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
Use of Organic Acids as Additives for Plasma Electrolytic Oxidation (PEO) of Titanium
Coatings 2024, 14(6), 703; https://doi.org/10.3390/coatings14060703 - 3 Jun 2024
Abstract
The present study investigates the influence of organic acids, added to the electrolytic solution, on the structure, morphology, and corrosion behaviour of plasma electrolytic oxidation (PEO) coatings produced on titanium grade 2. Particular attention is paid to the role of functional groups in
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The present study investigates the influence of organic acids, added to the electrolytic solution, on the structure, morphology, and corrosion behaviour of plasma electrolytic oxidation (PEO) coatings produced on titanium grade 2. Particular attention is paid to the role of functional groups in the modification of the oxide’s properties. For this reason, all three selected acids, namely glutaric, glutamic, and tartaric acid, display two carboxylic groups, thus they interact with the substrate material mainly through –COO− adsorption. However, glutamic acid also has an amine group, while tartaric acid has two hydroxyl groups. The presence of such additional functional groups is found to impact the formation of the PEO coatings. According to scanning electron microscopy (SEM) analyses, the number of defects and their dimension increase with an increasing number of active groups present in the organic molecules. Then, when glutaric acid with only two carboxyl groups, is employed as an additive, smaller pores are produced. The dimension of defects increases when glutamic and tartaric acid are used. X-ray diffraction (XRD) testing demonstrates that rutile and anatase are present in all the coatings and that when using tartaric acid, a relatively high level of amorphism is reached. The electrochemical and corrosion behaviours are evaluated by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) performed in a heated sulphuric acid solution. It is found that all types of coatings provide protection against corrosion, with oxides produced using glutamic acid showing the lowest corrosion current density (0.58 mA·m−2) and low corrosion rate (1.02 μm·y−1).
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(This article belongs to the Section Corrosion, Wear and Erosion)
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Open AccessArticle
Effect of Simultaneous Application of Glass Fiber Reinforcement and Polymer-Modified Asphalt Emulsion on DBST’s Resistance to Aggregate Loss Using Laboratory Investigation
by
Je Won Kim and Carlo Elipse
Coatings 2024, 14(6), 702; https://doi.org/10.3390/coatings14060702 - 3 Jun 2024
Abstract
Double bituminous surface treatment (DBST) has been a widely utilized pavement maintenance material due to its capability to restore the surface roughness of existing pavement and provide a layer of protection against weathering, aging, and moisture. However, DBST is highly prone to aggregate
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Double bituminous surface treatment (DBST) has been a widely utilized pavement maintenance material due to its capability to restore the surface roughness of existing pavement and provide a layer of protection against weathering, aging, and moisture. However, DBST is highly prone to aggregate loss at an early stage, which is a very common problem experienced by surface treatment. Therefore, to lessen the aggregate loss and prolong the service life of DBST, fiber additive can be incorporated to strengthen the adhesion between the asphalt emulsion and aggregates. This study investigated the performance of glass fiber-reinforced polymer-modified DBST against aggregate loss by conducting laboratory tests using typical DBST as the benchmark of the test results. Four laboratory tests were chosen to represent different loading applications on the surface of the pavement: the bitumen bond strength (BBS) test, the sweep test, the Hamburg wheel-track test (HWT test), and a one-third-scale model mobile load simulator (MMLS3) model. Furthermore, the curing time of the asphalt emulsion was considered in the BBS test and sweep test. Based on all results from the conducted laboratory tests, polymer-modified DBST with glass fiber reinforcement presented an increased resistance to aggregate loss compared with typical DBST. Moreover, it was found that a longer curing time of the asphalt emulsion, whether it was typical or modified, strengthened the surface treatment’s resistance to aggregate loss.
