Coatings

9 pages, 4711 KB

Open AccessEditor’s ChoiceArticle

High Light Output Power Density AlGaN-Based Deep Ultraviolet Micro-Light-Emitting Diodes

by Xinyu Wang, Xuejiao Sun, Sijia Wu, Mingfeng Gong, Rongxin Zhang, Tong Zhang, Xuecheng Wei, Cheng Lei, Ting Liang, Jianchang Yan, Junxi Wang, Naixin Liu and Jinmin Li

Coatings 2026, 16(4), 408; https://doi.org/10.3390/coatings16040408 - 27 Mar 2026

Cited by 1 | Viewed by 689

Abstract

Compared with mercury lamps, AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) possess many distinctive advantages, including their being pollution-free, their long lifespan, their low operating voltage, their compact size, and their high-frequency modulation capability. However, poor light extraction efficiency (LEE) and inhomogeneous current [...] Read more.

Compared with mercury lamps, AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) possess many distinctive advantages, including their being pollution-free, their long lifespan, their low operating voltage, their compact size, and their high-frequency modulation capability. However, poor light extraction efficiency (LEE) and inhomogeneous current spreading hinder their wider application in fields such as sterilization, disinfection, and non-line-of-sight solar-blind communication. To solve the issues above, high light output power (LOP) density AlGaN-based DUV micro-light-emitting diodes (Micro-LEDs) were fabricated in this work. The Micro-LED, with a peak emission wavelength of 281 nm, exhibited a 605% enhancement in peak LOP density of up to 77.1 W/cm² at a high current density of 2.3 kA/cm² compared to conventional DUV LEDs. Meanwhile, the LEE of the TE-polarized light of the Micro-LED was improved by 68%, which benefited from the small-size effect, and the peak external quantum efficiency (EQE) of the Micro-LED was enhanced by 24.6%. Moreover, the Micro-LED also showed a lower leakage current. This work provides an effective strategy to improve the efficiency characteristics of DUV Micro-LEDs. Full article

(This article belongs to the Section Surface Engineering for Energy Harvesting, Conversion, and Storage)

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14 pages, 5013 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Microstructure and Mechanical Properties of CVD TiN/TiB₂ Multilayer Coatings

by Nina Schalk, Michael Tkadletz, Alexandra Lechner, Martin Krobath, Jozef Keckes, Juraj Todt, Manfred Burghammer, Bernhard Sartory, Werner Ecker and Christoph Czettl

Coatings 2026, 16(4), 394; https://doi.org/10.3390/coatings16040394 - 24 Mar 2026

Cited by 1 | Viewed by 802

Abstract

Chemical vapor deposited (CVD) TiN and TiB₂ are both commonly used as wear-resistant hard coatings. The two materials exhibit pronounced differences in their properties, which can be exploited by combining them in a multilayer architecture. Thus, two multilayer coatings with different bilayer [...] Read more.

Chemical vapor deposited (CVD) TiN and TiB₂ are both commonly used as wear-resistant hard coatings. The two materials exhibit pronounced differences in their properties, which can be exploited by combining them in a multilayer architecture. Thus, two multilayer coatings with different bilayer periodicities of ~80 and ~220 nm were synthesized. The multilayer architecture constrains the TiN grain size to dimensions comparable to the individual sublayer thickness, which are substantially smaller than those observed in the single-layer TiN reference coating. This grain refinement leads to significantly higher hardness of the TiN sublayers within the multilayer system compared to the single-layer coating. In contrast, the low grain size of the TiB₂ coating appears unaffected, and the hardness of the TiB₂ layers in the multilayer and corresponding bilayer reference coating is also comparable. The compressive residual stress in the TiB₂ layers decreases with decreasing layer thickness, while the tensile residual stress in the TiN layers increases, resulting in a roughly constant stress difference between the sublayers, which is also comparable to the conventional TiN/TiB₂ bilayer reference coating. However, while the tensile stress in the TiN sublayers is constant over coating thickness, TiB₂ exhibits a pronounced gradient with only low compressive stress at the interface to the substrate, which increases significantly with increasing coating thickness. The fracture properties of the multilayers range between the values obtained for the corresponding reference coatings. Complementary finite element method simulations revealed that, for the multilayer coatings, the common assumption of a stress-free state of micro-cantilevers used for bending tests is not valid. Full article

(This article belongs to the Special Issue Chemical Vapor Deposition (CVD): Technology and Applications)

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19 pages, 2771 KB

Open AccessEditor’s ChoiceArticle

Characterization of Corona-Charged Composite PLA Films as Potential Active Packaging Applications

by Asya Viraneva, Aleksandar Grigorov, Maria Marudova, Temenuzhka Yovcheva and Rumen Mladenov

Coatings 2026, 16(3), 385; https://doi.org/10.3390/coatings16030385 - 21 Mar 2026

Viewed by 418

Abstract

A major drawback of many proposed biobased alternatives of the most commonly used petroleum-based packaging materials is their relatively poor physical properties. In order to develop more viable alternative packaging materials, these properties need to be modified, while maintaining and improving the other [...] Read more.

A major drawback of many proposed biobased alternatives of the most commonly used petroleum-based packaging materials is their relatively poor physical properties. In order to develop more viable alternative packaging materials, these properties need to be modified, while maintaining and improving the other desired characteristics. An investigation was done on corona-charged curcumin-containing PLA films to determine how the addition of the polyphenol impacts its physical properties. Measurements of the surface potential of the films were performed, as was the impact of low pressure on the electret properties. The effect of the corona discharge treatment on the physicochemistry of the surface of composite PLA films was investigated systematically using some complementary surface analytical techniques, such as surface wettability and morphology by scanning electron microscopy. The mechanical properties and conductance of the films were also investigated. A dependency of the decay of the surface potential on the film type and the polarity of the corona was found. It was also established that modifying the surface of the films with corona discharge can cause an increase in their wettability and surface free energy, while also improving their adhesion properties. This is caused by the creation of polar functional groups on the film surface during the charging process. It was also determined that the introduction of curcumin in the PLA films decreases their stiffness, which may be caused by a decrease in intramolecular cohesion. Full article

(This article belongs to the Section Coatings for Food Technology and System)

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15 pages, 4064 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Study on the Interlayer Contact Mechanism of Foamed Cold-Recycled Asphalt Mixture Under Static Loads

by Han Zhao, Jiangyu Liu and Junyan Yi

Coatings 2026, 16(3), 378; https://doi.org/10.3390/coatings16030378 - 17 Mar 2026

Viewed by 492

Abstract

To investigate the interlayer contact mechanism of foamed cold-recycled asphalt mixture under static loads, a three-layer asphalt pavement discrete element model (DEM) was established, with the surface layer composed of asphalt concrete-13 (AC-13), asphalt concrete-20 (AC-20) and asphalt-treated base-25 (ATB-25) foamed cold-recycled asphalt [...] Read more.

To investigate the interlayer contact mechanism of foamed cold-recycled asphalt mixture under static loads, a three-layer asphalt pavement discrete element model (DEM) was established, with the surface layer composed of asphalt concrete-13 (AC-13), asphalt concrete-20 (AC-20) and asphalt-treated base-25 (ATB-25) foamed cold-recycled asphalt mixture and cement-stabilized macadam as the base. Based on mortar theory, the pavement was divided into coarse aggregate, asphalt mastic and air void phases, and the Burgers Model, Linear Parallel Bond Model and Linear Model were adopted to characterize the bonding of asphalt-aggregate, cement contact interface and subgrade-surface layer, respectively. Static loads of 0.7 MPa, 1.1 MPa, 1.5 MPa and 1.9 MPa were applied to analyze the mechanical responses of asphalt-based and cement-based pavement systems from tensile strain, vertical compressive stress and vertical displacement. Results showed that mechanical indices of the pavement increase monotonically with static load and present obvious layered distribution. The cement-stabilized macadam base provides rigid support, significantly reducing tensile strain (TS) and vertical displacement (VD) of asphalt layers, while the asphalt-based system has flexible stress transfer and superior stress dissipation in the bottom layer. The two systems exhibit respective structural advantages, with the cement-based system outstanding in deformation control and the asphalt-based system suitable for flexible stress adaptation working conditions. Full article

(This article belongs to the Special Issue Surface Treatment and Mechanical Properties of Sustainable Pavement Materials, 2nd Edition)

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13 pages, 3188 KB

Open AccessEditor’s ChoiceArticle

Pulse Electrodeposition-Assisted Ni Catalysts for Methane-Derived Carbon Nanostructure Growth on Woven Carbon Fabrics

by Mei-Hsueh Nien and Shinn-Shyong Tzeng

Coatings 2026, 16(3), 357; https://doi.org/10.3390/coatings16030357 - 12 Mar 2026

Viewed by 403

Abstract

Engineering carbon nanostructures directly on carbon fiber fabrics offers an effective route to constructing hierarchical multifunctional coating systems. In this study, methane-based chemical vapor deposition (CVD) was employed to investigate nanocarbon coating formation on woven carbon fabrics supported by electrodeposited Ni catalysts. Catalyst [...] Read more.

Engineering carbon nanostructures directly on carbon fiber fabrics offers an effective route to constructing hierarchical multifunctional coating systems. In this study, methane-based chemical vapor deposition (CVD) was employed to investigate nanocarbon coating formation on woven carbon fabrics supported by electrodeposited Ni catalysts. Catalyst morphology was systematically engineered through surface pretreatment, electric-field configuration, and pulse electrodeposition. At 700 °C, methane activation was insufficient to sustain continuous nanocarbon growth, indicating a temperature-dependent activation threshold. Raising the growth temperature to 900 °C enabled sustained methane decomposition and produced dense nanocarbon coatings; hydrogen assistance suppressed amorphous deposition and promoted more ordered nanofilament features. Pulse electrodeposition refined Ni catalyst dispersion and nucleation density, improving coating uniformity compared with direct-current deposition. Structural ordering was further supported by Raman spectroscopy (D and G bands with an average ID/IG of 0.678 ± 0.068 for methane-grown samples versus 0.798 ± 0.011 for electrodeposition-only controls) and by HRTEM revealing multi-layer graphitic walls (~0.34 nm interlayer spacing). Together, the results support a methane-derived dissolution–diffusion–precipitation growth pathway governed by catalyst morphology, temperature, and gas composition. This controllable, textile-compatible catalyst engineering approach provides a scalable route to hierarchical graphitic coatings for carbon-fabric-based composites, electromagnetic interference shielding, and thermal management applications. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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19 pages, 1899 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Development and Characterization of Chitosan-Based Films Enriched with Callistemon citrinus Extract for Food Packaging of Cheddar Cheese

by Marika Avitabile, Dimitris Charalampopoulos, C. Valeria L. Giosafatto and Seyedeh Fatemeh Mirpoor

Coatings 2026, 16(3), 334; https://doi.org/10.3390/coatings16030334 - 8 Mar 2026

Viewed by 668

Abstract

This study investigated the effect of Callistemon citrinus flower extract (C.E.) on the structural and functional properties of chitosan-based bioplastics for food packaging applications. Increasing C.E. concentration produced changes in colour and opacity, with reduced L values and higher a values at 5% [...] Read more.

This study investigated the effect of Callistemon citrinus flower extract (C.E.) on the structural and functional properties of chitosan-based bioplastics for food packaging applications. Increasing C.E. concentration produced changes in colour and opacity, with reduced L values and higher a values at 5% C.E., resulting in a reddish appearance. Film opacity increased from 2.49% ± 0.10 for control to 13.60% ± 0.72 for film with 5% C.E., reducing transparency. The addition of 5% C.E. improved oxygen barrier properties, reducing O₂ permeability compared to the control that was similar to Low-density polyethylene (LDPE). A qualitative antimicrobial screening showed that 5% C.E. effectively inhibited S. aureus (16 mm) and L. monocytogenes (12 mm), while no inhibition was detected against E. coli. Cheddar cheese packaged in films with C.E. exhibited higher weight loss (11.63% at 28 days) than LDPE (2.90%), whereas moisture retention remained moderate (76.62% for the film with 5% C.E.). Oxidative stability improved with lower lipid oxidation (K₂₃₂ = 2.90 at 28 days) in cheese wrapped in C.E. films. Consumer evaluation indicated a positive perception, with 73% of participants willing to purchase products in C.E.-packaged films. Overall, C.E. enhanced antioxidant and antibacterial benefits, but further optimization may be required to improve moisture retention. Full article

(This article belongs to the Special Issue Biopolymer-Based Coatings for Sustainable and Functional Food Packaging)

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18 pages, 2459 KB

Open AccessEditor’s ChoiceArticle

Influence of Groove Structures on Flow Field and Bacterial Adhesion: A CFD-DEM Coupling Study

by Lei Chen, Hongjun Ye and Xiaodong Ruan

Coatings 2026, 16(3), 321; https://doi.org/10.3390/coatings16030321 - 6 Mar 2026

Viewed by 386

Abstract

Stringent cleanliness standards govern process fluid transport in integrated circuit (IC) manufacturing. Cavitation-induced surface defects on flow control components promote bacterial adhesion, thereby compromising wafer fabrication. To elucidate the coupling mechanisms among surface topography, hydrodynamics, and bacterial retention, this study utilizes a one-way [...] Read more.

