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
Prussian Blue Encapsulated with Brush-like Polyorganosiloxane Nanospheres with Tunable Functionality
Coatings 2024, 14(6), 677; https://doi.org/10.3390/coatings14060677 (registering DOI) - 27 May 2024
Abstract
Faced with higher demands of pigments in various applications, the performance of pigments in a specific system is in urgent need of optimization and improvement. Polyorganosiloxane (POS) stands out among various encapsulating polymeric materials for pigment modification due to its superior thermal stability
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Faced with higher demands of pigments in various applications, the performance of pigments in a specific system is in urgent need of optimization and improvement. Polyorganosiloxane (POS) stands out among various encapsulating polymeric materials for pigment modification due to its superior thermal stability and alkali resistance. However, the inherent hydrophobicity of POS causes poor stability in aqueous systems, which is usually applied in environmentally friendly applications. Grafting hydrophilic polymer chains on the surface of POS could improve water dispersity. In addition, the encapsulated pigment can also be endowed with various functionalities by selecting or combining grafted polymers. Herein, we reported a strategy to encapsulate Prussian blue (PB27) with POS grafted with poly(acrylic acid) (PAA) or poly(N-(2-hydroxyethyl) acrylamide) (PHEAA) to allow better stability and functionality of the composite pigment particles, denoted as PB27@POS@PAA or PB27@POS@PHEAA, respectively. The effect of the number of monomers and the amount of initiator potassium persulfate (KPS) on the brush thickness of the grafted polymers was studied, along with various performance properties and the functionality of PB27@POS@PAA and PB27@POS@PHEAA. The dispersity, alkali resistance, and high-temperature stability are studied. The brush-like composite pigment performs better after centrifugation (5000 rpm, 30 min) or treatment under 90 °C when the dosage of grafting monomer AA or HEAA reaches 400 wt%. Optimal alkali resistance was obtained for PB27@POS@PAA (AA, 200 wt%) with a particle size variation of only 31 nm after 8 h. Comparably, PB27@POS@PHEAA behaved worse under similar conditions. Moreover, PB27@POS grafted with PAA was responsive to pH and that with PHEAA showed excellent antifouling properties, which could also be replaced by other functional monomers if needed.
Full article
(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)
Open AccessArticle
Numerical Simulation of the Dynamic Behavior Exhibited by Charged Droplets Colliding with Liquid Film
by
Jun Wang, Dongzhou Jia, Min Yang, Yanbin Zhang, Da Qu and Zhenlin Lv
Coatings 2024, 14(6), 676; https://doi.org/10.3390/coatings14060676 - 27 May 2024
Abstract
Since droplet collision with walls has become a research hotspot, scholars have conducted a large number of studies on the dynamic behavior of electrically neutral droplets colliding with dry walls. However, with the rapid development of electrostatic spray technology, there is an increasingly
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Since droplet collision with walls has become a research hotspot, scholars have conducted a large number of studies on the dynamic behavior of electrically neutral droplets colliding with dry walls. However, with the rapid development of electrostatic spray technology, there is an increasingly urgent need to study the dynamic process of collision between charged droplets and walls. In this paper, considering the actual working conditions of electrostatic spray, an electric field model is introduced based on the two-phase flow field. Through the coupling of a multiphase flow field and electric field and a multiphysics field, the dynamic numerical calculation method is used to explore the collision electrodynamic behavior of charged droplets and liquid film. The dynamic evolution process of the formation and development of the liquid crown in the collision zone was clarified, and the critical velocity and critical Weber number of the rebound, spreading, and splashing of charged droplets were tracked. The distribution characteristics of electrostatic field, pressure field, and velocity field under different working conditions are analyzed, and the dynamic mechanism of the charged droplet collision liquid film under multi-physics coupling is revealed based on the electro-viscous effect. It is confirmed that the external electric field can increase the critical velocity of droplet splashing and fragmentation and promote the spreading and fusion behavior of droplets and liquid films. The influence of the impact angle of charged droplets on the collision behavior was further explored. It was found that the charged droplets not only have a smaller critical angle for fragmentation and splashing, but also have a faster settling and fusion speed.
