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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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21 pages, 3617 KB  
Article
Numerical and Experimental Study of Enhanced Heat Dissipation Performance of Graphene-Coated Heating Cables
by Zhenzhen Chen, Chenchen Xu, Feilong Zhang and Tao Sun
Coatings 2025, 15(7), 777; https://doi.org/10.3390/coatings15070777 - 30 Jun 2025
Viewed by 1198
Abstract
Low-temperature radiant heating systems utilizing heating cables face challenges including low heat dissipation efficiency and high energy consumption, hindering widespread application. Graphene coatings, characterized by high thermal conductivity and far-infrared radiation properties, offer a novel approach to enhance cable heat dissipation efficiency. This [...] Read more.
Low-temperature radiant heating systems utilizing heating cables face challenges including low heat dissipation efficiency and high energy consumption, hindering widespread application. Graphene coatings, characterized by high thermal conductivity and far-infrared radiation properties, offer a novel approach to enhance cable heat dissipation efficiency. This study systematically investigates the effects of coating position, thickness, and ambient temperature on cable heat dissipation using numerical simulations and experiments. A three-dimensional heat transfer model of the heating cable was established using Fluent software (2022R1). The radiation heat transfer equation was solved using the Discrete Ordinates (DO) model, and the coating position and thickness parameters were optimized. The reliability of the simulation results was validated using a temperature-rise experimental platform. The results indicate that graphene coatings significantly improve the heat dissipation performance of cables. Under optimal parameters (coating thickness: 100 μm, coating position: aluminum fin surface, initial temperature: 5 °C), the heat flux increased by approximately 26%, aluminum fin surface temperature decreased to 41.5 °C, and experimental temperature-rise efficiency improved by nearly 50%. The discrepancy between simulated and experimental results was within 8.5%. However, when coating thickness exceeded 100 μm, interfacial thermal resistance increased, reducing heat dissipation efficiency. Additionally, higher ambient temperatures suppressed heat dissipation. These findings provide a theoretical basis for optimizing the energy efficiency of low-temperature radiant heating systems. Full article
(This article belongs to the Section Surface Characterization, Deposition and Modification)
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29 pages, 897 KB  
Article
Identification of Potential Migrants in Food Contact Materials Labeled as Bio-Based and/or Biodegradable by GC-MS
by Emma López Sanvicente, Letricia Barbosa-Pereira, Raquel Sendón, Ana Rodríguez Bernaldo de Quirós and Antía Lestido-Cardama
Coatings 2025, 15(7), 751; https://doi.org/10.3390/coatings15070751 - 25 Jun 2025
Viewed by 3188
Abstract
Bio-based and/or biodegradable food contact materials are being developed as alternatives to conventional petroleum-based materials. Like other food contact materials, these are subject to regulatory requirements. The characterization of these biomaterials enables the identification of chemical substances that could potentially migrate from these [...] Read more.
Bio-based and/or biodegradable food contact materials are being developed as alternatives to conventional petroleum-based materials. Like other food contact materials, these are subject to regulatory requirements. The characterization of these biomaterials enables the identification of chemical substances that could potentially migrate from these materials into food and may pose a risk to consumer health. In this work, commercial samples of food contact materials labeled as bio-based and/or biodegradable were analyzed. To tentatively identify compounds, two analytical methods were optimized: purge and trap (P&T) for volatile compounds and methanolic extract injection for the determination of semi-volatile compounds, both using gas chromatography coupled with mass spectrometry (GC-MS). Compound toxicity was estimated using an in silico methodology, namely Cramer’s rules. More than 200 compounds of different natures were tentatively identified, but only 29 are included in Regulation (EU) 10/2011 on plastic materials intended to come into contact with food, and 38 of them were classified as high-toxicity compounds. Full article
(This article belongs to the Special Issue Bio-Based and Biodegradable Packaging Materials for Food Contact)
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13 pages, 6374 KB  
Article
Synthesis of (Bi2O3)1-x(PbO)x Thin Films by Plasma-Assisted Reactive Evaporation
by Aleksandras Iljinas, Vytautas Stankus, Darius Virbukas and Remigijus Kaliasas
Coatings 2025, 15(7), 748; https://doi.org/10.3390/coatings15070748 - 24 Jun 2025
Cited by 2 | Viewed by 957
Abstract
Thin, dense and nanocrystal bismuth oxide films were prepared by the in situ plasma-assisted reactive evaporation (ARE) method using lead doping. Thin films were deposited at room temperature and at 500 °C temperature on glass and silicon substrates. X-ray diffraction, SEM, EDS, and [...] Read more.
Thin, dense and nanocrystal bismuth oxide films were prepared by the in situ plasma-assisted reactive evaporation (ARE) method using lead doping. Thin films were deposited at room temperature and at 500 °C temperature on glass and silicon substrates. X-ray diffraction, SEM, EDS, and optical measurements were applied to characterize these bismuth oxide films. The results showed that it is possible to synthesize the δ-Bi2O3 phase thin films at a temperature lower than 729 °C using an plasma-assisted reactive evaporation (ARE) method and stabilize it (to room temperature) using the additives of lead oxide. The influence of lead oxide concentration on phase formation was investigated. The optimal amount of lead oxide dopant was determined. An excess of lead oxide concentration forms PbO and δ-Bi2O3 mixture phases and nanorods appear in films. The synthesized δ-Bi2O3 phase was metastable; it transformed into the β-Bi2O3 phase after thermal impact during impedance measurements. The cross section of thin film sample shows the dense and monolithic structure. Optical measurements show that the optical band gap increases with increasing lead concentration. It was found that the highest total ionic conductivity of (Bi1−xPb0.26)2O3 is 0.165 S/cm at 1073 K temperature and activation energy is ΔEtot = 0.5 eV. Full article
(This article belongs to the Special Issue Advances in Novel Coatings)
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17 pages, 4465 KB  
Article
Sustainable Use of Expired Metoprolol as Corrosion Inhibitor for Carbon Steel in Saline Solution
by Mircea Laurențiu Dan, Nataliia Rudenko, Cristian George Vaszilcsin and George-Daniel Dima
Coatings 2025, 15(7), 742; https://doi.org/10.3390/coatings15070742 - 22 Jun 2025
Viewed by 1069
Abstract
The current paper examines the sustainable possibility for recycling unused or expired Metoprolol (MET), a benzodiazepine derivative, as an effective corrosion inhibitor for carbon steel in saline solutions. Repurposing expired medicinal drugs aligns with green chemistry concepts and supports circular economy initiatives by [...] Read more.
The current paper examines the sustainable possibility for recycling unused or expired Metoprolol (MET), a benzodiazepine derivative, as an effective corrosion inhibitor for carbon steel in saline solutions. Repurposing expired medicinal drugs aligns with green chemistry concepts and supports circular economy initiatives by reducing pharmaceutical waste and averting the production of new synthetic inhibitors. The technical benefit of recycling expired MET drugs pertains to the elimination of costs associated with organic inhibitor manufacturing and the decrease in disposal expenses for the expired medication. A combination of electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy) and quantum chemical calculations was employed to evaluate the inhibitory mechanism and efficacy of MET. At a concentration of 10−3 M, MET reduced the corrosion current density from 19.38 to 5.97 μA cm−2, achieving a maximum IE of 69.1%. Adsorption Gibbs free energy, determined using different adsorption isotherms, revealed that interactions between metal atoms and MET adsorbed molecules have a chemical character with a ∆Goads value of −50.7 kJ·mol−1. Furthermore, quantum chemistry calculations indicate that the investigated drug, owing to its molecular structure (EHOMO = −9.12 eV, ELUMO = 0.21 eV, µ = 3.95 D), possesses the capacity to establish an adsorption layer on the metal surface, thereby impeding the diffusion of molecules and ions involved in the overall corrosion process. The results obtained using the different techniques were in good agreement and highlighted the effectiveness of MET in the corrosion inhibition of carbon steel. Full article
(This article belongs to the Special Issue Sustainable and Environmentally Friendly Technologies for Advanced Functional Coatings and Materials)
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15 pages, 4154 KB  
Article
Femtosecond Laser-Modulated Oxygen Vacancies in LiFePO4 Thick Electrodes for Rapid Ion Transport
by Xiaowei Han, Lu Chen, Hongshui Wang, Ban Chen, Tai Yang, Donghui Wang and Chunyong Liang
Coatings 2025, 15(7), 738; https://doi.org/10.3390/coatings15070738 - 20 Jun 2025
Cited by 1 | Viewed by 952
Abstract
Although thick electrodes hold significant potential for enhancing battery energy density, their practical application is limited by restricted ion transport kinetics. Constructing porous structures within thick electrodes is a widely adopted strategy to address this limitation, but it often compromises mass retention and [...] Read more.
Although thick electrodes hold significant potential for enhancing battery energy density, their practical application is limited by restricted ion transport kinetics. Constructing porous structures within thick electrodes is a widely adopted strategy to address this limitation, but it often compromises mass retention and mechanical integrity. In this study, a microchannel structure that balances the electrochemical and mechanical properties of the electrode was identified through simulation and precisely fabricated using femtosecond laser technology. Furthermore, the ultra-short pulse duration and high pulse energy of femtosecond lasers introduce oxygen vacancies into the electrode material, thereby enhancing its electrical conductivity. The obtained electrode exhibited excellent electrochemical performance under high-rate charging and discharging conditions, achieving significantly enhanced cycling stability and capacity retention, with a capacity 1.99 times greater than that of the unstructured electrode after 100 cycles. Meanwhile, the mechanical stability of the laser-processed electrode was maintained. This study provides new insights into the structural design and processing of the thick electrode and contributes to advancements in the field of energy storage. Full article
(This article belongs to the Special Issue Electrodes and Coatings for Energy Storage Applications: Batteries and Supercapacitors)
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20 pages, 14981 KB  
Article
Multi-Scale Modelling of Residual Stress on Arbitrary Substrate Geometry in Atmospheric Plasma Spray Process
by Jose Martínez-García, Venancio Martínez-García and Andreas Killinger
Coatings 2025, 15(6), 723; https://doi.org/10.3390/coatings15060723 - 17 Jun 2025
Viewed by 993
Abstract
This work presents an exhaustive parametric study of the multi-scale residual stress analysis on arbitrary substrate geometry based on a one-way-coupled thermo-mechanical model in an Atmospheric Plasma Spray process. It was carried out by modifying key process parameters, such as substrate surface geometry, [...] Read more.
This work presents an exhaustive parametric study of the multi-scale residual stress analysis on arbitrary substrate geometry based on a one-way-coupled thermo-mechanical model in an Atmospheric Plasma Spray process. It was carried out by modifying key process parameters, such as substrate surface geometry, substrate pre-heating temperature, and coating thickness, in an Al2O3 coating process on an aluminium substrate. The relationship of these parameters to the generation of quenching stress, thermal stress and residual stress was analysed at three different sub-modelling scales, from the macroscopic dimension of the substrate to the microscopic dimension of the splats. The thermo-mechanical phenomena occurring during the deposition process at the microscopic level were discussed in the proposed cases. Understanding these phenomena helps to optimise the parameters of the coating process by identifying the underlying mechanisms responsible for the generation of residual stresses. The simulated residual stresses of the 200 μm Al2O3 outer coated aluminium cylinder were experimental validated using the incremental high-speed micro-hole drilling and milling method. Full article
(This article belongs to the Special Issue Advances in Surface Coatings for Wear and Corrosion Protection)
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18 pages, 3833 KB  
Article
Protective ALD Thin Films for Morphologically Diverse Types of Limestone
by Gillian P. Boyce, Suveena Sreenilayam, Eleonora Balliana, Elisabetta Zendri and Raymond J. Phaneuf
Coatings 2025, 15(6), 698; https://doi.org/10.3390/coatings15060698 - 10 Jun 2025
Viewed by 836
Abstract
We report on the results of investigations of atomic layer deposited (ALD) amorphous alumina (Al2O3) coatings for the protection of limestone with a wide range of porosity against acid-based dissolution. The protective effects of the ALD coatings were investigated [...] Read more.
