corrosion-Resistance Coatings)
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Open AccessArticle
Preparation of Toddalia asiatica (L.) Lam. Extract Microcapsules and Their Effect on Optical, Mechanical and Antibacterial Performance of Waterborne Topcoat Paint Films
by
Ying Wang and Xiaoxing Yan
Coatings 2024, 14(6), 655; https://doi.org/10.3390/coatings14060655 - 22 May 2024
Abstract
The antibacterial microcapsules were prepared by encapsulating Toddalia asiatica (L.) Lam. extracts with urea–formaldehyde resin. The orthogonal test was designed to investigate the effects of the mass ratio of core and wall materials (Wcore:Wwall), emulsifier concentration, reaction temperature and
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The antibacterial microcapsules were prepared by encapsulating Toddalia asiatica (L.) Lam. extracts with urea–formaldehyde resin. The orthogonal test was designed to investigate the effects of the mass ratio of core and wall materials (Wcore:Wwall), emulsifier concentration, reaction temperature and reaction time on the yield rate and coverage rate of microcapsules, and to obtain the best preparation technology for microcapsules. The single-factor results indicated that the maximum influence factor was the Wcore:Wwall of the microcapsules; the larger the Wcore:Wwall, the easier the microcapsules were to agglomerate; and when the Wcore:Wwall was 0.8:1, the coverage rate reached the maximum value of 11.0%. The waterborne topcoat paint film was prepared by adding the microcapsules in the same content. The yield rate, coverage rate, and microscopic morphology of Toddalia asiatica (L.) Lam. extract microcapsules were analyzed, as well as the effects of microcapsules on the microscopic morphology, optical properties, cold liquid resistance, mechanical properties and antibacterial properties of a waterborne topcoat paint film. Combining the optical properties, cold liquid resistance, physical properties, and antibacterial properties of the waterborne topcoat paint film, the comprehensive performance of the waterborne topcoat paint film with the Wcore:Wwall of 0.8:1 was superior. The gloss was 8.07 GU, color difference ΔE was 9.21, visible light transmittance was 82.90%, resistance to citric acid, ethanol and detergent were grade 1, 2 and 2, respectively, elongation at break was 15.68%, and roughness was 3.407 µm. The antibacterial activity against Escherichia coli and Staphylococcus aureus were 42.82% and 46.05%, respectively. In this study, a waterborne topcoat paint film with a microcapsule-coated plant-derived antibacterial agent as the core was prepared, expanding the application prospect of plant-derived antibacterial microcapsules.
Full article
(This article belongs to the Special Issue Multilayer and Functional Graded Coatings—2nd Edition)
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Open AccessArticle
Preparation Process Optimization for Melamine Resin-Covered Pomelo Peel Flavonoid Antibacterial Microcapsules and Their Effect on Waterborne Paint Film Performance
by
Tingting Ding and Xiaoxing Yan
Coatings 2024, 14(6), 654; https://doi.org/10.3390/coatings14060654 - 21 May 2024
Abstract
Pomelo peel is a natural substance with antibacterial properties. Its extraction process is simple, and the raw materials are abundant. Microcapsules were prepared using melamine resin as the wall material and pomelo peel flavonoids as the core material. The optimization of microcapsule preparation
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Pomelo peel is a natural substance with antibacterial properties. Its extraction process is simple, and the raw materials are abundant. Microcapsules were prepared using melamine resin as the wall material and pomelo peel flavonoids as the core material. The optimization of microcapsule preparation was explored by orthogonal and single-factor experiments. The findings indicated that the optimum process for the preparation of microencapsulation was a 0.12:1 mass ratio of core to wall material, 60 °C microencapsulation reaction temperature, 800 rpm microencapsulation reaction stirring speed, and 2% emulsifier concentration. On this basis, the microcapsules were applied to waterborne coatings at different levels, 0%, 3.0%, 6.0%, 9.0%, 12.0%, and 15.0%, respectively, to prepare paint films, and the properties of the paint films were tested and explored. The test showed that the microcapsules added to the waterborne paint film exhibited antibacterial activity while retaining good optical and mechanical properties. In comparison with Escherichia coli, the microcapsules had a greater antibacterial rate against Staphylococcus aureus. When the content of microcapsules was 6.0%, the general performance of the waterborne paint film was optimal. The antibacterial rate of the paint film against Staphylococcus aureus and Escherichia coli was 40.5% and 50.5%, respectively. The color difference was 3.28. The paint film had a certain elasticity area, the elongation at break was 10.8%, and the roughness was 1.75 μm. We successfully prepared microcapsules capable of improving the antibacterial performance of waterborne paint film, which expands the application field of waterborne coatings and provides a certain reference value for the antibacterial research of waterborne coatings.
