Search Results (8,518)

This work investigated the effect of high-nitrogen/low-hydrogen mixed atmosphere heat treatment on the electrochemical corrosion and wear resistance of plasma-sprayed FeCoNiCrAl high-entropy alloy (HEA) coatings. The HEA coatings were sequentially prepared through annealing at 400, 600, and 800 °C for 6 h. The heat treatment method was conducted in a vacuum tube furnace under 0.1 MPa total pressure, with gas flow rates set to 300 sccm N₂ and 100 sccm H₂. The XRD results indicated that the as-deposited coating exhibited α-Fe (BBC) and Al_0.9Ni_4.22 (FCC) phases, with an Fe_0.64N_0.36 nitride phase generated after 800 °C annealing. The electrochemical measurements suggested that an exceptional corrosion performance with higher thicknesses of passive film and double-layer capacitance can be detected based on the point defect model (PDM) and effective capacitance model. Wear tests revealed that the friction coefficient at 800 °C decreased by 3.84% compared to that in the as-sprayed state due to the formation of a dense nitride layer. Molecular orbital theory pointed out that the formation of bonding molecular orbitals, resulting from the overlap of valence electron orbitals of different atomic species in the HEA coating system, stabilized the structure by promoting atomic interactions. The wear mechanism associated with stress redistribution and energy balance from compositional synergy is proposed in this work. Full article

Poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) stands out as a renowned commercial conducting polymer composite, boasting extensive and promising applications in the realm of film electronics. In this study, we have made a concerted effort to overcome the inherent drawbacks of PEDOT:PSS films (especially, high moisture absorption, mechanical damage vulnerability, insufficient substrate adhesion ability, etc.) by uniformly blending them with polydimethylsiloxane polyurea (PDMS-PUa) and silica (SiO₂) nanoparticles through a feasible mechanical stirring process, which effectively harnesses the intermolecular interactions, as well as the morphological and structural characteristics, among the various components. The Si−O bonds within PDMS-PUa and the −CH₃ groups attached to Si atoms significantly enhance the hydrophobicity of the composite film (as evidenced by a water contact angle of 132.89° under optimized component ratios). Meanwhile, SiO₂ microscopically modifies the surface morphology, resulting in increased surface roughness. This composite film not only maintains high conductivity (1.21 S/cm, in contrast to 0.83 S/cm for the PEDOT:PSS film) but also preserves its hydrophobicity and electrical properties under rigorous conditions, including high-temperature exposure (60–200 °C), ultraviolet (UV) aging (365.0 nm, 1.32 mW/cm²), and abradability testing (2000 CW abrasive paper, drag force of approximately 0.98 N, 40 cycles). Furthermore, the film demonstrates enhanced resistance to both acidic (1 mol/L, 24 h) and alkaline (1 mol/L, 24 h) environments, along with excellent self-cleaning and de-icing capabilities (−6 °C), and satisfactory adhesion (Level 2). Notably, the dried composite film can be re-dispersed into a solution with the aid of isopropanol through simple magnetic stirring, and the sequentially coated films also exhibit good surface hydrophobicity (136.49°), equivalent to that of the pristine film. This research aims to overcome the intrinsic performance drawbacks of PEDOT:PSS-based materials, enabling them to meet the demands of complex application scenarios in the field of organic electronics while endowing them with multifunctionality. Full article

Protective coatings are essential for extending the service life of components exposed to harsh conditions, such as pipes used in industrial systems, where wear and corrosion remain constant challenges. This study explores the development of a nano-sized TiO₂-reinforced electroless nickel-based ternary (Ni-W-P) alloy and composite coating on API X60 steel, a high-strength carbon steel pipe grade widely used in oil and gas pipelines, using an alkaline hypophosphite-reduced bath. The surface morphology, microstructure, elemental composition, structure, phase evolution, adhesion, and roughness of the coatings were analyzed using optical microscopy, FESEM, EDS, XRD, AFM, cross-cut tape test, and 3D profilometry. The tribological performance was evaluated via Vickers microhardness measurements and reciprocating wear tests conducted under dry conditions at a 5 N load. The TiO₂ nanoparticle-reinforced composite coating achieved a consistent thickness of approximately 24 µm and exhibited enhanced microhardness and reduced coefficient of friction (COF), although the addition of nanoparticles increased surface roughness (S_a). Annealing the electroless composites at 400 °C led to a significant improvement in their tribological properties, primarily owing to the grain growth, phase transformation, and Ni₃P crystallization. XRD analysis revealed phase evolution from an amorphous state to crystalline Ni₃P upon annealing. Both the alloy and composite coatings exhibited excellent adhesion performances. The combined effect of TiO₂ nanoparticles, tungsten, and Ni₃P crystallization greatly improved the wear resistance, with abrasive and adhesive wear identified as the dominant mechanisms, making these coatings well suited for high-wear applications. Full article