We report on the results of investigations of atomic layer deposited (ALD) amorphous alumina (Al2O3) coatings for the protection of limestone with a wide range of porosity against acid-based dissolution. The protective effects of the ALD coatings were investigated by aqueous acid immersion. The solution pH was tracked over time for a constant volume of acetic acid solution with an initial pH of 4 with the stone samples immersed. We find the protective effect of ALD alumina coatings is extremely promising, with 90 nm thick coatings slowing the initial and total rate of substrate mass loss significantly by up to two orders of magnitude. The eventual failure of the ALD coatings during immersion was also investigated. Pitted areas on the substrate were discovered and were found to have an area fraction that correlates to the changing pH of the acid solution during immersion. The variation of the protective action of the films with thickness is consistent with kinetics, which are limited by diffusion within the pits rather than through the films. Our findings point to the dominant role of defects in the coatings in their eventual failure. We also show that the appearance of the stone does not change significantly for the thickest and most protective ALD films, making the treatment promising for cultural heritage applications. Full article
(This article belongs to the Special Issue Advanced Coating Material for Heritage Preservation, 2nd Edition)
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20 pages, 6756 KB  
Article
Optimization of Film Thickness Uniformity in Hemispherical Resonator Coating Process Based on Simulation and Reinforcement Learning Algorithms
by Jingyu Pan, Dongsheng Zhang, Shijie Liu, Jianguo Wang and Jianda Shao
Coatings 2025, 15(6), 700; https://doi.org/10.3390/coatings15060700 - 10 Jun 2025
Viewed by 1070
Abstract
Hemispherical resonator gyroscopes (HRGs) are critical components in high-precision inertial navigation systems, typically used in fields such as navigation, weaponry, and deep space exploration. Film thickness uniformity affects device performance through its impact on the resonator’s Q value. Due to the irregular structure [...] Read more.
Hemispherical resonator gyroscopes (HRGs) are critical components in high-precision inertial navigation systems, typically used in fields such as navigation, weaponry, and deep space exploration. Film thickness uniformity affects device performance through its impact on the resonator’s Q value. Due to the irregular structure of the resonator, there has been limited research on the uniformity of film thickness on the inner wall of the resonator. This study addresses the challenge of thickness non-uniformity in metallization coatings, particularly in the meridional direction of the resonator. By integrating COMSOL-based finite element simulations with reinforcement learning-driven optimization through the Proximal Policy Optimization (PPO) algorithm, a new paradigm for coating process optimization is established. Furthermore, a correction mask is designed to address the issue of low coating rate. Finally, a Zygo white-light interferometer is used to measure film thickness uniformity. The results show that the optimized coating process achieves a film thickness uniformity of 11.0% in the meridional direction across the resonator. This study provides useful information and guidelines for the design and optimization of the coating process for hemispherical resonators, and the presented optimization method constitutes a process flow framework that can also be used for precision coating engineering in semiconductor components and optical elements. Full article
(This article belongs to the Special Issue AI-Driven Surface Engineering and Coating)
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13 pages, 4643 KB  
Article
Optimizing Substrate Bias to Enhance the Microstructure and Wear Resistance of AlCrMoN Coatings via AIP
by Haoqiang Zhang, Jia Liu, Xiran Wang, Chengxu Wang, Haobin Sun, Hua Zhang, Tao Jiang, Hua Yu, Liujie Xu and Shizhong Wei
Coatings 2025, 15(6), 673; https://doi.org/10.3390/coatings15060673 - 1 Jun 2025
Viewed by 731
Abstract
In this work, arc ion plating (AIP) was employed to deposit AlCrMoN coatings on cemented carbide substrates, and the effects of substrate bias voltages (−80 V, −100 V, −120 V, and −140 V) on the microstructures, mechanical properties, and tribological behaviors of the [...] Read more.
In this work, arc ion plating (AIP) was employed to deposit AlCrMoN coatings on cemented carbide substrates, and the effects of substrate bias voltages (−80 V, −100 V, −120 V, and −140 V) on the microstructures, mechanical properties, and tribological behaviors of the coatings were investigated. The results showed that all AlCrMoN coatings exhibited a single-phase face-centered cubic (FCC) structure with columnar crystal growth and excellent adhesion to the substrate. As the negative bias voltage increased, the grain size of the coatings first decreased and then increased, while the hardness and elastic modulus showed a trend of first increasing and then decreasing, with the maximum hardness reaching 36.2 ± 1.33 GPa. Room-temperature ball-on-disk wear tests revealed that all four coatings demonstrated favorable wear resistance. The coating deposited at −100 V exhibited the lowest average friction coefficient of 0.47 ± 0.02 and wear rate ((3.27 ± 0.10) × 10−8 mm3/(N∙m)), featuring a smooth wear track with minimal oxide debris. During the steady-state wear stage, the dominant wear mechanisms of the AlCrMoN coatings were identified as oxidative wear combined with abrasive wear. Full article
(This article belongs to the Special Issue Multi-Principal Element Alloy Design and Surface Modification Technology)
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12 pages, 3151 KB  
Article
Photocurrent Generation and Collection in a WSe2-Based Composite Detector
by Yulin Zhu, Sheng Ni, Fengyi Zhu, Zhenzhi Hu, Changyi Pan, Xuhao Fan, Yuhang Ma, Shian Mi, Changlong Liu, Weiwei Tang, Guanhai Li and Xiaoshuang Chen
Coatings 2025, 15(6), 672; https://doi.org/10.3390/coatings15060672 - 31 May 2025
Cited by 1 | Viewed by 1642
Abstract
Two-dimensional (2D) van der Waals materials have been actively investigated for broadband, high-sensitivity, low-power-consumption photodetection owing to their highly customizable band structures and fast interfacial charge transfers. Studying photocurrent generation mechanisms provides insights into charge carrier dynamics in WSe2-based detectors, linking [...] Read more.
Two-dimensional (2D) van der Waals materials have been actively investigated for broadband, high-sensitivity, low-power-consumption photodetection owing to their highly customizable band structures and fast interfacial charge transfers. Studying photocurrent generation mechanisms provides insights into charge carrier dynamics in WSe2-based detectors, linking spatial factors (e.g., photocurrent generation/collection) with interfacial band alignment. Here, we employ scanning photocurrent microscopy to spatially resolve the processes of photocurrent generation and collection in WSe2-based composite structures. Photocurrent polarity and magnitude at interface reflects interfacial band alignment and potential gradients at metal–WSe2 and WSe2–In2Se3 junctions. Strong electric fields at metal–WSe2 interfaces drive more efficient electron–hole separation and yield higher photocurrents, compared with WSe2–In2Se3 interfaces. The photodetector exhibits broadband detection capabilities from visible to infrared light, achieving a high responsivity of 17.7 A/W and an excellent detectivity of 3.7 × 1012 Jones, as well as fast response times of <113 µs. Furthermore, object imaging with a resolution better than 0.5 mm was successfully demonstrated, highlighting the potential of this photoresponse for practical imaging applications. This work reveals that photocurrent is distributed with a clear dependence on device configuration, offering a new avenue for optimizing 2D material-based photoelectric devices. Full article
(This article belongs to the Special Issue Metasurfaces and Low-Dimensional Materials for Photonic and Optoelectronic Applications)
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13 pages, 5966 KB  
Article
Effect of Nb on Laves Phase Formation and Wear Resistance in Laser-Cladding CrFeNi Medium-Entropy Alloy Coatings
by Zehuan Chen, Fangyan Luo, Hongtao Jin, Zhen Peng, Wenqing Shi and Jiang Huang
Coatings 2025, 15(6), 667; https://doi.org/10.3390/coatings15060667 - 30 May 2025
Cited by 1 | Viewed by 997
Abstract
In this study, 20 wt.% of Nb was incorporated into a CrFeNi medium-entropy alloy (MEA) powder system to prepare CrFeNi-Nb composite coatings on a Q235B mild steel substrate by laser cladding technology. The effects of Nb addition on the phase composition, microstructure, and [...] Read more.
In this study, 20 wt.% of Nb was incorporated into a CrFeNi medium-entropy alloy (MEA) powder system to prepare CrFeNi-Nb composite coatings on a Q235B mild steel substrate by laser cladding technology. The effects of Nb addition on the phase composition, microstructure, and wear resistance of CrFeNi coatings were systematically investigated. Microstructural characterization revealed that the CrFeNi coating exhibited a single face-centered cubic (FCC) phase structure, while the CrFeNi-Nb composite coating demonstrated a dual-phase structure comprising FCC phase and Laves phase. The Laves phase significantly enhanced the microhardness and wear resistance of the coating. The average microhardness of the CrFeNi-Nb coating increased by 259.62% compared to the substrate and 190.58% compared to the Nb-free CrFeNi coating. The average coefficient of friction (COF) of the coating decreased from 0.74 to 0.68; the wear rate reduced from 5.77 × 10−4 mm3 N−1 m−1 to 2.26 × 10−4 mm3 N−1 m−1; and the weight loss decreased from 10.77 mg to 4.3 mg. The experimental results demonstrated that the addition of Nb promoted the formation of the Laves phase in the CrFeNi MEA, which effectively improved the wear resistance of the coating. Full article
(This article belongs to the Special Issue Effects of Laser Treatment on Surface Characterization and Mechanical Properties of Alloys, 2nd Edition)
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21 pages, 4658 KB  
Article
Potentiostatic Plasma Electrolytic Oxidation (PEO) of Aluminum Alloy AA6082: Effect of Electrical Input on Coating Microstructure and Corrosion Resistance
by Alberto Berardi, Matteo Gamba, Luca Paterlini, Federica Ceriani and Marco Ormellese
Coatings 2025, 15(6), 653; https://doi.org/10.3390/coatings15060653 - 29 May 2025
Cited by 1 | Viewed by 1470
Abstract
Aluminum alloy AA6082 (Al-Si-Mg) is a lightweight alloy that requires thick barrier coatings to be protected from localized corrosion. Plasma Electrolytic Oxidation (PEO) coating is a common anodic surface treatment used for growing protective oxides; the main process variables of PEO are the [...] Read more.
Aluminum alloy AA6082 (Al-Si-Mg) is a lightweight alloy that requires thick barrier coatings to be protected from localized corrosion. Plasma Electrolytic Oxidation (PEO) coating is a common anodic surface treatment used for growing protective oxides; the main process variables of PEO are the composition of the electrolytic solution and the electrical input. This work focuses on the optimization of the electrical input by comparing different coatings produced by potentiostatic PEO at the effective potential of 350 V, applied by different combinations of voltage ramps with various slopes and maintenance times at the fixed potential. All processes lasted five minutes. The innovative character of this research work is the evaluation of the combined effect of the anodizing voltage and its different trends with time on the coating structure and morphology. The corrosion resistance of coated AA6082 is assessed in contact with chlorides, reproducing seawater. The resulting anodic coatings were compared in terms of structure, composition (thickness, XRD, SEM-EDS) and corrosion resistance (potentiodynamic polarization and electrochemical impedance spectroscopy), finding that longer maintenance at high anodizing potentials promotes localized high-energy plasma discharges, producing larger pores and thicker, but less protective coatings. Results show that the coating thickness increases with the maintenance time (maximum thickness value~17.6 μm). Shorter maintenance periods and longer voltage ramps lead to a lower surface porosity and enhanced corrosion performances of the oxide. The thinnest and least porous coating exhibits the best corrosion behavior (CR~1.1 μm/year). Full article
(This article belongs to the Special Issue Tribomechanical and Corrosion Tests for Advanced Surface Characterization)
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19 pages, 15431 KB  
Article
Effect of Fe2O3@SiO2 Core–Shell Nanoparticle Doping Ratio on Color Appearance of Synthetic Opal Films Inspired by Natural Fire Opal
by Bowen Li and Andy Hsitien Shen
Coatings 2025, 15(6), 646; https://doi.org/10.3390/coatings15060646 - 27 May 2025
Cited by 1 | Viewed by 1323
Abstract
Synthetic opal-based photonic materials with tunable optical properties not only exhibit significant application potential but also provide valuable models in terms of understanding color formation mechanisms in natural gemstones. Inspired by natural fire opals containing small amounts of Fe2O3 nanoparticle [...] Read more.
Synthetic opal-based photonic materials with tunable optical properties not only exhibit significant application potential but also provide valuable models in terms of understanding color formation mechanisms in natural gemstones. Inspired by natural fire opals containing small amounts of Fe2O3 nanoparticle inclusions (0 wt%~0.23 wt%), we fabricated short-range ordered opal films doped with low concentrations (0 wt%~2.00 wt%) of Fe2O3@SiO2 core–shell nanoparticles using a modified vertical deposition method. The Fe2O3@SiO2 nanoparticles were synthesized via a sol–gel process to encapsulate the Fe2O3 core with a 10-nm-thick SiO2 shell, preventing agglomeration and enhancing the chemical stability. Experimental results show that even small amounts of doping significantly affect the reflection peak intensity of the films, leading to notable color appearance changes. Combined with numerical simulations, we attribute this modulation to both light absorption and backward scattering effects introduced by the doped nanoparticles. Moreover, the numerical simulation results for Fe2O3 nanoparticles and Fe2O3@SiO2 nanoparticles (with a 10 nm silica shell and similar particle size) show comparable optical properties, suggesting that such inclusions may contribute similarly to the color formation mechanisms in natural fire opals. This work demonstrates that low-concentration Fe2O3@SiO2 NP doping provides an effective strategy to tune the color appearance of opal films, with implications for both structural color material development and gemological research. Full article
(This article belongs to the Special Issue Modification and Technology of Nanoparticles and Thin Films)
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17 pages, 2733 KB  
Article
Study on the Mechanism and Control Technology of Biodeterioration at the Sanyangzhuang Earthen Site
by Xiang Chang, Yu Ye, Qingwen Ma, Haitao Yan, Zhining Li and Fang Guo
Coatings 2025, 15(5), 617; https://doi.org/10.3390/coatings15050617 - 21 May 2025
Viewed by 802
Abstract
Biodeterioration poses a significant challenge in the conservation of cultural heritage, particularly for earthen sites in humid environments, which are highly susceptible due to their inherent material properties. To address the diverse biological threats affecting such sites, we developed a novel broad-spectrum biocide, [...] Read more.