Full article
(This article belongs to the Special Issue Biolubricants: Synthesis, Properties, Applications and Future Prospects)
Open AccessArticle
Energy-Absorption Behavior of Novel Bio-Inspired Thin-Walled Honeycomb Tubes Filled with TPMS Structure
by
Jian Song, Qidong Huo, Dongming Li, Bingzhi Chen and Jun Zhang
Coatings 2024, 14(6), 675; https://doi.org/10.3390/coatings14060675 - 27 May 2024
Abstract
The application of bionic structures for the design of energy-absorbing structures has been proposed recently. The rapid advancement of additive manufacturing technology provides technical support for the fabrication of non-traditional structures and further improves the energy-absorbing properties of bionic structures. This work proposes
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The application of bionic structures for the design of energy-absorbing structures has been proposed recently. The rapid advancement of additive manufacturing technology provides technical support for the fabrication of non-traditional structures and further improves the energy-absorbing properties of bionic structures. This work proposes a novel bionic hybrid structure that consists of honeycomb-inspired thin-walled tubes filled with weevil-inspired diamond TPMS (triple periodic minimal surface) structures. The energy-absorbing properties and the deformation behaviors of these topologies under axial crushing loads were investigated using combined numerical simulations and experimental tests. First, the effect of filling quantity and filling distribution on energy absorption of the hybrid structures was investigated. Results show that honeycomb tubes and diamond TPMS structures produce a synergistic effect during compression, and the hybrid structures exhibit excellent stability and energy absorption capacity. The bionic hybrid structure improves specific energy absorption (SEA) by 299% compared to honeycomb tubes. Peak crush force (PCF) and SEA are more influenced by filling quantity than by filling distribution. The effects of diamond TPMS structure volume fraction and honeycomb tube wall thickness on the energetic absorptive capacity of the hybrid structure were furthermore investigated numerically. Finally, a multi-objective optimization method was used to optimize the design of the bionic hybrid structure and balance the relationship between crashworthiness and cost to obtain a bionic hybrid energy-absorbing structure with superior performance. This study provides valuable guidelines for designing and fabricating lightweight and efficient energy-absorbing structures with significant potential for engineering applications.
Full article
(This article belongs to the Special Issue Laser Additive Manufacturing: Materials, Technologies, and Applications)
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Open AccessArticle
Comparative Study of Multilayer Hard Coatings Deposited on WC-Co Hardmetals
by
Mateja Šnajdar, Danko Ćorić and Matija Sakoman
Coatings 2024, 14(6), 674; https://doi.org/10.3390/coatings14060674 - 27 May 2024
Abstract
This paper examines the impact of a multilayered gradient coating, applied via plasma-activated chemical vapor deposition (PACVD), on the structural and mechanical attributes of nanostructured WC-Co cemented carbides. WC-Co samples containing 5 and 15 wt.% Co were synthesized through a hot isostatic pressing
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This paper examines the impact of a multilayered gradient coating, applied via plasma-activated chemical vapor deposition (PACVD), on the structural and mechanical attributes of nanostructured WC-Co cemented carbides. WC-Co samples containing 5 and 15 wt.% Co were synthesized through a hot isostatic pressing (HIP) process using nanoparticle powders and coated with two distinct multilayer coatings: titanium nitride (TiN) and titanium carbonitride (TiCN). Nanosized grain formation without microstructural defects of the substrates, prior to coating, was confirmed by magnetic saturation and coercivity testing, microstructural analysis, and field emission scanning electron microscope (FESEM). Nanoindentation, fracture toughness and hardness testing were conducted for uncoated samples. After coatings deposition, characterizations including microscopy, surface roughness determination, adhesion testing, coating thickness measurement, and microhardness examination were conducted. The impact of deposited coatings on wear resistance of produced hardmetals was analyzed via scratch test and dry sliding wear test. Samples with higher Co content exhibited improved adhesion, facilitating surface cleaning and activation before coating. TiN and TiCN coatings demonstrated similar roughness on substrates of identical composition, suggesting Co content’s minimal influence on layer growth. Results of the mechanical tests showed higher microhardness, higher elastic modulus, better adhesion, and overall superior tribological properties of the TiCN coating.
Full article
(This article belongs to the Special Issue Advances in Deposition and Characterization of Hard Coatings)
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Open AccessArticle
Influence of Flow Rates and Flow Times of Plasma-Enhanced Atomic Layer Deposition Purge Gas on TiN Thin Film Properties
by
Ju Eun Kang, Surin An and Sang Jeen Hong
Coatings 2024, 14(6), 673; https://doi.org/10.3390/coatings14060673 - 27 May 2024
Abstract
This study investigated the effect of purge gas flow rate and purge gas flow time on the properties of TiN thin films via chemical reaction simulation and the plasma-enhanced atomic layer deposition (PEALD) process along purge gas flow rates and time settings. Chemical
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This study investigated the effect of purge gas flow rate and purge gas flow time on the properties of TiN thin films via chemical reaction simulation and the plasma-enhanced atomic layer deposition (PEALD) process along purge gas flow rates and time settings. Chemical reaction simulation unveiled an incremental increase in generating volatile products along purge gas flow rates. In contrast, increased purge gas flow times enhanced the desorption of physically adsorbed species flow time in the film surface. Subsequent thin film analysis showed that the increased Ar purge gas flow rate caused a shift of 44% in wafer non-uniformity, 46% in carbon composition, and 11% in oxygen composition in the deposited film. Modulations in the Ar purge gas flow time yielded variations of 50% in wafer non-uniformity, 46% in carbon composition, and 15% in oxygen content. Notably, 38% of the resistivity and 35% of the film thickness occurred due to experimental variations in the Ar purge step condition. Increased purge gas flow rates had a negligible impact on the film composition, thickness, and resistivity, but the film’s non-uniformity on a 6-inch wafer was notable. Extended purge gas flow times with inadequate flow rates resulted in undesired impurities in the thin film. This study employed a method that utilized reaction simulation to investigate the impact of purge gas flow and verified these results through film properties analysis. These findings can help in determining optimal purge conditions to achieve the desired film properties of PEALD-deposited TiN thin films.