Full article
(This article belongs to the Special Issue Advanced Polymeric Materials and Coatings: Synthesis, Properties and Applications)
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Open AccessArticle
Research on Key Technologies of Jewelry Design and Manufacturing Based on 3D Printing Technology
by
Guoqing Zhang, Jiangtao Wang, Junxin Li, Xiaoyu Zhou and Yongsheng Zhou
Coatings 2024, 14(6), 701; https://doi.org/10.3390/coatings14060701 - 3 Jun 2024
Abstract
In conjunction with the swift enhancement of China’s economic prowess, the demand for jewelry among the populace is gradually evolving towards personalized, customized, and intricate designs. Traditional manufacturing approaches are increasingly inadequate to meet these evolving demands. However, the advent of 3D printing
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In conjunction with the swift enhancement of China’s economic prowess, the demand for jewelry among the populace is gradually evolving towards personalized, customized, and intricate designs. Traditional manufacturing approaches are increasingly inadequate to meet these evolving demands. However, the advent of 3D printing technology presents a viable solution for the direct fabrication of such sophisticated jewelry. To this end, the conceptualization of personalized jewelry inspiration is initiated, followed by the implementation of parametric design using SolidWorks 2018 software. Subsequently, 3D printing technology is employed to materialize the jewelry directly. Results indicate that the “Guardian” jewelry model, crafted through the parametric modeling method, exhibits a commendable design, and adheres to processing requirements following a comprehensive risk analysis. The strategic adjustment of the jewelry’s position effectively reduces the required support, circumventing the necessity of adding support to critical surfaces. The surface of the Selective Laser Melting (SLM)-manufactured “Guardian” jewelry boasts a lustrous finish, showcasing optimal overlap between pillars and excellent connectivity among pores. Minimal powder adherence on the surface is observed, enabling direct utilization post-sandblasting, polishing, and plating. This establishes a solid foundation for the direct application of SLM-manufactured personalized jewelry.
Full article
(This article belongs to the Special Issue Recent Advances in Additive Manufacturing Techniques)
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Open AccessArticle
Optimization of Epitaxial Structures on GaN-on-Si(111) HEMTs with Step-Graded AlGaN Buffer Layer and AlGaN Back Barrier
by
Jeong-Gil Kim
Coatings 2024, 14(6), 700; https://doi.org/10.3390/coatings14060700 - 2 Jun 2024
Abstract
Recently, crack-free GaN-on-Si growth technology has become increasingly important due to the high demand for power semiconductor devices with high performances. In this paper, we have experimentally optimized the buffer structures such as the AlN nucleation layer and step-graded AlGaN layer for AlGaN/GaN
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Recently, crack-free GaN-on-Si growth technology has become increasingly important due to the high demand for power semiconductor devices with high performances. In this paper, we have experimentally optimized the buffer structures such as the AlN nucleation layer and step-graded AlGaN layer for AlGaN/GaN HEMTs on Si (111) substrate by varying growth conditions and thickness, which is very crucial for achieving crack-free GaN-on-Si epitaxial growth. Moreover, an AlGaN back barrier was inserted to reduce the buffer trapping effects, resulting in the enhancement of carrier confinement and suppression of current dispersion. Firstly, the AlN nucleation layer was optimized with a thickness of 285 nm, providing the smoothest surface confirmed by SEM image. On the AlN nucleation layer, four step-graded AlGaN layers were sequentially grown by increasing the Al composition from undermost layer to uppermost layer, meaning that the undermost one was close to AlN, and the uppermost was close to GaN, to reduce the stress and strain in the epitaxial layer gradually. It was also verified that the thicker step-graded AlGaN buffer layer is suitable for better crystalline quality and surface morphology and lower buffer leakage current, as expected. On these optimized buffer structures, the AlGaN back barrier was introduced, and the effects of the back barrier were clearly observed in the device characteristics of the AlGaN/GaN HEMTs on Si (111) substrate such as the transfer characteristics, output characteristics and pulsed I-V characteristics.
Full article
(This article belongs to the Special Issue Energy Storage and Conversion: From Materials, Devices to Applications)
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Open AccessArticle
Preparation of Silicone Coating and Its Anti-Ice and Anti-Corrosion Properties
by
Haopeng Wang, Jihu Wang, Shaoguo Wen, Sihong Jiang, Jia Song, Shengnan Ding and Hui Wu
Coatings 2024, 14(6), 699; https://doi.org/10.3390/coatings14060699 - 1 Jun 2024
Abstract
To enhance protection against corrosion and ice on iron metal material in frigid zones, an organic silicone resin coating was prepared using four monomers. Its structure and performance was analyzed via infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and
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To enhance protection against corrosion and ice on iron metal material in frigid zones, an organic silicone resin coating was prepared using four monomers. Its structure and performance was analyzed via infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and thermal analysis (TG). Corrosion resistance of coating was tested by saltwater resistance and salt spray resistance and assessed using an electrochemical workstation, alongside anti-icing tests. The results showed that the organic silicone resin was successfully synthesized. The coatings could delay freezing onset by one-third compared to controls in low temperatures, with a detachment time also reduced by one-third, indicating excellent corrosion and ice resistance. The methylphenyl silicone resin had good anti-corrosion and anti-ice properties, with a low corrosion current density (icorr) of 0.8793 μA/cm2 and a high charge transfer resistance (Rct) of 24,930 Ω·cm2 in saline.