The application of silicon–carbon (Si/C) composite materials in lithium-ion batteries faces problems regarding volume expansion and surface defects. Although coating is a popular modification scheme in the market, the influence of carbon layer quality on the electrochemical performance of Si/C still needs to be studied. By comparing the carbon layers produced by solid-phase and liquid-phase coating methods, an innovative solid–liquid coating technology was proposed to prepare high-strength and high-stiffness carbon layers, and the effects of different coating processes on the physical, mechanical, and electrochemical properties of the materials were systematically studied. Through physical properties and electrochemical testing, it was found that the solid–liquid coating method (Si/C@Pitch+RGFQ) can form a carbon layer with the least defects and the highest density. Compared with solid-phase coating and liquid-phase coating, its specific surface area (SSA) and carbon increment are the lowest, and the surface carbon content and oxygen content are significantly reduced after solid–liquid coating. Mechanical performance tests show that the Young’s modulus of the carbon layer prepared by this method reaches 30.3 GPa, demonstrating excellent structural strength and elastic deformation ability. The first coulombic efficiency (ICE) of Si/C@Pitch+RGFQ reached 88.17%, the interface impedance (23.2 Ω) was the lowest, and the lithium-ion diffusion coefficient was significantly improved. At a rate of 0.1 C to 2 C, the capacity retention rate is excellent. After one hundred and a half-cell cycles, the remaining capacity is 1420.5 mAh/g, and the capacity retention rate reaches 92.4%. The full-cell test further proves that the material has a capacity retention rate of 82.3% and 81.3% after 1000 cycles at room temperature and high temperature (45 °C), respectively. At the same time, it has good rate performance and high-/low-temperature performance, demonstrating good commercial application potential. The research results provide a key basis for the optimized preparation of the surface carbon layer of Si/C composite materials and promote the practical application of high-performance silicon-based negative electrode materials. Full article

To reduce reflective cracking in asphalt pavements, gravel base layers are commonly employed to disperse stress and delay structural damage. However, the loose nature of gravel bases results in complex interlayer contact conditions, typically involving interlocking between gravel particles in the base and aggregates in the asphalt surface course. In order to accurately simulate this interaction and to improve the interlayer shear performance, a mesoscale finite element model was developed and combined with macroscopic tests. Effects due to the type and amount of binder material, type of asphalt surface layer, and external loading on shear strength were systematically analyzed. The results indicate that SBS (Styrene–Butadiene–Styrene)-modified asphalt provides the highest interlayer strength, followed by SBR (Styrene–Butadiene Rubber)-modified emulsified asphalt and unmodified base bitumen. SBS (Styrene–Butadiene–Styrene)-modified asphalt achieves optimal interlaminar shear strength at a coating rate of 0.9 L/m². Additionally, shear strength increases with applied load but decreases with increasing void ratio and the nominal maximum aggregate size of the surface course in the analyzed spectra. Based on simulation and experimental data, an equivalent macro–meso predictive model relating shear strength to key influencing factors was established. This model effectively bridges mesoscale mechanisms and practical engineering applications, providing theoretical support for the design and performance optimization of asphalt pavements with gravel bases. Full article