Biodeterioration poses a significant challenge in the conservation of cultural heritage, particularly for earthen sites in humid environments, which are highly susceptible due to their inherent material properties. To address the diverse biological threats affecting such sites, we developed a novel broad-spectrum biocide, FACA, formulated by combining phenylcarbamoylthiazoles and isothiaquinolones to achieve triple efficacy: antimicrobial, anti-algal, and anti-lichen effects. Laboratory assessments demonstrated FACA’s rapid efficacy in eliminating molds, algae, and lichens. A 12-month field application at the Sanyangzhuang earthen site (Neihuang, Henan) yielded excellent results, confirming long-term protection against biological colonization without recurrence. Crucially, the treatment exhibited no adverse effects on the earthen sites, enabling sustainable coexistence between the heritage site and its surrounding ecosystem. These findings support the applicability of FACA for surface treatment across various humid earthen archeological sites. Full article
(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)
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17 pages, 1888 KB  
Article
Effects of Coating Thickness and Aggregate Size on the Damping Properties of Concrete: A Numerical Simulation Approach
by Yisihak Gebre Tarekegn, Tom Lahmer, Abrham Gebre Tarekegn and Esayas Gebreyouhannes Ftwi
Coatings 2025, 15(5), 610; https://doi.org/10.3390/coatings15050610 - 21 May 2025
Cited by 2 | Viewed by 839
Abstract
Concrete properties are investigated using intensive physical testing processes that require large amounts of labor and materials that are costly and time-consuming. Properly validated computer models can replace most of the existing physical testing procedures with computer simulations that are relatively quick and [...] Read more.
Concrete properties are investigated using intensive physical testing processes that require large amounts of labor and materials that are costly and time-consuming. Properly validated computer models can replace most of the existing physical testing procedures with computer simulations that are relatively quick and inexpensive. Therefore, in this study, the effects of coating thickness and aggregate size on the damping properties of concrete were investigated using numerical simulation with Abaqus/CAE 6.14-1 software. Two different groups of aggregates were used in the simulation, with maximum aggregate sizes of 25 mm and 32 mm. The coating thickness ranged from 0.4 mm to 5.0 mm, using epoxy, silicone, and rubber coatings. The results showed that coatings with smaller aggregate size led to an increase in the damping ratio compared to those with larger aggregate size. Moreover, replacing 20% of coarse aggregates with rubber-coated aggregates results in a damping ratio of 5.75% to 6.21%, reflecting an increase of 22.8% to 32.7%. This variation occurs with coating thicknesses ranging from 0.4 mm to 5.0 mm, with the optimal thickness of 5.0 mm leading to the maximum increase (32.7%) in the damping ratio of concrete. Full article
(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)
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16 pages, 4581 KB  
Article
PLA-Based Green Antimicrobial and Flame-Retardant Biocomposites Reinforced with Sida hermaphrodita Fibers
by Sandra Bischof, Tea Bušac, Tomislav Ivanković, Sabine Rolland du Roscoat, Bratislav Lukic and Zorana Kovačević
Coatings 2025, 15(5), 595; https://doi.org/10.3390/coatings15050595 - 17 May 2025
Cited by 2 | Viewed by 1193
Abstract
Enhanced demand for the development of sustainable materials has generated significant research interest in products containing biomass-derived fibers, such as the fibers extracted from the energy crop Sida hermaphrodita (SH). Green chemicals and green methods, such as microwave treatment, have been used for [...] Read more.
Enhanced demand for the development of sustainable materials has generated significant research interest in products containing biomass-derived fibers, such as the fibers extracted from the energy crop Sida hermaphrodita (SH). Green chemicals and green methods, such as microwave treatment, have been used for the isolation of fibers from biomass waste. In this study, long extracted fibers were used as a reinforcement of the PLA matrix to give them high strength, which is required for high-performance biocomposites. To enable composite usage in automotive industry, several additives were applied to enhance their mechanical, thermal, and antimicrobial properties. Therefore, vegetable drying oil, montmorillonite nanoclay (MMT), and milled cork were used to improve their mechanical and thermal properties. Zinc oxide (ZnO) was applied to enhance the biocomposite’s antimicrobial properties, which were confirmed through significant bacterial reduction across all tested biocomposite variants, particularly in samples functionalized with ZnO, cork, and montmorillonite. Additionally, X-ray microtomography provided detailed insight into fiber dispersion and internal structural heterogeneity, which is crucial for evaluating mechanical performance and flame-retardant behavior. All characterization methods, including mechanical ones, lead to the conclusion that green and sustainable biocomposites based on PLA and Sida hermaphrodita fibers treated with antimicrobial (AM) and flame-retardant (FR) agents can be successfully applied for a wide variety of antimicrobial and flame-retardant products. Full article
(This article belongs to the Special Issue Engineered Coatings for a Sustainable Future)
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35 pages, 9564 KB  
Review
Research Progress of the Coatings Fabricated onto Titanium and/or Titanium Alloy Surfaces in Biomaterials for Medical Applications for Anticorrosive Applications
by Qin Rao, Jinshuang Zhang, Yaqing Chen, Yujin Yang, Xu Chen, Donghao Liu, Ruilu Zhu, Ang Li, Yanping Lv and Shunli Zheng
Coatings 2025, 15(5), 599; https://doi.org/10.3390/coatings15050599 - 17 May 2025
Cited by 3 | Viewed by 1661
Abstract
Titanium (Ti) and its alloys have attracted more interest, as they are widely employed as biomaterials due to their great biocompatibility, excellent strength ratio, and lightweight. However, corrosion occurs slowly due to an electrochemical reaction once the Ti material has been placed in [...] Read more.
Titanium (Ti) and its alloys have attracted more interest, as they are widely employed as biomaterials due to their great biocompatibility, excellent strength ratio, and lightweight. However, corrosion occurs slowly due to an electrochemical reaction once the Ti material has been placed in the human body, contributing to infection and failure of implants in medical applications. Thus, the corrosion phenomenon has caused great concern in the biomedical field. It is desirable to make the surface modification to provide better corrosion resistance. The fabrication techniques of the coatings fabricated onto Ti and/or Ti alloy surfaces have been reported, including sol–gel, annealing, plasma spraying, plasma immersion ion implantation, physical vapor deposition, chemical vapor deposition, anodization, and micro-arc oxidation. This review first describes the corrosion types, including localized corrosion (both pitting and crevice corrosion), galvanic corrosion, selective leaching, stress corrosion cracking (SCC), corrosion fatigue (CF), and fretting corrosion. In the second part, the effects of corrosion on the human body were discussed, and the primary cause for clinical failure and allergies has been identified as the excessive release of poisonous and dangerous metal ions (Co, Ni, and Ti) from corroded implants into bodily fluids. The inclusion and exclusion criteria during the selection of literature are described in the third section. In the last section, we emphasized the current research progress of Ti alloy (particularly Ti6Al4V alloy) coatings in biomaterials for medical applications involving dental, orthopedic, and cardiovascular implants for anticorrosive applications. However, there are also several problems to explore and address in future studies, such as the release of excessive metal ions, etc. This review will draw attention to both researchers and clinicians, which could help to increase the coatings fabricated onto Ti and/or Ti alloy surfaces for anticorrosive applications in biomaterials for medical applications. Full article
(This article belongs to the Special Issue Innovative Coatings for Corrosion Protection of Alloy Surfaces)
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31 pages, 2749 KB  
Review
Modern Innovations and Applications in Plasma Electrolytic Oxidation Coatings on Aluminum, Magnesium, and Titanium
by Angus G. McCarroll and Pradeep L. Menezes
Coatings 2025, 15(5), 592; https://doi.org/10.3390/coatings15050592 - 16 May 2025
Cited by 5 | Viewed by 3538
Abstract
Plasma electrolytic oxidation (PEO) is an electrochemical surface modification technique for producing dense oxide layers on valve metals. This review compiles the various modifications to the PEO process that have been used to improve the produced coatings and make them suitable for specific [...] Read more.
Plasma electrolytic oxidation (PEO) is an electrochemical surface modification technique for producing dense oxide layers on valve metals. This review compiles the various modifications to the PEO process that have been used to improve the produced coatings and make them suitable for specific applications, with a focus on examples of aluminum, magnesium, and titanium substrates. An overview of the PEO process is given, highlighting the various process parameters and their effects on the final surface. The challenges with light metals that motivate the use of surface modifications are summarized, along with some of the other modifications that attempt to overcome them. Two broad categories of modifications to the PEO process are presented: in situ modifications, influencing the properties of the coating during its formation, and ex situ modifications, augmenting the properties of an already-formed coating. Finally, specific examples of applications for modified PEO processes are discussed, including battery, biomedical, water treatment, and energy production applications. Full article
(This article belongs to the Collection Feature Paper Collection in Plasma Coatings, Surfaces & Interfaces)
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29 pages, 6857 KB  
Article
Physicochemical and Preliminary Biological Properties of Thin Films Based on Fluoride-Doped Hydroxyapatite in a Dextran Matrix for Biomedical Applications
by Liliana Ghegoiu, Daniela Predoi, Simona Liliana Iconaru, Carmen Steluta Ciobanu, Krzysztof Rokosz, Steinar Raaen, Monica Luminita Badea and Mihai Valentin Predoi
Coatings 2025, 15(5), 565; https://doi.org/10.3390/coatings15050565 - 9 May 2025
Cited by 3 | Viewed by 1109
Abstract
A spin-coating technique was used to produce new thin films of fluoride-doped hydroxyapatite (HApF) and fluoride-doped hydroxyapatite in a dextran matrix (HApF-Dx) with the potential to be used as nanocoatings for various biomedical implants. The stability of the suspensions used in obtaining the [...] Read more.
A spin-coating technique was used to produce new thin films of fluoride-doped hydroxyapatite (HApF) and fluoride-doped hydroxyapatite in a dextran matrix (HApF-Dx) with the potential to be used as nanocoatings for various biomedical implants. The stability of the suspensions used in obtaining the thin films was confirmed by ultrasonic measurements with double-distilled water as a reference. The HApF and HApF-Dx thin films obtained by spin-coating showed diffraction patterns corresponding to hexagonal hydroxyapatite. The X-ray photoelectron spectroscopy studies confirmed the partial substitution of hydroxyl groups (-OH) by fluoride ions. The FTIR studies were conducted in order to highlight the presence of the functional group specific for the HAp in the samples and the influence of the dextran addition on the vibrational characteristics. The surface morphologies of the HApF and HApF-Dx thin films were explored using scanning electron microscopy (SEM), atomic force microscopy (AFM), and metallographic microscopy (MM). The surfaces of the HApF and HApF-Dx thin films were found to be smooth, homogenous, and nanostructured. The biocompatibility assays on HGF-1 cells confirmed that both coatings exhibited good cell viability for all the tested time intervals (24 and 48 h). The findings highlighted the potential of HApF and HApF-Dx coatings for biomedical applications. Additional information about the HGF-1 adherence and development on the surface of the HApF and HApF-Dx coatings was obtained using metallographic microscopy, scanning electron microscopy, and atomic force microscopy techniques. This research demonstrates that the spin-coating method can be successfully used to fabricate HApF and HApF-Dx nanocoatings for potential biomedical applications. Full article
(This article belongs to the Special Issue Films and Coatings with Biomedical Applications)
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13 pages, 7814 KB  
Article
Understanding the Chamber Wall-Deposited Thin Film of Plasma Deposition Equipment for the Efficiency of In Situ Dry-Cleaning
by Jiseok Lee, Jiwon Jang and Sang Jeen Hong
Coatings 2025, 15(5), 563; https://doi.org/10.3390/coatings15050563 - 8 May 2025
Viewed by 2905
Abstract
In plasma-enhanced chemical vapor deposition (PECVD) processes, thin films can accumulate on the inner chamber walls, resulting in particle contamination and process drift. In this study, we investigate the physical and chemical properties of these wall-deposited films to understand their spatial variation and [...] Read more.