Stringent cleanliness standards govern process fluid transport in integrated circuit (IC) manufacturing. Cavitation-induced surface defects on flow control components promote bacterial adhesion, thereby compromising wafer fabrication. To elucidate the coupling mechanisms among surface topography, hydrodynamics, and bacterial retention, this study utilizes a one-way coupled Computational Fluid Dynamics and Discrete Element Method (CFD-DEM) approach integrated with extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory. We constructed a numerical model of rod-shaped Pseudomonas aeruginosa, integrated with a customized API-based coupling scheme to resolve temporal scale disparities, and systematically simulated flow evolution and adhesion behaviors across varying groove geometries (quadrilateral, triangular, and semicircular) and inlet velocities (1–3 m/s). The results indicate that groove-induced flow separation and recirculation vortices drive bacterial accumulation at the trailing edge. Triangular profiles exhibited superior flow stability, yielding significantly lower adhesion than quadrilateral and semicircular shapes. Bacterial retention scaled inversely with flow velocity due to enhanced hydrodynamic shear. These findings provide theoretical and engineering insights for the anti-contamination design of ultra-clean flow control components in IC manufacturing. Full article

(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)

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32 pages, 10841 KB

Open AccessEditor’s ChoiceArticle

Deposition and Rebound Behavior of a Single Particle on Superhydrophobic Surfaces with Ribbed and Random Roughness Structures

by Wenjun Zhao and Hao Lu

Coatings 2026, 16(3), 326; https://doi.org/10.3390/coatings16030326 - 6 Mar 2026

Viewed by 411

Abstract

Particle deposition, rebound, and adhesion on rough surfaces play a crucial role in a wide range of powder handling, aerosol transport, and fouling-related processes. However, the underlying mechanisms governing single-particle interactions with rough surfaces, particularly those with complex surface morphologies, remain insufficiently understood. [...] Read more.

Particle deposition, rebound, and adhesion on rough surfaces play a crucial role in a wide range of powder handling, aerosol transport, and fouling-related processes. However, the underlying mechanisms governing single-particle interactions with rough surfaces, particularly those with complex surface morphologies, remain insufficiently understood. In this work, the deposition and elastic rebound behavior of an individual particle impacting superhydrophobic surfaces with ribbed and randomly distributed roughness structures are systematically investigated through a combined experimental and numerical approach. A coupled Lattice Boltzmann Method (LBM) and Discrete Particle Model (DPM) was developed, in which a new particle–surface contact model is proposed to account for adhesion, elastic deformation, and localized roughness effects through multi-node interactions. Randomly distributed rough surfaces are reconstructed using a Fast Fourier Transform (FFT)-based method, and single-particle impact experiments are conducted to validate the numerical predictions. Good agreement is achieved between simulated and measured values, with a relative error for the maximum rebound height of only 5.9% and a peak velocity deviation prior to impact of approximately 5.4%. Parametric analyses demonstrate that particle diameter, Young’s modulus, surface energy, surface roughness morphology, and flow Reynolds number all influence particle deposition outcomes. Larger particles exhibit significantly higher rebound heights due to increased stored elastic energy; specifically, when particle size increases from 20 μm to 100 μm, the maximum rebound height increases by a factor of 2.1. In contrast, smaller particles are more prone to adhesion after repeated impacts. The rebound height of particles decreases as surface energy increases. When surface energy rises from 0.01 J/m² to 0.05 J/m², rebound height drops from 53.65% to 38.66%. At 0.5 J/m², particles adhere immediately. Compared with ribbed surfaces, randomly distributed rough surfaces promote particle rebound by reducing effective contact area and inducing complex impact orientations. Particle rebound behavior is primarily governed by particle diameter, while material properties such as Young’s modulus and surface energy exhibit secondary and nonlinear effects. The proposed model provides a validated and transferable framework for analyzing particle–surface interactions on rough surfaces and offers physical insights relevant to the control of particle deposition in powder and particulate systems. Full article

(This article belongs to the Section Surface Engineering for Energy Harvesting, Conversion, and Storage)

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18 pages, 3978 KB

Open AccessEditor’s ChoiceArticle

Preliminary Study on the Role of Humic Substances in the Early Corrosion Behavior of High-Tin Bronze Alloys Under Simulated Soil Conditions

by Yuyang Miao and Lu Yang

Coatings 2026, 16(3), 320; https://doi.org/10.3390/coatings16030320 - 6 Mar 2026

Viewed by 1370

Abstract

To investigate the influence of humus on the corrosion behavior of high-tin bronze in soil environments, potentiostatic polarization was applied to simulate early-stage corrosion under controlled conditions. Open-circuit potential and potentiodynamic polarization tests were performed, and corrosion products were characterized by stereo microscopy, [...] Read more.

To investigate the influence of humus on the corrosion behavior of high-tin bronze in soil environments, potentiostatic polarization was applied to simulate early-stage corrosion under controlled conditions. Open-circuit potential and potentiodynamic polarization tests were performed, and corrosion products were characterized by stereo microscopy, SEM-EDS, and confocal Raman spectroscopy. A Cu–Sn–Pb ternary alloy was examined in simulated archaeological soil solutions with selective humus addition at different pH values. A bilayer structure, consisting of a secondary corrosion layer and a semi-corroded transition zone, developed in all media, with more extensive corrosion under weakly acidic conditions. In acidic environments, humus enhanced preferential α-phase corrosion, associated with copper depletion and tin enrichment as SnO₂. Under weakly alkaline conditions, humus mainly affected surface color and micro-morphology without altering the overall corrosion pattern. Electrochemical testing reproduced corrosion layer structures similar to those formed during early burials, but differences in morphology were observed. The results suggest that, as an accelerated corrosion technique, electrochemical methods can reproduce key features of early-stage corrosion in high-tin bronze and serve as an effective tool for monitoring corrosion behavior. Full article

(This article belongs to the Section Corrosion, Wear and Erosion)

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17 pages, 3053 KB

Open AccessEditor’s ChoiceArticle

Deposition Characteristics of SiN Thin Film Deposited by Applying the Chucking Function in a Mono Polar ESC Heater

by Baek-Ju Lee

Coatings 2026, 16(3), 302; https://doi.org/10.3390/coatings16030302 - 1 Mar 2026

Viewed by 945

Abstract

This study investigates the deposition of silicon nitride (SiN) thin films for advanced semiconductor applications, with a specific focus on overcoming thermal challenges in plasma-enhanced atomic layer deposition (PE-ALD) at an elevated temperature of 550 °C. At such high temperatures, a critical obstacle [...] Read more.

This study investigates the deposition of silicon nitride (SiN) thin films for advanced semiconductor applications, with a specific focus on overcoming thermal challenges in plasma-enhanced atomic layer deposition (PE-ALD) at an elevated temperature of 550 °C. At such high temperatures, a critical obstacle is wafer warpage induced by thermal and mechanical stress, which increases localized thermal contact resistance and degrades film uniformity. To address this, a wafer chucking function was integrated into a monopolar electrostatic chuck (ESC) heater. The ESC secures the wafer to the heater surface, effectively mitigating warpage and ensuring a uniform temperature distribution. Chucking performance was verified by monitoring lift-up motor torque variations and plasma parameters, such as self-bias voltage (Vdc) and peak-to-peak voltage (Vpp), confirming the formation of stable electrostatic coupling. A comparative analysis was conducted between SiN films deposited with and without a chucking voltage of +1000 V. Statistical evaluation across repeated experimental runs (n = 3) confirmed that ESC chucking significantly enhanced spatial uniformity without altering the fundamental PE-ALD growth mechanism. Notably, the application of ESC chucking suppressed the localized temperature drop at the wafer periphery, reducing the in-wafer temperature gradient from 7~8 °C to 2~3 °C. This thermal stability resulted in improved thickness uniformity (variation < 1 Å) and an increase in film density from 2.83 to 2.94 g/cm³. Furthermore, the physical contact between the wafer and the heater effectively eliminated backside deposition to near-zero levels. Pattern evaluation revealed an exceptional step coverage of 99% in high-aspect-ratio (20:1) structures. These results suggest that ESC-assisted PE-ALD provides a robust and reproducible method for high-quality SiN deposition by minimizing thermally induced film variations. Full article

(This article belongs to the Section Thin Films)

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22 pages, 4649 KB

Open AccessEditor’s ChoiceArticle

Current Density-Dependent Microstructural Evolution and Properties of NiCo-CeO₂ Composite Coatings

by Shuxin You, Xinquan Zhang, Qinyao Sun, Chuanhai Jiang and Honghao Zhang

Coatings 2026, 16(3), 296; https://doi.org/10.3390/coatings16030296 - 28 Feb 2026

Viewed by 639

Abstract

This study investigates the effects of current density on the microstructure and properties of electrodeposited NiCo-CeO₂ composite coatings. Results demonstrate that current density significantly influences coating composition, with higher CeO₂ and lower Co content increasing surface roughness (minimum at 30 mA/cm [...] Read more.

This study investigates the effects of current density on the microstructure and properties of electrodeposited NiCo-CeO₂ composite coatings. Results demonstrate that current density significantly influences coating composition, with higher CeO₂ and lower Co content increasing surface roughness (minimum at 30 mA/cm², maximum at 100 mA/cm²). Microstructural homogeneity improves with optimized Co/CeO₂ content, where the A30 coating (30 mA/cm²) exhibits the weakest texture among all coatings due to peak Co incorporation. Texture intensifies at higher current densities (30–100 mA/cm²) as Co and CeO₂ contents diminish. Internal stress depends on electrodeposition kinetics and particle dispersion, ranging from −2.22 MPa (A20) to 651 MPa (A50). Hardness correlates with (111) plane dominance and Co/CeO₂ content, reaching 449.8 HV for A30 but dropping to 288.8 HV for A100. Optimal current density tuning refines grains, enhances (111) texture, and improves compositional uniformity, endowing the A30 coating with balanced hardness and corrosion performance (corrosion potential: −224 mV; current density: 0.225 μA/cm²). These findings provide guidelines for tailoring high-performance NiCo-CeO₂ coatings through current density regulation. Full article

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20 pages, 4430 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Anti-Icing Performance of Base Formulations for Coatings for Aeronautical Applications

by Filomena Piscitelli, Andrea Diana, Giovanni Bruno, Gianmarco Caldore, Veronica Ambrogi and Giovanni Filippone

Coatings 2026, 16(3), 298; https://doi.org/10.3390/coatings16030298 - 28 Feb 2026

Viewed by 797

Abstract

Icing on surfaces presents a significant challenge across various technological fields, with added weight and operational interference impacting aircraft wings, wind turbine blades, and electrical equipment. While electrothermal methods effectively accelerate ice melting through the Joule effect, their substantial cost and energy consumption [...] Read more.

Icing on surfaces presents a significant challenge across various technological fields, with added weight and operational interference impacting aircraft wings, wind turbine blades, and electrical equipment. While electrothermal methods effectively accelerate ice melting through the Joule effect, their substantial cost and energy consumption necessitate careful consideration. In the past two decades, anti-icing and icephobic coatings have garnered significant interest due to advancements in nanomaterials and a deeper understanding of ice nucleation and adhesion. These coatings are designed to prevent water droplet adhesion, delay freezing, and/or reduce ice adhesion, without the need for additional energy. Moreover, the combination of active Ice Protection Systems with passive coatings could prevent ice formation with an improved energy efficiency and reduced CO₂ emissions. Aligned with this aim, this study focuses on the development of anti-icing coatings, detailing the selection and characterization of the materials used in the coating formulations, including their chemical and physical properties. Subsequently, the experimental results are presented and analyzed, focusing on the characterization and anti-icing performance of the fabricated coatings through a series of tests. Finally, it concludes with a discussion of the key findings, useful for the formulation of advanced anti-icing coatings mainly for aeronautical applications. Full article

(This article belongs to the Special Issue Research Progress and Application of Super-hydrophobic Anti-icing Surface)

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25 pages, 7930 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Multilayer Barrier Coatings with Starch/Bentonite for Paperboard—The Effects of the Number of Layers and the Drying Strategy on the Barrier Properties

by Lars Järnström, Hanna Christophliemk, Erik Bohlin, Johan Larsson and Per Emilsson

Coatings 2026, 16(3), 299; https://doi.org/10.3390/coatings16030299 - 28 Feb 2026

Viewed by 1180

Abstract

This study investigates the impact of multilayer structures and drying strategies on the barrier properties of high-speed starch/bentonite-coated paperboard. The study examines the impact of drying at a high machine speed of 400 m min⁻¹, addressing a key knowledge gap. The [...] Read more.