Full article
(This article belongs to the Special Issue Application of Advanced Plasma Technology in Coatings, Films and Etching)
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Open AccessArticle
Impact of Magnetic Field Direction on Performance and Structure of Ni-Co-SiC Coatings Fabricated via Magnetic-Field-Induced Electrodeposition
by
Chunyang Ma, Hongxin He, Hongbin Zhang, Zhiping Li, Lixin Wei and Fafeng Xia
Coatings 2024, 14(6), 672; https://doi.org/10.3390/coatings14060672 - 26 May 2024
Abstract
This study reports the synthesis of Ni-Co-SiC coatings onto Q235A steel substrates through magnetic-field-induced electrodeposition to improve the surface performances of the machine parts. The microstructure, topology, roughness, corrosion, and wear resistances of the coatings were investigated through X-ray diffraction (XRD), transmission electron
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This study reports the synthesis of Ni-Co-SiC coatings onto Q235A steel substrates through magnetic-field-induced electrodeposition to improve the surface performances of the machine parts. The microstructure, topology, roughness, corrosion, and wear resistances of the coatings were investigated through X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), hardness testing, electrochemical analysis, and friction wear testing, respectively. The Ni-Co-SiC coating deposited at 0.4 T (MS1) with a perpendicular magnetic direction showed the maximum SiC content and NiCo grain size (86.5 nm). The surface topology was also fine, dense, and smooth. In addition to that, the images obtained from the AFM characterization showed that the surface roughness of the MS1 coating was 76 nm, which was significantly lower compared to the roughness observed in Ni-Co-SiC coatings fabricated under the magnetic induction of 0 T (MS0) and magnetic field applied in a parallel direction to 0.4 T (MS2). The XRD results revealed that the preferential growth direction of the NiCo grains was changed from the (200) crystal plane to the (111) plane with the introduction of a perpendicular magnetic field. Moreover, MS2, MS1, and MS0 had thickness values of 25.3, 26.7, and 26.3 μm, respectively. Among all the coatings, MS1 showed the lowest friction coefficient and the highest hardness value (914.8 HV), suggesting enhanced wear resistance. Moreover, the MS1 coating revealed a maximum corrosion potential of −257 mV, and the lowest corrosion current of 0.487 μA/cm2, suggesting its improved corrosion resistance.
Full article
Open AccessArticle
Lady’s Mantle Flower as a Biodegradable Plant-Based Corrosion Inhibitor for CO2 Carbon Steel Corrosion
by
Katarina Žbulj, Gordana Bilić, Katarina Simon and Lidia Hrnčević
Coatings 2024, 14(6), 671; https://doi.org/10.3390/coatings14060671 - 25 May 2024
Abstract
Due to issues with the corrosion problem in the petroleum industry and the use of less ecologically acceptable corrosion inhibitors, great emphasis, within research on corrosion inhibitors, is now being put on green corrosion inhibitors (GCIs). In this study, Lady’s mantle flower extract
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Due to issues with the corrosion problem in the petroleum industry and the use of less ecologically acceptable corrosion inhibitors, great emphasis, within research on corrosion inhibitors, is now being put on green corrosion inhibitors (GCIs). In this study, Lady’s mantle flower extract (LMFE) has been observed as a plant-based GCI for carbon steel in a simulated CO2-saturated brine solution. The effectiveness of the inhibitor in static and flow conditions has been determined using potentiodynamic polarization with Tafel extrapolation and electrochemical impedance spectroscopy (EIS). In static conditions, the inhibitor has been tested at concentrations from 1 g/L to 5 g/L with an increment of 1 g/L per measurement, while, in dynamic (flow) conditions, the inhibitor has been tested at concentrations from 3 g/L to 6 g/L with an increment of 1 g/L per measurement. All measurements were performed at room temperature. EIS and potentiodynamic polarization methods showed that LMFE achieves maximum effectiveness in protecting carbon steel from corrosion when added at a concentration of 4 g/L in static conditions and at a concentration of 5 g/L in flow conditions. The test methods proved that the inhibitory effectiveness of LMFE is greater than 90% in both test conditions (static and flow). The inhibitor efficiency was attributed to the adsorption of LMFE on the carbon steel surface, which was demonstrated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). A biodegradability of 0.96 and a toxicity of 19.34% for LMFE were determined. The conducted laboratory tests indicate that LMFE could be used as an effective corrosion inhibitor for CO2 carbon steel corrosion.