Full article
(This article belongs to the Special Issue Multilayer and Functional Graded Coatings—2nd Edition)
Open AccessArticle
The Effect of Self-Healing Microcapsules in Corrosion Testing on Magnesium AZ31 Alloy and Fibre Metal Laminates
by
Monika Ostapiuk, Jarosław Bieniaś, Mónica V. Loureiro and Ana C. Marques
Coatings 2024, 14(6), 653; https://doi.org/10.3390/coatings14060653 - 21 May 2024
Abstract
Fibre metal laminates (FMLs) are the most interesting composite materials of the past decade. They possess the properties of both polymer composites and metallic alloys. However, there is a problem with corrosion when the outer layers are made of aluminium or magnesium. The
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Fibre metal laminates (FMLs) are the most interesting composite materials of the past decade. They possess the properties of both polymer composites and metallic alloys. However, there is a problem with corrosion when the outer layers are made of aluminium or magnesium. The electrochemical changes that occur during the corrosion process and the mechanisms associated with the corrosion phenomenon are still being investigated. Recently, self-healing phenomena have emerged as a useful approach to prevent corrosion. However, there is limited research on the combination of FMLs and self-healing layers. Therefore, the main purpose of this article is to evaluate the self-healing ability of a magnesium/PEO layer based on microcapsules in a corrosion environment. It was observed that the corrosion mechanism in magnesium alloys is very complex. However, the use of a barrier layer with PEO treatment and microcapsules yielded positive anti-corrosion results. The FML samples were subjected to a 6-week corrosion test, and the addition of microcapsules to the layers showed positive results. In contrast, the samples without microcapsules exhibited intergranular corrosion. In the future, comprehensive tests using self-healing microcapsules in FMLs could greatly enhance their anti-corrosion properties and improve the integrity of the structure.
Full article
(This article belongs to the Section Plasma Coatings, Surfaces & Interfaces)
Open AccessArticle
Performance of a Composite Inhibitor on Mild Steel in NaCl Solution: Imidazoline, Sodium Molybdate, and Sodium Dodecylbenzenesulfonate
by
Xue Wang, Changfeng Fan, Lanyi Sun, Hongyan Shang, Duxin Zhang, Nan Xu, Bin Wang and Jianbin Xu
Coatings 2024, 14(6), 652; https://doi.org/10.3390/coatings14060652 - 21 May 2024
Abstract
Mild steel corrosion is a significant challenge in oil and gas exploitation. Inhibitors are frequently employed to minimize the corrosive impact on mild steel. Mixing corrosion inhibitors is an effective method in reducing the dosage of toxic compounds and expanding the potential applications
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Mild steel corrosion is a significant challenge in oil and gas exploitation. Inhibitors are frequently employed to minimize the corrosive impact on mild steel. Mixing corrosion inhibitors is an effective method in reducing the dosage of toxic compounds and expanding the potential applications of inhibitors in NaCl solutions. Herein, a mixed corrosion inhibitor composed of imidazoline (IM), sodium molybdate, and sodium dodecylbenzenesulfonate (SDBS) for mild steel in a 3.5 wt% NaCl solution are investigated by orthogonal experimental design and electrochemical measurement. The imidazoline compound was synthesized and identified using Fourier transform infrared (FTIR) spectroscopy. The inhibitory effect is improved by higher concentrations of sodium molybdate and is further enhanced with the addition of 10 mg/L of SDBS. The electrochemical impedance spectroscopy indicates that the combination of IM (100 mg/L), sodium molybdate (50 mg/L), and SDBS (100 mg/L) results in excellent performance with electrochemical impedance (1.8 kohm·cm2). The mild steel surfaces after electrochemical measurement were analyzed using scanning electron microscopy (SEM). The information can contribute to the development of corrosion inhibitors with high performance or to understand the influence of mixing inhibitors on corrosion processes of mild steels.