The search for novel natural resources, such as extracts from algae and plant for use as reductants and capping agents for the synthesis of nanoparticles, may be appealing to medicine and nanotechnology. This study aimed to use Malva parviflora fruit extract as a novel source for the green synthesis of silver nanoparticles (AgNPs) and to evaluate their characterization. The results of biosynthesized AgNP characterization using multiple techniques, such as UV–Vis spectroscopy, scanning electron microscopy (SEM), FTIR analysis, and zeta potential (ZP), demonstrated that M. parviflora AgNPs exhibit a peak at 477 nm; possess needle-like and nanorod morphology with diameters ranging from 156.08 to 258.41 nm; contain –OH, C=O, C-C stretching from phenyl groups, and carbohydrates, pyranoid ring, and amide functional groups; and have a zeta potential of −21.2 mV. Moreover, the antibacterial activity of the M. parviflora AgNPs was assessed against two multidrug-resistant strains, including Staphylococcus aureus MRSA and Escherichia coli ESBL, with inhibition zones of 20.33 ± 0.88 mm and 13.33 ± 0.33 mm, respectively. The minimum bactericidal concentration (MBC) was 1.56 µg/mL for both. SEM revealed structural damage to the treated bacterial cells, and RAPD-PCR confirmed these genetic alterations. Additionally, M. parviflora AgNPs showed antioxidant activity (IC₅₀ = 0.68 mg/mL), 69% protein denaturation inhibition, and cytotoxic effects on MCF-7 breast cancer cells at concentrations above 100 µg/mL. These findings suggest that M. parviflora-based AgNPs are safe and effective for antimicrobial and biomedical applications, such as coatings for implanted medical devices, to prevent biofilm formation and facilitate drug delivery. Full article

We investigate TiAlZrTaNb nitride coatings deposited on Haynes 282 nickel superalloy substrates via high-power impulse magnetron sputtering (HiPIMS) under varying substrate bias voltages (0 V to −75 V). The influence of substrate bias on the microstructure, morphology, hardness, and wear resistance was systematically analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), nanoindentation, and ball-on-disk tribometry. The coatings exhibited a near equiatomic chemical composition with a face-centered cubic (FCC) crystal structure preferentially oriented along the (200) and (111) planes. Increasing the bias voltage reduced the grain size (3.65 nm to 2.84 nm) and lattice parameter (0.442 nm to 0.440 nm); meanwhile, the hardness (>45 GPa) and wear resistance were improved. The interplay between the deposition parameters and coating-substrate interactions are discussed in order to optimize HiPIMS-derived coatings for industrial applications. Full article

Erosive wear from suspended sediments significantly threatens the structural integrity and efficiency of composite tidal turbine blades. This study develops a novel framework for predicting erosion in FR4 glass fibre-reinforced polymers (GFRPs)—materials increasingly adopted for marine renewable energy components. While erosion models exist for metals, their applicability to heterogeneous composites with unique failure mechanisms remains unvalidated. We calibrated the Oka erosion model specifically for FR4 using a complementary experimental–computational approach. High-velocity slurry jet tests (12.5 m/s) were conducted at a 90° impact angle, and erosion was quantified using both gravimetric mass loss and surface profilometry. It revealed a distinctive W-shaped erosion profile with 3–6 mm of peak material removal from the impingement centre. Concurrently, CFD simulations employing Lagrangian particle tracking were used to extract local impact velocities and angles. These datasets were combined in a constrained nonlinear optimisation scheme (SLSQP) to determine material-specific Oka model coefficients. The calibrated coefficients were further validated on an independent 45° impingement case (same particle size and flow conditions), yielding 0.0143 g/h predicted versus 0.0124 g/h measured (15.5% error). This additional case confirms the accuracy and feasibility of the predictive model under input conditions different from those used for calibration. The calibrated model achieved strong agreement with measured erosion rates (R² = 0.844), successfully capturing the progressive matrix fragmentation and fibre debonding, the W-shaped erosion morphology, and highlighting key composite-specific damage mechanisms, such as fibre detachment and matrix fragmentation. By enabling the quantitative prediction of erosion severity and location, the calibrated model supports the optimisation of blade profiles, protective coatings, and maintenance intervals, ultimately contributing to the extended durability and performance of tidal turbine systems. This study presents a procedure and the output of calibration for the Oka erosion model, specifically for a composite material, providing a transferable methodology for erosion prediction in GFRPs subjected to abrasive marine flows. Full article