Full article
(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)
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Open AccessArticle
Impact of Interfacial Transition Zone on Concrete Mechanical Properties: A Comparative Analysis of Multiphase Inclusion Theory and Numerical Simulations
by
Qiong Liu, Congkai Jin and Xiujun Li
Coatings 2024, 14(6), 698; https://doi.org/10.3390/coatings14060698 - 1 Jun 2024
Abstract
With the increasing implementation of sustainable development strategies, recycled concrete (RC) has garnered attention in research circles due to its substantial environmental and economic advantages. The presence and properties of various interface transition zones (ITZs) in RC play a vital role in its
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With the increasing implementation of sustainable development strategies, recycled concrete (RC) has garnered attention in research circles due to its substantial environmental and economic advantages. The presence and properties of various interface transition zones (ITZs) in RC play a vital role in its mechanical properties. This research uses a combination of multiphase inclusion theory and finite element numerical simulation to investigate and compare the impact of ITZs on concrete’s mechanical properties. The multiphase inclusion theory offers a theoretical framework for understanding ITZ behavior in concrete, categorizing it into new mortar, old mortar, new ITZ, old ITZ, and natural aggregate based on meso-structure. With simplified RC at the mesoscale, the study accurately predicts the mechanical properties of RC by adjusting the elastic modulus, Poisson’s ratio, and thickness of new and old ITZ models. Through finite element simulation and theoretical validation, the study achieves a minimal error of 6.24% in predicting the elastic modulus and 1.75% in predicting Poisson’s ratio. These results highlight the effectiveness of multiphase inclusion theory in capturing the meso-structure characteristics of RC and forecasting its macroscopic mechanical behavior while comprehensively considering the complexity of ITZs.
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(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)
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Open AccessArticle
Research on Layered Steel Fiber Reinforced Concrete Mix Ratio Design Based on Orthogonal Test
by
Zijian Wang, Hongkun Li, Xiangyang Ye, Wenyu Luo, Bin Zhang, Anlin Hu and Liming Wu
Coatings 2024, 14(6), 697; https://doi.org/10.3390/coatings14060697 - 1 Jun 2024
Abstract
The aim of this study was to investigate the effect of different mix ratios on the mechanical properties of steel fiber-reinforced concrete (LSFRC) and to determine an optimum mix ratio. The effects of four factors, namely, fly ash content, volume fraction of steel
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The aim of this study was to investigate the effect of different mix ratios on the mechanical properties of steel fiber-reinforced concrete (LSFRC) and to determine an optimum mix ratio. The effects of four factors, namely, fly ash content, volume fraction of steel fibers, water–cement ratio, and sand rate, on the mechanical properties of LSFRC were investigated through orthogonal experiments. The microstructure of LSFRC at different mix ratios was analyzed using scanning electron microscopy (SEM), and an optimal mix ratio was derived. The results showed that the water–cement ratio and the volume fraction of steel fibers were the main factors affecting the mechanical properties of LSFRC. When the water–cement ratio was 0.38 and 0.42, the combined mechanical properties of concrete were superior. Steel fiber content between 0.6% and 1% had a significant effect on the splitting tensile strength of concrete. The effect of sand rate on compressive and splitting tensile strengths was consistent, with a significant effect on both at a sand rate of 40%. In terms of microstructure, 20% fly ash content promotes the hydration of concrete. The optimum LSFRC mix ratio determined was 0.42 water–cement ratio, 0.6% steel fiber content, 40% sand rate, and 20% fly ash content. Experimental verification using this mix ratio showed that the compressive, flexural, and split tensile strengths were increased by 3%, 19%, and 33%, respectively, when compared to ordinary concrete.
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(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)
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Open AccessArticle
Calcium Phosphate Coatings Deposited on 3D-Printed Ti–6Al–4V Alloy by Plasma Electrolytic Oxidation
by
Amangeldi Sagidugumar, Dmitriy Dogadkin, Amanzhol Turlybekuly and Daniyar Kaliyev
Coatings 2024, 14(6), 696; https://doi.org/10.3390/coatings14060696 - 1 Jun 2024
Abstract
In this article, the process of creating calcium phosphate coatings through plasma electrolytic oxidation was investigated. Calcium phosphate coatings were deposited onto titanium substrates fabricated via the selective laser melting (SLM) method. The correlation between the characteristics of the coating and the applied
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In this article, the process of creating calcium phosphate coatings through plasma electrolytic oxidation was investigated. Calcium phosphate coatings were deposited onto titanium substrates fabricated via the selective laser melting (SLM) method. The correlation between the characteristics of the coating and the applied voltage (200, 250, and 300 V) of PEO was studied. The surface morphology analysis indicates that an increase in applied voltage results in a larger pore size. It was discovered that, when a voltage of 300 V was applied, a layer of hydroxyapatite formed. However, at 300 V, the coating cracked, producing a significantly rough surface. Our analysis of the elemental composition of sample cross sections indicates the presence of TiO2 layers that are enriched with calcium (Ca) and phosphorus (P). The coefficient of friction and wear rate are primarily influenced by the morphology, pore size, and density of the titanium dioxide layer. Furthermore, a rise in the quantity of the beta phase of the titanium on the surface can be noticed as the applied voltage increases. As a result, it also affects the mechanical and tribological characteristics of the coating. The sample treated to a voltage of 250 V demonstrates a higher resistance to wear and a lower elastic modulus in comparison to the other two coatings.
