Search Results (188)

The bioinspired superhydrophobic surfaces have demonstrated many fascinating performances in fields such as self-cleaning, anti-corrosion, anti-icing, energy-harvesting devices, and antibacterial coatings. However, developing a low-cost, feasible, and scalable production approach to fabricate robust superhydrophobic surfaces has remained one of the main challenges in the past decades. In this paper, we propose an uncommon method for the fabrication of a durable superhydrophobic coating on the surface of the glass slide (GS). By utilizing the screen printing method and high-temperature curing, the epoxy resin grid (ERG) coating was uniformly and densely loaded on the surface of GS (ERG@GS). Subsequently, the hydrophobic silica (H-SiO₂) was deposited on the surface of ERG@GS by the impregnation method, thereby obtaining a superhydrophobic surface (H-SiO₂@ERG@GS). It is demonstrated that the micro-grooves in ERG can provide a large specific surface area for the deposition of low surface energy materials, while the micro-columns can offer excellent protection for the superhydrophobic coating when it is subjected to mechanical wear. It is important to note that micro-columns, micro-grooves, and nano H-SiO₂ jointly form the micro–nano structure, providing a uniform and robust rough structure for the superhydrophobic surface. Therefore, the combination of a micro–nano rough structure, low surface energy material, and air cushion effect endow the material with excellent durability and superhydrophobic property. The results show that H-SiO₂@ERG@GS possesses excellent self-cleaning property, mechanical durability, and chemical stability, indicating that this preparation method of the robust superhydrophobic coating has significant practical application value. Full article

Metal materials are widely used in power grid infrastructure, but they are prone to metal corrosion due to long-term exposure to various environmental conditions, resulting in significant losses. The existing superhydrophobic coatings have good anti-corrosion performance, but poor wear resistance. Therefore, it is extremely important to improve the wear resistance of superhydrophobic coatings. In this study, a kind of fluorine-modified SiO₂ particle was prepared with pentafluorooctyltrimethoxysilane (FAS-13) as the low surface energy modifier, following the fabrication of a superhydrophobic coating on metal substrate via a PDMS-doped spray deposition method to reinforcement wear resistance property. XPS, FT-IR and Raman spectra confirmed the successful introduction of FAS-13 on SiO₂ particles, as evidenced by the characteristic fluorine-related peaks. TGA revealed that the fluorine modified SiO₂ (F-SiO₂) particles exhibited excellent thermal stability, with an initial decomposition temperature of 354 °C. From the perspective of surface morphology, the relevant data indicated a peak-to-valley height difference of only 88.7 nm, with Rq of 11.9 nm and Ra of 8.86 nm. And it also exhibited outstanding superhydrophobic property with contact angle (CA) of 164.44°/159.48°, demonstrating remarkable self-cleaning performance. And it still maintained CA of over 150° even after cyclic abrasion of 3000 cm with 800 grit sandpaper under a 100 g load, showing exceptional wear resistance. In addition, it was revealed that the coated electrode retained a high impedance value of 8.53 × 10⁸ Ω·cm² at 0.1 Hz after 480 h of immersion in 5 wt% NaCl solution, with the CPE exponent remaining close to unity (from 1.00 to 0.97), highlighting its superior anti-corrosion performance and broad application prospects for metal corrosion prevention. Full article

Anti-icing materials have attracted considerable research interest due to their potential applications in preventing ice accretion and growth. However, a major challenge in the field is how to enhance durability while maintaining anti-icing performance. This study proposes a facile fabrication method for anti-icing coatings with anti-aging and self-healing abilities. A three-dimensionally cross-linked block copolymer, synthesized from polydimethylsiloxane, 4-aminophenyl disulfide, and trimethylolpropane triglycidyl ether, yielded a coating with excellent anti-icing/de-icing performance, including a low ice adhesion strength (29.2 kPa) and a high icing delay time (1389 s). The introduction of 4-aminophenyl disulfide enables dynamic disulfide bond reorganization and aromatic framework formation, synergistically conferring the icephobic coating with self-repair mechanisms and an anti-aging function. The coating exhibited a rapid self-healing capability (within 4 h), which is facilitated by the dynamic exchange of its hydrogen and disulfide bonds. Furthermore, the material demonstrated outstanding durability against physical wear and ultraviolet radiation. After being subjected to a 1000-cycle abrasion test and ultraviolet aging, the coating successfully retained more than 70% of its original performance in both icing delay time and ice adhesion strength. This paper proposes a facile strategy for developing self-healing and anti-aging anti-icing coatings and proposes innovative strategies for multifunctional anti-icing coatings. Full article