Full article
(This article belongs to the Special Issue Investigation on Corrosion Behaviour of Metallic Materials)
Open AccessArticle
Investigation of the Influence of Powder Fraction on Tribological and Corrosion Characteristics of 86WC-10Co-4Cr Coating Obtained by HVOF Method
by
Bauyrzhan Rakhadilov, Nazerke Muktanova, Dauir Kakimzhanov, Zarina Satbayeva, Leila Kassenova and Nurtoleu Magazov
Coatings 2024, 14(6), 651; https://doi.org/10.3390/coatings14060651 - 21 May 2024
Abstract
Samples using powders of four different fractions, 15–20 μm, 20–30 μm, 30–40 μm and 40–45 μm, were fabricated to investigate the wear resistance, corrosion resistance and tribological properties of the 86WC-10Co-4Cr coating obtained using the HVOF method. The phase composition, microstructure and elemental
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Samples using powders of four different fractions, 15–20 μm, 20–30 μm, 30–40 μm and 40–45 μm, were fabricated to investigate the wear resistance, corrosion resistance and tribological properties of the 86WC-10Co-4Cr coating obtained using the HVOF method. The phase composition, microstructure and elemental distribution were analyzed using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy techniques. The hardness was measured on a Vickers microhardness tester, the friction coefficient and wear rate were investigated using a tribometer, and the corrosion resistance was evaluated on an electrochemical corrosion station. The results showed that the cross-sectional microstructure of the coating is mainly represented by multifaceted WC crystals embedded in the Co-Cr matrix and the presence of lower tungsten carbides, particularly W2C. The 15–20 μm fraction particles were subjected to superheating, contributing to the decarburization process. The 20–30 µm and 30–40 µm sized particles prevented overheating and had a more homogeneous structure. The 40–45 µm powder fractions did not reach sufficient temperature for complete melting, resulting in the formation of pores in the coating layers. The phase composition of the coatings included WC, W2C and CoO phases. According to the results of the study, it was found that the optimal powder fraction for coating the 86WC-10Co-4Cr composition with improved characteristics is the fraction of the 20–30 µm sized particles.
Full article
(This article belongs to the Special Issue Applications of Ceramic and Cermet Coatings)
Open AccessRetraction
RETRACTED: Raya et al. Synthesis, Characterization and Photodegradation Studies of Copper Oxide–Graphene Nanocomposites. Coatings 2021, 11, 1452
by
Indah Raya, Awais Ahmad, Ayad F. Alkaim, Dmitry Bokov, Enas R. Alwaily, Rafael Luque, Mabkhoot Alsaiari and Mohammed Jalalah
Coatings 2024, 14(6), 650; https://doi.org/10.3390/coatings14060650 - 21 May 2024
Abstract
The Coatings Editorial Office retracts the article, “Synthesis, Characterization and Photodegradation Studies of Copper Oxide–Graphene Nanocomposites” [...]
Full article
Open AccessArticle
Effects of ZrW2O8 Content on the Microstructures and Properties of Composite Coatings Produced by Laser Cladding
by
Pengxian Zhang, Chang Liu and Yibin Pang
Coatings 2024, 14(5), 649; https://doi.org/10.3390/coatings14050649 - 20 May 2024
Abstract
Addressing the issue of cracking in laser-cladding Ni-based composite coatings with WC particles, this study explored an approach to fabricating a crack-free coating by incorporating ZrW2O8 powder. The influence of varying ZrW2O8 contents on the crack susceptibility,
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Addressing the issue of cracking in laser-cladding Ni-based composite coatings with WC particles, this study explored an approach to fabricating a crack-free coating by incorporating ZrW2O8 powder. The influence of varying ZrW2O8 contents on the crack susceptibility, microstructure, microhardness, wear resistance, and corrosion resistance of Ni60/WC composite coatings was systematically examined. The findings indicate that the ZrW2O8 content significantly impacts the microstructure and functional properties of the coating. Furthermore, it is suggested that the main contributors to preventing crack formation and diffusion are believed to be the pressure interaction caused by the negative expansion effect of ZrW2O8, as well as the in situ phase transition and diffusion toughening of ZrO2 during its decomposition process. The feasibility of achieving crack selfhealing through the addition of specific amounts of ZrW2O8 powder has been conclusively demonstrated.