Full article
(This article belongs to the Section Surface Characterization, Deposition and Modification)
Open AccessArticle
Oxidation Resistance of Ir/HfO2 Composite Coating Prepared by Chemical Vapor Deposition: Microstructure and Elemental Migration
by
Junyu Zhu, Wenting Li, Hongzhong Cai, Xian Wang, Xingqiang Wang, Yan Wei, Changyi Hu, Xingdong Zhao and Xuxiang Zhang
Coatings 2024, 14(6), 695; https://doi.org/10.3390/coatings14060695 - 1 Jun 2024
Abstract
In this study, a HfO2 coating was developed on an Ir matrix using a customized open-tube airflow, cold-wall chemical vapor deposition instrument. The preparation process and structure of the as-prepared coating were investigated to gain insights into its characteristics. The HfO2
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In this study, a HfO2 coating was developed on an Ir matrix using a customized open-tube airflow, cold-wall chemical vapor deposition instrument. The preparation process and structure of the as-prepared coating were investigated to gain insights into its characteristics. The HfO2 coating effectively prevents direct contact between Ir and O, leading to a reduction in the oxidation rate of Ir. Furthermore, defects such as micropores and cracks generated during sealed oxidation erosion contribute to Ir’s decelerated oxidation failure. The as-prepared HfO2 coating exhibits low thermal conductivity and a high heat radiation rate, reducing the coating’s surface temperature. These characteristics significantly enhance adversity tolerance and increase the working temperature of the coating. Moreover, the as-prepared HfO2 coating can serve as a diffusion barrier, blocking both the direct contact of O with the Ir coating and the diffusion of other elements to the Ir coating. As a result, the rates of diffusion of other elements to the Ir coating are reduced.
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(This article belongs to the Section Surface Characterization, Deposition and Modification)
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Open AccessArticle
The Effects of Halogen (Cl, Br) Decorating on the Gas Adsorption Behaviors of the Pristine Black Phosphorene: A First-Principles Study
by
Xinjun Tan, Lan Lin, Touwen Fan and Kaiwang Zhang
Coatings 2024, 14(6), 694; https://doi.org/10.3390/coatings14060694 - 1 Jun 2024
Abstract
As a novel two-dimensional (2D) material, black phosphorene (BP) finds wide applications in gas adsorption and detection devices due to its distinctive optical, thermoelectric, and surface properties. However, numerous studies have demonstrated that BP exhibits strong selectivity towards gas adsorption and displays significant
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As a novel two-dimensional (2D) material, black phosphorene (BP) finds wide applications in gas adsorption and detection devices due to its distinctive optical, thermoelectric, and surface properties. However, numerous studies have demonstrated that BP exhibits strong selectivity towards gas adsorption and displays significant affinity towards gas molecules containing the element N, thereby greatly impeding its utilization in gas detection. To partially compensate for this deficiency, this study investigates the impact of halogen atom decoration on the adsorption behavior of BP towards CO2, H2O, and O2 molecules. Furthermore, a comparison is made between the variations in gas adsorption energy with and without decorated halogen atoms. The results showed that the adsorbates of CO2, H2O, and O2 molecules and halogen atoms (Cl, Br) adsorbed at the top (T) site of BP was much stronger than those at the bridge (B) and the hollow (H) sites of the P-P bond of BP, owing to their low adsorption energies. After the t position of BP is modified by the halogen (Cl, Br) atom, the optimal adsorption of CO2 changes from −0.85 eV to −1.70 eV (Cl) and −1.64 eV (Br), and the optimal adsorption of H2O changes from −0.72 eV to −1.48 eV (Cl) and −1.23 eV (Br), respectively. The adsorption properties were significantly enhanced. That is to say, the gas adsorption properties of BP have been largely improved by halogen Cl (Br) atoms decorating.
