Coatings

22 pages, 5247 KB

Open AccessArticle

Enhanced Corrosion Resistance of Water-Based Aluminum Phosphate Coatings via Graphene Oxide Modification: Mechanisms and Long-Term Performance

by Feng Ding, Jiahui Xu, Xiaoxin Wei, Jiangdong Cao, Hongyan Wu, Lang Bai, Yujie Ma, Dongqian Li, Yilin Wang, Jiahan You and Bochen Jiang

Coatings 2026, 16(1), 11; https://doi.org/10.3390/coatings16010011 (registering DOI) - 20 Dec 2025

Abstract

In this study, we have developed a water-based aluminum phosphate (WAP) coating consisting of a base layer and a surface layer. Graphene oxide (GO) was used to modify the base layer. Three different GO concentrations—0.5, 0.75, and 1 wt.%—were employed to assess their [...] Read more.

In this study, we have developed a water-based aluminum phosphate (WAP) coating consisting of a base layer and a surface layer. Graphene oxide (GO) was used to modify the base layer. Three different GO concentrations—0.5, 0.75, and 1 wt.%—were employed to assess their impact on the corrosion resistance of the coating and to explore the underlying mechanisms. The corrosion resistance mechanism was also examined. In the coating, GO combined with phosphate to form large blocks that effectively blocked the pores, and the porosity decreased with the increase in GO content. This led to an improvement in the substrate protection efficiency by over 10%. Impedance spectroscopy revealed that the main mechanism behind the enhanced corrosion resistance was the shielding effect of GO, which created a “maze effect” that improved the coating’s protective properties. However, an excessive amount of GO reduced the corrosion resistance of the coating. Overall, the WAP coating modified with 0.75 wt.% GO exhibited the best corrosion resistance. Full article

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

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14 pages, 3206 KB

Open AccessArticle

Microstructured Coatings and Surface Functionalization of Poly(caprolactone-co-lactide) Using Gas-Permeable Mold

by Mano Ando, Naoto Sugino, Yoshiyuki Yokoyama, Nur Aliana Hidayah Mohamed and Satoshi Takei

Coatings 2026, 16(1), 10; https://doi.org/10.3390/coatings16010010 (registering DOI) - 20 Dec 2025

Abstract

Low-melting bioabsorbable polymers, such as poly(caprolactone-co-lactide) (PCLA), hold significant promise for biomedical applications. However, achieving high-precision micro- and nanotopographical functionalization remains a formidable challenge due to the material’s susceptibility to thermal deformation during conventional thermal molding processes. In this study, functional microstructured PCLA [...] Read more.

Low-melting bioabsorbable polymers, such as poly(caprolactone-co-lactide) (PCLA), hold significant promise for biomedical applications. However, achieving high-precision micro- and nanotopographical functionalization remains a formidable challenge due to the material’s susceptibility to thermal deformation during conventional thermal molding processes. In this study, functional microstructured PCLA coatings were engineered via low-temperature nanoimprint lithography utilizing a TiO₂–SiO₂ gas-permeable mold. These molds were synthesized via a sol–gel method utilizing titanium dioxide and silicon precursors. The gas-permeable nature of the mold facilitated the efficient evacuation of trapped air and volatiles during the imprinting process, enabling the high-fidelity replication of microstructures (1.3 μm height, 3 μm pitch) and nanostructured PCLA coatings featuring linewidths as narrow as 600 nm. The resultant microstructured PCLA coatings demonstrated modulated surface wettability, evidenced by an increase in water contact angles from 70.1° to 91.4°, and exhibited enhanced FD4 elution kinetics. These results confirm morphology-driven functionalities, specifically hydrophobicity and controlled release capabilities. Collectively, these findings underscore the efficacy of this microfabrication approach for polycaprolactone-based materials and highlight its potential to catalyze the development of high-value-added biomaterials for advanced medical and life science applications. This study establishes a foundational framework for the practical deployment of next-generation bioabsorbable materials and is anticipated to drive innovation in precision medical manufacturing. Full article

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

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19 pages, 1132 KB

Open AccessReview

Review on the Mechanical Properties of Cr-N Coatings Prepared by Physical Vapor Deposition

by Guanghui Wang, Yueqiu Jiang, Xiukun Wang and Cean Guo

Coatings 2026, 16(1), 9; https://doi.org/10.3390/coatings16010009 (registering DOI) - 20 Dec 2025

Abstract

Chromium nitride (Cr-N) coatings fabricated by physical vapor deposition (PVD) have gained significant interest in the field of surface protection with the exceptional hardness, robust adhesion to substrates, and superior wear resistance. The mechanical properties of Cr-N coatings are predominantly determined by their [...] Read more.