Full article
(This article belongs to the Special Issue Surface Modification, Repairing and Forming of Metallic Materials by Additive Manufacturing)
Open AccessArticle
Wear Resistance Behavior of Low-, Mid-, and High-Phosphorus Electroless Ni-P Coatings Heat-Treated in the Air Environment
by
Dhani Ram Dhakal, Young Uk Han, Byung Geon Lee, Tae Ho Kim, Gi Bum Jang and Sung Youl Cho
Coatings 2024, 14(5), 648; https://doi.org/10.3390/coatings14050648 - 20 May 2024
Abstract
The high-temperature heat treatment of electroless nickel–phosphorus (Ni-P) coatings in an air environment, and its consequences have scarcely been investigated. This work investigated tribological characteristics of the high-temperature, heat-treated, electroless Ni-P coatings on steel substrates with low-, mid-, and high-phosphorus content for which
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The high-temperature heat treatment of electroless nickel–phosphorus (Ni-P) coatings in an air environment, and its consequences have scarcely been investigated. This work investigated tribological characteristics of the high-temperature, heat-treated, electroless Ni-P coatings on steel substrates with low-, mid-, and high-phosphorus content for which the average phosphorus content was 2.4 wt.%, 7.1 wt.%, and 10.3 wt.%, respectively. X-ray fluorescence and energy dispersive spectroscopy were implemented to determine the phosphorus content of the coatings. The oxidation of Ni and the formation of the NiO layer on the coating surface was confirmed by the X-ray diffraction technique. A reciprocating sliding method on a ball-on-flat system was utilized to evaluate the coating’s friction and wear behavior. Among the coatings with varying phosphorus content, a high hardness of 1086 HV was found for high-phosphorus coating when heat-treated at 400 °C in an air environment, and that was decreased to 691 HV when heat-treated at 650 °C. The oxidation of nickel in the electroless Ni-P coating occurred when heat-treated at 400 °C in an air environment, and this phenomenon was increased more when the temperature was increased to 650 °C. The characteristics of the NiO layer that formed on the surface of the heat-treated electroless Ni-P coating were influenced by the concentration of phosphorus, which caused different colors of NiO to be seen on the Ni-P coating surface. A greenish black NiO layer on the low-phosphorus and black NiO layer on the mid- and high-phosphorus Ni-P coating was developed during heat treatment at 650 °C in an air atmosphere. The adhesion and tribological characteristics of the Ni-P coatings were affected by the NiO layer developed on the heat-treated Ni-P coating surfaces. The Ni-P coatings with mid- and high-phosphorus content showed enhanced wear-resistance characteristics when they underwent heat treatment in an air atmosphere at the high temperature of 650 °C. The wear volume obtained for as-plated mid-phosphorus and high-phosphorus Ni-P coatings was 0.111 mm3 and 0.128 mm3, respectively, and that was reduced to 0.031 mm3 and 0.051 mm3, respectively, after the high-temperature heat treatment.
Full article
(This article belongs to the Special Issue Advanced Wear-Resistant Materials and Coatings)
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Open AccessArticle
Terahertz Nondestructive Measurement of Heat Radiation Performance of Thermal Barrier Coatings Based on Hybrid Artificial Neural Network
by
Zhou Xu, Changdong Yin, Yiwen Wu, Houli Liu, Haiting Zhou, Shuheng Xu, Jianfei Xu and Dongdong Ye
Coatings 2024, 14(5), 647; https://doi.org/10.3390/coatings14050647 - 20 May 2024
Abstract
Effective control of the micro- and nanostructure of thermal barrier coatings is essential to enhance the thermal radiation performance of the coating, which helps to determine the remaining service life of the coating. This paper proposed a method to measure the radiation properties
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Effective control of the micro- and nanostructure of thermal barrier coatings is essential to enhance the thermal radiation performance of the coating, which helps to determine the remaining service life of the coating. This paper proposed a method to measure the radiation properties of thermal barrier coatings by terahertz nondestructive testing technique, using APS-prepared thermal barrier coatings as the object of study. Radiative properties were a comprehensive set of properties characterized by the diffuse reflectance, transmittance, and absorptance of the thermal barrier coating. The coating data in actual service were obtained by scanning electron microscopy and metallographic experiments, and the data were used as the simulation model critical value. The terahertz time-domain simulation data of coatings with different microstructural features were obtained using the finite-different time-domain (FDTD) method. In simulating the real test signals, white noise with a signal-to-noise ratio of 20 dB was added, and fast Fourier transform (FFT), short-time Fourier transform (STFT), and wavelet transform (WT) were used to reduce the noise and compare their noise reduction effects. Different machine learning methods were used to build the model, including support vector machine algorithm (SVM) and k-nearest neighbor algorithm (KNN). The principal component algorithm (PCA) was used to reduce the dimensionality of terahertz time-domain data, and the SVM algorithm and KNN algorithm were optimized using the particle swarm optimization algorithm (PSO) and the ant colony optimization algorithm (ACO), respectively, to improve the robustness of the system. The K-fold cross-validation method was used to construct the model to improve the adaptability of the model. It could be clearly seen that the novel hybrid PCA-ACO-SVM model had superior prediction performance. Finally, this work proposed a novel, convenient, nondestructive, online, safe and highly accurate method for measuring the radiation performance of thermal barrier coatings, which could be used for the judgment of the service life of thermal barrier coatings.