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

We aimed to address the issue of fretting wear on the rollers and raceways of pitch bearings in wind turbines during shutdown and under intermittent high loads. This study focuses on triple-row cylindrical roller bearings. A finite element wear simulation of the contact area between a single roller and the raceway was established based on Hertzian contact theory and the modified Archard model. The wear coefficient values of the model before and after coating were verified through experiments, with results of k₁ = 3.125 × 10⁻⁸ and k₂ = 4.5 × 10⁻¹⁰, respectively. The effects of normal load, displacement amplitude, and cycle number on the fretting wear behavior of rollers under both uncoated and GLC-coated conditions were investigated. The results show that the GLC (Glassy Carbon-like Carbon) film significantly reduces the friction coefficient and wear. Compared to uncoated rollers, it reduces the maximum wear depth by approximately 90.53% across various normal loads, displacement amplitudes, and numbers of cycles. Additionally, the wear rate of the coated rollers remains consistently low with small fluctuations. The conclusion holds that the GLC film reduces the interface shear force and effective slip amplitude, enhances surface hardness and stability, and improves the fretting wear resistance of pitch bearings by an order of magnitude under complex load and oil-starved conditions. The primary objective of this work is to investigate the mechanisms for enhancing the anti-fretting wear performance of pitch bearings, with the goal of significantly extending their service life and reliability in harsh operating environments. Full article

Smart self-healing polymer materials are breaking open new pathways in industry, minimizing waste, and enhancing the long-term reliability of applications. Moreover, when they possess anti-corrosive properties, they effectively protect surfaces from wear and corrosion, leading to improved and more robust products. In the present work, we develop a series of new self-healing polyurethane coatings activated by temperature, through the encapsulation of vegetable oils (VO), namely olive, soybean, and castor oil, in the core of polyurea microcapsules (VO-MCs). Using a green method, water-dispersible microcapsules were embedded in water-based polyurethane matrices. Both the self-healing ability and the anti-corrosive properties of the respective films were evaluated after mechanical damage. Encapsulation allowed for the direct release of VOs into the damaged area; subsequently, the temperature increase reduced the viscosity of the oils, facilitating their flow and diffusion into the damaged area and accelerating the healing process. Soybean oil and olive oil showed remarkable performance in terms of self-healing and high anti-corrosion ability for the polyurethane coatings, while castor oil showed a limited anti-corrosion effect but quite satisfactory effectiveness in terms of self-healing. Overall, the study highlights the potential of using encapsulated oils in environmentally friendly, active coatings with dual action: corrosion protection and self-repair of damage. Full article

High-entropy alloy (HEA) coatings have attracted significant attention in the nuclear power field due to their exceptional properties, showing great potential for accident-tolerant fuel (ATF) applications. In this study, novel AlCrFeMoZr HEA coatings with a near-equal molar ratio were successfully fabricated via magnetron sputtering at different bias voltages (−50 V, −100 V, and −150 V). The influence of bias voltage on the microstructure and mechanical properties of the coatings was systematically investigated. The results reveal that all HEA coatings exhibit a body-centered cubic structure with a (110) preferential orientation. As the bias voltage increased, the Al content in the HEA coating decreased, and the microstructure coarsened. The microhardness and friction and wear test results demonstrate that an HEA coating deposited at −100 V exhibited optimal mechanical properties owing to its good balance between hardness and toughness, leading to an improved tribological performance. Furthermore, a high-temperature water vapor oxidation experiment was conducted at 1200 °C in order to preliminarily study the differences in the anti-oxidation behavior of the new composition, an AlCrFeMoZr HEA coating, when deposited at various biases. Full article