Chromium nitride (Cr-N) coatings fabricated by physical vapor deposition (PVD) have gained significant interest in the field of surface protection with the exceptional hardness, robust adhesion to substrates, and superior wear resistance. The mechanical properties of Cr-N coatings are predominantly determined by their chemical composition, phase structure, and microstructure. The selection of deposition technique and regulation of process parameters, such as N₂ flow rate, play a crucial role in optimizing coating performance. This review systematically summarizes recent research advancements in PVD-fabricated Cr-N coatings with a specific focus on both monolayer and multilayer architectures. It explores the impact of process parameters on the hardness, adhesion strength, and tribological properties. Furthermore, it outlines the design strategies and fabrication methodologies for high-performance Cr-N coatings. Results indicate that the mechanical properties of monolayer Cr-N coating are primarily governed by the process parameters. As for multilayer coatings, the incorporation of ductile Cr layers can enhance the coating-substrate adhesion strength and wear resistance while preserving a relatively high hardness. This study aims to provide a theoretical foundation and technical reference for future research and applications of the Cr-N coating material system. Full article

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

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16 pages, 2228 KB

Open AccessArticle

Machine Learning-Based Modeling and Multi-Objective Optimization of Magnetron-Sputtered Platinum Coatings

by Matej Kljajo, Nikša Čatipović, Ivan Peko and Janez Gotlih

Coatings 2026, 16(1), 8; https://doi.org/10.3390/coatings16010008 - 19 Dec 2025

Abstract

Platinum coatings produced by magnetron sputtering are highly valued due to their exceptional properties, including excellent electrical conductivity, high catalytic activity, and superior corrosion resistance. The quality of these coatings, however, is strongly dependent on the sputtering parameters. This study performs optimization of [...] Read more.

Platinum coatings produced by magnetron sputtering are highly valued due to their exceptional properties, including excellent electrical conductivity, high catalytic activity, and superior corrosion resistance. The quality of these coatings, however, is strongly dependent on the sputtering parameters. This study performs optimization of platinum thin film deposition on stainless steel substrates by systematically varying magnetron sputtering parameters. Experimental data were obtained under different conditions of discharge current, pressure, and deposition time. The results were analyzed using both classical regression techniques and advanced machine learning approaches to assess the influence of process parameters on deposition rate and coating thickness. Among the tested models, Gaussian Process Regression (GPR) demonstrated the highest accuracy and stability. The findings indicate that deposition time is the dominant factor influencing coating thickness, while discharge current primarily governs the deposition rate. Furthermore, multi-objective optimization and active learning approaches highlighted the potential of combining artificial intelligence methods with experimental design to reduce the number of required trials and improve process efficiency. Full article

(This article belongs to the Special Issue Recent Advances in Magnetron Sputtering for Functional Films and Coatings)

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16 pages, 3852 KB

Open AccessArticle

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

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

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

Abstract

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

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

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

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15 pages, 3748 KB

Open AccessReview

A Comprehensive Review of Intelligent Laser Rust Removal Technology in Offshore Wind Power Operation and Maintenance

by Yicheng Lai, Zhizheng Wang, Youchen Wang, Xingyu Liu, Shiheng Liu, Yong Han, Yuantao Zhao, Liang Meng, Wenge Li and Xiancheng Rong

Coatings 2026, 16(1), 6; https://doi.org/10.3390/coatings16010006 - 19 Dec 2025

Abstract

Corrosion difficulties have emerged as a key obstacle to the safe functioning of offshore wind turbine towers, prompting academics to focus on rust removal maintenance studies. Existing research focuses mostly on automated rust removal systems, which have limitations such as limited flexibility and [...] Read more.