Full article
(This article belongs to the Special Issue Investigation on Corrosion Behaviour of Metallic Materials)
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Open AccessArticle
Analysis of Surface Characteristics of Titanium Alloy Milling with Ball-End Milling Cutters Based on Mesoscopic Geometric Features
by
Xin Tong, Shoumeng Wang, Xiyue Wang and Qiang Qu
Coatings 2024, 14(6), 670; https://doi.org/10.3390/coatings14060670 - 25 May 2024
Abstract
In order to further reduce the height of burrs on the surface of the workpiece when milling titanium alloy with ball-end milling cutters and optimize the quality of the workpiece, this article takes the mesoscopic geometric feature of ball-end milling cutters as the
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In order to further reduce the height of burrs on the surface of the workpiece when milling titanium alloy with ball-end milling cutters and optimize the quality of the workpiece, this article takes the mesoscopic geometric feature of ball-end milling cutters as the research object and establishes the theoretical relationship between the mesoscopic geometric feature parameters and the height of titanium alloy burrs during milling. A milling test platform was built to explore the influence of micro-texture, blunt edge single factor, and their interaction with cutting parameters on the force-thermal characteristics and workpiece burr in the milling process. The influence mechanism was revealed, and the prediction model was established. The results show that the ball-end milling cutter with mesoscopic geometric features was able to suppress burrs, and the burr height was reduced by 21% compared with the non-textured milling cutter. The micro-texture reduced the contact area and improved the heat dissipation conditions, thereby reducing the force-thermal characteristics and thus inhibiting the formation of some burrs. The blunt edge can disperse the stress, diffuse the local heat in the tool–chip contact area, and reduce the burr height. In the interaction test considering cutting parameters, the interaction between R and ap was significant. The optimized parameters based on the simulated annealing algorithm were as follows: the radius of the blunt edge was 33.242 μm, the distance between the texture and the edge was 114.621 μm, the texture diameter was 59.820 μm, the texture spacing L1 was 131.410 μm, the cutting depth ap was 0.310 mm, the cutting speed V was 140.019 mm/min, and the feed f was 60 μm/z. This provides a basis for the study of strengthening the tool to suppress burr size.
Full article
(This article belongs to the Special Issue Oxidation, Wear, Corrosion Behaviors and Activated Bonding Properties of Coatings Deposited on Metals)
Open AccessArticle
Effects of Process Parameters on Microstructure and Wear Resistance of Laser Cladding A-100 Ultra-High-Strength Steel Coatings
by
Tengfei Han, Zimin Ding, Wanxi Feng, Xinyu Yao, Fangfang Chen and Yuesheng Gao
Coatings 2024, 14(6), 669; https://doi.org/10.3390/coatings14060669 - 25 May 2024
Abstract
To improve the hardness and wear resistance of mild steel, A-100 ultra-high-strength steel cladding coatings were prepared on the surface of mild steel by laser cladding. In this study, the effects of laser cladding process parameters on the forming quality, phase composition, microstructure,
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To improve the hardness and wear resistance of mild steel, A-100 ultra-high-strength steel cladding coatings were prepared on the surface of mild steel by laser cladding. In this study, the effects of laser cladding process parameters on the forming quality, phase composition, microstructure, microhardness and wear resistance of the A-100 ultra-high-strength steel cladding coatings were researched. The results show that the main phase of the coating is martensite and a small amount of austenite. The microstructures of the upper part of the cladding coatings are mainly equiaxed grains, while those of the lower part are mainly columnar grains. With an increase in laser specific energy, the microstructures of the cladding coatings become coarse. When the laser specific energy is 70.8 J/mm2, the microhardness of the cladding coating is the highest, and the maximum average microhardness of the cladding coatings is 548.3 HV. When the laser specific energy is low, the wear of the cladding coatings is mainly pitting, while when the laser specific energy is high, the wear type of the cladding coatings is mainly adhesive wear. Moreover, the microhardness and wear resistance of the cladding coatings are reduced if the laser specific energy is too high.
Full article
(This article belongs to the Section Laser Coatings)
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Open AccessArticle
Effect of Glazing Protocol on the Surface Roughness and Optical Properties of Lithia-Based Glass-Ceramics
by
Amanda Maria de Oliveira Dal Piva, Nina Storm van Leeuwen, Lucas Saldanha da Rosa, Cornelis Johannes Kleverlaan and João Paulo Mendes Tribst
Coatings 2024, 14(6), 668; https://doi.org/10.3390/coatings14060668 - 24 May 2024
Abstract
Background: New lithia-based glass–ceramics, including Advanced Lithium Disilicate (ALD), have become popular in dentistry. However, it is unclear if glazing protocols for ALD might compromise its surface or optical properties. Thus, evaluating color and translucency changes in ALD and traditional lithium disilicate (LD)
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Background: New lithia-based glass–ceramics, including Advanced Lithium Disilicate (ALD), have become popular in dentistry. However, it is unclear if glazing protocols for ALD might compromise its surface or optical properties. Thus, evaluating color and translucency changes in ALD and traditional lithium disilicate (LD) is crucial. Methods: This study aimed to assess how different firing protocols affect the surface and optical properties of LD and ALD. Sixty disc-shaped specimens were prepared, divided into three subgroups based on firing protocols, and subjected to surface roughness analysis. Specimens were immersed in coffee, wine, and water for 7 days, and then brushed. Color and translucency were measured. Results: Firing protocols significantly influenced surface roughness in LD (0.09–1.39 µm) and ALD (0.05–0.88 µm). Color differences were observed in both LD and ALD after 7 days, with visible changes within clinically acceptable thresholds. Translucency remained stable across firing protocols and staining liquids. Conclusions: Varying firing protocols impact surface roughness and color stability in LD and ALD. Despite differences, color and translucency changes remained within acceptable clinical thresholds, suggesting both materials are suitable for dental applications. Therefore, this study reinforces the reliability and versatility of these materials in restorative dentistry.