This study investigates the impact of multilayer structures and drying strategies on the barrier properties of high-speed starch/bentonite-coated paperboard. The study examines the impact of drying at a high machine speed of 400 m min⁻¹, addressing a key knowledge gap. The hypotheses were that thin multilayer coatings reduce oxygen permeability more effectively than thick single or double coatings and that gentle infrared (IR) drying would be required to achieve this effect. The experiments comprised up to six consecutive coating applications, each providing a dry coat weight between 0.5 and 1.5 g m⁻². The IR dryer power ranged from 207 kW to 829 kW, and different IR frame positions were tested. The results indicated that thin multilayer coatings resulted in fewer pinholes, lower oxygen transmission rates, and improved grease resistance compared with one or two thick layers. However, the effectiveness of the multilayer-coated paperboard was influenced by the employed drying strategy. Specifically, gentle IR drying reduced pinholes, lowered oxygen transmission rates and enhanced grease resistance. Full article

(This article belongs to the Special Issue Advanced Materials and Films for Food Packaging)

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22 pages, 9837 KB

Open AccessEditor’s ChoiceArticle

Multi-Scale Dual-Attention Feature Network with Bidirectional Temporal Constraints for Tool Wear Monitoring

by Youqiang Xu, Rongyi Li, Xianli Liu, Haotuo Liu, Ying Wang, Xiaohua Liu and Yuqiang Gan

Coatings 2026, 16(3), 291; https://doi.org/10.3390/coatings16030291 - 27 Feb 2026

Cited by 1 | Viewed by 573

Abstract

Accurate tool wear monitoring plays a decisive role in machining efficiency, product quality and reliability in modern manufacturing systems. Existing deep learning methods struggle to balance the high-frequency transient features and low-frequency evolution trends in tool wear signals, often losing key temporal evolution [...] Read more.

Accurate tool wear monitoring plays a decisive role in machining efficiency, product quality and reliability in modern manufacturing systems. Existing deep learning methods struggle to balance the high-frequency transient features and low-frequency evolution trends in tool wear signals, often losing key temporal evolution details when processing long-range degradation data. Therefore, this paper proposes an online prediction method of tool wear value that combines multi-scale convolution and dual-attention temporal features. This method extracts local mutation and trend features in wear signals through multi-scale convolution, captures wear evolution features through bidirectional cyclic network, and adaptively fuses local detail information and global trend through dual attention mechanism SWGC-DA to generate a multi-scale time series feature-driven prediction model. The ablation experiment based on the PHM2010 public data set verifies the effectiveness of the network structure design and demonstrates the model’s superior predictive ability. Experiments on the self-built TiAl alloy milling dataset achieved a stable prediction of R² up to 99.1%, with MAE and RMSE of 2.29 and 2.47, respectively. The results show that this method significantly improves the accuracy and robustness of wear prediction. Full article

(This article belongs to the Special Issue Cutting Performance of Coated Tools)

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30 pages, 5210 KB

Open AccessEditor’s ChoiceReview

Electrospun Janus Fibrous Membranes: Property and Potential Biomedical Applications

by Haodong Chen, Wenbo Wu, Xinyu Li, Lili Gao and Tifeng Jiao

Coatings 2026, 16(3), 281; https://doi.org/10.3390/coatings16030281 - 26 Feb 2026

Viewed by 1402

Abstract

The Janus membrane, as a kind of functional material with asymmetric wettability, is endowed with a unique “liquid diode” effect by its hydrophilic/hydrophobic properties on both sides, which can realize unidirectional fluid transport that shows an important value for biomedical and other applications. [...] Read more.

The Janus membrane, as a kind of functional material with asymmetric wettability, is endowed with a unique “liquid diode” effect by its hydrophilic/hydrophobic properties on both sides, which can realize unidirectional fluid transport that shows an important value for biomedical and other applications. Electrospinning technology, with the advantages of flexible processing and controllable fiber structure, has become a mainstream method for preparing Janus membranes with customizable structure and function. Electrospun Janus membranes are widely used in biomedical fields, especially in wound dressings. Their unidirectional drainage property can effectively remove wound exudate, and combined with functional components, they can simultaneously achieve antibacterial, anti-inflammatory, sustained drug release, and rapid hemostasis, and can even realize wound condition monitoring through functional modification, showing great potential in smart medical dressings. While Janus membrane studies have achieved notable breakthroughs, they still face challenges such as poor asymmetric interlayer bonding, lack of long-term stability, organic solvent contamination from electrostatic spinning, and large-scale production. In the future, we need to focus on material interface modification, green preparation process development, and theoretical model improvement to advance the real-world utilization of Janus membranes across diverse applications. Full article

(This article belongs to the Special Issue Emerging Trends in Functional Coatings for Biomedical Applications)

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24 pages, 4485 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Polycarboxylic Acid/Calcium Carbonate Nanopowder-Derived Chelates as Sustainable Cross-Linked Wood Coatings with Improved Thermal Properties

by Jovale Vincent Tongco and Armando Gabriel McDonald

Coatings 2026, 16(2), 268; https://doi.org/10.3390/coatings16020268 - 23 Feb 2026

Cited by 2 | Viewed by 796

Abstract

This study presents a sustainable strategy for improving the thermal properties of pine wood through the application of calcium carbonate nanopowder (CCNP) chelated with polycarboxylic acids (citric acid (CA) and tartaric acid (TA)) as coatings. The chelation reaction was confirmed by the detection [...] Read more.

This study presents a sustainable strategy for improving the thermal properties of pine wood through the application of calcium carbonate nanopowder (CCNP) chelated with polycarboxylic acids (citric acid (CA) and tartaric acid (TA)) as coatings. The chelation reaction was confirmed by the detection of carbon dioxide (CO₂) gas. CCNP was characterized using microscopy and particle size analysis. The formation of crystalline calcium citrate and calcium tartrate was verified using FTIR and Raman spectroscopies, and XRD analysis. Wood treatment was conducted using different volumetric ratios of CA and TA. The CA-TA-treated (coated) wood blocks achieved the highest mass gain after treatment of around 89%, while the pure TA treatment exhibited enhanced leaching resistance, maintaining around 69% mass gain after leaching test. TGA conducted under oxidative (air) conditions showed that the coatings promoted char formation and produced inorganic residues from 6.4% to 7.8%, with the control resulting in negligible residual mass. Flame retardancy tests showed that the chelated coatings effectively delayed combustion and inhibited heat transfer, with the TA treatment showing improved flame retardancy performance by limiting the surface temperature to ~200 °C after 60 s of exposure, as compared to >550 °C for the control. Full article

(This article belongs to the Special Issue New Materials as Protective Coatings for Different Substrates (Wood, Stone, Paper, and Textile): Synthesis, Characterization Techniques and Their Applications)

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19 pages, 3707 KB

Open AccessEditor’s ChoiceArticle

PEI-Functionalized Surface Coating on Carbonized ZIF-8 for Enhanced Adsorption of Methyl Orange

by Zhenqiao Ma, Yuanyuan Xiong, Yiqing Deng, Peini Li, Xiandi Yang, Zhi Ye and Qiang Zhao

Coatings 2026, 16(2), 242; https://doi.org/10.3390/coatings16020242 - 13 Feb 2026

Viewed by 645

Abstract

The contamination of water resources by high concentrations of organic dyes poses severe threats to human health, making the removal of these pollutants critical. Metal–organic frameworks (MOFs) have shown promising potential in dye adsorption due to their high surface area and chemical stability. [...] Read more.

The contamination of water resources by high concentrations of organic dyes poses severe threats to human health, making the removal of these pollutants critical. Metal–organic frameworks (MOFs) have shown promising potential in dye adsorption due to their high surface area and chemical stability. Zeolitic imidazolate framework-8 (ZIF-8), a typical MOF, is known for its thermal stability and is frequently used in removing organic dyes. To enhance its adsorption performance, ZIF-8 is often carbonized to form porous carbon-based materials. However, carbonized ZIF-8 (CZ) often demonstrates restricted adsorption capacity and sluggish kinetics. To address these limitations, we chemically modified low-temperature carbonized ZIF-8 (CZ-550) with polyethyleneimine (PEI) using cyanuric chloride (CC) as a crosslinking agent, producing a novel composite (CZ@PEI/CC-7) featuring abundant amine-rich active sites for adsorption. This study evaluated the adsorption performance of CZ@PEI/CC-7 in removing methyl orange (MO) dye. Our findings reveal that CZ@PEI/CC-7 exhibits accelerated adsorption kinetics aligning with the pseudo-second-order kinetic model, while its isotherms fit the Freundlich and Temkin models, highlighting a favorable multilayer adsorption. Significantly, CZ@PEI/CC-7 achieved an adsorption capacity of 3150 mg/g for MO, compared to 1100 mg/g for unmodified CZ-550. Furthermore, the composite demonstrated excellent acid-base stability across a broad pH range (2–12), retaining structural integrity and adsorption efficiency. These findings suggest that CZ@PEI/CC-7 is a promising candidate for efficient MO removal from water. Full article

(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)

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13 pages, 2279 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Development of Nickel Electrodes for Molten Carbonate Fuel Cells: Performance Characterization and Optimization of the Manufacturing Process

by Martino Prati, Dario Bove, Roberto Spotorno and Barbara Bosio

Coatings 2026, 16(2), 237; https://doi.org/10.3390/coatings16020237 - 12 Feb 2026

Viewed by 730

Abstract

The growing need to reduce CO₂ emissions and promote the energy transition has driven the development of high-efficiency electrochemical technologies such as Molten Carbonate Fuel Cells (MCFCs), which can simultaneously generate electricity and capture CO₂. This work focuses on the [...] Read more.

The growing need to reduce CO₂ emissions and promote the energy transition has driven the development of high-efficiency electrochemical technologies such as Molten Carbonate Fuel Cells (MCFCs), which can simultaneously generate electricity and capture CO₂. This work focuses on the development of nickel electrodes produced by electrodeposition, a technique that enables precise control over the morphology and porosity of the deposited material. The experimental activity mainly investigated the influence of electrical parameters (current density and potential difference) and deposition time on metal film growth, with the aim of optimizing the porous structure and enhancing electrochemical performance. The prepared samples were characterized in terms of mass, thickness, and morphology by scanning electron microscopy, confirming consistency with Faraday’s law. Subsequently, the electrodes were tested in cell stations to evaluate their electrochemical behavior under operating conditions representative of MCFC operation. The results demonstrated that an appropriate combination of electrical parameters and deposition time enables the formation of uniform, porous nickel coatings suitable for electrolyte retention. Electrodeposition thus proved to be an effective and scalable approach for the fabrication of optimized nickel electrodes for molten carbonate fuel cell applications. Full article

(This article belongs to the Special Issue Surface Engineering of Solid-State Electrochemical Systems for Energy Conversion and Storage)

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14 pages, 1099 KB

Open AccessEditor’s ChoiceArticle

Cradle-to-Grave Life Cycle Assessment of Asphalt Pavements Incorporating Recycled Tire Rubber and Warm Mix Additives

by Ana María Rodríguez-Alloza and Daniel Garraín

Coatings 2026, 16(2), 229; https://doi.org/10.3390/coatings16020229 - 11 Feb 2026

Cited by 1 | Viewed by 767

Abstract

Reducing the environmental impacts associated with road infrastructure is a key challenge in the transition toward more sustainable construction practices. Asphalt pavements, due to their extensive material use and energy demand over long service periods, offer significant opportunities for improvement through innovative materials [...] Read more.