Corrosion difficulties have emerged as a key obstacle to the safe functioning of offshore wind turbine towers, prompting academics to focus on rust removal maintenance studies. Existing research focuses mostly on automated rust removal systems, which have limitations such as limited flexibility and poor performance. In contrast, intelligent laser rust removal has emerged as a revolutionary solution due to its great efficiency and environmental friendliness. As a result, this paper examines and summarizes the strengths and limits of laser rust removal research before presenting a new offshore wind power operation and maintenance solution—the drone-based intelligent laser rust removal system. This technology uses solar and wave energy coupling to power the drone, resulting in a completely green operation that includes power supply, rust removal, and corrosion avoidance. The results show that this system has major advantages, such as high efficiency, environmental friendliness, safety, and advanced intelligence, making it an efficient solution for intelligent operation and maintenance in the offshore wind power industry. Full article

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21 pages, 2765 KB

Open AccessArticle

Development of Ordered Poly(aspartic Acid)-Oleic Acid Coatings with Enhanced Antimicrobial Activity: A Proof-of-Concept Study

by Michael Swaenepoel and Justin Miller

Coatings 2026, 16(1), 5; https://doi.org/10.3390/coatings16010005 - 19 Dec 2025

Abstract

The leading cause of post-surgical hospital readmission is the emergence of hospital-acquired infections (HAIs), where surgical site infections (SSIs) constitute a substantial negative impact on patient outcome and contribute annual direct costs estimated to range from $28.4 billion to $45 billion in the [...] Read more.

The leading cause of post-surgical hospital readmission is the emergence of hospital-acquired infections (HAIs), where surgical site infections (SSIs) constitute a substantial negative impact on patient outcome and contribute annual direct costs estimated to range from $28.4 billion to $45 billion in the U.S. To address the need for novel antimicrobial coating strategies, previous research has demonstrated that certain microbes can degrade poly(aspartic acid) (PAA)-based coatings, suggesting potential limitations of single-compound approaches that must be considered when designing antimicrobial surfaces. In this proof-of-concept study, we investigated whether ordered sequential coatings combining thermally synthesized PAA (tPAA) and oleic acid (OleA) might produce enhanced antimicrobial effects compared to individual compounds. Despite concerns regarding PAA biodegradability, the benefits of using PAA include low cytotoxicity and an ability to chelate metals such as calcium and facilitate bone mineralization and growth post-surgery. Using simple yet effective methods of surface coating applications which utilize tPAA and OleA, we investigated the potential of these ordered coatings to attenuate planktonic and sessile (biofilm) growth and development in Pseudomonas aeruginosa and Escherichia coli in vitro. Application of these ordered coatings resulted in up to 62% reduction in bacterial carrying capacity for P. aeruginosa and up to 43% reduction in biofilm mass relative to untreated controls. Further, confocal imaging via immunohistochemical labeling revealed methods for evaluating the impact of treatments targeting biofilm development through extracellular DNA quantification. Additionally, these coatings show dose-dependent cytotoxic effects against 3T3 mouse fibroblast cells. These preliminary findings, along with results derived from cytotoxicity assessment and physicochemical characterization via dynamic light scattering, suggest that ordered tPAA-OleA coating systems warrant further investigation as potential antimicrobial strategies, though additional validation, including testing against diverse clinical isolates, mechanistic studies, and in vivo evaluation, would be required before clinical application. Full article

(This article belongs to the Section Bioactive Coatings and Biointerfaces)

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2 pages, 1159 KB

Open AccessCorrection

Correction: Pineda-Domínguez et al. Remineralizing Effect of Three Fluorinated Varnishes on Dental Enamel Analyzed by Raman Spectroscopy, Roughness, and Hardness Surface. Coatings 2025, 15, 1091

by Karla Itzel Pineda-Domínguez, Samuel Eloy Morales-Gonzalez, Sandra E. Rodil, Isela Lizbeth Arredondo-Velazquez, Nelly Rivera-Yañez, Cesar Adolfo Callejas-Gomez, Oscar Nieto-Yañez and Cecilia Carlota Barrera-Ortega

Coatings 2026, 16(1), 4; https://doi.org/10.3390/coatings16010004 - 19 Dec 2025

Abstract

Error in Author Name [...] Full article

21 pages, 6221 KB

Open AccessArticle

Model of Mechanical Properties of Concrete in Western Saline Soil Regions Based on Grey Theory

by Deqiang Yang, Tian Su, Bangxiang Li, Xuefeng Mei and Fakai Dou

Coatings 2026, 16(1), 3; https://doi.org/10.3390/coatings16010003 - 19 Dec 2025

Abstract

Concrete structures in western saline soil regions are subjected to extreme environments with coupled dry-wet cycles and high concentrations of erosive ions such as Cl⁻, SO₄²⁻, and Mg²⁺, leading to severe degradation of mechanical properties. This [...] Read more.