In plasma-enhanced chemical vapor deposition (PECVD) processes, thin films can accumulate on the inner chamber walls, resulting in particle contamination and process drift. In this study, we investigate the physical and chemical properties of these wall-deposited films to understand their spatial variation and impact on chamber maintenance. A 6-inch capacitively coupled plasma (CCP)-type PECVD system was used to deposit SiO2 films, whilst long silicon coupons were attached vertically to the chamber side walls to collect contamination samples. The collected contamination samples were comparatively analyzed in terms of their chemical properties and surface morphology. The results reveal significant differences in hydrogen content and Si–O bonding configurations compared to reference films deposited on wafers. The top chamber wall, located near the plasma region, exhibited higher hydrogen incorporation and larger Si–O–Si bonding angles, while the bottom wall exhibited rougher surfaces with larger particulate agglomerates. These variations were closely linked to differences in gas flow dynamics, precursor distribution, and the energy state of the plasma species at different chamber heights. The findings indicate that top-wall contaminants are more readily cleaned due to their high hydrogen content, while bottom-wall residues may be more persistent and pose higher risks for particle generation. This study provides insights into wall contamination behavior in PECVD systems and suggests strategies for spatially optimized chamber cleaning and conditioning in high-throughput semiconductor processes. Full article
(This article belongs to the Special Issue Advanced Plasma Surface Treatments and Their Applications in Coating Technologies)
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12 pages, 3903 KB  
Article
Microstructure and Electrical Properties of Scandium-Doped Aluminum Nitride Thin Film
by Jiaqiang Chen, Junxi Zhang, Zhiyang Fan and Ping Yu
Coatings 2025, 15(5), 549; https://doi.org/10.3390/coatings15050549 - 4 May 2025
Cited by 4 | Viewed by 2264
Abstract
Highly (0002)-oriented Al1−xScxN thin films with different Sc doping concentrations (x = 0, 0.2, 0.25, 0.3, and 0.43) were prepared via a magnetron sputtering system. The effects of Sc doping on the crystal structure and electrical property [...] Read more.
Highly (0002)-oriented Al1−xScxN thin films with different Sc doping concentrations (x = 0, 0.2, 0.25, 0.3, and 0.43) were prepared via a magnetron sputtering system. The effects of Sc doping on the crystal structure and electrical property of the as-prepared thin films were investigated experimentally. The results of synchrotron radiation grazing-incidence wide-angle X-ray scattering (GIWAXS) and X-ray diffraction (XRD) demonstrated that the Sc3+ substitution for Al3+ induced asymmetric lattice distortion: the a-axis exhibited monotonic expansion (reaching 3.46 Å at x = 0.43) due to the larger atomic radius of Sc (~0.87 Å), while the c-axis attained a maximum value of 5.14 Å at x = 0.2 and subsequently contracted as the bond angle reduction became dominant. The dielectric constant increased to 34.67 (225% enhancement) at x = 0.43, attributed to the enhanced polarization of Sc-N bonds and interfacial charge accumulation effects. Simultaneously, the dielectric loss increased from 0.15% (x = 0) to 6.7% (x = 0.43). Leakage current studies revealed that high Sc doping (x = 0.43) elevated the leakage current density to 10−6 A/cm2 under an electric field of 0.2 MV/cm, accompanied by a transition from Ohmic conduction to space-charge-limited current (SCLC) at a low electric field strength (<0.072 MV/cm). Full article
(This article belongs to the Section Thin Films)
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24 pages, 28123 KB  
Article
The Role of Titanium Carbides in Forming the Microstructure and Properties of Ti-33Mo-0.2C Alloy
by Wojciech Szkliniarz and Agnieszka Szkliniarz
Coatings 2025, 15(5), 546; https://doi.org/10.3390/coatings15050546 - 2 May 2025
Viewed by 924
Abstract
This study presents the characteristics of the Ti-33Mo-0.2C alloy, which belongs to the group of titanium alloys with a stable β phase and contains 0.27 wt% carbon; this is significantly higher than the permissible level for this alloy, which is 0.1 wt%. The [...] Read more.
This study presents the characteristics of the Ti-33Mo-0.2C alloy, which belongs to the group of titanium alloys with a stable β phase and contains 0.27 wt% carbon; this is significantly higher than the permissible level for this alloy, which is 0.1 wt%. The Ti-33Mo-0.2C alloy was melted in a vacuum induction furnace with a cold copper crucible and subsequently processed into a 12 mm diameter rod through hot rolling and annealing under standard conditions. The microstructure, as well as the mechanical and physicochemical properties of the Ti-33Mo-0.2C alloy, were compared with those of the Ti-33Mo alloy of a similar chemical composition. The following techniques were used to characterize the microstructure and properties of the alloys: LM; SEM/EDS (WDS); XRD; and mechanical, creep, and corrosion testing. The conducted analyses demonstrated that the addition of approximately 0.2 wt% carbon to the Ti-33Mo alloy leads to the expected improvement in microstructural stability by reducing grain growth and inhibiting the precipitation of the α phase at β grain boundaries. Consequently, a unique simultaneous enhancement of both strength and ductility, with increased creep resistance, is observed while maintaining the excellent corrosion resistance of the investigated alloy. The observed beneficial effects and additional capabilities resulting from the presence of carbon in the investigated alloy justify the conclusion that carbon should no longer be regarded as an undesirable impurity, which stands in contrast to some previous statements. Full article
(This article belongs to the Section Surface Characterization, Deposition and Modification)
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24 pages, 28892 KB  
Article
Mechanical and Tribological Behavior of TiAlSiN/AlSiN Coatings Depending on the High-Temperature Treatment
by Stefan Kolchev, Lilyana Kolaklieva, Daniela Kovacheva, Genoveva Atanasova, Tetiana Cholakova, Vasiliy Chitanov, Ekaterina Zlatareva, Roumen Kakanakov and Chavdar Pashinski
Coatings 2025, 15(5), 542; https://doi.org/10.3390/coatings15050542 - 30 Apr 2025
Cited by 1 | Viewed by 930
Abstract
TiAlSiN/AlSiN coatings, with 3 and 30 periods, were successfully deposited by cathodic-arc evaporation technology. The composition, structure, mechanical, and tribological properties were studied at thermal treatment from 700 °C to 900 °C. The SEM observation and EDS analysis verified the dense structure and [...] Read more.
TiAlSiN/AlSiN coatings, with 3 and 30 periods, were successfully deposited by cathodic-arc evaporation technology. The composition, structure, mechanical, and tribological properties were studied at thermal treatment from 700 °C to 900 °C. The SEM observation and EDS analysis verified the dense structure and stable element composition in the coating depth at increased temperatures. A limited surface oxidation was identified at 800 °C, which increased moderately at a higher temperature of 900 °C. The coating period displays a nanocomposite structure of TiAl(Si)N and AlN nanograins incorporated in an amorphous Si3N4 matrix obtained by XRD and XPS analyses. The coatings exhibit high hardness of 41.1 GPa and 36.4 GPa for the 3- and 30-period coatings, respectively. The coatings with higher modulation periods demonstrate an excellent high temperature hardness and resistance to elastic and plastic deformations up to 900 °C. The hardness of the coatings with a smaller modulation period reduces to 29.7 GPa at the same temperature, causing a decrease in the H/E and H3/E*2 ratios. The tribological tests found that the high-temperature wear resistance depends strongly on the coating composition and architecture. An oxidation wear mechanism dominates the coatings with a large modulation period, and the wear rate decreases with a temperature increase. Abrasive wear is predominant in coatings with a lower modulation period, leading to an increasing wear rate. Wear rate values of 7.27 × 10−6 mm3/N·m and 8.53 × 10−6 mm3/N·m were determined after annealing at 900 °C for the 3- and 30-period coatings, respectively. Full article
(This article belongs to the Special Issue Tribological and Mechanical Properties of Coatings)
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12 pages, 3562 KB  
Article
Stabilization of Epitaxial NiO(001) Ultra-Thin Films on Body-Centered-Cubic Ni(001)-p(1x1)O
by Andrea Picone, Franco Ciccacci, Lamberto Duò and Alberto Brambilla
Coatings 2025, 15(5), 507; https://doi.org/10.3390/coatings15050507 - 23 Apr 2025
Cited by 1 | Viewed by 868
Abstract
Ultrathin NiO films, ranging from 1 to 16 monolayers (ML) in thickness, have been stabilized via reactive molecular beam epitaxy on the (001) surface of a metastable body-centered cubic (BCC) Ni film. Low-energy electron diffraction (LEED) confirms that NiO grows as a crystalline [...] Read more.
Ultrathin NiO films, ranging from 1 to 16 monolayers (ML) in thickness, have been stabilized via reactive molecular beam epitaxy on the (001) surface of a metastable body-centered cubic (BCC) Ni film. Low-energy electron diffraction (LEED) confirms that NiO grows as a crystalline film, exposing the (001) surface. Auger electron spectroscopy (AES) reveals a slight oxygen excess compared to a perfectly stoichiometric NiO film. Scanning tunneling microscopy (STM) shows that at low coverages the film exhibits atomically flat terraces, while at higher coverage a “wedding cake” morphology emerges. Scanning tunneling spectroscopy (STS) reveals a thickness-dependent evolution of the electronic band gap, which increases from 0.8 eV at 3 ML to 3.5 eV at 16 ML. The center of the band gap is approximately 0.2 eV above the Fermi level, indicating that NiO is p-doped. Full article
(This article belongs to the Special Issue Accelerated Development of Nanomaterials, Coatings, and Thin Films for Optical and Electronic Applications)
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14 pages, 2221 KB  
Article
Antifouling Performance and Long-Term Efficiency of a Zwitterionic Sulfobetaine-Hydroxyethyl-Containing Polymethylmethacrylate Ter-Co-Polymer Coating Against Biomass-Producing Photosynthetic Strains
by Rana Haider Ali, Vincenzo Zammuto, Marco Nicolò, Filomena De Leo, Sandra Lo Schiavo and Clara Urzì
Coatings 2025, 15(4), 462; https://doi.org/10.3390/coatings15040462 - 13 Apr 2025
Viewed by 4018
Abstract
The antifouling performance of a zwitterionic sulfobetaine-hydroxyethyl-containing polymethylmethacrylate ter-co-polymer (PSBM) is evaluated against three photosynthetic strains, namely Chlorella sp., Nannochloropsis sp., and Arthrospira maxima. PSBM-coated polymethylmethacrylate (PMMA) surfaces displayed a significantly reduced propensity for biofilm formation compared to rough and untreated controls, [...] Read more.
The antifouling performance of a zwitterionic sulfobetaine-hydroxyethyl-containing polymethylmethacrylate ter-co-polymer (PSBM) is evaluated against three photosynthetic strains, namely Chlorella sp., Nannochloropsis sp., and Arthrospira maxima. PSBM-coated polymethylmethacrylate (PMMA) surfaces displayed a significantly reduced propensity for biofilm formation compared to rough and untreated controls, leaving clean surfaces after 7 days of exposure. A tribological approach was adopted to estimate the long-term durability of the PSBM coating. Repeated cycles of exposure to Chlorella sp., Nannochloropsis sp., and A. maxima biomass subject the coating to stress and continuous biofilm challenges. After several cycles, the PSBM coating maintains a higher antifouling efficacy than the untreated PMMA surface, suggesting stability and high potential in photobioreactor applications. Full article
(This article belongs to the Special Issue Trends in Coatings and Surface Technology, 2nd Edition)
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30 pages, 10226 KB  
Article
Environmentally Friendly Solutions as Potential Alternatives to Chromium-Based Anodization and Chromate Sealing for Aeronautic Applications
by Norica Godja and Florentina-Daniela Munteanu
Coatings 2025, 15(4), 439; https://doi.org/10.3390/coatings15040439 - 8 Apr 2025
Cited by 3 | Viewed by 2027
Abstract
The adoption of chrome-free anodizing and sealing systems for aluminum alloys, particularly AA2024, is gaining prominence due to environmental and health concerns associated with traditional Cr(VI)-based processes. This study evaluates the environmental and economic impacts of sulfuric acid anodizing (SAA) combined with sealing [...] Read more.