Full article
(This article belongs to the Special Issue Surface Properties of Dental Materials and Instruments, 2nd Edition)
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Open AccessArticle
Study on Stable Loose Sandstone Reservoir and Corresponding Acidizing Technology
by
Wei Song, Kun Zhang, Daqiang Feng, Qi Jiang, Hai Lin, Li Liao, Ruixin Kang, Baoming Ou, Jing Du, Yan Wang and Erdong Yao
Coatings 2024, 14(6), 667; https://doi.org/10.3390/coatings14060667 - 24 May 2024
Abstract
The Sebei gas field is in the Sanhu depression area of the Qaidam Basin, which is the main gas-producing area and a key profit pillar for the Qinghai oilfield. The Sebei gas field within the Qinghai oilfield is characterized by high mud content,
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The Sebei gas field is in the Sanhu depression area of the Qaidam Basin, which is the main gas-producing area and a key profit pillar for the Qinghai oilfield. The Sebei gas field within the Qinghai oilfield is characterized by high mud content, poor lithology, interflow between gas and water layers, and a propensity for sand production. The reservoir rocks are predominantly argillaceous siltstone with primarily argillaceous cement. These rocks are loose and tend to produce sand, which can lead to blockage. During its development, the Sebei gas field exhibited significant issues with scale formation and sand production in gas wells. Conventional acidization technologies have proven to be slow acting and may even result in adverse effects. These methods can cause loose sandstone to disperse, exacerbating sand production. Therefore, it is necessary to elucidate the mechanisms of wellbore plugging and to develop an acidizing system for plug removal that is tailored to unconsolidated sandstone reservoirs. Such a system should not only alleviate gas well plugging damage but also maintain reservoir stability and ensure efficient and sustained stimulation from acidization treatments. In this paper, the stability of unconsolidated sandstone reservoirs and the acid dissolution plugging system, along with the technological methods for stabilizing sand bodies, are studied through mineral component analysis, acid dissolution experiments, core immersion experiments, and other laboratory tests. The principle of synergistic effects between different acids is applied to achieve “high-efficiency scale dissolution and low sandstone dissolution.” Three key indicators of dispersion, sand dissolution rate, and scale dissolution rate were created. The acid plugging solution formula of “controlled dispersion and differentiated dissolution” was developed to address these indicators. Laboratory tests have shown that the sandstone is predominantly composed of quartz and clay minerals, with the latter mainly being illite. The primary constituent of the wellbore blockage scale sample is magnesium carbonate, which exhibits nearly 100% solubility in acid. By adding a stabilizer prior to acid corrosion, the core’s corrosion can be effectively mitigated, particle dispersion and migration can be controlled, and the rock structure’s stability can be maintained. Laboratory evaluations indicate that the scale dissolution rate is greater than or equal to 95%, the sand dissolution rate is below 25%, and the system achieves a differentiated corrosion effect without dispersion for 24 h. Field tests demonstrate that the new acid solution plugging removal system enhances average well production and reduces operational costs. The system effectively mitigates the challenges of substantial sand production and reservoir dispersion, thereby furnishing a theoretical foundation and practical direction for acid plugging treatments in unconsolidated sandstone gas fields.
Full article
(This article belongs to the Special Issue Development and Characterization of New Construction Materials and Coatings)
Open AccessArticle
Activity in the Field of Blood Coagulation Processes of Poly(Lactide)-Zinc Fiber Composite Material Obtained by Magnetron Sputtering
by
Zdzisława Mrozińska, Michał B. Ponczek, Anna Kaczmarek, Małgorzata Świerczyńska and Marcin H. Kudzin
Coatings 2024, 14(6), 666; https://doi.org/10.3390/coatings14060666 - 24 May 2024
Abstract
This article presents the biochemical properties of poly(lactide)-zinc (PLA-Zn) composites obtained by DC magnetron sputtering of zinc onto melt-blown nonwoven fabrics. The biochemical properties were determined by the evaluation of the activated partial thromboplastin time (aPTT) and prothrombin time (PT). The antimicrobial activity
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This article presents the biochemical properties of poly(lactide)-zinc (PLA-Zn) composites obtained by DC magnetron sputtering of zinc onto melt-blown nonwoven fabrics. The biochemical properties were determined by the evaluation of the activated partial thromboplastin time (aPTT) and prothrombin time (PT). The antimicrobial activity of the PLA-Zn samples was additionally tested against representative Gram-positive and Gram-negative bacteria strains. A structural study of the PLA-Zn has been carried out using specific surface area and total pore volume (BET) analysis, as well as atomic absorption spectrometry with flame excitation (FAAS). PLA-Zn composites exhibited an antibacterial effect against the analyzed strains and produced inhibition zones against E. coli and S. aureus. Biochemical investigations revealed that the untreated PLA fibers caused the acceleration of the clotting of human blood plasma in the intrinsic pathway. However, the PLA-Zn composites demonstrated significantly different properties in this regard, the aPTT was prolonged while the PT was not altered.