Sediment-laden seawater (1.4 kg/m³) under controlled flow velocities (1.5 m/s and 3.0 m/s) was employed to evaluate degradation mechanisms in static anti-fouling coatings. Exposure to 1.5 m/s sediment-laden flow induced a 49% reduction in adhesion strength, a 4.9–5.2° decrease in water contact angle, and an elevation in surface roughness from 0.32 μm to 0.88 μm after 30 days. Concurrently, antibacterial rate and anti-algal rate declined by 11.9% and 14.6%, respectively. In comparison, pure seawater scouring at equivalent velocity reduced adhesion by 30% and contact angle by merely 1.1°. Low-flow (1.5 m/s) conditions accelerated abrasive wear, driving severe surface roughening, whereas higher flow velocity (3.0 m/s) disrupted sustained particle–coating contact through turbulence generation, attenuating roughness progression. Crucially, low-flow conditions intensified abrasive wear and promoted severe surface roughening, whereas higher flow velocities generated sufficient turbulence to disrupt sustained particle–coating contact, thereby slowing the progression of roughness. These findings reveal a previously unrecognized, flow-velocity-dependent erosion mechanism: lower velocities encourage particle deposition and progressive surface damage, while higher velocities unexpectedly produce a protective, turbulence-mediated buffering effect that mitigates surface roughening. These findings establish a theoretical foundation for developing advanced anti-fouling coatings with enhanced resistance to sediment erosion. Full article

Graphene exhibits great potential as an anti-friction coating material in MEMS. However, its underlying microscopic friction-reduction mechanism remains unclear. In this paper, the microstructural evolution and nanomechanical behavior of graphene coatings on copper substrates were systematically investigated by AFM friction experiments and MD simulations. MD simulations reveal that the anti-friction properties of graphene coatings primarily stem from microstructural regulation and load-bearing reinforcement of the substrate. The graphene coatings increase indentation diameter by forming transition radii at the indentation edges, and suppress the plowing effect of the substrate by restricting atomic upward movement, both of which enhance the dislocation density and load-bearing capacity of the substrate. Additionally, graphene coatings also reduce the scratch edge angle, weakening the interlocking effect between the substrate and tip, further lowering the friction force. Experimental results indicate that the tribological behavior of graphene coatings exhibits staged characteristics: graphene coatings show excellent ultrafriction properties under intact structural conditions, while showing a higher friction force in wear and tear states. This research provides a theoretical basis and technical guidance for the development of anti-friction and wear-resistant coatings for micro-nano devices. Full article

Aluminum alloy surface microstructures possess functional characteristics such as hydrophilicity/hydrophobicity and anti-icing and have important applications in fields such as aerospace and power systems. In order to improve the filling quality of the microstructure and verify the anti-icing property of the microstructure, this work develops a scheme for achieving large-area hot embossing of anti-icing functional microstructures based on a multi-arc ion-plating mold. Compared with conventional steel, the hardness of the PVD-coated steel increases by 44.7%, the friction coefficient decreases by 66.2%, and the wear resistance is significantly enhanced. The PVD-coated punch-assisted embossing could significantly improve filling properties. While the embossing temperature is 300 °C, the PVD-coated punch-assisted embossing can ensure the complete filling of the micro-array channels. In contrast, under-filling defects occur in conventional hot embossing. Then, a large-area micro-channel specimen of 100 cm² was precisely formed without warping, and the average surface roughness Ra was better than 0.8 µm. The maximum freezing fraction of the micro-array channel was reduced by about 53.2% compared with the planar, and the complete freezing time was delayed by 193.3%. The main reason is that the air layer trapped by the hydrophobic structures hinders heat loss at the solid–liquid interface. Full article

Atmospheric plasma spraying was used to create composite coatings employing mixed alloy matrices supplemented with carbon-based solid lubricants as feedstock materials. The current study’s goal was to examine the tribological properties of these coatings and explore the potential benefits of using CNTs as a nano-additive to minimize wear and friction while enhancing lubrication conditions in tribosystems such as piston ring–cylinder liner systems. Pin-on-disk measurements are used to correlate the chemical composition of feedstock materials with the friction coefficient and wear rate during coating operation. The enhanced behavior of the produced coatings is investigated. The anti-wear performance of Co-based cermet and metal alloys coatings, as well as the enhanced lubrication conditions during operation, are shown. In-depth discussion is provided regarding how the features of the feedstock powder affect the quality and performance of the produced coatings. The results showed that coatings based on the CoMo alloy exhibited an increase in wear due to CNT agglomeration. In contrast, CNT addition led to an improvement in bonding strength by up to 33%, a reduction in wear rate by up to 80%, and a decrease in the coefficient of friction from approximately 0.70 to 0.35 in CoNi cermet coatings. These findings demonstrate the role of CNTs in coating performance for demanding tribological applications. Full article