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(This article belongs to the Special Issue Recent Progress in Surface and Interface Properties of Nanostructures)
Open AccessArticle
Preparation of ZnO Thick Films Activated with UV-LED for Efficient H2S Gas Sensing
by
Claudio Martínez-Pacheco, José Luis Cervantes-López, Antonia del Rocío López-Guemez, Angélica Silvestre López-Rodríguez, Pio Sifuentes-Gallardo, Juan Carlos Díaz-Guillen and Laura Lorena Díaz-Flores
Coatings 2024, 14(6), 693; https://doi.org/10.3390/coatings14060693 - 1 Jun 2024
Abstract
In this work, ZnO thick films were synthesized via two simple and easy methods, mechanochemical synthesis and screen-printing deposition. The ZnO powders were obtained through milling at low temperature with milling times of 20, 40, and 60 min. The ZnO thick films were
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In this work, ZnO thick films were synthesized via two simple and easy methods, mechanochemical synthesis and screen-printing deposition. The ZnO powders were obtained through milling at low temperature with milling times of 20, 40, and 60 min. The ZnO thick films were fabricated by depositing 10 cycles of ZnO inks onto glass substrates. The characterization of ZnO thick films revealed a thickness ranging from 4.9 to 5.4 µm with a surface roughness between 85 and 88 nm. The structural analysis confirmed a hexagonal wurtzite crystalline structure of ZnO, both in powders and in thick films, with a preferred orientation on the (002) and (101) planes. Nanostructures with sizes ranging from 36 to 46 nm were observed, exhibiting irregular agglomerated shapes, with an energy band found between 2.77 and 3.02 eV. A static experimental set up was fabricated for gas sensing tests with continuous UV-LED illumination. The ZnO thick films, well adhered to the glass substrate, demonstrated high sensitivity and selectivity to H2S gas under continuous UV-LED illumination at low operating temperatures ranging from 35 to 80 °C. The sensitivity was directly proportional, ranging from 3.93% to 22.40%, when detecting H2S gas concentrations from 25 to 600 ppm.
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(This article belongs to the Special Issue Printed Functional Thin Films for Electronic, Optoelectronic and Sensing Applications)
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Open AccessArticle
Study of the Performance of Emulsified Asphalt Shotcrete in High-Altitude Permafrost Regions
by
Yitong Hou, Kaimin Niu, Bo Tian, Xueyang Li and Junli Chen
Coatings 2024, 14(6), 692; https://doi.org/10.3390/coatings14060692 - 1 Jun 2024
Abstract
To improve the performance of shotcrete in high-altitude and low-temperature environments, emulsified asphalt shotcrete (EASC), which can be used in negative-temperature environments, was prepared by using low-freezing-point emulsified asphalt, calcium aluminate cement, and sodium pyrophosphate as modified materials. The effect of emulsified asphalt
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To improve the performance of shotcrete in high-altitude and low-temperature environments, emulsified asphalt shotcrete (EASC), which can be used in negative-temperature environments, was prepared by using low-freezing-point emulsified asphalt, calcium aluminate cement, and sodium pyrophosphate as modified materials. The effect of emulsified asphalt on the performance of shotcrete was investigated through concrete spraying and indoor tests. Then, the modification mechanism of emulsified asphalt with respect to EASC was analyzed by combining scanning electron microscopy images and the pore structure characteristics of EASC. The results showed that in a negative-temperature environment, the incorporation of emulsified asphalt delayed the formation of the peak of the cement hydration exotherm, slowed the rate of the cement hydration exotherm, reduced the thermal perturbation of permafrost by EASC, increased the cohesion of the concrete, improved the bond strength between EASC and permafrost, and reduced the rate of rebound. The mechanical strength of the studied EASC decreased upon increasing the amount of emulsified asphalt in the admixture, and its resistance to cracking gradually improved. A content of less than 5% emulsified asphalt could improve the internal pore structure of EASC, thus improving its durability. Increasing the content of emulsified asphalt affected the hydration process of the cement, and the volume content of the capillary pores and macropores increased, which reduced the durability of the EASC.
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(This article belongs to the Special Issue Novel Cleaner Materials for Pavements)
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Open AccessArticle
Cutting Energy Consumption Modeling by Considering Tool Wear and Workpiece Material Properties for Multi-Objective Optimization of Machine Tools
by
Yue Meng, Shengming Dong, Xinsheng Sun, Shiliang Wei and Xianli Liu
Coatings 2024, 14(6), 691; https://doi.org/10.3390/coatings14060691 - 1 Jun 2024
Abstract
The increasing demand for energy is leading to global depletion of fossil fuels and growing environmental pressures, which are issues that need to be addressed. Machine tools are basic energy-consuming equipment in manufacturing systems. However, existing theoretical models ignore tool wear as well
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The increasing demand for energy is leading to global depletion of fossil fuels and growing environmental pressures, which are issues that need to be addressed. Machine tools are basic energy-consuming equipment in manufacturing systems. However, existing theoretical models ignore tool wear as well as workpiece material properties. This makes it difficult to further improve the accuracy of the model. Therefore, this study begins with the point of view of energy dissipation in the metal material removal process. A milling power model for computer numerical control (CNC) machines, considering tool wear and workpiece material properties during machining, is established. At the same time, milling is taken as the research object. A multi-objective cutting parameter optimization model is established to ensure the surface quality of the workpiece. In addition, the cutting energy consumption is taken into account in the developed models. Based on the multi-objective manta ray foraging optimization algorithm (MOMRFO), the Pareto-optimal solution set under multiple cutting conditions is solved. Finally, the experimental results of optimized parameters are compared with empirical parameters. The average prediction accuracy of the proposed energy consumption prediction model is above 91%. The experiments show that machining quality improves by optimizing the cutting parameters, with SEC, MRR, and Ra increasing by more than 44%, 53%, and 38%, respectively. The goals of reducing energy consumption and increasing productivity are achieved.