The adoption of chrome-free anodizing and sealing systems for aluminum alloys, particularly AA2024, is gaining prominence due to environmental and health concerns associated with traditional Cr(VI)-based processes. This study evaluates the environmental and economic impacts of sulfuric acid anodizing (SAA) combined with sealing based on fluorozirconate, molybdate, and cerate. Comparative analyses were conducted against conventional Cr(VI) systems and SAA with Cr(III) sealing, focusing on corrosion resistance, energy consumption, washing steps and material flows. The entire anodizing process was examined, including pretreatment, anodization, and sealing. Electrochemical analyses and surface characterization through SEM/EDS, FIB, and XPS were conducted. The results demonstrate that the chromium-free system offers competitive corrosion resistance while significantly reducing environmental and economic costs. Furthermore, fluorozirconate, molybdate, and cerate-based post-treatments broaden its application spectrum in corrosion science and warrant further exploration. However, adopting new sealing technologies in aerospace requires extensive certification involving corrosion resistance, durability assessments, and stringent environmental simulations. Compliance with regulatory standards set by the FAA (Federal Aviation Administration) and EASA (European Union Aviation Safety Agency) necessitates thorough documentation, third-party validation, and testing to ensure safety and performance before industrial implementation. These challenges underscore the complexity of transitioning to more sustainable anodizing and sealing technologies in the aerospace industry. Full article
(This article belongs to the Special Issue Corrosion Protection of Metals and Alloys in Extreme Environments)
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13 pages, 14903 KB  
Article
Al2O3/ZnO Multilayer Coatings for Improvement in Functional Properties of Surgical Scalpel Blades
by Magdalena Monika Szindler, Marek Szindler, Jakub Bicz and Krzysztof Matus
Coatings 2025, 15(4), 436; https://doi.org/10.3390/coatings15040436 - 7 Apr 2025
Cited by 4 | Viewed by 1179
Abstract
This work aimed to investigate the structure and corrosion resistance of Al2O3/ZnO multilayer coatings deposited by ALD on the standard surgical scalpel blades made of carbon steel. The surface topography of the coatings was examined using a scanning electron [...] Read more.
This work aimed to investigate the structure and corrosion resistance of Al2O3/ZnO multilayer coatings deposited by ALD on the standard surgical scalpel blades made of carbon steel. The surface topography of the coatings was examined using a scanning electron microscope (SEM), revealing the significant effect of the number of deposited Al2O3/ZnO bilayers on the morphology of the multilayer coatings. The XRD method was used for the phase analysis, allowing to confirm the presence of ZnO and ZnAl2O4 phases. The presence of the ZnAl2O4 structure was also confirmed using a Raman spectrometer. A qualitative analysis of the chemical composition of the obtained coatings was performed using the energy dispersive spectrometry (EDX) method. In order to determine the corrosion resistance, potentiodynamic tests were performed using Ringer’s solution at a temperature of 37 °C. The beneficial effect of increasing the number of deposited Al2O3/ZnO bilayers on the corrosion resistance was confirmed, with the lowest corrosion current density value of 2.05 μA/cm2 and the highest polarization resistance of 12.15 kΩ obtained in the case of the N72 coating. Full article
(This article belongs to the Special Issue Advances in Corrosion Behaviors and Protection of Coatings)
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14 pages, 3801 KB  
Article
Synthesis and Characterization of Silane-Coupled Sodium Silicate Composite Coatings for Enhanced Anticorrosive Performance
by Minghui Liu, Zhiwen Tan, Shengda Xu, Yuantao Zhao, Haoran Wang, Shitao Zhang, Rong Ma, Tao Jiang, Zhen Ma, Ning Zhong and Wenge Li
Coatings 2025, 15(4), 428; https://doi.org/10.3390/coatings15040428 - 4 Apr 2025
Cited by 5 | Viewed by 1734
Abstract
Ships and offshore equipment operating in marine environments often face issues such as seawater corrosion and biofouling, leading to significant economic losses. To address the corrosion problems of ships and offshore equipment, heavy-duty anticorrosive coatings are widely used for corrosion protection in marine [...] Read more.
Ships and offshore equipment operating in marine environments often face issues such as seawater corrosion and biofouling, leading to significant economic losses. To address the corrosion problems of ships and offshore equipment, heavy-duty anticorrosive coatings are widely used for corrosion protection in marine environments due to their long-term effectiveness, cost-efficiency, and excellent applicability. In this study, silane coupling agent (KH-560) was employed to modify sodium silicate, and the modified sodium silicate was then incorporated as a reinforcing phase into polyurethane to ultimately prepare a modified sodium silicate/polyurethane coating. The feasibility of the modified sodium silicate/polyurethane coating was investigated by characterizing its conventional physicochemical properties, weather resistance, acid and alkali resistance, and salt spray corrosion resistance. Experimental results indicate that the silane coupling agent acts as a bridge between the organic and inorganic interfaces through the hydrolysis and condensation reactions of its bifunctional groups, forming an interfacial layer connected by hydrogen bonds and covalent bonds, thereby improving the compatibility between the organic resin and inorganic sodium silicate. Comprehensive performance analysis revealed that when the content of modified sodium silicate was 60 wt%, the coating hardness reached 4H. Additionally, electrochemical tests demonstrated that the coating exhibited higher impedance (9.62 × 104 Ω/cm2) and lower corrosion current density (5.82 × 10−7 A/cm2). This study provides a theoretical and experimental basis for the development of high-performance anticorrosive coatings for marine applications. Full article
(This article belongs to the Special Issue Advances in Protective Coatings: Materials, Fabrication, Corrosion and Applications)
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32 pages, 2425 KB  
Review
Development, Challenges, and Applications of Concrete Coating Technology: Exploring Paths to Enhance Durability and Standardization
by Hongbin Zhao, Qingzhou Wang, Ruipeng Shang and Shengkai Li
Coatings 2025, 15(4), 409; https://doi.org/10.3390/coatings15040409 - 30 Mar 2025
Cited by 3 | Viewed by 3646
Abstract
Concrete coating technology is a key measure that enhances the durability of concrete structures. This paper systematically studies the performance, applicability, and impact of different types of anti-corrosion coatings on concrete durability, focusing on their resistance to chloride ion penetration, freeze–thaw cycles, carbonation, [...] Read more.
Concrete coating technology is a key measure that enhances the durability of concrete structures. This paper systematically studies the performance, applicability, and impact of different types of anti-corrosion coatings on concrete durability, focusing on their resistance to chloride ion penetration, freeze–thaw cycles, carbonation, and sulfate corrosion. The applicability of existing testing methods and standard systems is also evaluated. This study shows that surface-film-forming coatings can create a dense barrier, reducing chloride ion diffusion coefficients by more than 50%, making them suitable for humid and high-chloride environments. Pore-sealing coatings fill capillary pores, improving the concrete’s impermeability and making them ideal for highly corrosive environments. Penetrating hydrophobic coatings form a water-repellent layer, reducing water absorption by over 75%, which is particularly beneficial for coastal and underwater concrete structures. Additionally, composite coating technology is becoming a key approach to addressing multi-environment adaptability challenges. Experimental results have indicated that combining penetrating hydrophobic coatings with surface-film-forming coatings can enhance concrete’s resistance to chloride ion penetration while ensuring weather resistance and wear resistance. However, this study also reveals that there are several challenges in the standardization, engineering application, and long-term performance assessment of coating technology. The lack of globally unified testing standards leads to difficulties in comparing the results obtained from different test methods, affecting the practical application of these coatings in engineering. Moreover, construction quality control and long-term service performance monitoring remain weak points in their use in engineering applications. Some engineering case studies indicate that coating failures are often related to an insufficient coating thickness, improper interface treatment, or lack of maintenance. To further improve the effectiveness and long-term durability of coatings, future research should focus on the following aspects: (1) developing intelligent coating materials with self-healing, high-temperature resistance, and chemical corrosion resistance capabilities; (2) optimizing multilayer composite coating system designs to enhance the synergistic protective capabilities of different coatings; and (3) promoting the creation of global concrete coating testing standards and establishing adaptability testing methods for various environments. This study provides theoretical support for the optimization and standardization of concrete coating technology, contributing to the durability and long-term service safety of infrastructure. Full article
(This article belongs to the Special Issue Recent Progress in Reinforced Concrete and Building Materials)
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27 pages, 13116 KB  
Article
Numerical Examination of Particle and Substrate Oxide Layer Failure and Porosity Formation in Coatings Deposited Using Liquid Cold Spray
by Peyman Khamsepour, Ali Akbarnozari, Daniel MacDonald, Luc Pouliot, Christian Moreau and Ali Dolatabadi
Coatings 2025, 15(4), 405; https://doi.org/10.3390/coatings15040405 - 28 Mar 2025
Viewed by 982
Abstract
Cold spray (CS) uses high-velocity gas to deposit solid particles without oxidation or phase change. To make the spraying process more economical, a wider-sized cut of feedstock particles needs to be deposited. The liquid cold spray (LCS) process, which uses water as a [...] Read more.
Cold spray (CS) uses high-velocity gas to deposit solid particles without oxidation or phase change. To make the spraying process more economical, a wider-sized cut of feedstock particles needs to be deposited. The liquid cold spray (LCS) process, which uses water as a propellant, has been developed to achieve this goal. The use of water as a propellant may adversely affect particle deformation and adhesion. In this study, numerical methods are used to analyze particle and substrate oxide failure to determine the effects of wetting on particle adhesion to a substrate. The results indicate that water on the particle surface or on substrate would reduce the deformation of both. The area in which oxide layers fail and metallurgical bonding can occur would be reduced. A portion of the water may become entrapped between the particle and the substrate, adversely affecting the bonding area. Increasing particle velocity and decreasing water thickness can reduce the volume of trapped water and improve density by increasing particle deformation and decreasing pore size. Full article
(This article belongs to the Special Issue New Materials and New Applications for the Cold Gas Spray Process)
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23 pages, 7257 KB  
Article
Effect of Nanosecond Laser Ablation and Oxidation on the Surface Wettability and Microstructure of Cu-ETP Copper Sheets
by Monika Walkowicz, Piotr Osuch, Małgorzata Zasadzińska, Paweł Strzępek and Klaudia Kludacz
Coatings 2025, 15(4), 383; https://doi.org/10.3390/coatings15040383 - 25 Mar 2025
Cited by 3 | Viewed by 1737
Abstract
Nanosecond laser ablation effectively modifies Cu-ETP copper surfaces by controlling wettability and microstructure. This study examines the effects of nanosecond fiber laser processing and subsequent oxidation on surface evolution. The analyzed parameters include fluence (25.46–1018.59 J/cm2), wavelength (1064 nm), repetition rate [...] Read more.
Nanosecond laser ablation effectively modifies Cu-ETP copper surfaces by controlling wettability and microstructure. This study examines the effects of nanosecond fiber laser processing and subsequent oxidation on surface evolution. The analyzed parameters include fluence (25.46–1018.59 J/cm2), wavelength (1064 nm), repetition rate (25–1000 kHz), and pulse duration (2–500 ns). To investigate high energy densities, fluence values were set above typical ablation thresholds, inducing hierarchical surface structures affecting wettability. Post-ablation oxidation was examined under two conditions: natural oxidation in ambient air and accelerated oxidation via low-temperature annealing (200 °C) in air. Contact angle measurements revealed that over time, the initially hydrophilic (θ < 90°) laser-textured surfaces exhibited a transition toward hydrophobicity (θ > 90°), which can be attributed to the adsorption of airborne organic compounds rather than oxidation alone. In contrast, annealing significantly accelerated hydrophobicity, attributed to controlled copper oxide growth. SEM and EDS analyses confirmed that higher fluences enhanced roughness and oxidation, forming multi-scale textures and oxide layers, which influenced water repellency. These findings demonstrate that high-fluence laser ablation, combined with controlled oxidation, enables precise wettability engineering. This method provides an efficient strategy for tuning surface properties, offering potential applications in anti-corrosion coatings, self-cleaning surfaces, and heat exchangers, where hydrophobicity and durability are essential. Full article
(This article belongs to the Special Issue Advanced Additive Manufacturing and Surface Modifications of Metallic Materials)
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11 pages, 2921 KB  
Article
Optical Coating Deposition on Submicron-Patterned Surfaces
by Lina Grineviciute, Simas Melnikas, Julianija Nikitina, Mantas Drazdys, Algirdas Selskis and Darija Astrauskytė
Coatings 2025, 15(4), 372; https://doi.org/10.3390/coatings15040372 - 22 Mar 2025
Cited by 4 | Viewed by 1499
Abstract
Periodically modulated optical coatings, fabricated by depositing conformal films on modulated substrates, offer unique capabilities for spectral and spatial filtering of light. However, conventional deposition methods often do not achieve required replication and conformality on submicron-size structured surfaces. In this paper, we compare [...] Read more.