Concrete structures in western saline soil regions are subjected to extreme environments with coupled dry-wet cycles and high concentrations of erosive ions such as Cl⁻, SO₄²⁻, and Mg²⁺, leading to severe degradation of mechanical properties. This study employed a simulated accelerated, high-concentration solution (Solution A, ~8× seawater salinity) similar to the composition of actual saline soil to perform accelerated dry-wet cycling corrosion tests on ordinary C40 concrete specimens for six corrosion ages (0, 5, 8, 10, 15, and 20 months). For each age, three replicate cube specimens were tested per property. The changes in cube compressive strength, splitting tensile strength, prism stress–strain full curves, and microstructure were systematically investigated. Results show that in the initial corrosion stage (0–5 months), strength exhibits a brief increase (compressive strength by 11.87%, splitting tensile strength by 9.23%) due to pore filling by corrosion products such as ettringite, gypsum, and Friedel’s salt. It then enters a slow deterioration stage (5–15 months), with significant strength decline by 20 months, where splitting tensile strength is most sensitive to corrosion. Long-term prediction models for key parameters such as compressive strength, splitting tensile strength, elastic modulus, peak stress, and peak strain were established based on grey GM(1,1) theory using the measured data from 0 to 20 months, achieving “excellent” accuracy (C ≤ 0.1221, p = 1). A segmented compressive constitutive model that considers the effect of corrosion time was proposed by combining continuous damage mechanics and the Weibull distribution. The ascending branch showed high consistency with the experimental curves. Life prediction indicates that under natural dry-wet cycling conditions, the service life of ordinary concrete in this region is only about 7.5 years when splitting tensile strength drops to 50% of initial value as the failure criterion, far below the 50-year design benchmark period. This study provides reliable theoretical models and a quantitative basis for durability design and life assessment of concrete structures in western saline soil regions. Full article

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

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26 pages, 5025 KB

Open AccessArticle

Modification of Polyethylene Films in Low-Temperature Gliding Discharge Arc Plasma

by Undrakh Mishigdorzhiyn, Kirill Demin, Andrei Khagleev, Oksana Ayurova, Stephan Agnaev, Saian Dondukov, Alexander Semenov and Shunqi Mei

Coatings 2026, 16(1), 2; https://doi.org/10.3390/coatings16010002 - 19 Dec 2025

Abstract

Polyethylene (PE) films are widely used as waterproofing materials on the surfaces of metal pipelines. Poor adhesion of PE films to a metal substrate reduces durability, leading to shorter service life and higher economic costs. The current research aims to study the modification [...] Read more.

Polyethylene (PE) films are widely used as waterproofing materials on the surfaces of metal pipelines. Poor adhesion of PE films to a metal substrate reduces durability, leading to shorter service life and higher economic costs. The current research aims to study the modification of PE films in atmospheric pressure gliding arc plasma (GAP). The adhesion properties of the modified films were investigated using the contact angle method and adhesion work calculations. During the modification process, the GAP treatment duration and deflector nozzle angle of attack were optimized to 10 s and 135°, respectively. It was established that the adhesion work increased from 62.1 to 141.3 mJ/m² after 10 s GAP modification compared to untreated PE. GAP modifying of PE films for 30 s or more is impractical, as the increase in the adhesion work ceases after that. It was found that surface roughness R_max increased by up to 4.1 times after 10 s GAP modification compared with nontreated PE. The PE films acquired hydrophilic properties after plasma modification, due to changes in the polymer surface’s chemical structure. The results of IR spectroscopy studies indicated oxidation of the film surface, an increase in the concentration of surface polar groups (-COOH, OH, C=O), and the formation of double bonds (C=C), which led to improved adhesive properties. A study of the electret properties showed that the observed decline and subsequent stabilization of values occurred within the first 24 h. Mechanical tests indicated improved performance of the GAP-modified PE films compared to the non-treated ones in the PE–mastic–PE and PE–mastic–steel systems. Due to their enhanced contact properties, the modified PE films are of interest as a base material for creating waterproofing materials. Full article