Reducing the environmental impacts associated with road infrastructure is a key challenge in the transition toward more sustainable construction practices. Asphalt pavements, due to their extensive material use and energy demand over long service periods, offer significant opportunities for improvement through innovative materials and production technologies. This study evaluates the environmental performance of an asphalt pavement incorporating recycled tire crumb rubber and a warm mix asphalt additive (CR + WMA) in comparison with a conventional hot mix asphalt (HMA) pavement. A comprehensive cradle-to-grave life cycle assessment (LCA) was conducted in accordance with ISO 14040/44 standards, encompassing material production, construction, maintenance, and end-of-life stages. Different pavement service life scenarios were considered, and environmental impacts were quantified using sixteen midpoint categories of the environmental footprint (EF) 2.0 method. To enable a consistent comparison between pavement alternatives with different durability, results were normalized using a functional unit of 1 m²·year. The results show that the CR + WMA pavement consistently exhibits lower environmental impacts than the conventional HMA pavement across all impact categories. When identical service lives are assumed, impact reductions are primarily associated with lower production temperatures, partial substitution of virgin bitumen with recycled crumb rubber, reduced maintenance needs, and the normalization of life cycle impacts when results are expressed per m²·year. Overall, the CR + WMA pavement reduces life cycle environmental impacts by approximately 45%–60% across all EF midpoint categories compared to the conventional HMA pavement, depending on the impact category and service life scenario considered. These findings demonstrate the importance of explicitly accounting for service life and maintenance in pavement LCAs and highlight the potential of CR + WMA technology to reduce the life cycle environmental footprint of asphalt pavements, supporting more informed infrastructure design decisions and the development of more sustainable road pavement solutions. Full article

(This article belongs to the Special Issue Function-Oriented Modified Asphalt and Its Mixtures: Enhancing Pavement Performance and Sustainable Applications)

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27 pages, 5326 KB

Open AccessEditor’s ChoiceReview

Synergistic Control of Crystal Planes and Defects in CVD Single-Crystal Diamond: A Review of Growth Mechanisms and Frontier Applications

by Xiaohua Li, Jiaying Wei, Jie Gao, Yan Wang, Yongqiang Ma, Pengtao An, Shengwang Yu and Ke Zheng

Coatings 2026, 16(2), 218; https://doi.org/10.3390/coatings16020218 - 8 Feb 2026

Cited by 1 | Viewed by 1766

Abstract

Single-crystal diamond (SCD) demonstrates immense potential in high-power electronics, quantum information, and precision sensing due to its exceptional hardness, high thermal conductivity, wide bandgap, and superior chemical stability. Focusing on the crystallographic dependence of chemical vapor deposition (CVD) synthesis, this review systematically examines [...] Read more.

Single-crystal diamond (SCD) demonstrates immense potential in high-power electronics, quantum information, and precision sensing due to its exceptional hardness, high thermal conductivity, wide bandgap, and superior chemical stability. Focusing on the crystallographic dependence of chemical vapor deposition (CVD) synthesis, this review systematically examines the growth mechanisms, defect characteristics, and application progress of typical low-index planes, specifically (100), (111), and (110). The (100) plane, leveraging stable step-flow growth modes and a mature process window, has established itself as the primary orientation for large-size, high-quality homoepitaxy. Conversely, while the (111) plane faces challenges regarding growth rate and the suppression of twins and stacking faults, it offers unique advantages for high-efficiency doping and the preferential alignment of quantum color centers, such as NV and SiV centers. The (110) plane, characterized by its anisotropic surface structure and high effective growth rate, shows significant potential for textured film preparation, N-type doping epitaxy, and quantum sensing based on surface termination control. Furthermore, this article outlines progress in high-index planes (e.g., (113)) and hexagonal diamonds (HDs), highlighting their possibilities for rapid thick-film deposition, directional color center regulation, and novel superhard/quantum material design. Finally, from an integrated “Material-Defect-Device” perspective, we identify current critical scientific and engineering challenges, providing a roadmap for the synergistic optimization of crystal plane selection, defect engineering, and device structure. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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11 pages, 7022 KB

Open AccessEditor’s ChoiceArticle

Nanoporous-Based Oleocoating as a New Scheme for Green and Low-Toxic Marine Antifouling

by Ziqi Chen, Hao Jiang, Shixiang Rao, Shirong Du and Guoqing Wang

Coatings 2026, 16(2), 190; https://doi.org/10.3390/coatings16020190 - 3 Feb 2026

Viewed by 589

Abstract

Achieving environmentally friendly, green, and non-toxic marine antifouling has long been a development goal of the modern coatings industry. However, in complex marine environments, non-toxic or low-toxic antifouling coatings often have a significantly reduced service life. Therefore, achieving stable antifouling performance on a [...] Read more.

Achieving environmentally friendly, green, and non-toxic marine antifouling has long been a development goal of the modern coatings industry. However, in complex marine environments, non-toxic or low-toxic antifouling coatings often have a significantly reduced service life. Therefore, achieving stable antifouling performance on a low-toxic basis has always been a goal in this industry. By using fluorocarbon resin with low surface energy and spraying a well-mixed blend of alkaline earth metal oil-absorbing nanowires and nano zinc oxide particles that is under high pressure, half-embedded into the resin, and infiltrated with alkanes, the antifouling mechanism of these coatings is achieved by the slow release of oily components, creating a long-lasting liquid–liquid interface to separate biofouling from the coating. Thanks to this antifouling mechanism, the sample maintains a water contact angle of 100–110° for 42 days in static seawater, achieves over 98% resistance to bacterial adhesion, and reaches 99.9% resistance to protein and algae adhesion. This study provides a novel and promising solution for the strict implementation of low-toxic and harmless antifouling. Full article

(This article belongs to the Section Liquid–Fluid Coatings, Surfaces and Interfaces)

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15 pages, 5503 KB

Open AccessEditor’s ChoiceArticle

High-Uniformity Ultra-Broadband Composite Coatings for Large-Aperture Space Telescopes Using Dual-Ring Co-Evaporation

by Haifeng Wang, Jian Zhang, Xiaoyi Wang, Tongtong Wang, Zhenfeng Shen, Jingjie Pan, Haigui Yang and Zhen Liu

Coatings 2026, 16(2), 191; https://doi.org/10.3390/coatings16020191 - 3 Feb 2026

Viewed by 614

Abstract

In addressing the key technical challenges of achieving ultra-broadband and high film-thickness uniformity for meter-class large-aperture space telescopes, this study utilized a self-developed 4 m-class large-aperture thin-film deposition system. By employing plasma-assisted electron-beam evaporation technology and a co-evaporation method with inner and outer [...] Read more.

In addressing the key technical challenges of achieving ultra-broadband and high film-thickness uniformity for meter-class large-aperture space telescopes, this study utilized a self-developed 4 m-class large-aperture thin-film deposition system. By employing plasma-assisted electron-beam evaporation technology and a co-evaporation method with inner and outer dual-ring multi-evaporation sources, precise control of film-thickness uniformity within a 2 m range was achieved. A composite film structure combining a metal reflective layer and an ultraviolet-enhanced dielectric layer was adopted to realize high reflectivity across an ultra-broad spectrum from ultraviolet to long-wave infrared. Experimental results show that the average reflectance of the composite film reaches 91.52% in the 0.25~0.38 μm spectral band and 99.40% in the 0.38~12 μm spectral band. The thickness uniformity of ZrO₂ and MgF₂ films within the 2 m aperture area was controlled at 1.37% and 3.12%, respectively, meeting the requirements for high uniformity in large-aperture space applications. Radiation testing confirmed that the change in film reflectance is less than 1% under a total irradiation dose of 3.66 × 10⁸ rad(Si), satisfying the demands for operation in harsh space environments. This research provides an innovative solution for thin-film technology in large-aperture, ultra-broad-spectrum space optical systems and holds significant value for engineering applications. Full article

(This article belongs to the Section Thin Films)

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19 pages, 1692 KB

Open AccessEditor’s ChoiceReview

Scanning Electrochemical Microscopy for Investigating Nanocomposite Epoxy Coating Degradation and Corrosion Mechanisms

by Marina Samardžija, Marin Kurtela, Ivan Stojanović and Vesna Alar

Coatings 2026, 16(2), 165; https://doi.org/10.3390/coatings16020165 - 29 Jan 2026

Cited by 1 | Viewed by 679

Abstract

Scanning Electrochemical Microscopy represents one of the most advanced high-resolution techniques that enables detailed monitoring of electrochemical processes, with a particular focus on corrosion phenomena. Scanning Electrochemical Microscopy has become an indispensable tool in studying the behavior and degradation of protective coatings exposed [...] Read more.

Scanning Electrochemical Microscopy represents one of the most advanced high-resolution techniques that enables detailed monitoring of electrochemical processes, with a particular focus on corrosion phenomena. Scanning Electrochemical Microscopy has become an indispensable tool in studying the behavior and degradation of protective coatings exposed to aggressive environmental conditions. This technique allows researchers to precisely track local electrochemical reactions on material surfaces, providing valuable information about the stability and effectiveness of coatings. Scanning Electrochemical Microscopy enables the detection of localized current variations in the pA–nA range, allowing the identification of microdefects with nanometric width. In this paper, the basic principles of Scanning Electrochemical Microscopy operation are first presented, including a description of the device. The method of scanning the electrode is discussed through the modes and their interpretation of the obtained data for systems with protective anticorrosive coatings. Furthermore, Scanning Electrochemical Microscopy techniques enable a detailed study of the mechanisms and kinetics of new, modified coatings, which is especially significant in the case of nanoparticle-enriched coatings. Such modifications often enhance the protective properties of materials, and Scanning Electrochemical Microscopy allows monitoring of their performance under real conditions, providing insight into local electrochemical changes that are otherwise difficult to detect with standard methods. Special attention is given to the challenges researchers may encounter during experiments, such as calibration prior to measurement, interpretation of input parameters, and signal analysis. This paper aims to provide a comprehensive overview of the capabilities and limitations of Scanning Electrochemical Microscopy (SECM), emphasizing its importance as a tool for the development and optimization of new, high-performance coatings for industrial applications and scientific research. Full article

(This article belongs to the Special Issue Corrosion Resistance of Innovative Composite Coatings Based on Nanoparticles)

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16 pages, 7231 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Underwater Performance of Eco-Friendly Choline-Based Ionic Liquid Coatings Applied on Stone Surfaces

by Marika Luci, Filomena De Leo, Mirko Mutalipassi, Teresa Romeo, Silvestro Greco, Chiara Giommi, Lorenzo Evola, Mauro Francesco La Russa, Michela Ricca, Donatella de Pascale, Clara Enza Urzì, Sandra Lo Schiavo, Christian Galasso, Nadia Ruocco and Silvestro Antonio Ruffolo

Coatings 2026, 16(1), 136; https://doi.org/10.3390/coatings16010136 - 20 Jan 2026

Viewed by 776

Abstract

In the marine environment, numerous factors endanger the preservation of underwater rock surfaces as well as submerged archeological artifacts, including physical, chemical, and biological processes. Limestone and marble are common materials used in artifacts due to their availability and long-term durability. However, such [...] Read more.

In the marine environment, numerous factors endanger the preservation of underwater rock surfaces as well as submerged archeological artifacts, including physical, chemical, and biological processes. Limestone and marble are common materials used in artifacts due to their availability and long-term durability. However, such surfaces provide a suitable substrate for the settlement of micro- and macro-organisms, causing so-called biofouling, which significantly contributes to stone deterioration. Previous studies have demonstrated the applicability of antifouling coatings containing ionic liquids (ILs) on marble surfaces and assessed their durability for up to 15 days under submerged environments. To further corroborate these results, additional physical studies (colorimetric, contact angles, capillarity water absorption measurements, and UV aging) were carried out on treated limestone. Washout tests were also performed on both lithotypes to verify the coatings’ stability under medium-term underwater exposures. The results of these investigations are reported here. Our data confirm that the application of IL-based coatings had no effect on the intrinsic properties of the limestone surfaces, as previously reported for marble, including resistance to daily UV irradiation. In addition, laboratory tests demonstrated good coating durability against seawater erosive action for up to 6 months. Full article

(This article belongs to the Special Issue Heritage Conservation and Restoration: Surface Treatments, Coatings and Sustainable Approaches)

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18 pages, 2670 KB

Open AccessEditor’s ChoiceArticle

High-Efficient Photocatalytic and Fenton Synergetic Degradation of Organic Pollutants by TiO₂-Based Self-Cleaning PES Membrane

by Shiying Hou, Yuting Xue, Wenbin Zhu, Min Zhang and Jianjun Yang

Coatings 2026, 16(1), 125; https://doi.org/10.3390/coatings16010125 - 18 Jan 2026

Viewed by 1057

Abstract

In this study, we aimed to develop a high-performance, anti-fouling ultrafiltration membrane by integrating photocatalytic and Fenton-like functions into a polymer matrix, in order to address the critical challenge of membrane fouling and achieve simultaneous separation and degradation of organic pollutants. To this [...] Read more.

In this study, we aimed to develop a high-performance, anti-fouling ultrafiltration membrane by integrating photocatalytic and Fenton-like functions into a polymer matrix, in order to address the critical challenge of membrane fouling and achieve simultaneous separation and degradation of organic pollutants. To this end, a novel Fe-V_O-TiO₂-embedded polyethersulfone (PES) composite membrane was designed and fabricated using a facile phase inversion method. The key innovation lies in the incorporation of Fe-V_O-TiO₂ nanoparticles containing abundant bulk-phase single-electron-trapped oxygen vacancies, which not only modulate membrane morphology and hydrophilicity but also enable sustained generation of reactive oxygen species for the pollutant degradation under light irradiation and H₂O₂. The optimized Fe-V_O-TiO₂-PES-0.04 membrane exhibited a significantly enhanced pure water flux of 222.6 L·m⁻²·h⁻¹ (2.2 times higher than the pure PES membrane) while maintaining a high bovine serum albumin (BSA) retention of 93% and an improved hydrophilic surface. More importantly, the membrane demonstrated efficient and stable synergistic Photocatalytic-Fenton activity, achieving 82% degradation of norfloxacin (NOR) and retaining 75% efficiency after eight consecutive cycles. A key finding is the membrane’s Photocatalytic-Fenton-assisted self-cleaning capability, with an 80% flux recovery after methylene blue (MB) fouling, which was attributed to in situ reactive oxygen species (·OH) generation (verified by ESR). This work provides a feasible strategy for designing multifunctional membranes with enhanced antifouling performance and extended service life through built-in catalytic self-cleaning. Full article

(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)

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12 pages, 3279 KB

Open AccessEditor’s ChoiceArticle

Regulation of Droplet Spreading Behavior by Superhydrophobic Meshes Under Fluid Penetration Phenomena

by Lijie Sun, Shuang Chen and Bo Li

Coatings 2026, 16(1), 126; https://doi.org/10.3390/coatings16010126 - 18 Jan 2026

Viewed by 483

Abstract

Droplet impact on porous mesh surfaces is a common phenomenon in fields such as thermal management systems, biomedical manufacturing, and precision agriculture. As a substrate with microstructures, the mesh surface allows liquid penetration upon droplet impact. The resulting loss of liquid mass significantly [...] Read more.