Periodically modulated optical coatings, fabricated by depositing conformal films on modulated substrates, offer unique capabilities for spectral and spatial filtering of light. However, conventional deposition methods often do not achieve required replication and conformality on submicron-size structured surfaces. In this paper, we compare various thin film deposition techniques, including electron beam evaporation, atomic layer deposition, and ion beam sputtering, to evaluate their ability to control multilayer coating growth on periodically modulated substrates. Our study demonstrates that both single-layer and multilayer coatings produced by ion beam sputtering effectively replicate the initial geometry of structured surfaces, thereby enhancing optical performance. Full article
(This article belongs to the Special Issue Optical Coatings: From Materials to Applications)
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18 pages, 1388 KB  
Review
Ni-P Coatings as Hydrogen Permeation Barriers—A Review
by Deborah Biggio, Bernhard Elsener and Antonella Rossi
Coatings 2025, 15(4), 365; https://doi.org/10.3390/coatings15040365 - 21 Mar 2025
Cited by 4 | Viewed by 4515
Abstract
Hydrogen became one of the most studied energy carriers after the global energy crisis and can replace gas and oil as clean fuels. The main challenge is its safe storage and long-distance transportation: steel is among the materials most used for hydrogen storage [...] Read more.
Hydrogen became one of the most studied energy carriers after the global energy crisis and can replace gas and oil as clean fuels. The main challenge is its safe storage and long-distance transportation: steel is among the materials most used for hydrogen storage and transportation. However, steel is susceptible to hydrogen embrittlement (HE). HE can be prevented by depositing hydrogen barrier coatings on the steel surface. This review provides an overview of the hydrogen permeation mechanism and the analytical methods employed to evaluate the performance of the hydrogen permeation barriers. The focus is on Ni and electroless Ni-P coatings deposited on steel as hydrogen barriers. These coatings have been used so far for their anti-corrosion and wear properties; they are currently of interest due to their low hydrogen permeability. The simplicity of production and the possibility of achieving a homogeneous coating, regardless of the geometry of the substrate, make the electroless deposition process of the Ni-P alloy a candidate for ‘in situ’ applications in existing pipelines. This process can be implemented by using and adapting the established pig batch technology. Full article
(This article belongs to the Section Surface Engineering for Energy Harvesting, Conversion, and Storage)
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29 pages, 3266 KB  
Review
Pitfalls and Challenges in Specific Absorption Rate Evaluation for Functionalized and Coated Magnetic Nanoparticles Used in Magnetic Fluid Hyperthermia
by Nicusor Iacob
Coatings 2025, 15(3), 345; https://doi.org/10.3390/coatings15030345 - 17 Mar 2025
Cited by 2 | Viewed by 2396
Abstract
In recent decades, magnetic hyperthermia (MH) has gained considerable scientific interest in cancer treatment due to its ability to heat tumor tissues deeply localized inside the body. Functionalizing magnetic nanoparticles (MNPs) with vector molecules via specific organic molecules that coat the particle surface [...] Read more.
In recent decades, magnetic hyperthermia (MH) has gained considerable scientific interest in cancer treatment due to its ability to heat tumor tissues deeply localized inside the body. Functionalizing magnetic nanoparticles (MNPs) with vector molecules via specific organic molecules that coat the particle surface has enabled targeting particular tissues, thereby increasing the specificity of MH. MH relies on applying radiofrequency (RF) magnetic fields to a magnetic nanoparticle distribution injected in a tumor tissue. The RF field energy is converted into thermal energy through specific relaxation mechanisms and magnetic hysteresis-driven processes. This increases the tumor tissue temperature over the physiological threshold, triggering a series of cellular apoptosis processes. Additionally, the mechanical effects of low-frequency AC fields on anisotropic MNPs have been shown to be highly effective in disrupting the functional cellular components. From the macroscopic perspective, a crucial parameter measuring the efficiency of magnetic nanoparticle systems in MH is the specific absorption rate (SAR). This parameter is experimentally evaluated by different calorimetric and magnetic techniques and methodologies, which have specific drawbacks and may induce significant errors. From a microscopic perspective, MH relies on localized thermal and kinetic effects in the nanoparticle proximity environment. Studying MH at the cellular level has become a focused research topic in the last decade. In the context of these two perspectives, inevitable questions arise: could the thermal and kinetic effects exhibited at the cellular scale be linked by the macroscopic SAR parameter, or should we find new formulas for quantifying them? The present work offers a general perspective of MH, highlighting the experimental pitfalls encountered in SAR evaluation and motivating the necessity of standardizing the devices and protocols involved. It also discusses the challenges that arise in MH performance evaluation at the cellular level. Full article
(This article belongs to the Special Issue Advances of Nanoparticles and Thin Films)
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15 pages, 14089 KB  
Article
The Effect of Warm Shot Peening on Microstructure Evolution and Residual Stress in Gradient Nanostructured Mg-8Gd-3Y-0.4Zr Alloys
by Huabing Liu, Xiang Zhang, Xiaoxiao Wei, Jin Gan and Chuanhai Jiang
Coatings 2025, 15(3), 316; https://doi.org/10.3390/coatings15030316 - 9 Mar 2025
Cited by 4 | Viewed by 1226
Abstract
This work systematically investigated the effects of warm shot peening (WSP) on the microstructure evolution, residual stress, and microhardness of the Mg-8Gd-3Y-0.4Zr (GW83) alloy by X-ray diffraction line profile analysis, transmission electron microscopy, and X-ray stress analyzer and hardness tester. The results indicated [...] Read more.
This work systematically investigated the effects of warm shot peening (WSP) on the microstructure evolution, residual stress, and microhardness of the Mg-8Gd-3Y-0.4Zr (GW83) alloy by X-ray diffraction line profile analysis, transmission electron microscopy, and X-ray stress analyzer and hardness tester. The results indicated that severe plastic deformation induced by WSP resulted in a gradient nanostructure in the GW83 alloy, accompanied by significant compressive residual stress. In contrast to conventional SP, WSP led to working softening due to the dynamic recrystallization behavior. The formation of nanograins in the GW83 alloy during WSP occurs in three steps: (i) at an early stage, the introduction of a high density of dislocations and a few deformation twins subdivide bulk grains into substructures; (ii) through the processes of dislocation gliding, accumulation, and rearrangement, these substructures undergo further refinement, gradually evolving into ultrafine grains; and (iii) the inhomogeneous ultrafine grains develop into nanograins through dislocation-assisted lattice rotation and dynamic recrystallization. Full article
(This article belongs to the Special Issue Advancement in Heat Treatment and Surface Modification for Metals)
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21 pages, 6643 KB  
Article
Impact of Irradiation on Corrosion Performance of Hybrid Organic/Inorganic Coatings on Austenitic Stainless Steel
by Natalie Click, Andrew Knight, Brendan Nation, Makeila Maguire, Samay Verma, Gavin DeBrun, Tyler McCready, Adam Goff, Audrey Rotert, Don Hanson and Rebecca Filardo Schaller
Coatings 2025, 15(3), 312; https://doi.org/10.3390/coatings15030312 - 7 Mar 2025
Viewed by 1276
Abstract
The effects of gamma radiation on the performance of two corrosion-resistant coatings applied to stainless-steel 304L (SS304L) surfaces are presented. Specifically, the ability of the coatings to mitigate corrosion of SS304L surfaces as a function of the dose received (0–1300 Mrad) and dose [...] Read more.
The effects of gamma radiation on the performance of two corrosion-resistant coatings applied to stainless-steel 304L (SS304L) surfaces are presented. Specifically, the ability of the coatings to mitigate corrosion of SS304L surfaces as a function of the dose received (0–1300 Mrad) and dose rate (176 compared to 1054 rad/s) is evaluated using electrochemical methods, spectroscopy, and microscopy. Coating A, an organic/inorganic hybrid coating consisting of a two-part silica ceramic component and a polymer linker was evaluated in comparison to Coating B, which utilized Coating A as a topcoat for a commercial, off-the-shelf, Zn-rich primer. Post irradiation, Coating A demonstrated some corrosion protection following exposure to low levels of gamma radiation, but coating degradation occurred with an increased exposure dose and resulted in isolated regions of corrosion initiation. For Coating B, greater corrosion resistance was observed compared to Coating A due to the sacrificial nature of the Zn at elevated doses of gamma radiation. No effect of the dose rate (for the single dose examined) was observed for either coating. It is proposed for Coating B that as the polymer coating thermally degrades above 250 °C (bond scission of the polymer occurs), the remaining Zinc layer adhered to the SS304L post-irradiation enables enhanced corrosion resistance as compared to Coating A, which displays solely polymer degradation. The results presented herein establish an understanding of coating behavior with radiation exposure, specifically the relationship between corrosion coating performance and radiation dose, and can inform ageing and lifetime management for various applications. Full article
(This article belongs to the Section Corrosion, Wear and Erosion)
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13 pages, 7041 KB  
Article
Enhancing the Wear Resistance of CrAlN-Coated Tools in Milling and Turning Through Annealing with Optimized Duration
by Georgios Skordaris, Dimitrios Tsakalidis, Konstantinos-Dionysios Bouzakis, Fani Stergioudi and Antonios Bouzakis
Coatings 2025, 15(3), 311; https://doi.org/10.3390/coatings15030311 - 7 Mar 2025
Viewed by 759
Abstract
The work aimed to investigate the possibility of improving the mechanical properties, and therefore the wear resistance, of coated tools in manufacturing processes with continuous or interrupted cutting loads through appropriate annealing. In this context, PVD CrAlN coatings were deposited on cemented carbide [...] Read more.
The work aimed to investigate the possibility of improving the mechanical properties, and therefore the wear resistance, of coated tools in manufacturing processes with continuous or interrupted cutting loads through appropriate annealing. In this context, PVD CrAlN coatings were deposited on cemented carbide inserts. A part of these coated tools was annealed at a temperature of 400 °C, which was close to the deposition temperature, in an inert gas atmosphere. The annealing duration ranged up to 60 min. Nanoindentations and repeated perpendicular and inclined impact tests were carried out to characterize the strength, fatigue, and adhesion of the tool coatings before and after annealing. According to the results, the mechanical properties of the coating and the fatigue resistance were maximized after a short annealing period of about 15 min, while the adhesion of the coating remained unchanged. These facts led to a large increase in tool life in milling 42CrMo4 QT, when annealed coated tools were applied at 400 °C for 15 min. Furthermore, turning experiments using the mentioned hardened steel as well as GG30 cast iron to produce continuous or interrupted chips, respectively, confirmed the obtained results in milling. Therefore, annealing of coated cutting tools at an optimized duration is recommended as an effective method to extend tool life. Full article
(This article belongs to the Section Surface Characterization, Deposition and Modification)
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26 pages, 3340 KB  
Article
Antimicrobial Efficacy of Nanochitosan and Chitosan Edible Coatings: Application for Enhancing the Safety of Fresh-Cut Nectarines
by Virginia Prieto-Santiago, Marcela Miranda, Ingrid Aguiló-Aguayo, Neus Teixidó, Jordi Ortiz-Solà and Maribel Abadias
Coatings 2025, 15(3), 296; https://doi.org/10.3390/coatings15030296 - 3 Mar 2025
Cited by 4 | Viewed by 3061
Abstract
The growing demand for fresh foods, as well as the rise in ready-to-eat foods, is leading the food industry to study edible coatings to maintain the quality of fresh-cut fruit. The objective of this work was, first, to determine the antimicrobial activity of [...] Read more.
The growing demand for fresh foods, as well as the rise in ready-to-eat foods, is leading the food industry to study edible coatings to maintain the quality of fresh-cut fruit. The objective of this work was, first, to determine the antimicrobial activity of a commercial anti-browning solution (A), chitosan (CH), and nanochitosan (NCH) both in vitro and in vivo and, secondly, to assess the effects of those coatings on the quality of fresh-cut nectarines. Antimicrobial activity was studied against Listeria monocytogenes and Saccharomyces cerevisiae, which were used as models of a foodborne pathogen and a spoilage microorganism, respectively. After evaluating their effect against both microorganisms, including in nectarines (Prunus persica L. cv Nectagala), the fruit was treated with commercial anti-browning alone (A), anti-browning with chitosan (A + CH), and anti-browning with nanochitosan (A + NCH). The slices were then sealed in polyethylene plastic trays and stored at 5 °C for 6 days. pH, titratable acidity, soluble solids content, firmness, color, visual acceptance, and microbiological evolution were assessed. Total color difference (TCD) results demonstrated higher value in the fresh-cut fruit without coating. The chitosan coating controlled microbial growth during cold storage without causing significant alterations to the fruit’s quality, while it had the highest overall visual acceptance of the final product. Chitosan demonstrated clear advantages as an edible biocoating for fresh-cut nectarines, whereas nanochitosan did not perform as effectively as expected, indicating the need for further optimization to realize its potential benefits. The combination of chitosan and anti-browning agents presents a sustainable method for enhancing the quality and safety of fresh-cut nectarines, which may contribute to the extension of their shelf life Full article
(This article belongs to the Special Issue Chitosan and Other Edible Coatings with Antimicrobial Activity: Synthesis, Properties and Horticultural Applications II)
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18 pages, 15024 KB  
Article
Photocatalytically Induced Degradation of Nano-TiO2-Modified Paint Coatings Under Low-Radiation Conditions
by Maciej Kalinowski, Karol Chilmon, Justyna Kuziak, Paweł Łukowski and Wioletta Jackiewicz-Rek
Coatings 2025, 15(3), 281; https://doi.org/10.3390/coatings15030281 - 27 Feb 2025
Cited by 4 | Viewed by 3248
Abstract
Photocatalytic coatings incorporating nano-TiO2 have emerged as effective solutions for air purification, utilizing solar radiation to degrade airborne pollutants. However, the long-term stability of such coatings, particularly those based on organic binders, remains a concern due to their susceptibility to photocatalytic-driven degradation. [...] Read more.
