Search Results (368)

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

The use of waste rubbers and polyurethane has a significant impact on the abrasion resistance of the porous elastic road surface (PERS) mixture. The purpose of this work is to study the anti-abrasion performance of the PERS mixture under different contents of waste rubbers. First, features of the surface of the PERS mixture were collected by image processing technology. Then, the abrasion performance of the mixture was studied by image processing and wear tests. The correlation between the surface texture parameters and the anti-abrasion performance of the mixture was analyzed by the gray entropy correlation method. It is found that the change of convex particle area in the equivalent diameter range of 2–5 mm had the greatest correlation with the abrasion resistance of the PERS mixture. The effect of the waste rubber content of the mixture on the anti-abrasion performance was investigated, and a waste rubber content of 10% showed the best anti-abrasion performance. It is expected that this work can provide a new method for analyzing the anti-abrasion performance of functional pavement. Full article

Oil additives are essential for improving anti-wear (AW) properties and durability of mechanical components. In this study, a novel ionic liquid based on phosphate ammonium salt (coded as IL-NPAS) was designed using organic synthesis methods. The high-level objective of this work is to enhance the wear resistance ability of oil-lubricated steels with low-cost additives in terms of materials and manufacturing methods. The IL-NPAS additive was incorporated at concentrations of 0.1 wt% and 0.5 wt% in 150 SN oil, which served as the base oil. Additionally, the commercial oil additive (coded as AW6110) was utilized as a reference to evaluate the effectiveness of the synthesized additive. The frictional behaviour was evaluated with an SRV tribometer at test temperatures of 25 °C and 100 °C. After that, SEM, 3D profilometry, XPS, and TOF-SIMS techniques were employed to show the wear modes and determine the chemical composition of the lubricating tribolayer. Noticeably, the formulated lubricant based on the 0.5 wt% IL-NPAS additive provided AW performance almost identical to the AW6110 additive. The results showed that the 0.5 wt% IL-NPAS additive reduced the coefficient of friction (COF) and improved AW properties by 34–36% and 80–90%, respectively, compared to the 150 SN base oil. Overall, this study holds significant promise for the development of low-cost lubricating oil additives. 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

A series of poly(5-n-butyl-2-norbornene) oils with controlled molecular weights was synthesized via metathesis polymerization, fully hydrogenated, and characterized in terms of viscosity and tribological performance. In contrast to established lubricant base stocks—such as poly(α-olefins) and multiply alkylated cyclopentanes—these novel norbornene-based polymers remain underexplored, despite their promising anti-wear activity. Based on differential scanning calorimetry (DSC) data, all the synthesized products are amorphous compounds whose thermograms show a single glass transition temperature. The effect of molecular weight and temperature on the viscosity of poly(5-n-butyl-2-norbornene) oils was quantified over an extended temperature range, including extra-cold conditions down to −80 °C. The pour points of the oils were determined and can be as low as −66 °C, indicating excellent low-temperature fluidity. The tribological performance of the synthesized oils was evaluated using the four-ball test, with friction coefficient and wear scar diameter measured to assess anti-wear and antifriction properties. The tribological results were benchmarked against commercially available polyalphaolefin (PAO) oils (PAO-4, PAO-20, and PAO-80). Metathesis and hydrogenated poly(5-n-butyl-2-norbornene) oils outperform conventional PAOs by up to 67% in wear protection and 30% in friction reduction. These findings establish alicyclic molecular strain as a viable design parameter for next-generation lubricating oils, thereby expanding the toolbox for material development beyond conventional chemical functionalization. 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

Porous concrete is widely recognized as an eco-friendly pavement material; however, existing studies mainly focus on its use as a base course, and systematic investigations on porous concrete specifically designed for heavy-traffic pavements and multifunctional surface performance remain limited. In this study, a novel multifunctional porous concrete with integrated noise reduction and drainage performance (PCNRD) was developed as a top-layer pavement material, addressing the performance gap in current applications. A comprehensive evaluation of the surface properties of porous concrete was performed based on tests of the sound absorption, void ratio, permeability, and wear resistance. The results demonstrate that the porous concrete exhibits excellent sound absorption (sound absorption coefficient 0.22–0.35) and high permeability (permeability coefficient 0.63–1.13 cm/s), and superior abrasion resistance (abrasion loss ≤ 20%) within an optimized porosity range of 17–23%. Furthermore, an optimized pavement thickness (8–10 cm) was proposed, and functional correlations among key surface performance indicators were revealed for the first time. Based on a uniform experimental design, four key mix parameters (water–cement ratio, cement content, silica fume content, and cement strength grade) were examined using strength and effective porosity as dual control indices, leading to the development of a novel mix design method tailored for PCNRD. This study not only fills the technical gap in high-performance porous concrete for heavy-traffic pavement surfaces but also provides a practical scientific framework for its broader engineering application. Full article