Droplet impact on porous mesh surfaces is a common phenomenon in fields such as thermal management systems, biomedical manufacturing, and precision agriculture. As a substrate with microstructures, the mesh surface allows liquid penetration upon droplet impact. The resulting loss of liquid mass significantly alters the impact dynamics of the residual droplet on the surface. This study experimentally compares the behavior of water droplets impacting superhydrophobic mesh surfaces with different pore sizes against that on smooth surfaces. It focuses on analyzing how liquid penetration affects parameters such as spreading time (

t_{s}

), maximum spreading factor (

β_{m a x}

), contact time (

t_{c}

), and droplet height (

h

). The results show that the substantial liquid loss induced by large-pore meshes directly leads to a marked decrease in spreading time and maximum spreading factor. Furthermore, the “pancake bouncing” phenomenon observed on the superhydrophobic mesh surfaces significantly shortens the contact time, providing a new perspective for minimizing the contact duration between droplets and solid surfaces. By establishing the correlation between pore size and droplet impact behavior, this study provides key structural design guidelines for applications such as advanced printing systems and efficient pesticide spraying, thereby achieving the goal of proactively regulating liquid dynamics through surface microstructure. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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14 pages, 2317 KB

Open AccessEditor’s ChoiceArticle

Shrimp-Derived Chitosan for the Formulation of Active Films with Mexican Propolis: Physicochemical and Functional Evaluation of the Biomaterial

by Alejandra Delgado-Lozano, Pedro Alberto Ledesma-Prado, César Leyva-Porras, Lydia Paulina Loya-Hernández, César Iván Romo-Sáenz, Carlos Arzate-Quintana, Manuel Román-Aguirre, María Alejandra Favila-Pérez, Alva Rocío Castillo-González and Celia María Quiñonez-Flores

Coatings 2026, 16(1), 124; https://doi.org/10.3390/coatings16010124 - 17 Jan 2026

Cited by 1 | Viewed by 822

Abstract

The development of functional biomaterials based on natural polymers has gained increasing relevance due to the growing demand for sustainable and bioactive alternatives for biomedical and technological applications. In this study, chitosan was obtained from shrimp exoskeletons and used to formulate active films [...] Read more.

The development of functional biomaterials based on natural polymers has gained increasing relevance due to the growing demand for sustainable and bioactive alternatives for biomedical and technological applications. In this study, chitosan was obtained from shrimp exoskeletons and used to formulate active films enriched with Mexican propolis, aiming to evaluate the influence of the extract on the physicochemical and functional properties of the resulting biomaterial. Propolis was incorporated into the chitosan film-forming solution at a final concentration of 1.0% (v/v). The propolis employed met the requirements of the Mexican Official Standard NOM-003-SAG/GAN-2017 regarding flavonoid content, total phenolic compounds, and antimicrobial activity; additionally, it was evaluated through antioxidant activity, hemolysis, and acute toxicity (LD₅₀) assays to provide a broader biological and safety assessment. The extracted chitosan exhibited a degree of deacetylation of 74% and characteristic FTIR spectral features comparable to those of commercial chitosan, confirming the quality of the obtained polymer. Chitosan–propolis films exhibited antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans, whereas pure chitosan films showed no inhibitory effect. Thermal analyses (TGA/DSC) revealed a slight reduction in thermal stability due to the incorporation of thermolabile polyphenolic compounds, along with increased thermal complexity of the system. SEM observations demonstrated reduced microbial adhesion and marked morphological damage in microorganisms exposed to the functionalized films. Overall, the incorporation of Mexican propolis enabled the development of a hybrid biomaterial with enhanced antimicrobial performance and potential application in wound dressings and bioactive coatings. Full article

(This article belongs to the Special Issue Coatings with Natural Products)

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21 pages, 4628 KB

Open AccessEditor’s ChoiceArticle

Effect of Inclined Angles and Contouring Parameters on Upskin Surface Characteristics of Parts Made by Laser Powder-Bed Fusion

by Nismath Valiyakath Vadakkan Habeeb and Kevin Chou

Coatings 2026, 16(1), 119; https://doi.org/10.3390/coatings16010119 - 16 Jan 2026

Cited by 1 | Viewed by 878

Abstract

Surface finish plays a critical role in the tribological performance of additively manufactured engineering components. In exploring part characteristics in laser powder-bed fusion (L-PBF), this study investigates the effect of contouring strategies on the upskin surface of inclined specimens (30°, 45°, and 60°) [...] Read more.

Surface finish plays a critical role in the tribological performance of additively manufactured engineering components. In exploring part characteristics in laser powder-bed fusion (L-PBF), this study investigates the effect of contouring strategies on the upskin surface of inclined specimens (30°, 45°, and 60°) made with L-PBF, using post- and pre-contouring strategies with various levels of process parameters. The surface data of fabricated inclined specimens were acquired by white-light interferometry, followed by a quantitative analysis using surface images. The results show that post-contouring leads to better surface finishes, with the lowest S_a of 8.68 µm attained at the highest laser power (195 W) and the slowest scan speed (500 mm/s) on 30°-inclined specimens, likely due to increased remelting and less step-edges. In contrast, pre-contouring produces distinct surface textures on the upskin of L-PBF specimens, resulting in a rougher surface morphology, with a maximum S_a of 33.39 µm also from 30°-inclined specimens at the lowest power (100 W) and the highest speed (2000 mm/s), suggesting an insufficient remelting of surface defects. In comparative analysis, in general, post-contouring yields smoother upskin surfaces, with a 17%–30% reduction in S_a, than those from equivalent pre-contouring conditions, highlighting the potential of scan sequences for optimizing L-PBF to improve the surface finish of inclined structures. Full article

(This article belongs to the Special Issue Surface Topography Measurement Analysis of Additively Manufactured Modern Materials and Coatings)

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15 pages, 2335 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Early-Stage Biofilm Prevention Enabled by Rapid Microwave Waveguide Detection of Planktonic Microorganisms in Diesel Fuel

by Andrzej Miszczyk, Michał Kuna and Anna Brillowska-Dąbrowska

Coatings 2026, 16(1), 101; https://doi.org/10.3390/coatings16010101 - 13 Jan 2026

Viewed by 728

Abstract

Many industrial sectors are concerned about microbiological contamination and the associated risk of microbiologically influenced corrosion (MIC). This applies in particular to the transmission and storage of fuels in the refining industry. Exceeding a certain level of these contaminants poses a serious risk [...] Read more.

Many industrial sectors are concerned about microbiological contamination and the associated risk of microbiologically influenced corrosion (MIC). This applies in particular to the transmission and storage of fuels in the refining industry. Exceeding a certain level of these contaminants poses a serious risk to fuel quality and can cause storage and pipeline infrastructure corrosion. This situation requires an urgent evaluation of microorganism levels in the fuel to avert such detrimental consequences. Diesel fuels containing biofuel additives are particularly susceptible to these phenomena. Traditional detection methods are limited by low sensitivity, high costs, and long turnaround times, making them unsuitable for quick, on-site, and real-time detection and monitoring. A novel approach involves the application of microwave dielectric testing to quantify microbial load in diesel fuel. Microwave dielectric spectroscopy offers a non-destructive, label-free solution, providing rapid information on microorganism presence. Combined with chemometric techniques, it effectively estimates total microorganism counts in diesel fuel. Measurement in the X-band range (8.2–12.4 GHz) takes a few seconds. Calibration with known bacterial and fungal concentrations (10³ to 10⁷ CFU/mL) and principal component analysis (PCA) of the spectroscopic data allow for clear differentiation of contamination levels, categorizing them from acceptable to hazardous. The sensitivity limit of the proposed method corresponds to a bacterial concentration of 10³ CFU/mL. Full article

(This article belongs to the Special Issue Advanced Strategies for Biofilm Prevention and Disruption: Materials, Coatings, Nanotechnologies, and Predictive AI Models)

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10 pages, 1592 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Direct Regeneration of Spent LiNi_0.5Co_0.2Mn_0.3O₂ Cathodes by Utilizing Eutectic Lithium Salts for High-Performance Lithium-Ion Batteries

by Jian Yan, Yongji Xia, Sheng Lin, Yingpeng Du, Zhidong Zhou, Jintang Li and Guanghui Yue

Coatings 2026, 16(1), 107; https://doi.org/10.3390/coatings16010107 - 13 Jan 2026

Cited by 1 | Viewed by 967

Abstract

With the wide application of lithium-ion batteries (LIBs), many spent LIBs will face the problem of recycling and treatment in the future. The recycling of valuable substances from battery materials is particularly important. In this paper, the spent LiNi_0.5Co_0.2Mn [...] Read more.

With the wide application of lithium-ion batteries (LIBs), many spent LIBs will face the problem of recycling and treatment in the future. The recycling of valuable substances from battery materials is particularly important. In this paper, the spent LiNi_0.5Co_0.2Mn_0.3O₂ (S-NCM523) cathode material from used LIBs was regenerated by using the eutectic lithium salt of Li₂CO₃/LiOH. The lithium element lost by S-NCM523 was supplemented through solid–liquid contact with the molten lithium salt, restoring the layered structure at high temperatures. The successful repair of the regenerated material was verified by various characterization methods, including the elimination of the rock salt phase and the lower Li⁺/Ni²⁺ disorder. This research shows that the regenerated cathode material still has a high specific discharge capacity of 146.8 mAh/g after 100 cycles, with a capacity retention rate of 96.0%. The excellent electrochemical performance of the regenerated material demonstrates the feasibility of directly regenerating spent NCM using the molten salt method. Full article

(This article belongs to the Special Issue Advanced Coatings and Interfaces for Next-Generation Energy Storage Systems)

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34 pages, 4355 KB

Open AccessEditor’s ChoiceReview

Thin-Film Sensors for Industry 4.0: Photonic, Functional, and Hybrid Photonic-Functional Approaches to Industrial Monitoring

by Muhammad A. Butt

Coatings 2026, 16(1), 93; https://doi.org/10.3390/coatings16010093 - 12 Jan 2026

Cited by 4 | Viewed by 1822

Abstract

The transition toward Industry 4.0 requires advanced sensing platforms capable of delivering real-time, high-fidelity data under extreme industrial conditions. Thin-film sensors, leveraging both photonic and functional approaches, are emerging as key enablers of this transformation. By exploiting optical phenomena such as Fabry–Pérot interference, [...] Read more.

The transition toward Industry 4.0 requires advanced sensing platforms capable of delivering real-time, high-fidelity data under extreme industrial conditions. Thin-film sensors, leveraging both photonic and functional approaches, are emerging as key enablers of this transformation. By exploiting optical phenomena such as Fabry–Pérot interference, guided-mode resonance, plasmonics, and photonic crystal effects, thin-film photonic devices provide highly sensitive, electromagnetic interference-immune, and remotely interrogated solutions for monitoring temperature, strain, and chemical environments. Complementarily, functional thin films including oxide-based chemiresistors, nanoparticle coatings, and flexible electronic skins extend sensing capabilities to diverse industrial contexts, from hazardous gas detection to structural health monitoring. This review surveys the fundamental optical principles, material platforms, and deposition strategies that underpin thin-film sensors, emphasizing advances in nanostructured oxides, 2D materials, hybrid perovskites, and additive manufacturing methods. Application-focused sections highlight their deployment in temperature and stress monitoring, chemical leakage detection, and industrial safety. Integration into Internet of Things (IoT) networks, cyber-physical systems, and photonic integrated circuits is examined, alongside challenges related to durability, reproducibility, and packaging. Future directions point to AI-driven signal processing, flexible and printable architectures, and autonomous self-calibration. Together, these developments position thin-film sensors as foundational technologies for intelligent, resilient, and adaptive manufacturing in Industry 4.0. Full article

(This article belongs to the Section Thin Films)

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12 pages, 4120 KB

Open AccessEditor’s ChoiceArticle

The Effect of Micro-Cutting on the Residual Height of Surface Topography in NiTi Shape Memory Alloy Using a Small-Diameter Cutter

by Xinyi Wang, Zeming Li, Yansen Wang, Zelin Wang, Zhenshan Chen, Junxiang Liu, Jian Wang and Guijie Wang

Coatings 2026, 16(1), 100; https://doi.org/10.3390/coatings16010100 - 12 Jan 2026

Viewed by 537

Abstract

The milled surface topography of NiTi SMA critically affects its frictional behavior, corrosion resistance, and biocompatibility, which are essential for biomedical and aerospace applications. This study combines simulation and single-factor experiments to investigate the coupling behavior among surface topography evolution, work hardening, plastic [...] Read more.