Photocatalytic coatings incorporating nano-TiO2 have emerged as effective solutions for air purification, utilizing solar radiation to degrade airborne pollutants. However, the long-term stability of such coatings, particularly those based on organic binders, remains a concern due to their susceptibility to photocatalytic-driven degradation. This study investigates the effects of low-intensity UV-A irradiation (1–10 W/m2) on acrylic-based photocatalytic coatings’ structural integrity and air purification performance. The findings reveal that significant binder decomposition occurs even under low irradiation conditions—comparable to natural sunlight exposure in Northern and Central Europe during autumn and winter. The surface porosity increased from 2.28% to 9.09% due to polymer degradation, exposing more nano-TiO2 particles and enhancing NO removal efficiency from approximately 120 µg/hm2 to 360 µg/hm2 under UV-A irradiation (1 W/m2). However, this process also resulted in benzene emissions reaching approximately five ppb, raising concerns about secondary pollution and the potential release of nano-TiO2 due to polymer matrix disintegration. These findings highlight the need for optimized coating formulations that balance photocatalytic efficiency with long-term material stability, mitigating the environmental and health risks associated with secondary pollutant emissions. Full article
(This article belongs to the Special Issue Design of Nanostructures for Energy and Environmental Applications)
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14 pages, 10551 KB  
Article
Micro- and Nanofibrillated Cellulose Coatings as Barriers Against Water and Oil in Food Packaging Paper: A Sustainable Alternative to Plastic Coatings
by Marcin Dubowik, Kamila Przybysz, Jacek Dańczak, Aneta Lipkiewicz, Marta Gajadhur, Beata Górska, Ewelina Pawłowska, Robert Drozd and Piotr Przybysz
Coatings 2025, 15(3), 270; https://doi.org/10.3390/coatings15030270 - 24 Feb 2025
Cited by 2 | Viewed by 3411
Abstract
This research investigates the effectiveness of micro- and nanofibrillated cellulose (M-NFC) coatings compared to traditional synthetic coatings in enhancing the barrier properties of paper. Papers were coated at various grammages (1.2, 1.8, and 2.9 g/m2) and tested for properties such as [...] Read more.
This research investigates the effectiveness of micro- and nanofibrillated cellulose (M-NFC) coatings compared to traditional synthetic coatings in enhancing the barrier properties of paper. Papers were coated at various grammages (1.2, 1.8, and 2.9 g/m2) and tested for properties such as hydrophobicity, lyophobicity, and surface smoothness. Paper coated with 2.9 g/m2 M-NFC showed water absorbency of 10.5 g/m2 and castor oil absorbency of 9.6 g/m2, which were lower than for commercially available WBB-coated paper (respectively, 12.2 and 14.8 g/m2). The coatings were evaluated through microscopic analysis and physical testing methods including Cobb and Cobb–Unger absorbency tests and wettability measurements. The results indicate that M-NFC coatings provide a sustainable alternative with competitive barrier properties suitable for short-term use products, showcasing potential reductions in synthetic material usage, especially in food packaging. Full article
(This article belongs to the Special Issue Advanced Coatings and Films for Food Packing and Storage, 2nd Edition)
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14 pages, 15546 KB  
Article
Tuning Dielectric Properties of Ti-6Al-4V Powders with B4C and TiC via Ti4+ Electron Binding Energy Optimization
by Wenshu Zhang, Hui Chang, Ning Dang and Lian Zhou
Coatings 2025, 15(3), 262; https://doi.org/10.3390/coatings15030262 - 22 Feb 2025
Viewed by 911
Abstract
In this study, Ti-6Al-4V (TC4) powder was uniformly mixed with B4C and TiC, respectively. Subsequently, the dielectric properties of the B4C/TC4 and TiC/TC4 composite powders were measured. Meanwhile, XPS analysis was used to deeply analyze different atoms in these [...] Read more.
In this study, Ti-6Al-4V (TC4) powder was uniformly mixed with B4C and TiC, respectively. Subsequently, the dielectric properties of the B4C/TC4 and TiC/TC4 composite powders were measured. Meanwhile, XPS analysis was used to deeply analyze different atoms in these samples to obtain the electron binding energy data of each atom. The experimental results show that even when there is no phase structure transformation between B4C, TiC, and TC4, the dielectric coefficient of the composite powder and the electron binding energy values of various elements still exhibit significant changes. When the mass ratio of B4C or TiC to TC4 reaches 1:30, the dielectric constant of the composite powder is significantly increased from 5 (the original TC4) to about 11 and 15, respectively. At the same time, the electron binding energy of the Ti element in TC4 also reaches the maximum value. In addition, due to the difference in electronegativity between B4C and TiC, during the process of compounding with TC4, the incorporation contents and the occurrence frequencies of abnormal dispersion phenomena are different. Specifically, when the ratio of B4C to TC4 is 1:30, abnormal dispersion occurs at a frequency of 9.5 GHz; however, when the ratio of TiC to TC4 is 1:20, the composite coating shows an abnormal dispersion phenomenon at 8.5 GHz. Full article
(This article belongs to the Special Issue Effect of Heat Treatment on Structural and Mechanical Properties of Metallic Materials/Coatings)
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27 pages, 12594 KB  
Article
Chrome Doped Hydroxyapatite Enriched with Amoxicillin Layers for Biomedical Applications
by Carmen Steluta Ciobanu, Daniela Predoi, Simona Liliana Iconaru, Krzysztof Rokosz, Steinar Raaen, Catalin Constantin Negrila, Liliana Ghegoiu, Coralia Bleotu and Mihai Valentin Predoi
Coatings 2025, 15(2), 233; https://doi.org/10.3390/coatings15020233 - 15 Feb 2025
Cited by 8 | Viewed by 1314
Abstract
In the last decade, it has been observed that the field of biomaterials has gained the attention of the researchers. This study presents the physicochemical and biological properties of coatings based on chromium-doped hydroxyapatite (CrHAp) and chromium-doped hydroxyapatite enriched with amoxicillin (CrHApAx). The [...] Read more.
In the last decade, it has been observed that the field of biomaterials has gained the attention of the researchers. This study presents the physicochemical and biological properties of coatings based on chromium-doped hydroxyapatite (CrHAp) and chromium-doped hydroxyapatite enriched with amoxicillin (CrHApAx). The coatings were obtained for the first time using the dip coating technique, beginning from dense suspensions of CrHAp and CrHApAx. The obtained layers were then analyzed by various methods in order to have a comprehensive overview of their physicochemical properties. Stability studies performed using ultrasound measurements showed that the CrHAp suspension has very good stability (S = 6.86·10−6 s−1) compared to double-distilled water. The CrHApAx suspension (S = 0.00025 s−1) shows good but weaker stability compared to that of the CrHAp suspension. Following XRD studies, a single hydroxyapatite-specific phase was observed in the CrHAp sample, while in the case of the CrHApAx sample, an amoxicillin-specific peak was also observed. The AFM results showed that the CrHAp coatings had a surface topography of a homogenous and uniform layer, with no significant cracks and fissures, while the CrHApAx coatings exhibited a surface morphology of homogenous layers formed of particles conglomerates. The biocompatibility of CrHAp and CrHApAx coatings was assessed using the MG63 cell line. The cytotoxicity of the coatings was evaluated by measuring cell viability with the aid of an MTT assay after 24, 48, and 72 h of incubation with the CrHAp and CrHApAx coatings. The results demonstrated that both CrHAp and CrHApAx coatings exhibited good biocompatibility for all the tested time intervals. The in vitro antibacterial activity of the coatings was also assessed against Pseudomonas aeruginosa 27853 ATCC (P. aeruginosa) bacterial cells. The potential of P. aeruginosa bacterial cells to adhere and develop on the surfaces of CrHAp and CrHApAx coatings was also investigated using AFM analysis. The findings of the biological assays suggest that CrHAp and CrHApAx coatings could be considered as promising candidates for biomedical applications, including the development of novel antimicrobial materials. Full article
(This article belongs to the Special Issue Advanced Biomaterials and Coatings)
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15 pages, 4491 KB  
Article
Performance Study and Machine Learning Model Evaluation of Embedded Micro-Agglomerated Particle TBCs Based on Plasma-Spraying Process
by Shuheng Xu, Zhou Xu, Changdong Yin, Yiwen Wu, Feixiang Wu, Houli Liu, Zhijun Zhang, Guoqing Yang, Jibo Huang and Dongdong Ye
Coatings 2025, 15(2), 203; https://doi.org/10.3390/coatings15020203 - 7 Feb 2025
Viewed by 1155
Abstract
The spraying process affects the microstructure and service life of thermal barrier coatings. In this work, by changing the plasma-spraying process, the second-phase micron-agglomerated particles were introduced to prepare embedded micron-agglomerated particle thermal barrier coatings. Conventional thermal barrier coatings and embedded micron-agglomerated particle [...] Read more.
The spraying process affects the microstructure and service life of thermal barrier coatings. In this work, by changing the plasma-spraying process, the second-phase micron-agglomerated particles were introduced to prepare embedded micron-agglomerated particle thermal barrier coatings. Conventional thermal barrier coatings and embedded micron-agglomerated particle thermal barrier coatings were prepared by setting spraying process parameters with different powder feeding rates and distances between powder feeders. Sintering experiments and thermal cycling experiments were carried out on conventional thermal barrier coatings and embedded micron-agglomerated particle thermal barrier coatings. The effects of spraying process parameters on the microstructure and thermal cycle life of embedded micron-agglomerated particle thermal barrier coatings were systematically studied. Three machine learning models of BP, SVM, and GA-SVM were established to evaluate the relationship between spraying parameters and coating microstructure and thermal cycle life. The results show that the sintering resistance of the new thermal barrier coating is 500% higher than that of the conventional thermal barrier coating. When the distance between the two powder feeders is 35 mm and the powder feeder 1 rate is 12 g/min, the thermal cycle life of the coating is the best. When using machine learning model evaluation, the evaluation results of the three machine learning models have certain accuracy. Among them, the GA-SVM machine learning model has the best prediction effect and the smallest prediction error. The results of this paper provide a new paradigm for further preparation of thermal barrier coatings with high performance and long life. Full article
(This article belongs to the Special Issue Advanced Coatings with Noble and Refractory Alloy Metals in Extreme Environments)
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47 pages, 12325 KB  
Review
Crack-Templated Patterns in Thin Films: Fabrication Techniques, Characterization, and Emerging Applications
by Eleonora Sofia Cama, Mariacecilia Pasini, Umberto Giovanella and Francesco Galeotti
Coatings 2025, 15(2), 189; https://doi.org/10.3390/coatings15020189 - 6 Feb 2025
Cited by 6 | Viewed by 4827
Abstract
Crack-templated thin films, inspired by naturally occurring patterns such as leaf venation, spider webs, and the networked structure of dried egg white, represent a paradigm shift in the design of functional materials. Traditionally, cracks in coatings are seen as defects to be avoided [...] Read more.