Full article
(This article belongs to the Special Issue Smart Coatings)
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Open AccessArticle
Comparison of the Erosive Wear Resistance of Ductile Cast Iron Following Laser Surface Melting and Alloying
by
Jacek Górka, Aleksandra Lont, Damian Janicki, Tomasz Poloczek and Agnieszka Rzeźnikiewicz
Coatings 2024, 14(5), 646; https://doi.org/10.3390/coatings14050646 - 20 May 2024
Abstract
This article presents research results on the influence of the laser surface melting and alloying processes on the erosive wear resistance of ductile cast iron. For the research, an EN-GJS 350-22 ductile cast iron surface was laser-melted and laser-alloyed with titanium powder in
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This article presents research results on the influence of the laser surface melting and alloying processes on the erosive wear resistance of ductile cast iron. For the research, an EN-GJS 350-22 ductile cast iron surface was laser-melted and laser-alloyed with titanium powder in an argon and nitrogen atmosphere. Solid-particle erosion tests were carried out on the laser-melted and -alloyed surface layers and the base material according to the ASTM G76-04 standard with 30° and 90° impingement angles. The erosive wear resistance results were correlated with Vickers hardness and microstructural test results with the use of SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDS (energy dispersive spectroscopy), and XRD (X-ray diffraction). The mechanisms of erosive wear were also analyzed for the laser-treated surface layers and the base material. The research showed that the laser melting and alloying processes with titanium powder had a positive effect on the hardness and erosive wear resistance of the ductile cast iron surface due to microstructure modification. Moreover, despite the lower hardness of the laser-alloyed surface layers, their composite microstructure had a positive impact on the erosive wear resistance in comparison to the laser-melted surface layers.
Full article
(This article belongs to the Special Issue Laser-Assisted Coating Techniques and Surface Modifications)
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Open AccessArticle
Preparation of n-Tetradecane Phase Change Microencapsulated Polyurethane Coating and Experiment on Anti-Icing Performance for Wind Turbine Blades
by
Yiting Wang, He Shen, Zheng Sun, Yan Li and Fang Feng
Coatings 2024, 14(5), 645; https://doi.org/10.3390/coatings14050645 - 19 May 2024
Abstract
Icing is a common physical phenomenon, and the icing of wind turbine blades can significantly affect the performance of wind turbines. Therefore, researching methods to prevent icing is of great significance, and the coating method of anti-icing is an effective way to delay
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Icing is a common physical phenomenon, and the icing of wind turbine blades can significantly affect the performance of wind turbines. Therefore, researching methods to prevent icing is of great significance, and the coating method of anti-icing is an effective way to delay icing, with advantages such as low energy consumption and easy implementation. In this study, using the coating method as the background, tetradecane phase change microcapsules were prepared, with a melting enthalpy of 90.8 J/g and a crystallization enthalpy of 96.3 J/g, exhibiting good coverage and energy storage efficiency. After mixing tetradecane phase change microcapsules (PCMS) with polyurethane coating (PUR) and coating them on wind turbine blades, after a 5 min icing wind tunnel test, the coating could significantly delay the icing on the blade surface, with the highest anti-icing rate reaching 60.41%. This indicates that the coating has a good anti-icing effect and provides basic research data for exploring new anti-icing methods.