The milled surface topography of NiTi SMA critically affects its frictional behavior, corrosion resistance, and biocompatibility, which are essential for biomedical and aerospace applications. This study combines simulation and single-factor experiments to investigate the coupling behavior among surface topography evolution, work hardening, plastic deformation, and residual stress evolution. Results showed that increasing feed per tooth led to a significant rise in surface residual height and an improvement in surface isotropy. With the increase in feed per tooth, the error between the experimental and simulated heights gradually decreased from 105.6% to 30.9%, indicating that both material properties and feed per tooth strongly affect residual profile formation in the feed direction. In addition, larger feed per tooth intensifies work hardening and plastic deformation but reduces surface residual stress, thereby increasing microhardness. These effects can mitigate material rebound and improve surface profile accuracy. The results provide a direct basis for controlling the surface integrity of NiTi SMA components through machining parameter optimization, enabling precise tailoring of functional surface characteristics, such as wear performance, chemical stability, and biological response, which is of critical importance for high-end biomedical implants and aerospace systems. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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12 pages, 1200 KB

Open AccessFeature PaperEditor’s ChoiceArticle

In Vitro Evaluation of the Antimicrobial Properties of Chitosan–Vancomycin Coatings on Grade 4 Titanium Discs: A Preliminary Study

by João M. Pinto, Liliana Grenho, Susana J. Oliveira, Manuel A. Sampaio-Fernandes, Maria Helena Fernandes, Maria Helena Figueiral and Maria Margarida Sampaio-Fernandes

Coatings 2026, 16(1), 75; https://doi.org/10.3390/coatings16010075 - 8 Jan 2026

Viewed by 1056

Abstract

Peri-implant infections pose a significant challenge in dental implantology. This study aimed to develop and characterize a chitosan–vancomycin coating for titanium surfaces, focusing on drug loading, release kinetics, antimicrobial performance, and cytocompatibility. Grade 4 titanium discs were coated with a chitosan film using [...] Read more.

Peri-implant infections pose a significant challenge in dental implantology. This study aimed to develop and characterize a chitosan–vancomycin coating for titanium surfaces, focusing on drug loading, release kinetics, antimicrobial performance, and cytocompatibility. Grade 4 titanium discs were coated with a chitosan film using the dip-coating technique and subsequently loaded with vancomycin through immersion in an aqueous solution. Coating morphology was examined by scanning electron microscopy (SEM). Vancomycin loading was quantified by spectrophotometry, and release kinetics were monitored over 144 h (6-day). Antimicrobial activity was assessed through agar diffusion assays against Staphylococcus aureus. Cytocompatibility was evaluated using human mesenchymal stem cells (hMSCs), whose metabolic activity, adhesion, and morphology were assessed over a 19-day culture period by resazurin assay and SEM. SEM analysis revealed a uniformly distributed, smooth, and crack-free chitosan film, which remained stable after drug loading. The coating exhibited a biphasic release profile, characterized by an initial burst followed by sustained release over six days, which maintained antimicrobial activity, as confirmed by inhibition zones. hMSCs adhered and proliferated on the coated surfaces, displaying normal morphology despite a transient reduction in metabolic activity on vancomycin-containing films. These findings support the potential of chitosan–vancomycin coatings as localized antimicrobial strategies for implant applications, warranting further in vivo and mechanical evaluations. Full article

(This article belongs to the Special Issue Films and Coatings with Biomedical Applications)

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37 pages, 12271 KB

Open AccessEditor’s ChoiceArticle

Investigation on the Effect of Detonation Nanodiamonds on the Properties of Polymeric Active Food Packaging, Part I: Biological Activity, Surface Hydrophobicity, and Thermal Stability of Baseline Films

by Julia Mundziel, Leon Kukiełka, Totka Bakalova, Magdalena Mrózek, Martin Borůvka, Adam Hotař, Tomasz Rydzkowski and Katarzyna Mitura

Coatings 2026, 16(1), 72; https://doi.org/10.3390/coatings16010072 - 7 Jan 2026

Viewed by 743

Abstract

This article presents the results of the first stage of a four-phase research program aimed at the comprehensive evaluation and enhancement in the functional properties of polymeric packaging films intended for active food packaging systems through their modification with detonative nanodiamonds (DND). Stage [...] Read more.

This article presents the results of the first stage of a four-phase research program aimed at the comprehensive evaluation and enhancement in the functional properties of polymeric packaging films intended for active food packaging systems through their modification with detonative nanodiamonds (DND). Stage I involved the characterization of ten commercial single- and multi-layer films without the addition of DND, differing in structure, base material, thickness, and intended application. The scope of analyses included the assessment of biological and physicochemical properties relevant to food contact, such as surface wettability (contact angle), thermal stability (TGA, DSC), antimicrobial and antiviral activity (using E. coli and M. luteus models), as well as the quality of thermal seals examined by SEM. Biological activity was assessed in accordance with ISO 22196:2011. The results revealed significant differences among the tested samples in terms of microbiological resistance, surface properties, and thermal stability. Films with printed layers exhibited the highest antimicrobial activity, whereas some polypropylene samples showed no activity at all or even supported microbial survival. Cross-sectional analysis of welds indicated that the quality of thermal seals is strongly dependent on the surface properties of the base material. The obtained results provide a reference point for subsequent research stages, in which DND-modified films will be analyzed regarding their effects on mechanical, barrier, and biological properties. Preliminary trials with nanodiamonds confirmed their high application potential and the possibility of producing films with increased hydrophilicity or hydrophobicity and durability, which are crucial for the development of modern active food packaging systems. Full article

(This article belongs to the Special Issue Surface Modification, Functional Coatings, and Nanomaterials for Food Safety and Contact Applications)

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16 pages, 2561 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Biodegradable Polymer Films Based on Hydroxypropyl Methylcellulose and Blends with Zein and Investigation of Their Potential as Active Packaging Material

by Sofia Milenkova, Maria Marudova and Asya Viraneva

Coatings 2026, 16(1), 66; https://doi.org/10.3390/coatings16010066 - 6 Jan 2026

Cited by 4 | Viewed by 1098

Abstract

Active packages have become a significant center of attention, and especially those based on biodegradable materials, due to their ability to enhance food preservation and extend shelf life. A suitable base for obtaining such types of packages has turned out to be polymers [...] Read more.

Active packages have become a significant center of attention, and especially those based on biodegradable materials, due to their ability to enhance food preservation and extend shelf life. A suitable base for obtaining such types of packages has turned out to be polymers with natural origin, such as hydroxylpropyl methylcellulose (HPMC) and zein. Therefore, the present study is focused on developing films using the casting method based on pure HPMC and blends between HPMC and zein. Three types of polymer matrices were developed: pure HPMC film, HPMC 3:1 zein, and HPMC 1:1 zein. Further, all of them were loaded with curcumin to improve their biological activity, and mainly their antioxidant activity. In order to investigate the potential of these films, some of their most vital properties in terms of potential application as packaging material are established, such as mechanical properties (strain at break, Young’s modulus), barrier properties (water vapor transmission rate), and morphology. A significant change in the Young’s modulus was present after the addition of zein; it went from 276.98 ± 28.48 MPa for pure HPMC to 52.17 ± 10.19 MPa in a 1:1 ratio between the polymers. Meanwhile, strain at break showed a slight drop from 86.74 ± 8.64% to 72.44 ± 9.62%. Barrier properties were also influenced by the formation of composite film and the addition of polyphenol, lowering the water vapor transmission rate from 913.07 ± 74.01 g/m².24 h for pure HPMC to 873.05 ± 9.07 g/m².24 h for 1:1 ratio film and further to 826.35 ± 33.67 g/m².24 h after the addition of rutin to the latter. Additional characterization of radical scavenging ability towards DPPH free radicals showed a similar A-shaped trend to the values of Young’s modulus, due to the presence of hydrogen bonds, which affect both properties of the film structures. Thermal behavior and phase state investigation of the films obtained by differential scanning calorimetry prior to and after polyphenol addition was carried out, indicating full phase transition of rutin from crystalline to amorphous state. Full article

(This article belongs to the Special Issue Preparation and Applications of Bio-Based Polymer Coatings)

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32 pages, 641 KB

Open AccessEditor’s ChoiceReview

Synergistic Effects of Graphene and SiO₂ Nanoadditives on Dirt Pickup Resistance, Hydrophobicity, and Mechanical Properties of Architectural Coatings: A Systematic Review and Meta-Analysis

by Kseniia Burkovskaia, Michał Strankowski and Krzysztof Szafran

Coatings 2026, 16(1), 32; https://doi.org/10.3390/coatings16010032 - 28 Dec 2025

Cited by 1 | Viewed by 1298

Abstract

This article provides a comprehensive review of the literature on the use of graphene-based nanomaterials (graphene oxide, reduced graphene oxide, and graphene nanoplatelets) and nanosilica (SiO₂) in architectural paint and coatings. The aim was to quantitatively assess their effect on dirt [...] Read more.

This article provides a comprehensive review of the literature on the use of graphene-based nanomaterials (graphene oxide, reduced graphene oxide, and graphene nanoplatelets) and nanosilica (SiO₂) in architectural paint and coatings. The aim was to quantitatively assess their effect on dirt pickup resistance, hydrophobicity, and mechanical properties. In a systematic search across ScienceDirect, Scopus, and Web of Science (2010–2025), 20 studies that met the set inclusion criteria were identified. We extracted and generalized data with random-effects models (REML) based on standardized mean differences, conducting subgroup and meta-regression analyses to assess filler type, loading, and binder system impact. The results reveal that graphene-based fillers and SiO₂ improve coating performance at the same time, and hybrid graphene-SiO₂ systems may provide a synergistic improvement depending on the binder matrix. Our results present the first quantitative evidence of graphene-SiO₂ interaction in the coating formulations, identify remaining research gaps, and indicate methods for designing next-generation facade paints with better dirt repellence, durability, and sustainability. Full article

(This article belongs to the Special Issue Modern Polymer Coating Materials Containing Graphene Derivatives)

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16 pages, 3852 KB

Open AccessEditor’s ChoiceArticle

ATP-Responsive ZIF-90 Nanocontainers Encapsulating Natural Antifoulants for Intelligent Marine Coatings

by Yanrong Chao, Xingyan Feng, Bingui Wang, Linghong Meng, Peng Qi, Yan Zeng and Peng Wang

Coatings 2026, 16(1), 7; https://doi.org/10.3390/coatings16010007 - 19 Dec 2025

Viewed by 861

Abstract

Marine biofouling presents a persistent challenge for maritime industries, necessitating the development of eco-friendly and intelligent antifouling strategies. In this work, an ATP-responsive nanocontainer was developed by encapsulating a natural organic compound (CS106-10), isolated from Talaromyces trachyspermus in cold seep sediments, together with [...] Read more.

Marine biofouling presents a persistent challenge for maritime industries, necessitating the development of eco-friendly and intelligent antifouling strategies. In this work, an ATP-responsive nanocontainer was developed by encapsulating a natural organic compound (CS106-10), isolated from Talaromyces trachyspermus in cold seep sediments, together with D-phenylalanine (D-Phe) into ZIF-90 nanoparticles (D-Phe/CS106-10@ZIF-90). These nanoparticles were incorporated into zinc acrylate resin to fabricate a novel self-polishing antifouling coating. CS106-10, as a natural antifoulant, provided efficient and environmentally sustainable bactericidal activity, while D-Phe acted as a synergistic adjuvant to inhibit and disrupt biofilm formation. More importantly, the ATP-responsive ZIF-90 framework enabled controlled, on-demand release of antifouling agents in response to local metabolic signals associated with biofilm growth. Laboratory and real-sea evaluations confirmed that the composite coating effectively suppressed biofilm formation and significantly reduced the required dosage of conventional toxic antifoulants. This study integrates a natural antifoulant with an ATP-responsive metal–organic framework, providing new insight for developing antifouling coatings. Full article

(This article belongs to the Section Functional Polymer Coatings and Films)

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30 pages, 3827 KB

Open AccessEditor’s ChoiceReview

A Review of Anticoagulant Surface Modification Strategies for Blood-Contacting Materials: From Inertness to Bioinspired and Biointegration

by Shuguang Zhang, Zhixiang Deng, Yuhe Wang and Chao Zhao

Coatings 2025, 15(12), 1486; https://doi.org/10.3390/coatings15121486 - 16 Dec 2025

Cited by 2 | Viewed by 2246

Abstract

The coagulation cascade triggered by the contact between blood and the surface of implantable/interventional devices can lead to thrombosis, severely compromising the long-term safety and efficacy of medical devices. As an alternative to systemic anticoagulants, surface anticoagulant modification technology can achieve safer hemocompatibility [...] Read more.