(This article belongs to the Special Issue Multifunctional Polymer Thin Films for Surface Engineering)

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14 pages, 3758 KB

Open AccessArticle

A Comparative Study of the Microstructure and Properties of Al₂CrFe₂Ni₄Ti_1.5 Coatings Fabricated by Oscillating Laser Cladding Under Pulsed and Continuous Modes

by Wei Liu, Dongqing Li, Jian Gu, Guojun Xiao, Yundong Zhao, Zeyang Wang, Hanguang Fu and Kaiming Wang

Coatings 2026, 16(1), 1; https://doi.org/10.3390/coatings16010001 - 19 Dec 2025

Abstract

As high-end equipment manufacturing advances, demand for improved surface performance in critical components has increased. Laser cladding is an advanced surface strengthening technique that affords effective surface modification. During the laser cladding process, obtaining a fine grain microstructure usually helps to enhance the [...] Read more.

As high-end equipment manufacturing advances, demand for improved surface performance in critical components has increased. Laser cladding is an advanced surface strengthening technique that affords effective surface modification. During the laser cladding process, obtaining a fine grain microstructure usually helps to enhance the microhardness, wear resistance, and corrosion resistance of the cladding layer. However, conventional laser cladding often yields coarse columnar grains that limit further performance improvements, so process optimization to achieve grain refinement is necessary. In this study, oscillating laser cladding was combined with a pulsed-wave (PW) laser mode to deposit a fine-grained Al₂CrFe₂Ni₄Ti_1.5 high-entropy alloy cladding on Q550 steel substrates. Compared with continuous-wave (CW) laser cladding, the PW mode produced markedly refined grains and concomitant improvements in microhardness, wear resistance, and corrosion resistance. Specifically, the microhardness of the PW cladding layer reached approximately 673.34 HV_0.5, the wear volume was approximately 0.06 mm³, the wear rate was approximately 0.21 × 10⁻⁴ mm³/N·m, and the corrosion current density decreased to approximately 1.212 × 10⁻⁵ A·cm⁻². This work presents a novel approach for producing high-performance, wear-resistant, and corrosion-resistant high-entropy alloy cladding layers, and offers both theoretical insight and potential engineering applications. Full article

(This article belongs to the Section Laser Coatings)

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8 pages, 177 KB

Open AccessEditorial

Progress and Perspectives in Nanostructured Thin Films

by Hummaira Khan and Yujun Song

Coatings 2025, 15(12), 1502; https://doi.org/10.3390/coatings15121502 - 18 Dec 2025

Abstract

The field of nanostructured thin films is experiencing rapid development, with materials scientists creating ever more fascinating structures at the nanoscale or even subnanoscale [...] Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings, 2nd Edition)

19 pages, 4008 KB

Open AccessArticle

Enhanced PVDF Coating via Zr-Based Pretreatment on AZ31 Magnesium Alloy

by Hailuo Fu, Chenghao Zhu, Dali Wei, Qing Lin, Yihan Jiao and Shuyang Liu

Coatings 2025, 15(12), 1501; https://doi.org/10.3390/coatings15121501 - 18 Dec 2025

Abstract

Magnesium alloys are promising biodegradable orthopedic implant materials, but their clinical translation is hindered by rapid, unregulated corrosion in physiological environments. Polyvinylidene fluoride (PVDF) coating has attracted substantial attention for addressing the issue above. However, it suffers from insufficient interfacial adhesion to Mg [...] Read more.

Magnesium alloys are promising biodegradable orthopedic implant materials, but their clinical translation is hindered by rapid, unregulated corrosion in physiological environments. Polyvinylidene fluoride (PVDF) coating has attracted substantial attention for addressing the issue above. However, it suffers from insufficient interfacial adhesion to Mg alloy substrates. In this work, we propose a Zr-based pretreatment strategy to enhance PVDF coatings. The pretreatment was performed via a chemical conversion deposition method, which fabricated a Zr-based film on AZ31 magnesium alloy and greatly promoted the adhesion of the following PVDF coating. Interface analysis showed that coating adhesion was improved from 0.44 MPa to 2.48 MPa. In light of this, corrosion protection performance was significantly improved. Electrochemical tests in simulated body fluid revealed the enhanced PVDF coating shifted the corrosion potential from −1.594 V to −1.392 V and reduced the corrosion current density by over five orders of magnitude. Immersion tests also showed stable pH level, low weight loss, and good hydrophobicity with the enhanced PVDF coating. In summary, the enhanced PVDF coating provides excellent corrosion protection for magnesium alloys, thus boosting their biomedical use. Full article