Full article
Open AccessArticle
Effect of Thickness on the Residual Stress Profile of an Aluminum Cold Spray Coating by Finite Element Analysis
by
Felipe Torres and Ruben Fernandez
Coatings 2024, 14(6), 665; https://doi.org/10.3390/coatings14060665 - 24 May 2024
Abstract
This research investigates the influence of thickness on residual stress profiles in aluminum cold spray coatings using finite element analysis (FEA). Residual stress is a critical factor that impacts coating adhesion, fatigue life, and susceptibility to delamination in thermal spray processes. Despite its
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This research investigates the influence of thickness on residual stress profiles in aluminum cold spray coatings using finite element analysis (FEA). Residual stress is a critical factor that impacts coating adhesion, fatigue life, and susceptibility to delamination in thermal spray processes. Despite its acknowledged importance, predictive analysis of these stresses on a layer-by-layer basis remains relatively unexplored. This study introduces an innovative numerical methodology to analyze the progression of residual stresses across various deposition efficiencies (10%, 40%, 60%, and 100%) and layer thicknesses, thereby enhancing predictive accuracy for cold spray coatings. The findings demonstrate that the number of deposited layers significantly affects residual stress profiles in both coatings and the substrate, with compressive residual stress predominating in the coatings and deeper tensile stress predominating in the substrate. Residual stress behavior near the last deposited layer aligns with the expected peening effect. Discrepancies in substrate stress distributions may arise from variations in deposition parameters and unconsidered temperature effects. While the model generally aligns with theoretical and some empirical data, observed discrepancies underscore the need for further validation. This study lays the groundwork for informed decision-making for cold spray processes by providing insights into stress management, thereby contributing to enhancing coating integrity and performance.
Full article
(This article belongs to the Section Plasma Coatings, Surfaces & Interfaces)
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Open AccessArticle
Effect of Polytetrafluoroethylene Coating on Corrosion Wear Properties of AZ31 Magnesium Alloy by Electrophoretic Deposition
by
Jilun Zhang, Chaoyi Chen, Junqi Li and Li Chen
Coatings 2024, 14(6), 664; https://doi.org/10.3390/coatings14060664 - 24 May 2024
Abstract
In this study, we aim to enhance the corrosion and wear resistance of AZ31 magnesium alloy using electrophoretic deposition (EPD) technology to apply a hydrophobic polytetrafluoroethylene (PTFE) coating. Polyethyleneimine (PEI) serves as a charged dispersant, facilitating uniform deposition of PTFE particles on the
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In this study, we aim to enhance the corrosion and wear resistance of AZ31 magnesium alloy using electrophoretic deposition (EPD) technology to apply a hydrophobic polytetrafluoroethylene (PTFE) coating. Polyethyleneimine (PEI) serves as a charged dispersant, facilitating uniform deposition of PTFE particles on the alloy surface. Results demonstrate a significant reduction in corrosion current density (from 67.5 μA/cm2 to 5.2 μA/cm2) and improved wear resistance (wear volume decreased from 0.24167 mm3 to 0.00167 mm3) in a 3.5 wt% NaCl solution compared to uncoated alloy. Moreover, the friction coefficient of the coated sample decreases. These findings underscore the potential of nano-PTFE coatings prepared via EPD in enhancing AZ31 magnesium alloy’s corrosion and wear resistance, providing a foundation for future protective coating design and optimization.