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(This article belongs to the Special Issue Oxidation, Wear, Corrosion Behaviors and Activated Bonding Properties of Coatings Deposited on Metals)
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Open AccessCommunication
Predicting New Single/Multiphase-Structure High-Entropy Alloys Using a Pattern Recognition Network
by
Fang Wang, Jiahao Wang, Jiayu Wang, Ruirui Wu and Ke Liu
Coatings 2024, 14(6), 690; https://doi.org/10.3390/coatings14060690 - 1 Jun 2024
Abstract
Machine learning methods were employed to predict the phase structures of high-entropy alloys (HEAs). These alloys were classified into four categories: bcc (body-centered cubic), fcc (face-centered cubic), bcc+fcc (body-centered cubic and face-centered cubic) and others (containing intermetallic compounds and other structural alloys). The
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Machine learning methods were employed to predict the phase structures of high-entropy alloys (HEAs). These alloys were classified into four categories: bcc (body-centered cubic), fcc (face-centered cubic), bcc+fcc (body-centered cubic and face-centered cubic) and others (containing intermetallic compounds and other structural alloys). The utilized algorithm was a Pattern Recognition Network (PRN) utilizing cross-entropy as the loss function, enabling the prediction of HEAs’ phase formation probability. The PRN algorithm demonstrated an accuracy exceeding 87% based on the test data. The PRN algorithm successfully predicted the transformation from fcc to fcc+bcc and subsequently to a bcc structure with the increase in Al content in AlxCoCu6Ni6Fe6 and AlxCoCrCuNiFe HEAs. In addition, AlxCoCu6Ni6Fe6 (x = 1, 3, 6, 9) HEAs were prepared using a vacuum arc furnace, and the microstructure of the as-cast alloy was tested by means of XRD, SEM, and EBSD, confirming the high consistency between the predicted and observed phase structures. This study showcases the efficacy of the PRN algorithm in predicting both single- and multiphase-structure high-entropy alloys, offering valuable insights into alloy design and development.
Full article
(This article belongs to the Special Issue Research and Application of High Entropy Alloys)
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Open AccessArticle
Microstructure and Biocompatibility of Graphene Oxide/BCZT Composite Ceramics via Fast Hot-Pressed Sintering
by
Bingqing Zhao, Qibin Liu, Geng Tang and Dunying Wang
Coatings 2024, 14(6), 689; https://doi.org/10.3390/coatings14060689 - 1 Jun 2024
Abstract
Improving fracture toughness, electrical conductivity, and biocompatibility has consistently presented challenges in the development of artificial bone replacement materials. This paper presents a new strategy for creating high-performance, multifunctional composite ceramic materials by doping graphene oxide (GO), which is known to induce osteoblast
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Improving fracture toughness, electrical conductivity, and biocompatibility has consistently presented challenges in the development of artificial bone replacement materials. This paper presents a new strategy for creating high-performance, multifunctional composite ceramic materials by doping graphene oxide (GO), which is known to induce osteoblast differentiation and enhance cell adhesion and proliferation into barium calcium zirconate titanate (BCZT) ceramics that already exhibit good mechanical properties, piezoelectric effects, and low cytotoxicity. Using fast hot-pressed sintering under vacuum conditions, (1 − x)(Ba0.85Ca0.15Zr0.1Ti0.9)O3−xGO (0.2 mol% ≤ x ≤ 0.5 mol%) composite piezoelectric ceramics were successfully synthesized. Experimental results revealed that these composite ceramics exhibited high piezoelectric properties (d33 = 18 pC/N, kp = 62%) and microhardness (173.76 HV0.5), meeting the standards for artificial bone substitutes. Furthermore, the incorporation of graphene oxide significantly reduced the water contact angle and enhanced their wettability. Cell viability tests using Cell Counting Kit-8, alkaline phosphatase staining, and DAPI staining demonstrated that the GO/BCZT composite ceramics were non-cytotoxic and effectively promoted cell proliferation and growth, indicating excellent biocompatibility. Consequently, with their superior mechanical properties, piezoelectric performance, and biocompatibility, GO/BCZT composite ceramics show extensive potential for application in bone defect repair.