We are witnessing a global commitment to sustainable mobility that requires advanced materials and manufacturing techniques, such as fused filament fabrication (FFF), to create lightweight, durable, and recyclable machine components. Acknowledging that friction and wear significantly contribute to energy loss globally, developing high-performance polymeric materials with customizable properties is essential for greener mechanical systems. FFF inherently drives resource efficiency and offers the geometric freedom necessary to engineer complex internal structures, such as the gyroid pattern, enabling substantial mass reduction. This study evaluates the tribological performance of FFF-printed thermoplastic polyurethane (TPU 82A) specimens fabricated with three distinct gyroid infill densities (10%, 50%, and 100%). Ball-on-disc testing was conducted under dry sliding conditions against a 100Cr6 spherical ball, with a constant normal load of 5 N, resulting in an initial maximum theoretical Hertz contact pressure of 231 MPa, over a total sliding distance of 300 m. Shore A hardness and surface roughness (R_a) were also measured to correlate mechanical and structural characteristics with frictional response. Results reveal a non-monotonic relationship between infill density and friction, with a particular absence of quantifiable mass loss across all samples. The intermediate 50% infill (75.9 ± 1.80 Shore A) exhibited the peak mean friction coefficient of $\overline{\mu }=1.002$ (${\mu }_{\max }=1.057$), which can be attributed to its balanced structural stiffness that promotes localized surface indentation and an increased real contact area during sliding. By contrast, the rigid 100% infill (86.3 ± 1.92 Shore A) yielded the lowest mean friction ($\overline{\mu }$ = 0.465), while the highly compliant 10% infill (44.3 ± 1.94 Shore A) demonstrated viscoelastic energy damping, stabilizing at $\overline{\mu }$ = 0.504. This work highlights the novelty of using FFF gyroid architectures to precisely tune TPU 82A’s tribological behavior, offering design pathways for sustainable mobility. The ability to tailor components for low-friction operations (e.g., μ ≈ 0.465 for bushings) or high-grip requirements (e.g., μ ≈ 1.002 for anti-slip systems) provides eco-efficient solutions for automotive, railway, and micromobility applications, while the exceptional wear resistance supports extended service life and material circularity. 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

In the river environments of Xinjiang characterized by high sediment content and high flow velocities, hydraulic concrete is highly susceptible to damage from the impact and abrasion of bed load. Consequently, this imposes more stringent requirements on its mechanical properties and abrasion resistance. The incorporation of crumb rubber, a recyclable material, into concrete presents a dual benefit: it enables resource recycling while simultaneously offering a novel pathway for the development of concrete technology. This study takes rubber powder concrete as the research object. With the same water-to-binder ratio, rubber powder was incorporated at three volume fractions: 0%, 5%, and 10% of the cementitious material. The drop weight impact test and underwater steel ball method are adopted to evaluate its impact resistance and anti-scouring-abrasion performance, respectively. By testing the compressive strength, impact toughness, wear rate, anti-scouring-abrasion strength and three-dimensional morphological characteristics, the influence of rubber powder content on the mechanical properties and anti-scouring-abrasion performance of concrete is systematically analyzed. The research results show that the addition of rubber powder reduces the compressive strength of concrete, but significantly improves its impact resistance and anti-scouring-abrasion performance. Among all test groups, the concrete with 10% rubber powder content has the most significant decrease in compressive strength, with a decrease of about 37% compared with the 5% content group, while the 5% content group has a decrease of about 27% compared with the control group. However, its impact toughness at 3d, 7d and 15d is increased by about 84.7%, 88.4% and 84.4%, respectively, compared with the control group, showing the largest improvement range. At the same time, the wear rate of this group is reduced by about 42.5%, and the anti-scouring-abrasion strength is increased by about 61%. Combined with the three-dimensional morphology analysis, it can be seen that the specimens in this group exhibit the optimal anti-scouring-abrasion performance. In terms of microstructure, the porosity of rubber powder concrete increases, the generation of C-S-H gel decreases and its continuity is damaged, leading to a significant decrease in compressive strength. The reduction in the generation of delayed ettringite enhances the toughness and anti-scouring-abrasion performance. In general, the increase in rubber powder content will lead to a decrease in the compressive strength of concrete, but within a certain range, it can significantly improve its impact resistance and anti-scouring-abrasion performance. Crumb rubber effectively enhances the impact and abrasion resistance of hydraulic concrete, demonstrating strong application potential in high-flow, sediment-laden river environments. Full article

M50 steel is a critical bearing material, yet its tribological properties may deteriorate in engineering applications. To reduce the frictional resistance between M50 steel and contact surfaces, this study utilized laser processing technology to fabricate square- and wave-shaped textures (with a depth of ~30 μm) in both linear and staggered arrangements. The tribological performance of these textured surfaces was evaluated under dry and oil-lubrication conditions. Experimental results demonstrated that under dry friction conditions, linearly arranged textures reduced frictional resistance, while staggered textures exhibited superior anti-wear performance. Under oil-lubrication conditions, both linear and staggered textures contributed to friction and wear reduction. Moreover, a synergistic effect was observed for the composite staggered pattern, which achieved the maximum reduction in friction coefficient by up to 8.92% and 8.23% under dry and oil-lubricated conditions, respectively. Full article

An operational test and degradation analysis of a hydraulic fluid based on synthetic esters was performed in three types of work machines. To enhance its performance, ZDDP anti-wear agents were added. Hydraulic fluids are susceptible to degradation by oxidation; therefore, to ensure the long service life of the equipment, it is essential to monitor their current condition through laboratory analyses during machine operation. Emission spectrometry was used to determine the presence of contaminants and the concentration of additive substances in the oil. Pollution was assessed by cleanliness code analysis according to ISO 4406-2021, alongside Total Acid Number (TAN) analysis and LNF analysis of wear and contamination in lubricants. The combination of cleanliness code analysis and LNF analysis of particle type and origin allows for monitoring not only the count but also the origin of contaminating metallic particles, which increases the probability of correct diagnostics and successful detection and resolution of wear problems. All three machines were still operational at the end of the test interval, meaning the tested hydraulic fluid is a suitable alternative to mineral variants. However, in all three pieces of equipment, it is necessary to replace the hydraulic fluid and flush the system before further operation. Furthermore, we recommend replacing the filter elements and inspecting the internal spaces of rotating parts with an increased potential for wear. From the oil’s perspective, it is advisable to add more anti-wear additives (ZDDP), which are depleted the fastest. Full article