Carbide-bonded graphene (CBG) coating, with its unique 3D cross-linked network structure, shows significant potential for protecting silicon substrates. However, a comprehensive understanding of its macroscale tribological properties remains lacking. This study investigated the macroscale friction and wear behaviors of CBG-coated silicon wafers using reciprocating sliding tests against steel balls under various loads and sliding cycles. The CBG coating exhibited excellent friction-reduction and anti-wear performance, reducing the steady friction coefficient from 0.80 to 0.17 and wear rate by an order of magnitude compared to those of bare silicon. Higher loads slightly decreased both friction coefficients and wear rates, primarily due to the formation of denser tribofilms and transfer layers. Re-running experiments revealed three distinct wear stages—adhesive, abrasive, and accelerated substrate wear—driven by the evolution of tribofilms, transfer layers, and unabraded flat areas. Furthermore, comparative experiments confirmed that these “unabraded flat areas” on the wear track play a critical role in sustaining low friction and prolonging coating life. The findings identify CBG as a robust solid lubricant for high-contact-pressure applications and emphasize the influence of tribo-layer dynamics and wear debris behavior on coating performance. Full article

Cold gas dynamic spraying (CGDS) enables the production of protective coatings without melting or oxidation. In this study, Al–Zn–TiO₂ composite powders were prepared by wet agglomeration with binders and by dry mechanical mixing, and deposited onto mild steel substrates. COMSOL simulations of gas dynamics and particle acceleration identified optimal parameters (0.6 MPa, 600 °C, 15 mm, 90°), which were then validated experimentally. Coatings formed under these conditions exhibited dense microstructures, minimal porosity (~0.5%), and continuous, defect-free interfaces with the substrate. SEM and XRD confirmed solid-state bonding without new phase formation. Corrosion tests in 3.5% NaCl revealed a tenfold reduction in corrosion current density compared to bare steel, resulting from synergistic sacrificial (Zn), barrier (Al), and reinforcing/passivating (TiO₂) effects. Tribological tests demonstrated reduced friction (CoF ≈ 0.4–0.5) and wear volume. Compared with reported Al- or Zn-based cold- and thermal-sprayed coatings, the optimized Al–Zn–TiO₂ system shows superior performance, highlighting its potential for industrial anti-corrosion and wear-resistant applications. Full article

In view of the need to increase the durability of working tools exposed to intense friction, this study analysed hybrid coatings (TiAlCN, AlTiCN, AlCrTiN, TiN, CrN) with a DLC (Diamond-Like Carbon) layer, deposited using PVD (Physical Vapour Deposition) methods (arc evaporation and magnetron sputtering). The structural characteristics of the coatings were determined using SEM (Scanning Electron Microscope) and AFM (Atomic Force Microscope) microscopy, as well as Raman spectroscopy, which confirmed the compact structure and amorphous nature of the DLC layer. Tribological tests were performed using a ball-on-disc test, revealing that DLC hybrid coatings significantly reduce the coefficient of friction (stabilisation in the range of 0.10 to 0.14 due to DLC graphitisation), limiting tool wear even under increased load. The SEM-EDS (Scanning Electron Microscope-Energy Dispersive Spectroscopy) microscopic examination revealed that the dominant wear mechanisms are abrasive and adhesive damage, and the AlCrTiN/DLC system is characterised by low wear and high adhesion (L_c = 10⁵ N), making it the optimal configuration for the given loads. Microhardness tests showed that high hardness does not always automatically translate into increased wear resistance (e.g., the AlTiCN coating with 4220 HV showed the highest wear), while coating systems with moderate hardness (TiAlCN/DLC, CrN/DLC) achieved very low wear values (~0.17 × 10⁻⁵ mm³/Nm), which highlights the importance of synergy between the hardness of the sublayer and the low friction of DLC in the design of protective coatings. Full article

An environmentally friendly phosphating process was proposed, which used the synergistic action of citric acid and sodium citrate to form a uniform and dense phosphating film. Compared to the phosphate coating without sodium citrate, the |Z_0.01 Hz| of the coating with 0.8 g/L sodium citrate was approximately double. The friction coefficient and wear rate decreased by 29.25% and 94.8%, respectively. The phosphating treatment method reported in this study is expected to become an important way for the anti-corrosion field to environmental protection and economic benefits development. Full article