Full article
(This article belongs to the Special Issue Functional Thin Films and Coatings: Present Status, Challenges, and a Look Forward)
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Open AccessArticle
Protective Properties of Calcareous Deposit Layer for Cathodically Polarized AH36 Steel in Natural Seawater
by
Quoc Quang Nong, Van Kien Dong, Van Trieu Nguyen, Van Chi Nguyen, Hong Quan Le and Nhat Linh Cao
Coatings 2024, 14(5), 644; https://doi.org/10.3390/coatings14050644 - 19 May 2024
Abstract
A calcareous deposit is a by-product of the cathodic polarization in seawater environments. This study presents the results of evaluating the anticorrosion and anti-macro-biofouling effectiveness of a calcareous deposit layer on the surface of the cathodically polarized AH36 structural steel in tropical seawater.
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A calcareous deposit is a by-product of the cathodic polarization in seawater environments. This study presents the results of evaluating the anticorrosion and anti-macro-biofouling effectiveness of a calcareous deposit layer on the surface of the cathodically polarized AH36 structural steel in tropical seawater. The polarization is induced with initial current densities at which the calcareous deposit layer formed with both aragonite and brucite for 12 months continuously. The protective properties of the layer were compared with those of the passive layer from corrosion products under the same environmental conditions. The macro-biofouling in the tropical seawater is observed in the closed and open surfaces of the steel. The comparison of the anticorrosion property shows that, to some degree, the calcareous deposit layer contributes to surface passivation, as in the case of the corrosion product layer. In addition, the composition of the brucite and aragonite in the calcareous layer in the study plays a role as a macro-biofouling growth-limiting factor.
Full article
(This article belongs to the Special Issue Organic and Polymeric Materials: Synthesis, Properties and Applications)
Open AccessArticle
Experimental Evaluation of Ceramic Coatings for Die Protection in Low-Pressure Die-Casting Process
by
Ainara López-Ortega, Olatz Areitioaurtena, Elena Fuentes, Amaya Igartua, Luis Merchán, Enrique Pardo, Jessica Montero, Roberto Granado, Ignacio Martinez de la Pera, Joannes Mendizabal and Borja Zabala
Coatings 2024, 14(5), 643; https://doi.org/10.3390/coatings14050643 - 19 May 2024
Abstract
One of the most important factors in the LPDC process is the heat transfer during the solidification of the molten alloys, which is responsible for the resulting microstructure and, thus, the quality of the cast piece. The use of foundry coatings has been
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One of the most important factors in the LPDC process is the heat transfer during the solidification of the molten alloys, which is responsible for the resulting microstructure and, thus, the quality of the cast piece. The use of foundry coatings has been lately suggested as a proper strategy to control the heat transfer while protecting bonded moulds from aluminium adhesion by providing a barrier between the surface and the liquid metal. LPDC die coating failures usually come from the loss of adherence or excessive wear originated in the successive filling processes, which requires stopping production for the reapplication of the coating. In the present work, coatings with different insulation capabilities have been evaluated, in terms of adherence and wear tests, in order to select the most promising alternative for LPDC die coating. This study confirmed that surface preparation and cleanliness are vital for an adequate adhesion of the coatings to ensure their durability. The results evinced that the use of a primer layer provided a higher adhesion of the coatings and considerably improved their perfomance. The coating that presented the best results in terms of adhesion and wear resistance under different abrasive testing conditions was coating B3.