(This article belongs to the Special Issue Advances in Alloy Coatings: Tailored Performance for Modern Applications)

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17 pages, 4159 KB

Open AccessArticle

Effect of Cathodic Voltage on Phase Composition, Microstructure, and Elevated-Temperature Oxidation Resistance of Micro-Arc Oxidation Ceramic Coatings on Ti65 Alloy

by Haitao Li, Yu Ma, Baicheng Liu, Xugang Wang and Hongliang Zhang

Coatings 2025, 15(12), 1500; https://doi.org/10.3390/coatings15121500 - 18 Dec 2025

Abstract

This study investigates the effect of cathodic voltage on the thickness, morphology, composition, phase structure, adhesion, and elevated-temperature oxidation resistance of the micro-arc oxidation (MAO) ceramic coatings on Ti65 alloy. Coatings were fabricated via MAO under cathodic voltages of 50 V, 100 V, [...] Read more.

This study investigates the effect of cathodic voltage on the thickness, morphology, composition, phase structure, adhesion, and elevated-temperature oxidation resistance of the micro-arc oxidation (MAO) ceramic coatings on Ti65 alloy. Coatings were fabricated via MAO under cathodic voltages of 50 V, 100 V, 150 V, and 200 V. Results indicate that the coatings primarily consist of rutile TiO₂ (R-TiO₂), anatase TiO₂ (A-TiO₂), and amorphous SiO₂. The thickness of the MAO coatings increased with rising cathodic voltage, while the surface porosity and average pore size of the coatings were first decreased and then increased with the increase in cathodic voltage. Excellent coating adhesion to the substrate was confirmed by 50 thermal shock cycles between 700 °C and room temperature. Cyclic oxidation tests at 750 °C for 100 h demonstrated that all MAO coatings significantly enhanced elevated-temperature oxidation resistance compared to the bare Ti65 substrate. Notably, the coating produced at 100 V exhibited the lowest oxidation weight gain (0.50 mg/cm²), amounting to only one-third of the substrate’s gain. The effect of the cathodic voltage on the high-temperature oxidation performance of the MAO coatings was systematically analyzed. Full article

(This article belongs to the Section Ceramic Coatings and Engineering Technology)

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17 pages, 14285 KB

Open AccessArticle

Seismic Performance of Concrete Square Column Confined by Five-Spiral Composite Stirrups

by Shanshan Sun, Tao Yu, Xiangyu Gao, Zhaoqiang Zhang, Tian Su and Zhixing Hao

Coatings 2025, 15(12), 1499; https://doi.org/10.3390/coatings15121499 - 18 Dec 2025

Abstract

In order to solve the problem of inadequate confinement provided by traditional rectangular stirrups in concrete square columns under stringent seismic fortification requirements, a spiral stirrup with a better constraint effect was used in the square columns in this study. Through a comprehensive [...] Read more.