The coagulation cascade triggered by the contact between blood and the surface of implantable/interventional devices can lead to thrombosis, severely compromising the long-term safety and efficacy of medical devices. As an alternative to systemic anticoagulants, surface anticoagulant modification technology can achieve safer hemocompatibility on the device surface, holding significant potential for clinical application. This article systematically elaborates on the latest research progress in the surface anticoagulant modification of blood-contacting materials. It analyzes and discusses the main strategies and their evolution, spanning from physically inert carbon-based coatings and heparin-based drug-functionalized surfaces to hydrophilic/hydrophobic dynamic physical barriers, biologically signaling regulatory coatings, and bio-integrative/regenerative endothelium-mimicking surfaces. The advantages and limitations of the respective methods are outlined, and the potential for synergistic application of multiple strategies is explored. A special emphasis is placed on current research hotspots regarding novel anticoagulant surface technologies, such as hydrogel coatings, liquid-infused surfaces, and 3D-printed endothelialization, aiming to provide insights and references for developing long-term, safe, and hemocompatible cardiovascular implantable devices. Full article

(This article belongs to the Collection Feature Paper Collection in 'Surface Coatings for Biomedicine and Bioengineering')

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16 pages, 3130 KB

Open AccessEditor’s ChoiceArticle

Mechanical, Structural, and Electrochemical Performance of Polyurethane Coatings for Corrosion Protection in Wind Energy Systems

by Oscar Xosocotla, María del Pilar Rodríguez-Rojas, Rafael Campos-Amezcua, Horacio Martínez, Victoria Bustos-Terrones and Oscar Guadarrama Pérez

Coatings 2025, 15(12), 1476; https://doi.org/10.3390/coatings15121476 - 15 Dec 2025

Cited by 3 | Viewed by 1042

Abstract

Erosion of the leading edge is one of the most severe forms of damage in wind turbine blades, particularly in offshore wind farms. This degradation, mainly caused by rain, sand, and airborne particles through droplet impingement wear, significantly decreases blade aerodynamic efficiency and [...] Read more.

Erosion of the leading edge is one of the most severe forms of damage in wind turbine blades, particularly in offshore wind farms. This degradation, mainly caused by rain, sand, and airborne particles through droplet impingement wear, significantly decreases blade aerodynamic efficiency and power output. Since blades, typically made of fiber-reinforced polymer composites, are the most expensive components of a turbine, developing protective coatings is essential. In this study, polyurethane (PU) composite coatings reinforced with titanium dioxide (TiO₂) particles were added on glass fiber substrates by spray coating. The incorporation of TiO₂ improved the mechanical and electrochemical performance of the PU coatings. FTIR and XRD confirmed that low TiO₂ loadings (1 and 3 wt%) were well dispersed within the PU matrix due to hydrogen bonding between TiO₂ –OH groups and PU –NH groups. The PU/TiO₂ 3% coating exhibited ~61% lower corrosion current density (I_corr) compared to neat PU, indicating superior corrosion resistance. Furthermore, uniform TiO₂ dispersion resulted in statistically significant improvements (p < 0.05) in hardness, yield strength, elastic modulus, and adhesion strength. Overall, the PU/TiO₂ coatings, particularly at 3 wt% loading, show strong potential as protective materials for wind turbine blades, given their enhanced mechanical integrity and corrosion resistance. Full article

(This article belongs to the Special Issue Recent Progress in Thin Films and Surfaces: Deposition, Characterization and Various Applications)

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37 pages, 15016 KB

Open AccessEditor’s ChoiceReview

Technical Analyses of Particle Impact Simulation Methods for Modern and Prospective Coating Spraying Processes

by Yi Wang and Sergii Markovych

Coatings 2025, 15(12), 1480; https://doi.org/10.3390/coatings15121480 - 15 Dec 2025

Cited by 1 | Viewed by 1155

Abstract

With the growing requirements for multi-particle process simulation, improving computational accuracy, efficiency, and scalability has become a critical challenge. This study generally focused on comprehensive analyses of existing numerical methods for simulating particle–substrate interactions in gas–thermal spraying (including gas–dynamic spraying processes), covering both [...] Read more.

With the growing requirements for multi-particle process simulation, improving computational accuracy, efficiency, and scalability has become a critical challenge. This study generally focused on comprehensive analyses of existing numerical methods for simulating particle–substrate interactions in gas–thermal spraying (including gas–dynamic spraying processes), covering both single-particle and multi-particle models to develop practical recommendations for the optimization of modern coating spraying processes. First of all, this paper systematically analyzes the key limitations of current approaches, including their inability to handle high deformations effectively or high computational complexity and their insufficient accuracy in dynamic scenarios. A comparative evaluation of four numerical methods (Lagrangian, Arbitrary Lagrangian–Eulerian (ALE), Coupled Eulerian–Lagrangian (CEL), and Smoothed Particle Hydrodynamics (SPH)) revealed their strengths and weaknesses in modeling of real gas–thermal spraying processes. Furthermore, this study identifies the limitations of the widely used Johnson–Cook (JC) constitutive model under extreme conditions. The authors considered the Zerilli–Armstrong (ZA), Mechanical Threshold Stress (MTS), and Preston–Tonks–Wallace (PTW) models as more realistic alternatives to the Jonson–Cook model. Finally, comparative analyses of theoretical and realistic deformation and defect-generation processes in gas–thermal coatings emphasize the critical need for fundamental changes in the simulation strategy for modern gas–thermal spraying processes. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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15 pages, 697 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Optical Properties at 1550 nm of Ion-Beam Sputtered Silicon Nitride Thin Films

by Diksha, Alex Amato, Gianluigi Maggioni, Christophe Michel, David Hofman, Massimo Granata and Jessica Steinlechner

Coatings 2025, 15(12), 1465; https://doi.org/10.3390/coatings15121465 - 10 Dec 2025

Viewed by 1360

Abstract

Coating Brownian thermal noise is a major limitation to the sensitivity of gravitational-wave detectors. To reduce it, future detectors are planned to operate at cryogenic temperatures. This implies a change of their mirror coating materials and the use of a longer laser wavelength, [...] Read more.

Coating Brownian thermal noise is a major limitation to the sensitivity of gravitational-wave detectors. To reduce it, future detectors are planned to operate at cryogenic temperatures. This implies a change of their mirror coating materials and the use of a longer laser wavelength, such as 1550 nm. A stack of amorphous silicon and silicon nitride layers has previously been proposed as a promising combination of low- and high-refractive index materials to realize low-noise highly-reflective coatings. An essential step towards such coatings is the production of both materials via ion-beam sputtering. In this paper, for the first time, we present a study of the optical properties at 1550 nm of silicon nitride thin films deposited via ion beam sputtering. The refractive index and optical absorption as a function of post-deposition heat treatment temperature are investigated using a spectrophotometer and a photo-thermal common-path interferometer. Finally, we discuss the prospect of combining this material with amorphous silicon. Full article

(This article belongs to the Section Thin Films)

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16 pages, 2645 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Direct Measurement of Effective Electrical Capacitance in Systems with a Constant-Phase Element Behavior Using the Example of Barrier Coatings

by Andrzej Miszczyk

Coatings 2025, 15(12), 1429; https://doi.org/10.3390/coatings15121429 - 5 Dec 2025

Cited by 5 | Viewed by 1589

Abstract

For various reasons, many dielectric and electrochemical systems exhibit behavior described by a constant-phase element (CPE) instead of a pure capacitor. However, in many applications, it is desirable to determine the electrical capacitance of such systems as a physically meaningful quantity. For this [...] Read more.

For various reasons, many dielectric and electrochemical systems exhibit behavior described by a constant-phase element (CPE) instead of a pure capacitor. However, in many applications, it is desirable to determine the electrical capacitance of such systems as a physically meaningful quantity. For this purpose, models are developed that allow for the conversion of the parameters of the studied system into the so-called effective electrical capacitance of the system. This study aims to replace model-based effective capacitance estimation with an approach based on direct measurements using electrochemical impedance spectroscopy (EIS). This approach utilizes the phenomenon of electrical resonance in the studied system. Using the described approach, the effective electrical capacitance of the coating system on steel was determined during over 300 h of exposure in Harrison’s solution. The CPE parameters were also determined during exposure. Using the Brasher–Kingbury equation, the kinetics of water absorption by the coating were compared using the obtained effective capacitance and the CPE parameter (pseudocapacitance). It was observed that using the effective capacitance yields significantly lower values of water content in the coating. The proposed method eliminates the uncertainty associated with speculative modeling and enables reliable tracking of the dielectric and electrochemical properties of systems, which is particularly important in batteries, supercapacitors, sensors, and protective coatings, where capacitance is a key indicator of performance and degradation. Full article

(This article belongs to the Special Issue Anti-Corrosion Coatings: New Ideas to Make Them More Effective)

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15 pages, 5434 KB

Open AccessEditor’s ChoiceArticle

Improving Boundary Lubrication of Phenolic-Based Coatings via Rare Earth Compound-Promoted Transfer Film Growth

by Guitao Li, Delong Wang, Huimin Qi and Ga Zhang

Coatings 2025, 15(12), 1417; https://doi.org/10.3390/coatings15121417 - 3 Dec 2025

Viewed by 670

Abstract

Polymer composite coatings are promising for tribological protection, with stable transfer films being key to their friction-reducing and anti-wear performance, yet the mechanism by which rare-earth compounds, known to enhance polymer tribological properties, regulate transfer film growth remains unclear. In this work, the [...] Read more.

Polymer composite coatings are promising for tribological protection, with stable transfer films being key to their friction-reducing and anti-wear performance, yet the mechanism by which rare-earth compounds, known to enhance polymer tribological properties, regulate transfer film growth remains unclear. In this work, the tribological performance of phenolic resin (PF)-based coatings filled with lanthanum oxide (La₂O₃) and lanthanum fluoride (LaF₃) was systematically investigated. The results demonstrate that the friction coefficients of 5La₂O₃/PF and 3LaF₃/PF decrease to 0.024 and 0.031, representing a 79.66% and 73.95% reduction compared to pure PF, which compensates for the inadequacy of oil lubrication. Tribochemical analyses and characterizations of tribofilm structures confirm that complex tribochemical reactions involving rare-earth compounds occur, promoting the growth of a solid-lubricating tribofilm at the boundary lubrication interface. This work provides a theoretical foundation for the design of high-performance polymer lubricating coatings. Full article

(This article belongs to the Special Issue Tribological and Corrosion Properties of the Surfaces)

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19 pages, 5883 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Pulse-Controlled Electrodeposition of Ni/ZrO₂ with Coumarin Additive: A Parametric Study

by Maria Myrto Dardavila and Constantina Kollia

Coatings 2025, 15(12), 1400; https://doi.org/10.3390/coatings15121400 - 1 Dec 2025

Viewed by 682

Abstract

Ni/ZrO₂ composite coatings are increasingly employed, yet the influence of organic additives under a pulse current regime on their electrodeposition remains insufficiently addressed. This study investigates the combined effect of pulse frequency (0.01–100 Hz) and coumarin concentration (0–2 mmol L⁻¹) [...] Read more.

Ni/ZrO₂ composite coatings are increasingly employed, yet the influence of organic additives under a pulse current regime on their electrodeposition remains insufficiently addressed. This study investigates the combined effect of pulse frequency (0.01–100 Hz) and coumarin concentration (0–2 mmol L⁻¹) on the co-deposition behavior, microstructure, and properties of Ni/ZrO₂ coatings electrodeposited from a Watts-type bath. The structural, morphological, and compositional features were analyzed through SEM/EDS, FE-SEM, and XRD, while microhardness and surface roughness were determined to establish processing–structure–property correlations. The results revealed that coumarin acts as an effective levelling agent, promoting smoother and finer-grained coatings while modifying ZrO₂ incorporation and Ni crystallographic orientation. Increasing coumarin concentration led to a notable refinement of nickel crystallites and a rise in hardness, reaching values close to 650 HV under optimal PC conditions. Pulse frequency was found to strongly influence the microstructural characteristics and particle co-deposition rates, particularly at low frequencies, where a balance between additive adsorption and current modulation favored particle incorporation and enhanced the microhardness. It was demonstrated that the synergistic control of pulse parameters and coumarin concentration enables the design of Ni/ZrO₂ composite coatings with tailored microstructure, low roughness, and superior hardness for demanding applications. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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24 pages, 8476 KB

Open AccessEditor’s ChoiceArticle

Ferroelectric Phase Stabilization and Charge-Transport Mechanisms in Doped HfO₂ Thin Films: Influence of Dopant Chemistry and Thickness

by Florin Năstase, Nicoleta Vasile, Silviu Vulpe, Cosmin Romanițan, Raluca Gavrilă, Oana Brîncoveanu, Lucia Monica Veca and Miron Adrian Dinescu

Coatings 2025, 15(12), 1396; https://doi.org/10.3390/coatings15121396 - 29 Nov 2025

Viewed by 1700

Abstract

Ferroelectricity in hafnium oxide (HfO₂)-based thin films has emerged as a scalable pathway toward CMOS-compatible non-volatile memories and logic devices. This study examines how dopant chemistry and film thickness influence the stabilization of the ferroelectric phase in ALD-grown HfO₂ thin [...] Read more.