Full article
(This article belongs to the Special Issue Development and Characterization of Coatings and Surface Treatments for Corrosion, Wear, and Tribocorrosion Protection of Materials in Hostile Environments)
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Open AccessArticle
Investigating the Effectiveness of Novel Repellent Labels Produced from Invasive Plant Species
by
Klemen Možina, Zala Mavrič and Urška Vrabič-Brodnjak
Coatings 2024, 14(5), 642; https://doi.org/10.3390/coatings14050642 - 19 May 2024
Abstract
Although N,N-diethyl-3-methylbenzamide (DEET) remains the most effective repellent against mosquitoes and ticks, concerns about skin irritation, rashes, and neurological problems in children have driven the search for natural alternatives. The aim of this research was to develop, manufacture, and test prototype stickers derived
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Although N,N-diethyl-3-methylbenzamide (DEET) remains the most effective repellent against mosquitoes and ticks, concerns about skin irritation, rashes, and neurological problems in children have driven the search for natural alternatives. The aim of this research was to develop, manufacture, and test prototype stickers derived from invasive plant species in Europe. These labels contained a coating with encapsulated repellents made from essential oils to protect against mosquito bites and similar blood-sucking insects. Six samples of invasive plant species in Europe such as Japanese knotweed (Fallopia japonica), goldenrod (Solidago gigantea), and black locust (Robinia pseudoacacia) were coated with two essential oil mixtures (of geranium, lavender, and eucalyptus) and were encapsulated on solid carriers for prolonged evaporation. Analysis of the structural properties (weight, thickness, density, and specific volume) were carried out on the coated label samples. Analysis of surface properties (roughness and porosity), capillary absorption, and a comparison of time and evaporation of essential oils were also carried out. Scanning electron microscopy was performed on the samples and the solid carrier with different mixtures of essential oils. The Japanese knotweed sample, coated with a blend of geranium, lavender, and eucalyptus essential oils, showed the highest efficacy and stability.
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(This article belongs to the Special Issue Sustainable Coatings for Functional Textile and Packaging Materials)
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Open AccessArticle
Influence of Surfactant Types on the Anti-Corrosion Performance of Phosphate Chemical Conversion Coated Mg-8wt.%Li Alloy
by
Liji Cui, Baojie Wang, Jiyu Hou, Daokui Xu and Jie Sun
Coatings 2024, 14(5), 641; https://doi.org/10.3390/coatings14050641 - 18 May 2024
Abstract
In this work, the morphology, anti-corrosion performance and degradation mechanisms of two phosphate chemical conversion coatings containing the AEO (fatty alcohol polyoxyethylene ether) and AES (fatty alcohol polyoxyethylene ether sodium sulfate) on an as-cast Mg-8wt.%Li alloy were explored and compared. Although two coating
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In this work, the morphology, anti-corrosion performance and degradation mechanisms of two phosphate chemical conversion coatings containing the AEO (fatty alcohol polyoxyethylene ether) and AES (fatty alcohol polyoxyethylene ether sodium sulfate) on an as-cast Mg-8wt.%Li alloy were explored and compared. Although two coating layers had a petal-shaped structure and were composed of leaf-shaped particles, the coating layer of the AES-coated sample was relatively dense due to the smaller size of the formed petal-shaped structure. Based on the electrochemical data and hydrogen evolution measurements, the corrosion protectability of the coating layer on the AES-coated sample was better than that on the AEO-coated sample. The determined corrosion current densities (icorr) of the AES-coated and AEO-coated samples in the 3.5 wt.% NaCl solution were, respectively, 7.8 mA·cm−2 and 11.7 mA·cm−2, whereas the icorr value of the coated sample without a surfactant was 36.2 mA·cm−2.
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(This article belongs to the Special Issue Environmental Corrosion of Metals and Its Prevention)
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Open AccessArticle
Boosting the Anti-Infection Ability of Titanium Implants by Coating Polydopamine–Curcumin
by
Manlong Chen, Wenyi Yu, Qi Shi, Han Wen, Guojing Li, Yunliang Wang, Tao Wang, Shibin Liu and Tingting Yang
Coatings 2024, 14(5), 640; https://doi.org/10.3390/coatings14050640 - 18 May 2024
Abstract
To reduce the risk of infection, improving the anti-infection ability of Ti-based implantation has become a very meaningful task. In this work, by employing polydopamine (PDA) as a carrier and curcumin (CUR) as an anti-biotic/inflammatory, a series of Ti-PDA@CURx (x = 0.5, 1.0,
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To reduce the risk of infection, improving the anti-infection ability of Ti-based implantation has become a very meaningful task. In this work, by employing polydopamine (PDA) as a carrier and curcumin (CUR) as an anti-biotic/inflammatory, a series of Ti-PDA@CURx (x = 0.5, 1.0, 1.5, 2.0, 2.5) was successfully fabricated and characterized by scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy, and the water contact angle, where Ti plates were firmly coated by PDA@CUR. The test result of CUR content shows that the maximum loading of CUR in PDA can reach 0.6506%, where the CUR concentration is 1.5 mg/mL. The antibacterial test results demonstrate that Ti-PDA@CUR-x (x = 0.5, 1.0, 1.5, 2.0, 2.5) exhibit significant antibacterial activities against Escherichia coli and S. aureu, where [email protected] has the highest antibacterial rate of 62.7% against Escherichia coli and 52.6% against S. aureus. The cytotoxicity test shows that Ti-PDA, Ti-PDA@CUR-x (x = 0.5, 1.0, 1.5, 2.0, 2.5) has almost no toxicity.