In order to solve the problem of inadequate confinement provided by traditional rectangular stirrups in concrete square columns under stringent seismic fortification requirements, a spiral stirrup with a better constraint effect was used in the square columns in this study. Through a comprehensive analysis of test results, numerical simulations, and theoretical derivations, the seismic performance and shear capacity calculation methods of concrete square columns confined with five-spiral composite stirrups were investigated. This study provides pertinent technical data to facilitate the engineering application of such columns. The existing low-cycle repeated loading tests of 13 concrete square columns confined with five-spiral composite stirrups were collected and analyzed; some of these specimens were selected for finite element numerical simulation, and the simulation results were compared with the test results. The results indicate that the hysteresis curves and skeleton curves obtained from the numerical simulation agree well with the experimental curves, which verifies the rationality of the numerical simulation model proposed in this paper; post-peak load behavior reveals a pronounced compound confinement effect attributable to the five-spiral stirrups; during mid-to-late loading stages, the tensile stress in small spiral stirrups at intersections with larger spirals escalates rapidly, resulting in maximum transverse confinement within these areas. Based on the validated numerical simulation approach, a comprehensive analysis was performed to investigate the effects of axial compression ratio, shear-span ratio, spacing of small spiral stirrups, and diameter ratio of large-to-small spiral stirrups on the seismic performance of the specimens. The results demonstrate that when the spacing of large and small spiral stirrups is kept consistent, the specimens yield optimal strength and ductility. With the diameter of the central large-spiral stirrup fixed, either an increase or a decrease in the diameter of small spiral stirrups will induce varying degrees of reduction in both strength and ductility of the specimens. Furthermore, the five-spiral reinforced columns achieve the best overall seismic performance when the diameter of the central large spiral stirrup reaches the maximum allowable value for the cross-section, and the diameter of small spiral stirrups is set to one-third that of the large spiral stirrup. Finally, the shear mechanism and influencing factors of the shear capacity of the concrete square columns confined with five-spiral composite stirrups were discussed, and a practical formula for calculating the shear capacity of such columns was proposed. Full article

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

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16 pages, 2368 KB

Open AccessArticle

Thermo-Chemo-Mechanical Coupling in TGO Growth and Interfacial Stress Evolution of Coated Dual-Pipe System

by Weiao Song, Tianliang Wu, Junxiang Gao, Xiaofeng Guo, Bo Yuan and Kun Lv

Coatings 2025, 15(12), 1498; https://doi.org/10.3390/coatings15121498 - 18 Dec 2025

Abstract

Improving the energy efficiency of advanced ultra-supercritical (USC) power plants by increasing steam operating temperature up to 700 °C can be achieved, at reduced cost, by using novel engineering design concepts, such as coated steam pipe systems manufactured from high temperature materials commonly [...] Read more.

Improving the energy efficiency of advanced ultra-supercritical (USC) power plants by increasing steam operating temperature up to 700 °C can be achieved, at reduced cost, by using novel engineering design concepts, such as coated steam pipe systems manufactured from high temperature materials commonly used in current operational power plants. The durability of thermal barrier coatings (TBC) in advanced USC coal power systems is critically influenced by thermally grown oxide (TGO) evolution and interfacial stress under thermo-chemo-mechanical coupling. This study investigates a novel dual-pipe coating system comprising an inner P91 steel pipe with dual coatings and external cooling, designed to mitigate thermal mismatch stresses while operating at 700 °C. A finite element framework integrating thermo-chemo-mechanical coupling theory is developed to analyze TGO growth kinetics, oxygen diffusion, and interfacial stress evolution. Results reveal significant thermal gradients across the coating, reducing the inner pipe surface temperature to 560 °C under steady-state conditions. Oxygen diffusion and interfacial curvature drive non-uniform TGO thickening, with peak regions exhibiting 23% greater thickness than troughs after 500 h of oxidation. Stress analysis identifies axial stress dominance at top coat/TGO and TGO/bond coat interfaces, increasing from 570 MPa to 850 MPa due to constrained volumetric changes and incompatible growth strains. The parabolic TGO growth kinetics and stress redistribution mechanisms underscore the critical role of thermo-chemo-mechanical interactions in interfacial degradation. These research findings will facilitate the optimization of coating architectures and the enhancement of structural integrity in high-temperature energy systems. Meanwhile, clarifying the stress evolution within the coating can improve the ability to predict failures in USC coal power technology. Full article

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

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16 pages, 4447 KB

Open AccessArticle

Effects of Relaxation and Nanocrystallization on Wear and Corrosion Behaviors of Fe-Based Amorphous Coating

by Shenghai Weng, Zhibin Zhang, Yuxi Fu, Lin Xue, Peisong Song, Liliang Shao, Xiubing Liang, Jiangbo Cheng and Binbin Zhang

Coatings 2025, 15(12), 1497; https://doi.org/10.3390/coatings15121497 - 18 Dec 2025

Abstract

In this study, amorphous Fe₆₀Nb₃B₁₇Si₆Cr₆Ni₄Mo₄ coatings were prepared using the high-velocity air fuel method. The microstructure, wear resistance, and corrosion resistance of the Fe₆₀Nb₃B₁₇Si [...] Read more.