Full article
(This article belongs to the Special Issue Advances of Ceramic and Alloy Coatings, 2nd Edition)
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Open AccessArticle
The Effect of Preheating Temperature on the Corrosion Resistance and Porosity Defects Development Behaviour of Ni60A Coating
by
Fule Huang, Chen Li, Hailin Guo, Shuqin Huang, Fanghai Ling and Qijun Fu
Coatings 2024, 14(6), 688; https://doi.org/10.3390/coatings14060688 - 1 Jun 2024
Abstract
The laser cladding of nickel-based fusion alloys makes them prone to cracks and defects that affect the overall performance of the coating. In this study, Ni60A coatings were prepared at different preheating temperatures (25 °C, 200 °C, 400 °C and 600 °C). The
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The laser cladding of nickel-based fusion alloys makes them prone to cracks and defects that affect the overall performance of the coating. In this study, Ni60A coatings were prepared at different preheating temperatures (25 °C, 200 °C, 400 °C and 600 °C). The effect of the preheating temperature of the substrate on the corrosion resistance of the coating as well as on the development of defects were investigated by electrochemical tests and immersion experiments in a 65 wt% H2SO4 solution at 60 °C. The results indicate that preheating the substrate to 200 °C can completely eliminate cracks in the coating and reduce porosity. Preheating leads to a decrease in the corrosion resistance of the coating. The size of the porosity defects is related to the law of longitudinal development of the defects. Porosity defects with diameters smaller than 100 μm have a more pronounced tendency to expand vertically than those with diameters larger than 100 μm.
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(This article belongs to the Section Corrosion, Wear and Erosion)
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Open AccessArticle
Experimental Study on Microwave Drying Aluminum Hydroxide
by
Xuemei Zheng, Fuqin Yuan, Aiyuan Ma and Shihong Tian
Coatings 2024, 14(6), 687; https://doi.org/10.3390/coatings14060687 - 1 Jun 2024
Abstract
The aluminum hydroxide produced by the Bayer process contains a large amount of water which leads to the consumption of a large amount of heat for moisture removal in the calcination process, resulting in an increased energy consumption. The effects of temperature and
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The aluminum hydroxide produced by the Bayer process contains a large amount of water which leads to the consumption of a large amount of heat for moisture removal in the calcination process, resulting in an increased energy consumption. The effects of temperature and microwave power on the dehydration ratio and the dry matter ratio of aluminum hydroxide were investigated. The characteristics of temperature variation during drying were discussed. X-ray diffraction (XRD), scanning electron microscopy (SEM), laser particle size, Fourier transform infrared (FTIR) spectroscopy, and dielectric property analyses were made to characterize the dried materials. The analysis results showed that within the range of bench-scale experimental parameters, the dehydration ratio was higher and the proportion of dry matter was lower at a higher final temperature. Within the range of pilot-scale experimental parameters, the dehydration ratio increased with the increasing microwave power from 500 W to 1500 W. XRD spectra revealed that when the final temperature exceeded 220 °C, a part of the aluminum hydroxide underwent a low-temperature phase transition to boehmite. The SEM images and a particle size analysis showed that there was no significant difference between the morphologies of the powder obtained by microwave drying and conventional drying methods. The powder obtained by both processes had an average particle size of around 80 μm. The dielectric constant and the dielectric loss of the dried material decreased greatly.
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(This article belongs to the Special Issue Oxidation, Wear, Corrosion Behaviors and Activated Bonding Properties of Coatings Deposited on Metals)
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A Comparative Study of Machining Property in Inconel 718 Superalloy Grinding with Al2O3- and CBN/Fe-Based Spherical Magnetic Abrasives
by
Linzhi Jiang, Guixiang Zhang, Haozhe Zhang, Yandan Xia and Jinli Xiang
Coatings 2024, 14(6), 686; https://doi.org/10.3390/coatings14060686 - 1 Jun 2024
Abstract
A comparative analysis was studied on the finishing performance of spherical CBN/Fe-based magnetic abrasive particles (MAPs) and Al2O3/Fe-based magnetic abrasive particles (MAPs) prepared by the gas atomization method in the magnetic abrasive finishing (MAF) of the Inconel 718 superalloy.