Ice accretion on critical transportation infrastructure presents serious operational risks and economic challenges, highlighting the need for sustainable anti-icing solutions. This study develops a strong PDMS-based composite coating on aluminum by incorporating carbon nanotubes (CNTs) and carbon powder, effectively merging passive superhydrophobicity with photothermal capabilities. We systematically assess how different ratios of CNTs to carbon powder (3:1, 1:1, 1:3) influence surface morphology, wettability, anti-icing performance, mechanical durability, and corrosion resistance. The morphological analysis shows the formation of hierarchical micro/nano-structures, with the optimal 1:3 ratio (designated as P13) resulting in dense, porous agglomerates of intertwined CNTs and carbon powder. P13 demonstrates high-performing superhydrophobicity, with a contact angle of 139.7° and a sliding angle of 9.4°, alongside a significantly extended freezing delay of 180 s at −20 °C. This performance is attributed to reduced water–surface interaction and inhibited ice nucleation. Mechanical abrasion tests indicate remarkable durability, as P13 retains a contact angle of 132.5° and consistent anti-icing properties after enduring 100 abrasion cycles. Electrochemical analysis reveals exceptional corrosion resistance, particularly for P13, which achieves a notable 99.66% corrosion inhibition efficiency by creating a highly tortuous diffusion barrier that protects against corrosive agents. This multifunctional coating effectively utilizes the photothermal properties of CNTs, the affordability of carbon powder, the low surface energy of PDMS, and the thermal conductivity of aluminum, presenting a robust and high-performance solution for anti-icing applications in challenging environments. Full article

In the last decades, small satellites such as CubeSats and PocketQubes have become popular platforms for scientific and applied missions in low Earth orbit (LEO). However, prolonged exposure to atomic oxygen, ultraviolet radiation, and thermal cycling in LEO leads to gradual degradation of onboard solar panels, reducing mission lifetime and performance. This study addresses the need to quantify and compare the degradation behavior of different solar cell technologies and protective coatings used in nanosatellites and pico-satellites. The aim is to evaluate the in-orbit performance of monocrystalline silicon (Si), gallium arsenide (GaAs), triple-junction (TJ) structures, and copper indium gallium selenide (CIGS) cells under varying orbital and satellite parameters. Telemetry data from recent small satellite missions launched after 2020, combined with numerical modeling in GNU Octave, were used to assess degradation trends. The models were validated using empirical mission data, and statistical goodness-of-fit metrics (RMSE, R²) were applied to evaluate linear and exponential degradation patterns. Results show that TJ cells exhibit the highest resistance to LEO-induced degradation, while Si-based panels experience more pronounced power loss, especially in orbits below 500 km. Furthermore, smaller satellites (<10 kg) display higher degradation rates due to lower thermal inertia and limited shielding. These findings provide practical guidance for the selection of solar cell technologies, anti-degradation coatings, and protective strategies for long-duration CubeSat missions in diverse LEO environments. Full article

To expand the application of silver nanowires (AgNWs) in the field of flexible sensors, this study developed a stretchable flexible sensor based on thermoplastic polyurethane (TPU). Initially, the TPU nanofiber membrane was prepared by electrospinning. Subsequently, high-aspect-ratio AgNWs were synthesized via a one-step polyol reduction method. The AgNWs with the optimal aspect ratio were selected for the conductive layer and spray-coated onto the surface of the TPU nanofiber membrane. Another layer of TPU nanofiber membrane was then laminated on top, resulting in a flexible thin-film sensor with a “sandwich” structure. Through morphological, chemical structure, and crystallinity analyses, the primary factors influencing AgNWs’ growth were investigated. Performance tests revealed that the prepared AgNWs had an average length of approximately 130 μm, a diameter of about 80 nm, and an average aspect ratio exceeding 1500, with the highest being 1921. The obtained sensor exhibited a low initial resistance (26.7 Ω), high strain range (sensing, ε = 0–150%), high sensitivity (GF, over 19.21), fast response and recovery time (112 ms), and excellent conductivity (428 S/cm). Additionally, the sensor maintained stable resistance after 3000 stretching cycles at a strain range of 0–10%. The sensor could output stable and recognizable electrical signals, demonstrating significant potential for applications in motion monitoring, human–computer interaction, and healthcare fields. Full article