Full article
(This article belongs to the Special Issue Thin-Film Synthesis, Characterization and Properties)
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Open AccessArticle
Microstructure, Hardness, Wear Resistance, and Corrosion Resistance of As-Cast and Laser-Deposited FeCoNiCrAl0.8Cu0.5Si0.5 High Entropy Alloy
by
Xiaohu Ji, Lihua Zhou and Heng Li
Coatings 2024, 14(6), 663; https://doi.org/10.3390/coatings14060663 - 24 May 2024
Abstract
FeCoNiCrAl0.8Cu0.5Si0.5 high-entropy alloys were fabricated using vacuum induction melting and laser deposition processes, followed by a comparison of the structural and mechanical properties of two distinct sample types. The as-cast FeCoNiCrAl0.8Cu0.5Si0.5 alloy is comprised of BCC1, BCC2, and Cr3Si phases, while the laser-deposited
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FeCoNiCrAl0.8Cu0.5Si0.5 high-entropy alloys were fabricated using vacuum induction melting and laser deposition processes, followed by a comparison of the structural and mechanical properties of two distinct sample types. The as-cast FeCoNiCrAl0.8Cu0.5Si0.5 alloy is comprised of BCC1, BCC2, and Cr3Si phases, while the laser-deposited alloy primarily features BCC1 and BCC2 phases. Microstructural analysis revealed that the as-cast alloy exhibits a dendritic morphology with secondary dendritic arms and densely packed grains, and the laser-deposited alloy displays a dendritic structure without the formation of granular interdendritic regions. For mechanical properties, the as-cast FeCoNiCrAl0.8Cu0.5Si0.5 alloy demonstrated higher hardness than the as-deposited alloy, with values of 586 HV0.2 and 557 HV0.2, respectively. The wear rate for the as-cast alloy was observed at 3.5 × 10−7 mm3/Nm, with abrasive wear being the primary wear mechanism. Conversely, the as-deposited alloy had a wear rate of 9.0 × 10−7 mm3/Nm, characterized by adhesive wear. The cast alloy exhibited an icorr of 4.062 μA·cm−2, with pitting as the form of corrosion. The laser-deposited alloy showed an icorr of 3.621 μA·cm−2, with both pitting and intergranular corrosion observed. The laser-deposited alloy demonstrated improved corrosion resistance. The investigation of their microstructure and mechanical properties demonstrates the application potential of FeCoNiCrAl0.8Cu0.5Si0.5 alloys in scenarios requiring high hardness and enhanced wear resistance.
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(This article belongs to the Special Issue Surface Science of Degradation and Surface Protection)
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Atomic Layer Deposition Growth and Characterization of Al2O3 Layers on Cu-Supported CVD Graphene
by
Peter Rafailov, Vladimir Mehandzhiev, Peter Sveshtarov, Blagoy Blagoev, Penka Terziyska, Ivalina Avramova, Kiril Kirilov, Bogdan Ranguelov, Georgi Avdeev, Stefan Petrov and Shiuan Huei Lin
Coatings 2024, 14(6), 662; https://doi.org/10.3390/coatings14060662 - 24 May 2024
Abstract
The deposition of thin uniform dielectric layers on graphene is important for its successful integration into electronic devices. We report on the atomic layer deposition (ALD) of Al2O3 nanofilms onto graphene grown by chemical vapor deposition onto copper foil. A
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The deposition of thin uniform dielectric layers on graphene is important for its successful integration into electronic devices. We report on the atomic layer deposition (ALD) of Al2O3 nanofilms onto graphene grown by chemical vapor deposition onto copper foil. A pretreatment with deionized water (DI H2O) for graphene functionalization was carried out, and, subsequently, trimethylaluminum and DI H2O were used as precursors for the Al2O3 deposition process. The proper temperature regime for this process was adjusted by means of the ALD temperature window for Al2O3 deposition onto a Si substrate. The obtained Al2O3/graphene heterostructures were characterized by Raman and X-ray photoelectron spectroscopy, ellipsometry and atomic force and scanning electron microscopy. Samples of these heterostructures were transferred onto glass substrates by standard methods, with the Al2O3 coating serving as a protective layer during the transfer. Raman monitoring at every stage of the sample preparation and after the transfer enabled us to characterize the influence of the Al2O3 coating on the graphene film.
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(This article belongs to the Special Issue Application of Graphene and Two-Dimensional Materials in Thin Films)
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The Impact of Bonding Agents and Bone Defects on the Fracture Resistance of Reattached Vertically Root-Fractured Teeth
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Satheesh B. Haralur, Nasser Mohammed Alshahrani, Saeed Hadi Alafra, Muath Ali Hakami, Omar Abdulaziz AbuMesmar, Mohammed A. Al-Qarni, Saeed M. AlQahtani and Nasser M. Alqahtani
Coatings 2024, 14(6), 661; https://doi.org/10.3390/coatings14060661 - 23 May 2024
Abstract
Many patients experience vertical root fractures, and clinicians often consider conservative treatment options like reattaching the fractured root segments. The study investigated the impact of different bonding agents on the fracture resistance of rebonded vertically fractured teeth with various alveolar bone defects. Human
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Many patients experience vertical root fractures, and clinicians often consider conservative treatment options like reattaching the fractured root segments. The study investigated the impact of different bonding agents on the fracture resistance of rebonded vertically fractured teeth with various alveolar bone defects. Human premolar teeth with a single root were sectioned and reattached using dual-cure resin cement (DCRC), resin-modified glass ionomer (RMGI), and cyanoacrylate. The reattached teeth were then restored with a resin fiber post, composite resin core, and full veneer metal copings. These teeth were embedded in acrylic blocks with angular, V-shaped, and step-shaped bone defects to simulate various alveolar bone conditions. After subjecting the samples to thermal cycling, the fracture resistance was evaluated using a universal testing machine. Teeth samples reattached with RMGI exhibited a higher average fracture resistance. The study also found that DCRC proved to be an effective bonding agent for VRF teeth. However, cyanoacrylate-rebonded teeth exhibited the lowest fracture resistance. The V-shaped defects had a significant impact on the fracture resistance of reattached VRF teeth, with largely unfavorable fractures observed in these cases. Predominantly favorable fractures were observed in the teeth treated with RMGI. The fracture loads in both RMGI and DCRC groups exceeded the expected masticatory load.