Ferroelectricity in hafnium oxide (HfO₂)-based thin films has emerged as a scalable pathway toward CMOS-compatible non-volatile memories and logic devices. This study examines how dopant chemistry and film thickness influence the stabilization of the ferroelectric phase in ALD-grown HfO₂ thin films doped with Zr, Al, and Y. Structural, morphological, and electrical characterizations were carried out using AFM, GIXRD, P–E, in-plane I/W–E, and C–V measurements on films with thicknesses of 7 nm and 100 nm. AFM revealed atomically smooth and dense surfaces (R_q < 0.5 nm), while GIXRD confirmed the stabilization of the orthorhombic Pca2₁ phase in doped 7 nm films and its relaxation toward the monoclinic phase at 100 nm. The 7 nm HfZrO and HfYO films exhibited robust ferroelectric hysteresis with remanent polarization values up to 60 μC·cm⁻², whereas HfAlO showed a narrower but still distinct switching response. In-plane I/W–E characteristics indicated a combination of Poole–Frenkel and injection-limited conduction, consistent with defect-assisted polarization reversal and asymmetric contact barriers. At 100 nm, all films showed reduced polarization and partially dielectric behavior, as corroborated by the C–V data. These results demonstrate that nanoscale confinement, dopant-induced strain, and oxygen vacancy related defect chemistry collectively stabilize the orthorhombic ferroelectric phase, with Zr doping providing the most favorable balance between polarization strength and leakage control. Full article

(This article belongs to the Special Issue Recent Developments in Thin Films for Technological Applications)

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19 pages, 10290 KB

Open AccessEditor’s ChoiceArticle

Influence of Mo Content on the Microstructure and Mechanical Properties of Cu-Mo Composites Fabricated by Mechanical Alloying and Spark Plasma Sintering

by Jie Wu, Xiuqing Li and Qingxia Yang

Coatings 2025, 15(12), 1387; https://doi.org/10.3390/coatings15121387 - 27 Nov 2025

Cited by 1 | Viewed by 768

Abstract

In this work, Mo particles were incorporated into a Cu matrix, with the hope of retaining the advantageous properties of Cu while improving its mechanical performance. Mechanical ball milling was employed to fabricate Cu-Mo composite powders with different Mo concentrations; the Mo particles [...] Read more.

In this work, Mo particles were incorporated into a Cu matrix, with the hope of retaining the advantageous properties of Cu while improving its mechanical performance. Mechanical ball milling was employed to fabricate Cu-Mo composite powders with different Mo concentrations; the Mo particles were incorporated at mass fractions of 5%, 10%, 15%, and 20%, which were subsequently densified by spark plasma sintering (SPS) to achieve a high-density composite. Phase identification and microstructural analysis were performed using X-ray diffraction (XRD). Tensile strength, compressive strength, and Vickers hardness measurements were performed to evaluate the mechanical performance of the Cu-Mo composite. Microstructural characterization of the tensile specimen was conducted via electron backscatter diffraction (EBSD), energy dispersive X-ray spectroscopy (EDS), and field-emission scanning electron microscopy (FE-SEM). The results demonstrate a consistent decrease in grain size and a corresponding increase in density with higher Mo content in the composite. For Cu-15wt%Mo composite, the Vickers hardness is 135 HV, compressive strength is 300 MPa, and tensile strength is 371 MPa. Compared with pure Cu, they were increased by 74%, 115%, and 64%, respectively. The main strengthening mechanisms have been revealed. This research can offer a foundation and reference for designing and developing high-performance Cu-Mo composite. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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22 pages, 7329 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Investigation and Modelling of the Wear Resistance of Diamond Roller Dressers Made of Synthetic Diamonds with Mixed Grit Size

by Irina Aleksandrova and Hristian Mitev

Coatings 2025, 15(12), 1376; https://doi.org/10.3390/coatings15121376 - 24 Nov 2025

Cited by 2 | Viewed by 729

Abstract

The wear resistance of diamond dressing rolls depends on the manufacturing technology used and the characteristics of the working diamond layer, such as the type and grain size of the diamond grains, the type of bond, and the concentration and distribution of the [...] Read more.

The wear resistance of diamond dressing rolls depends on the manufacturing technology used and the characteristics of the working diamond layer, such as the type and grain size of the diamond grains, the type of bond, and the concentration and distribution of the diamonds. To optimise the lifetime of diamond rolls made of synthetic diamonds using the electroplating method, this paper proposes an innovative approach to compacting the intergranular spaces by treating them with diamond grains finer than the main fraction. To implement this approach, analytical dependencies were derived for the distance between the diamond grains. Intensive wear of the diamond roller bond was observed when the distance was exceeded as a result of contact with the abrasive grains of the grinding wheel. A ratio between the grain sizes of the main and additional diamond fractions is also recommended. Diamond roller dressers made of synthetic diamonds with a medium or high strength and a mixed grit size were created and their wear resistance was studied during the uni-directional and counter-directional dressing of electrocorundum grinding wheels using the plunge-grinding method. Theoretical and experimental models were constructed to predict the lifetime and the wear of diamond rolls in relation to the radial feed rate, the dressing speed ratio, the dress-out time, and the grit size ratio. Multi-objective optimisation based on a genetic algorithm was used to determine the optimal dressing conditions, ensuring the best combination of the maximum lifetime and minimum wear of the diamond rolls. The results obtained confirm the validity and correctness of the proposed approach for increasing the wear resistance of diamond roller dressers. Full article

(This article belongs to the Special Issue Fatigue and Wear Mechanisms of Different Surface Coatings for Industrial Application)

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18 pages, 3647 KB

Open AccessFeature PaperEditor’s ChoiceArticle

The Amorphous Carbon Layers Deposited by Various Magnetron Sputtering Techniques

by Rafal Chodun, Lukasz Skowronski, Marek Trzcinski, Dobromil Zaloga, Katarzyna Nowakowska-Langier, Piotr Domanowski and Krzysztof Zdunek

Coatings 2025, 15(12), 1367; https://doi.org/10.3390/coatings15121367 - 22 Nov 2025

Cited by 2 | Viewed by 973

Abstract

This study investigates the synthesis and characterization of amorphous carbon (a-C) layers using three magnetron sputtering (MS) techniques: Pulsed MS (PMS), Gas Injection MS (GIMS), and High Power GIMS (HiPGIMS). The primary objective was to understand how these methods influence the sp³ [...] Read more.

This study investigates the synthesis and characterization of amorphous carbon (a-C) layers using three magnetron sputtering (MS) techniques: Pulsed MS (PMS), Gas Injection MS (GIMS), and High Power GIMS (HiPGIMS). The primary objective was to understand how these methods influence the sp³/sp² hybridization ratio, a critical parameter for tailoring the properties of amorphous carbon. Plasma diagnostics via Optical Emission Spectroscopy revealed distinct discharge characteristics, with HiPGIMS exhibiting the highest current density and plasma ionization. Structural and compositional analyses using Raman Spectroscopy and X-ray Photoelectron Spectroscopy (XPS) demonstrated a clear trend: sp³ content increased significantly from PMS to GIMS to HiPGIMS, reaching up to 50% (Raman) and 39% (XPS). This enhancement is attributed to the higher plasma density and more energetic ion bombardment in HiPGIMS, which promotes the formation of sp³ bonds. Ellipsometric spectroscopy further supported these findings, showing that HiPGIMS produced layers with the widest bandgap, indicative of higher sp³ content. The research highlights the effectiveness of advanced MS techniques, particularly HiPGIMS, in precisely controlling the sp³/sp² ratio and thereby the electrical, optical, and mechanical properties of a-C layers for various applications. Full article

(This article belongs to the Special Issue Present Status of Thin Films and Coatings Fabricated by Magnetron Sputtering)

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16 pages, 4514 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Investigation of Scaling and Materials’ Performance of EHLA-Fabricated Cladding in Simulated Geothermal Brine

by David Martelo, Erfan Abedi Esfahani, Namrata Kale, Tomaso Maccio and Shiladitya Paul

Coatings 2025, 15(12), 1366; https://doi.org/10.3390/coatings15121366 - 22 Nov 2025

Cited by 3 | Viewed by 1101

Abstract

This study investigates the corrosion and scaling behaviour of Extreme High-speed Laser Application (EHLA)-fabricated corrosion-resistant alloy (CRA) claddings under simulated geothermal brine conditions. EHLA 316L stainless steel and alloy 625 coatings were produced and tested in simulated brine (chloride–carbonate–silica geothermal brine) at 70 [...] Read more.

This study investigates the corrosion and scaling behaviour of Extreme High-speed Laser Application (EHLA)-fabricated corrosion-resistant alloy (CRA) claddings under simulated geothermal brine conditions. EHLA 316L stainless steel and alloy 625 coatings were produced and tested in simulated brine (chloride–carbonate–silica geothermal brine) at 70 °C for 720 h to evaluate the influence of additive manufacturing (AM) microstructures on corrosion performance. The EHLA coatings exhibited dense, metallurgically bonded microstructures with minimal porosity. Microstructural analysis revealed Nb- and Mo-rich segregation in EHLA 625 and fine columnar dendritic morphology in all coatings. EHLA 625 developed a stable passive film with only a thin deposit of Mg-O-containing compounds, whereas EHLA 316L exhibited localised pitting and significant Si- and Mg-containing scale accumulation, especially in as-built conditions. Surface finishing reduced corrosion activity by minimising roughness and defect-driven localised attack. Critical pitting temperature (CPT) tests confirmed the superior localised corrosion resistance of EHLA 625 relative to EHLA 316L under laboratory conditions. While these results indicate promising corrosion and scaling resistance of EHLA coatings, further process optimisation and post-deposition thermal treatments might be required to achieve coating performance comparable to wrought alloys. The results indicate the potential of EHLA-fabricated coatings for producing corrosion and scaling resistance surfaces. Full article

(This article belongs to the Special Issue Engineered Coatings for a Sustainable Future)

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17 pages, 6617 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Ultrahigh-Speed Deposition of Diamond-like Carbon on a Pipe Surface Using a Scanning Deposition Method via Local High-Density Plasma

by Akihiko Ito, Masahiro Esaki, Su-Min Bae, Taketo Nagai, Hiroyuki Kousaka and Toru Harigai

Coatings 2025, 15(11), 1348; https://doi.org/10.3390/coatings15111348 - 19 Nov 2025

Viewed by 618

Abstract

This study presents a highly effective method for depositing diamond-like carbon (DLC) films onto pipe substrates using a scanning deposition by plasma enhanced chemical vapor deposition. A microwave–sheath voltage combination plasma was employed to generate local high-density plasma along a rotating pipe. While [...] Read more.

This study presents a highly effective method for depositing diamond-like carbon (DLC) films onto pipe substrates using a scanning deposition by plasma enhanced chemical vapor deposition. A microwave–sheath voltage combination plasma was employed to generate local high-density plasma along a rotating pipe. While conventional contact-mode deposition using a metal contactor suffers from arcing and surface damage due to unstable sliding contact during rotation, a non-contact deposition using a metal antenna was developed to overcome these limitations. Electromagnetic field simulations were conducted to evaluate microwave power absorption in various antenna geometries, showing that the flat-plate antenna demonstrated the most effective power coupling. Subsequent scanning deposition experiments to a rotating pipe using flat-plate antennas of different lengths revealed that the 100 mm configuration achieved the highest deposition volume rate (exceeding that of the contact-mode) while avoiding arcing. Optical emission observations during deposition confirmed the formation of high-density plasma surrounding the flat-plate antenna and Raman spectroscopy of the deposited film showed typical spectra of DLC films. The deposition rates of DLC-coated pipe showed no significant variation with respect to rotational angle, suggesting that rotation during deposition contributes to achieving uniform film thickness along the circumferential direction of the pipe. Full article

(This article belongs to the Special Issue Plasma Coating and Interface Technology: New Horizons in Surface Science)

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