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A comparative analysis was studied on the finishing performance of spherical CBN/Fe-based magnetic abrasive particles (MAPs) and Al2O3/Fe-based magnetic abrasive particles (MAPs) prepared by the gas atomization method in the magnetic abrasive finishing (MAF) of the Inconel 718 superalloy. In the MAF, it was found that compared with Al2O3/Fe-based MAPs, CBN/Fe-based MAPs have a lower grinding temperature and generate less heat during the grinding of the Inconel 718 superalloy. The grinding pressure generated on the workpiece is relatively stable (Al2O3/Fe-based MAPs have a larger fluctuation range of grinding pressure on the workpiece surface during the grinding process). The surface roughness of the workpiece rapidly drops from Ra 0.57 μm to Ra 0.039 μm, and the material removal reaches 42 mg within 20 min. After finishing, the scratches on the surface of the workpiece basically disappear, the contour curve is relatively flat, and there is almost no adhesion on the surface of the workpiece. The mirror effect of the superalloy surface is good, and ultimately a better surface quality can be obtained.
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(This article belongs to the Special Issue Oxidation, Wear, Corrosion Behaviors and Activated Bonding Properties of Coatings Deposited on Metals)
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A Multifunctional Magnetic Fluorescent Nanoprobe for Copper(II) Using ZnS-DL-Mercaptosuccinic Acid-Modified Fe3O4 Nanocomposites
by
Ping Xu, Xin Chen, Jie Chen, Shihua Yu, Xiaodan Zeng and Zhigang Liu
Coatings 2024, 14(6), 685; https://doi.org/10.3390/coatings14060685 - 1 Jun 2024
Abstract
Cu2+ has increasingly become a great threat to the natural environment and human health due to its abundant content and wide application in various industries. DL-Mercaptosuccinic acid and ZnS-modified Fe3O4 nanocomposites were designed, synthesized, and applied in the determination
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Cu2+ has increasingly become a great threat to the natural environment and human health due to its abundant content and wide application in various industries. DL-Mercaptosuccinic acid and ZnS-modified Fe3O4 nanocomposites were designed, synthesized, and applied in the determination of Cu2+. The prepared nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopes (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and thermogravimetric analyzer (TG). The magnetic fluorescent nanoprobe exhibited highly selective and sensitive fluorescence-quenching characteristics with Cu2+ ions. The fluorescence detection linear range was 0–400 μM, with the detection limit being 0.489 μM. In addition, the magnetic fluorescent nanoprobe exhibited a high adsorption and removal rate for Cu2+. It had been successfully applied to detect Cu2+ in real water samples with a satisfactory recovery rate. The magnetic fluorescent nanoprobe could simultaneously realize the functions of enrichment, quantitative detection, and separation, reduce the pollution of copper ions and probes, and establish an environment-friendly detection method. Consequently, the magnetic fluorescent nanoprobe offered a new pathway for the removal and detection of not only Cu2+ but also other heavy metal ions in water.
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(This article belongs to the Special Issue Mitigating Environmental and Health Risks of Coatings: Advances in Safer Formulation, Use, and Disposal)
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Influence of Ni on the Organization and Properties of AlCoCrFeMn High-Entropy Alloys by Laser-Sintering Technique
by
Yajun An, Bojin Jiang, Chuanjiu Jiang, Haocheng Liu and Yiming Li
Coatings 2024, 14(6), 684; https://doi.org/10.3390/coatings14060684 - 1 Jun 2024
Abstract
In order to investigate the effect of the Ni element on the properties of AlCoCrFeMn HEAs, this experiment prepared AlCoCrFeMn and AlCoCrFeNiMn HEAs by using a laser-ignition self-propagation sintering technique with an equal molar ratio. And analyzed the effect of the Ni element
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In order to investigate the effect of the Ni element on the properties of AlCoCrFeMn HEAs, this experiment prepared AlCoCrFeMn and AlCoCrFeNiMn HEAs by using a laser-ignition self-propagation sintering technique with an equal molar ratio. And analyzed the effect of the Ni element on the microstructure of AlCoCrFeMn HEAs by using a metallurgical optical microscope (OM), scanning electron microscope (SEM), energy spectroscopic analysis (EDS), X-ray diffraction (XRD), and other experiments. Characterization equipment was used to analyze the effect of the Ni element on the microstructure, physical phase structure, wear resistance, compressive properties, and corrosion resistance of AlCoCrFeMn HEA materials. The results show that after the addition of the Ni element, the AlCoCrFeNiMn HEA changes from a single BCC phase to one consisting of BCC and a small amount of an FCC phase, with an equiaxial organization, and the yield strength reaches 780 MPa and the compressive strength is 3920 MPa. The corrosion rate is 2.08 × 10−3 mm/a, and the corrosion resistance and mechanical properties are greatly increased.
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(This article belongs to the Section Laser Coatings)
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