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(This article belongs to the Special Issue Surface Properties of Dental Materials and Instruments, 2nd Edition)
Open AccessRetraction
RETRACTED: Sun et al. Study on the Removal Efficiency and Mechanism of Tetracycline in Water Using Biochar and Magnetic Biochar. Coatings 2021, 11, 1354
by
Hongwei Sun, Jingjie Yang, Yue Wang, Yucan Liu, Chenjian Cai and Afshin Davarpanah
Coatings 2024, 14(6), 660; https://doi.org/10.3390/coatings14060660 - 23 May 2024
Abstract
The Coatings Editorial Office retracts the article entitled “Study on the Removal Efficiency and Mechanism of Tetracycline in Water Using Biochar and Magnetic Biochar” [...]
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Study of Optical Performance and Structure of Yb/Al (1.5 wt.% Si) and Yb/Al (Pure) Multilayers Designed for the 73.6 nm Range
by
Bo Lai, Runze Qi, Zengbo Zhang and Zhanshan Wang
Coatings 2024, 14(6), 659; https://doi.org/10.3390/coatings14060659 - 23 May 2024
Abstract
Yb/Al multilayer films exhibit excellent theoretical reflectivity in the 54–90 nm wavelength range. This study attempted to incorporate 1.5% wt.% of Si impurities into Al to suppress the crystallization of Al, reduce interfacial roughness, and enhance the actual reflectivity of the prepared Yb/Al
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Yb/Al multilayer films exhibit excellent theoretical reflectivity in the 54–90 nm wavelength range. This study attempted to incorporate 1.5% wt.% of Si impurities into Al to suppress the crystallization of Al, reduce interfacial roughness, and enhance the actual reflectivity of the prepared Yb/Al multilayer films. Internal microstructure changes in the film layers before and after Si impurity doping were investigated using GIXRR, AFM, and XRD techniques. The reflectivity of two types of multilayer films, Yb/Al (1.5 wt.% Si) and Yb/Al (pure), was tested to evaluate the effect of Si impurity on film performance. The reflectivity of Yb/Al (1.5 wt.% Si) multilayers compared to Yb/Al (pure) multilayers increased by approximately 4%.
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The Effect of Heat Treatment on the Microstructure and Mechanical Properties of Al0.6CoFeNi2V0.5 High Entropy Alloy
by
Hui Liang, Jinxin Hou, Li Jiang, Zhaoxin Qi, Min Zhang and Zhiqiang Cao
Coatings 2024, 14(6), 658; https://doi.org/10.3390/coatings14060658 - 23 May 2024
Abstract
Al0.6CoFeNi2V0.5 high entropy alloy was successfully designed and prepared via the nonconsumable arc-melting process, and it was annealed at 600 °C, 800 °C, and 1000 °C for 4 h. Its microstructure and mechanical properties were studied. The as-cast
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Al0.6CoFeNi2V0.5 high entropy alloy was successfully designed and prepared via the nonconsumable arc-melting process, and it was annealed at 600 °C, 800 °C, and 1000 °C for 4 h. Its microstructure and mechanical properties were studied. The as-cast alloy consisted of FCC and BCC phases, and no phase transformation occurred during annealing at 600 °C. Hard Al3V-type metal compounds precipitated during annealing at 800 °C, and BCC particles precipitated in the FCC matrix during annealing at 1000 °C. After annealing, the strength and hardness of Al0.6CoFeNi2V0.5 high-entropy alloy both showed a decreasing trend, because the annealing process eliminated the internal stress in this alloy. However, as the annealing temperature increased, the strength and hardness of the Al0.6CoFeNi2V0.5 high-entropy alloy samples gradually increased. This is because the hard Al3V metal compounds precipitated when the annealing temperature was 800 °C, which produced the “second phase strengthening” effect. At 1000 °C, the larger volume fraction of the hard and fine BCC phase (21.81%) diffusely precipitated; the precipitation of this BCC phase not only produced a “second phase strengthening” effect, which also resulted in “solid solution strengthening”, ultimately exhibiting enhanced hardness and strength. These findings have important theoretical reference value for the study of the microstructure and mechanical properties of high-entropy alloys. And, this study plays a significant role in promoting the research and development of new component materials that bear compressive loads, such as columns in large factory buildings, supports for cranes, and clamping bolts for rolling mills in practical mechanical engineering.
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(This article belongs to the Section Surface Characterization, Deposition and Modification)
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