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(This article belongs to the Section Bioactive Coatings and Biointerfaces)
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Open AccessArticle
Competitive Mechanism of Alloying Elements on the Physical Properties of Al10Ti15Nix1Crx2Cox3 Alloys through Single-Element and Multi-Element Analysis Methods
by
Yu Liu, Lijun Wang, Juangang Zhao, Zhipeng Wang, Ruizhi Zhang, Yuanzhi Wu, Touwen Fan and Pingying Tang
Coatings 2024, 14(5), 639; https://doi.org/10.3390/coatings14050639 - 18 May 2024
Abstract
Altering the content of an alloying element in alloy materials will inevitably affect the content of other elements, while the effect is frequently disregarded, leading to subsequent negligence of the common influence on the physical properties of alloys. Therefore, the correlation between alloying
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Altering the content of an alloying element in alloy materials will inevitably affect the content of other elements, while the effect is frequently disregarded, leading to subsequent negligence of the common influence on the physical properties of alloys. Therefore, the correlation between alloying elements and physical properties has not been adequately addressed in the existing studies. In response to this problem, the present study focuses on the Al10Ti15Nix1Crx2Cox3 alloys and investigates the competitive interplay among Ni, Cr, and Co elements in the formation of physical properties through a single-element (SE) analysis and a multi-element (ME) analysis based on the first principles calculations and the partial least squares (PLS) regression. The values of C11 and C44 generally increase with the incorporation of Ni or Cr content in light of SE analysis, which is contrary to the inclination of ME analysis in predicting the impact of Ni and Cr elements, and the Ni element demonstrates a pronounced negative competitive ability. The overall competitive relationship among the three alloying elements suggests that increasing the content of Ni and Cr does not contribute to enhancing the elastic constants of alloys, and the phenomenon is also observed in the analysis of elastic moduli. The reason is that the SE analysis fails to account for the aforementioned common influence of multiple alloying elements on the physical properties of alloys. Therefore, the integration of SE analysis and ME analysis is more advantageous in elucidating the hidden competitive mechanism among multiple alloying elements, and offering a more robust theoretical framework for the design of alloy materials.
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(This article belongs to the Special Issue Microstructure, Mechanical and Tribological Properties of Alloys)
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Open AccessArticle
Effect of Nb Doping on the Electrical Contact Properties of AgNi Contact Materials
by
Jingqin Wang, Menghan Wang, Jing Chen and Guanglin Huang
Coatings 2024, 14(5), 638; https://doi.org/10.3390/coatings14050638 - 17 May 2024
Abstract
AgNi contact materials have received widespread attention with the acceleration of the process of replacing AgCdO contact materials. However, the practical applications of AgNi contact materials are limited due to its disadvantage of poor resistance to melting welding. Firstly, following the first principles
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AgNi contact materials have received widespread attention with the acceleration of the process of replacing AgCdO contact materials. However, the practical applications of AgNi contact materials are limited due to its disadvantage of poor resistance to melting welding. Firstly, following the first principles of the density functional theory, we simulated and tested an interfacial model of AgNi doped with varying amounts of Nb. Next, we fabricated AgNi electrical contact materials. Subsequently, we conducted electrical contact tests. Finally, the impact of Nb doping on the arc erosion behavior of AgNi electrical contact materials was analyzed. The results indicate that, with an increase in Nb doping content, the electrical contact performance and the degree of arc erosion exhibit a trend of initially decreasing and then increasing, which aligns with the simulation results. The mean values of arc energy, arc duration, and welding force for the material doped with 4.55% Nb were 181.02 mJ, 9.43 mS, and 38.45 cN, respectively. Moreover, the anode is more responsive to changes in Nb content compared to the cathode. The introduction of Nb enhances the viscosity of the molten pool in the AgNi electrical contact. Furthermore, the mechanisms of grain boundary strengthening and solid solution strengthening by Nb improve the weld performance resistance of the contact.
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(This article belongs to the Special Issue Manufacturing and Surface Engineering IV)
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