Crack-templated thin films, inspired by naturally occurring patterns such as leaf venation, spider webs, and the networked structure of dried egg white, represent a paradigm shift in the design of functional materials. Traditionally, cracks in coatings are seen as defects to be avoided due to their potential to compromise mechanical integrity and performance. However, in this context, cracks are deliberately induced and meticulously controlled to serve as templates for versatile applications. This review explores the latest advances in preparation techniques, including solvent evaporation and thermal stress induction, with a focus on the interplay between material properties (e.g., polymers and ceramics) and process parameters (e.g., drying rates and temperature, layer thickness, substrate interactions) that govern crack behavior. The resulting crack patterns offer tunable features, such as density, width, shape, and orientation, which can be harnessed for applications in semitransparent electrodes, flexible sensors, and wearable and energy storage devices. Our study aims to navigate the advancements in crack engineering in the last 10 years and underscores its importance as a purposeful and versatile strategy for next-generation thin-film technologies, offering a novel and affordable approach to transforming perceived defects into assets for cutting-edge thin-film technologies. Full article
(This article belongs to the Special Issue Accelerated Development of Nanomaterials, Coatings, and Thin Films for Optical and Electronic Applications)
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18 pages, 11216 KB  
Article
Advanced Techniques for the Fabrication of Nanostructured Porous Silicon Using Photoelectrochemical Etching and Ultrasonic Vibration
by Chao-Ching Chiang and Philip Nathaniel Immanuel
Coatings 2025, 15(2), 179; https://doi.org/10.3390/coatings15020179 - 5 Feb 2025
Cited by 1 | Viewed by 1998
Abstract
This study presents a novel method combining photoelectrochemical etching with ultrasonic vibration for the formation of nanocrystalline porous silicon (NC-PS). This combined process enhances the band gap energy absorption (BEA) by reducing bubble accumulation in the etching area. It is found that laser [...] Read more.
This study presents a novel method combining photoelectrochemical etching with ultrasonic vibration for the formation of nanocrystalline porous silicon (NC-PS). This combined process enhances the band gap energy absorption (BEA) by reducing bubble accumulation in the etching area. It is found that laser irradiation can decrease the etching rate, while ultrasonic vibration aids with bubble expulsion, preventing accumulation in the etching area, resulting in more uniform etching and increasing the porosity of the porous silicon (PS). High porosity in NC-PS structures enhances the surface area, thereby increasing electron mobility and improving the electron energy distribution. Our experiments demonstrate that this combined process leads to more uniform and deeper etching and the creation of well-defined porous structures. The more uniform PS size distribution (8–14 nm) achieved by photoelectrochemical etching combined with ultrasonic vibration enhances the optical properties of the material due to quantum confinement effects. Porosity measurements provide essential surface characterization information that is crucial for determining the performance of PS diode components in various applications. Our findings demonstrate that this combination technique improves the uniformity, efficiency, and precision of porous silicon etching, producing material for high-performance applications, including sensors, catalysts, and photonic devices. Full article
(This article belongs to the Special Issue Energy Storage and Conversion: From Materials, Devices to Applications)
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16 pages, 8936 KB  
Article
Evaluating the Application of Cold Spray Technology for the Deposition of Copper–Graphene Composite Coatings
by Fatemeh Zarei, Amir Ardeshiri Lordejani, Siyuan Ruan, Shuo Yin, Mario Guagliano, Rocco Lupoi and Sara Bagherifard
Coatings 2025, 15(2), 153; https://doi.org/10.3390/coatings15020153 - 31 Jan 2025
Viewed by 1799
Abstract
The design and implementation of two-dimensional materials into a metal matrix have been the focus of considerable research interest for achieving enhanced properties. Nevertheless, conventional and modern manufacturing techniques often struggle to fabricate bulk 2D metal matrix composites (2DMMCs) while preserving the desired [...] Read more.
The design and implementation of two-dimensional materials into a metal matrix have been the focus of considerable research interest for achieving enhanced properties. Nevertheless, conventional and modern manufacturing techniques often struggle to fabricate bulk 2D metal matrix composites (2DMMCs) while preserving the desired distribution and preventing thermomechanical damage to the constituent phases. Cold spray technology is a solid-state manufacturing method known for maintaining the composition of the original feedstock without causing significant detrimental changes during the deposition process. This study investigates the influence of cold spray process parameters on the microstructure, porosity, and microhardness of copper composites reinforced with 1 wt.% graphene platelets. The copper–graphene composite powder was synthesized via high-energy ball milling and subsequently deposited using two distinct sets of cold spray parameters employing medium- and high-pressure systems. Scanning electron microscopy, dispersive X-ray spectroscopy, porosity measurements, microhardness testing, and Raman spectroscopy were used to comprehensively evaluate the deposits. The findings demonstrate the preservation of the 2D phase and show how cold spray parameters influence porosity, hardness, and the incorporation of graphene within the copper matrix. Full article
(This article belongs to the Special Issue New Materials and New Applications for the Cold Gas Spray Process)
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24 pages, 7590 KB  
Article
The Influence of Roughness of Surfaces on Wear Mechanisms in Metal–Rock Interactions
by Vlad Alexandru Florea, Mihaela Toderaș and Ciprian Danciu
Coatings 2025, 15(2), 150; https://doi.org/10.3390/coatings15020150 - 30 Jan 2025
Cited by 6 | Viewed by 2532
Abstract
The processes of rock excavation and processing involve intense mechanical stresses on cutting, displacing, and transporting tools, inevitably leading to the phenomenon of dry friction wear. The factors influencing the intensity and mechanisms of wear are complex and interdependent, being conditioned by the [...] Read more.
The processes of rock excavation and processing involve intense mechanical stresses on cutting, displacing, and transporting tools, inevitably leading to the phenomenon of dry friction wear. The factors influencing the intensity and mechanisms of wear are complex and interdependent, being conditioned by the physical–mechanical properties of the rocks, the geometric characteristics and materials of the tools, as well as the cutting process parameters (cutting force, feed rate). Previous studies have mainly addressed the global aspect of wear without delving into the microstructural evolution of the contact surfaces during the friction process. In this paper, through controlled tribometric tests, we have investigated in detail the abrasive wear mechanisms of metallic materials in contact with different types of rocks, with an emphasis on the role played by surface roughness and the mineralogical properties of the rocks. Experimentally, we varied the applied forces and the number of friction cycles to simulate different working conditions and evaluate how these parameters influence wear intensity and surface morphology evolution. Microstructural analysis of the samples, combined with roughness measurements, allowed the identification of the predominant degradation mechanisms (abrasion, adhesion, fatigue) and their correlation with the material properties and the friction process parameters. The results have shown a strong correlation between the wear capacity of rocks and their petrographic properties, such as hardness, porosity, and hard mineral content. It was also found that the roughness of the contact surfaces plays an essential role in wear mechanisms, influencing both the initiation and propagation of its effects. Depending on the experimental data, we have developed a classification of rocks based on their abrasive potential and proposed criteria for the optimal adoption of materials and working parameters for the tools of technological equipment depending on the type of rock encountered. The results of this study can contribute to improving the durability of tools, as well as mining equipment, and reducing operating costs. Full article
(This article belongs to the Special Issue Friction and Wear Behaviors in Mechanical Engineering)
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15 pages, 5737 KB  
Article
Guidance of Osteoblast Migration Using Femtosecond Laser-Induced Hierarchical Structures
by Johannes Heitz, Simon Glachs, Lukas Wagner, Christoph Wolf, Cristina Plamadeala, Martina Muck, Karoline Seibert, Christian Maier, Romy Marek, Agnes Weth and Werner Baumgartner
Coatings 2025, 15(2), 127; https://doi.org/10.3390/coatings15020127 - 23 Jan 2025
Cited by 1 | Viewed by 1435
Abstract
The adhesion and alignment of osteoblasts and fibroblasts on titanium alloy (Ti-6Al-4V) surfaces can be adjusted over a wide range by femtosecond laser treatment and anodization. The great differences in cell behavior between different experimental conditions raised further questions about the role of [...] Read more.
The adhesion and alignment of osteoblasts and fibroblasts on titanium alloy (Ti-6Al-4V) surfaces can be adjusted over a wide range by femtosecond laser treatment and anodization. The great differences in cell behavior between different experimental conditions raised further questions about the role of cell migration, which will be addressed in this study. For that, Ti-6Al-4V surfaces were laser-structured to obtain a surface covered with ripples, i.e., laser-induced periodic surface structures (LIPSS), or micro-cones superimposed with ripples. Then, cells were seeded either directly onto the non-structured or laser-structured areas on the titanium alloy samples or beside such samples where they can reach the surface by cell migration. After two weeks in culture, the cell coverage of the samples was evaluated by scanning electron microscopy (SEM). The results showed that cells directly seeded onto the non-structured or laser-structured areas covered the surface nearly completely and eventually aligned along the ripple direction for the laser-structured areas. In contrast, for cell-seeding beside the samples, the laser-structured areas remain nearly cell-free while the non-structured areas were covered with cells in a similar non-oriented manner as for direct cell-seeding. These results on reduced osteoblast migration due to laser structuring are in line with the findings in animal experiments. There, the new bone formation of laser-processed samples was 26.1% ± 16.9% lower in comparison to untreated samples of the same type, which can be explained by hindered cell migration on the laser-processed areas of the screws. Full article
(This article belongs to the Special Issue Bioadhesion on Laser Functionalized Surfaces)
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16 pages, 2152 KB  
Article
The Effect of Ti(C,N)-Based Coating Composition on Ni-Cr Alloys on the Initial Adhesion of E. coli Bacteria and C. albicans Fungi
by Katarzyna Banaszek, Katarzyna Dąbrowska, Witold Jakubowski, Leszek Klimek and Zofia Kula
Coatings 2025, 15(2), 121; https://doi.org/10.3390/coatings15020121 - 21 Jan 2025
Cited by 1 | Viewed by 1005
Abstract
Under natural physiological conditions, the oral cavity is colonized by a diverse range of microorganisms, which inhabit its anatomical structures as well as prosthetic restorations and the supragingival surfaces of implants. The metabolic activity of these microorganisms can contribute to microbiological corrosion, leading [...] Read more.
Under natural physiological conditions, the oral cavity is colonized by a diverse range of microorganisms, which inhabit its anatomical structures as well as prosthetic restorations and the supragingival surfaces of implants. The metabolic activity of these microorganisms can contribute to microbiological corrosion, leading to the degradation of metal prosthetic materials. No material used for prosthetic elements is entirely resistant to bacterial adhesion. However, the application of protective coatings, such as Ti(C,N) coatings, on prosthetic surfaces can significantly reduce microorganism adherence. This study aimed to evaluate the influence of carbon and nitrogen content in Ti(C,N) coatings on reducing microorganism adhesion. Tests were conducted on five groups of Ni-Cr alloy specimens, each coated with Ti(C,N) layers containing varying amounts of carbon and nitrogen. The adhesion of E. coli bacteria and C. albicans fungi was assessed under both stationary and dynamic flow conditions. Results demonstrated that all tested coatings significantly reduced microorganism adhesion compared to uncoated Ni-Cr alloy samples. Full article
(This article belongs to the Special Issue Ceramic and Metallic Biomaterials. Application in Medical Sciences)
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25 pages, 19542 KB  
Article
Preparation and Characterization of Mg-Based Biomaterials with Bioactive Surfaces Functionalized with EU/Gd NPs for Bone Tissue Regeneration Obtained via PEO Process
by Klaudia Kuźmiak, Łukasz Janus, Aleksandra Sierakowska-Byczek and Julia Radwan-Pragłowska
Coatings 2025, 15(2), 124; https://doi.org/10.3390/coatings15020124 - 21 Jan 2025
Viewed by 1721
Abstract
This study aimed to develop a novel type of biodegradable magnesium (Mg)-based implant with enhanced biological activity through surface modification using plasma electrolytic oxidation (PEO) combined with the incorporation of rare earth ions (Eu and Gd). Magnesium is recognized for its lightweight nature, [...] Read more.
This study aimed to develop a novel type of biodegradable magnesium (Mg)-based implant with enhanced biological activity through surface modification using plasma electrolytic oxidation (PEO) combined with the incorporation of rare earth ions (Eu and Gd). Magnesium is recognized for its lightweight nature, biocompatibility, and bone-like mechanical properties, making it a promising alternative to titanium implants. Unlike titanium, Mg-based biomaterials can be safely used in pediatric surgery due to their ability to degrade naturally within the body. However, pure magnesium is highly reactive in physiological fluids, necessitating surface modifications to mitigate biocorrosion prior to clinical application. To address this challenge, the PEO process was employed, resulting in surface passivation and the formation of a protective coating. Experimental evaluations demonstrated reduced biodegradation rates and magnesium ion release, confirming the beneficial role of rare earth elements in decreasing reactivity. Wettability tests indicated high hydrophilicity, while scanning electron microscopy (SEM) revealed appropriate surface morphology and element deposition conducive to bone regeneration. Electrochemical analyses further validated the protective efficacy of the magnesium oxide layers enhanced with rare earth ions. Finally, in vitro cytotoxicity tests on the MG-63 osteosarcoma cell line confirmed the biocompatibility of the modified magnesium implants. Overall, this study highlights the potential of Mg-based biomaterials, modified through PEO and rare earth ion incorporation, for use in medical implants. Full article
(This article belongs to the Section Surface Coatings for Biomedicine and Bioengineering)
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