This study focuses on optimizing a sol–gel based electrodeposition–sintering process for producing yttria-stabilized zirconia (YSZ) ceramic coatings on stainless steel substrates. Four key process variables—precursor concentration, current density, sintering time, and temperature—were evaluated in terms of two response variables: R (electrodeposition yield) and S (sintering yield). A fractional factorial design was used to reduce the number of experiments while enabling robust statistical modeling. Multiple linear regression analysis revealed that precursor concentration and current density were the most influential factors for both R and S, whereas sintering time and temperature had a lesser effect. Under central conditions (42.9 g·L⁻¹, 1.5 A·cm², 500 °C, 20 min), coatings exhibited yields of ~3.9 mg·cm² and superior morphological uniformity. Higher current density (3 A·cm²) increased R to 6.9 mg·cm² but induced porosity and cracking. Compared to conventional sol–gel derived coatings, the proposed methodology enables a more controlled microstructure with a trade-off between mass deposition and structural integrity. This predictive, statistically validated approach facilitates the optimization of electrodeposition parameters to obtain defect-minimized ceramic coatings, particularly suited for protective and thermal barrier applications in demanding environments. Full article

The long-term durability of steel structures in contact with soil remains a critical challenge due to the complex and aggressive nature of many soil environments. This study presents a thorough evaluation of the corrosion resistance and microstructural evolution of Magnelis^® ZM430-coated steel exposed to highly aggressive, heterogeneous soils. Gravimetric analysis revealed that the Magnelis^® ZM430 coating exhibits low corrosion rates and enhanced initial barrier properties, even under severe soil conditions. Although the literature frequently reports that Zn–Al–Mg coatings outperform conventional hot-dip galvanized coatings, our results highlight that this superiority is not universal and may be limited under highly aggressive, heterogeneous soils. Microstructural characterization by optical microscopy, SEM/EDS, and XRD demonstrated that the as-received coating consists of a homogeneous layer with well-distributed Zn-, MgZn₂-, and Al-rich phases. Upon soil exposure, corrosion preferentially initiates in the Mg- and Al-rich interdendritic and eutectic regions, leading to selective phase depletion and localized breakdown of the protective layer. Despite these localized vulnerabilities, the overall performance of Magnelis^® ZM430 remains superior, especially during the early stages of exposure. While no direct comparisons were performed in this work, our findings align with previous literature reporting superior performance of Zn–Al–Mg coatings compared to conventional hot-dip galvanized coatings in similar environments. Importantly, the integration of precise corrosion rate data with detailed soil characterization enables accurate prediction of coating service life, allowing for optimized coating thickness selection and proactive maintenance planning. These findings underscore the value of combining advanced Zn–Al–Mg coatings with site-specific environmental assessment to ensure the long-term integrity of buried steel infrastructure. Full article

This study examines the effects of several commercial surfactants on the dispersion of catalyst inks for proton exchange membrane fuel cells (PEMFCs). Catalyst inks containing Pt/C were spray-coated and assembled into membrane electrode assemblies (MEAs) by hot pressing. The structural and electrochemical properties of the resulting catalyst layers were characterized through particle size analysis, zeta potential measurements, contact angle determinations, and single-cell performance tests. Among the formulations evaluated, the ink with non-ionic surfactant Triton X-100 (TX) delivered the best performance, achieving a current density of 1134 mA/cm² at 0.3 V—substantially higher than that of the surfactant-free control. These findings provide practical guidance for selecting appropriate surfactants to optimize catalyst-ink preparation and enhance PEMFC performance. Full article

Diamond–copper composites, due to their exceptional thermal conductivity, hold significant potential in the field of electronic device thermal management. Hot-press sintering is a promising fabrication technique with industrial application prospects; however, the thermal conductivity of composites prepared by this method has yet to reach optimal levels. In this study, tungsten was deposited on the surface of diamond particles by magnetron sputtering as an interfacial transition layer, and hot-press sintering was employed to fabricate the composites. The findings reveal that with prolonged annealing time, tungsten gradually transformed into W₂C and WC, significantly enhancing interfacial bonding strength. When the diamond volume content was 50% and the interfacial coating consisted of 2 wt.% W, 92 wt.% WC, and 6 wt.% W₂C, the composite exhibited a thermal conductivity of 640 W/(m·K), the highest value reported among hot-press sintered composites with diamond content below 50%. Additionally, the AMM (Acoustic Mismatch Model) and DMM (Diffusion Mismatch Model) models were utilized to calculate the interfacial thermal conductance between different phases, identifying the optimal interfacial structure as diamond/W₂C/WC/W₂C/Cu. This composite material shows potential for application in high-power electronic device cooling, thermal management systems, and thermoelectric conversion, providing a more efficient thermal dissipation solution for related devices. Full article