In this study, amorphous Fe₆₀Nb₃B₁₇Si₆Cr₆Ni₄Mo₄ coatings were prepared using the high-velocity air fuel method. The microstructure, wear resistance, and corrosion resistance of the Fe₆₀Nb₃B₁₇Si₆Cr₆Ni₄Mo₄ coatings were examined for various levels of nanocrystallization. In contrast to the as-sprayed coating, the samples that were heat-treated formed partial α-Fe and crystalline Cr₂O₃. The generated nanocrystals exerted a dispersion-strengthening effect on the coatings, leading to enhanced hardness and fracture toughness. When the annealing temperature was below the initial crystallization temperature, the wear resistance improved by approximately 1.65 times, the wear rate decreased to half of that in the as-sprayed state, and the depth of the wear scar reduced. However, the resistance of the coatings to corrosion deteriorated as the degree of crystallization increased. X-ray photoelectron spectroscopy analysis revealed that heat treatment modified the composition of the passive film, thereby influencing its corrosion resistance. These results provide crucial insights into the application of Fe-based amorphous coatings in wear- and corrosion-resistant environments. Full article

(This article belongs to the Special Issue Advanced Corrosion- and Wear-Resistant Coatings)

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19 pages, 8828 KB

Open AccessArticle

Properties of Chromium Nitride and Diamond-like Coatings in Tribological Systems Lubricated with Artificial Blood

by Krystyna Radoń-Kobus and Monika Madej

Coatings 2025, 15(12), 1496; https://doi.org/10.3390/coatings15121496 - 18 Dec 2025

Abstract

This study investigated the tribological and mechanical properties of chromium nitride (CrN and CrN/DLC) coatings applied to 316L steel in an artificial blood environment. The wettability of the tested surfaces was determined and the hardness was also tested using the instrumental indentation. Friction-wear [...] Read more.

This study investigated the tribological and mechanical properties of chromium nitride (CrN and CrN/DLC) coatings applied to 316L steel in an artificial blood environment. The wettability of the tested surfaces was determined and the hardness was also tested using the instrumental indentation. Friction-wear tests were performed using a TRB³ tribometer in a rotating ball-on-disc configuration. The tests were performed under dry friction conditions and with lubrication using artificial blood at pH 7.45 (neutral environment) and pH 7.15 (acidified environment). Wear of the friction pairs was examined using an interferometric-confocal microscope. Artificial blood was chosen to simulate human body fluids. The use of the CrN/DLC coating reduced the coefficient of friction by 83% for dry friction, by 62% for friction with neutral artificial blood lubrication, and by 69% for friction with acidic artificial blood lubrication, respectively. Despite the increased coefficient of friction of the CrN coating, its use also contributed to reduced material wear. Full article

(This article belongs to the Special Issue Advancements in Surface Engineering, Coatings and Tribology)

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20 pages, 5137 KB

Open AccessReview

Recent Emerging MOF Textiles for Catalytic Degradation of Chemical Warfare Agents and Their Simulants

by Jia Liu, Yingqi Tang, Huijuan Zhao and Guodong Zhao

Coatings 2025, 15(12), 1495; https://doi.org/10.3390/coatings15121495 - 18 Dec 2025

Abstract

Chemical warfare agents (CWAs) threaten peace and global security due to their extreme toxicity and devastating effects. Prompt discovery and detoxification are imperative to protect ourselves from these perilous agents. Metal–organic frameworks (MOFs), characterized by high specific surface areas, tunable porosities, and chemical [...] Read more.

Chemical warfare agents (CWAs) threaten peace and global security due to their extreme toxicity and devastating effects. Prompt discovery and detoxification are imperative to protect ourselves from these perilous agents. Metal–organic frameworks (MOFs), characterized by high specific surface areas, tunable porosities, and chemical stability, have attracted growing interest for the catalytic degradation of CWAs. However, the powder form of MOFs hinders their application in protection, and it is challenging to combine them with flexible carriers to protect humans. In this context, we provide an update on the recent development of MOF textile materials for the efficient degradation of CWAs. The research progress on different technologies for the catalytic degradation of CWAs and their simulants in MOF textiles in recent years is presented. Furthermore, challenges in developing MOF textiles for the catalytic degradation of CWAs and their simulants are highlighted. It is expected that these useful insights will be beneficial in constructing relevant MOF textiles for the degradation of CWAs. Full article

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

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