Search Results (646)

Structural regulation is of great significance for improving the comprehensive performance of energetic materials (EMs). The structural regulation and properties of EMs were summarized. For single-component EMs, particle size control focuses on quality consistency and industrial scalability, morphology modification mainly improves sphericity through monomers or aggregates and explores the possibility of layered energetic materials in improving mechanical properties, and polycrystalline regulation suppresses metastable phases and explores novel crystalline forms using simulation-guided design. Composite EMs (CEMs) employ core–shell structures to balance safety with performance via advanced coating materials, cocrystal engineering to tailor energy release through intermolecular interactions, and lattice strain modulation, and mixing structures integrates component advantages while enhancing the reaction efficiency. Future directions emphasize computational simulations and novel fabrication methods to guide the rational design and precise preparation of next-generation EMs with specific functions. Full article

To address the limitations of single-layer nitride coatings, such as poor load adaptability and low long-term durability, MoN/TiN multilayer coatings were prepared via high-power impulse magnetron sputtering (HiPIMS). HiPIMS produces highly ionized plasmas that enable intense ion bombardment, yielding nitride films with enhanced mechanical strength, durability, and thermal stability versus conventional methods. The multilayer coating demonstrated a low coefficient of friction (COF, ~0.4) and wear rate (1.31 × 10⁻⁷ mm³/[N·m]). In contrast, both TiN and MoN coatings failed at 5 N and 10 N loads, respectively. Under increasing loads, the multilayer coating maintained stable wear rates (1.84–3.06 × 10⁻⁷ mm³/[N·m]) below 20 N, and ultimately failed at 25 N. Furthermore, the MoN layer contributes to COF reduction. Grazing-incidence X-ray diffraction analysis confirmed the enhanced crystallographic stability of the multilayer coating, thereby revealing a dominant (111) orientation. The multilayer architecture suppresses crack propagation while effectively balancing hardness and toughness, offering a promising design for extreme-load applications. Full article

Indium-based oxide semiconductors have been commercialized because of their excellent electrical properties, but the high cost, limited availability, and environmental toxicity of indium necessitate the development of alternative materials. Among the most promising candidates, zinc–tin oxide (ZTO) is an indium-free oxide semiconductor with considerable potential, but its relatively low carrier mobility and inherent limitations in thin-film quality demand further performance enhancements. This paper proposes a new approach to overcome these challenges by incorporating single-walled carbon nanotubes (SWNTs) as conductive fillers into the ZTO matrix and using a layer-by-layer multiple coating process to construct nanocomposite thin films. As a result, ZTO/SWNTs (0.07 wt.%) thin-film transistors (TFTs) fabricated with three coating cycles exhibited a high saturation mobility of 18.72 cm²/V·s, a threshold voltage of 0.84 V, and a subthreshold swing of 0.51 V/dec. These values represent an approximately four-fold improvement in mobility compared to ZTO TFT, showing that the multiple-coating-based nanocomposite strategy can effectively overcome the fundamental limitations. This study confirms the feasibility of achieving high-performance oxide semiconductor transistors without indium, providing a sustainable pathway for next-generation flexible electronics and display technologies. Full article

Ceramic dental prosthetics with internal metal structures are made from a cobalt–chromium alloy that is coated with ceramic. This study aims to validate surface treatments for the metal that enhance the adhesion of the ceramic coating under masticatory forces. Surface conditioning is performed using mechanical methods, like sandblasting (SB), and thermal methods, such as oxidation (O). The ceramic coating is applied to the metal component following the conditioning process, which can be conducted using either a single method or a combination of methods. Each conditioned sample undergoes characterization through various techniques, including drop shape analysis (DSA), scanning electron microscopy (SEM), X-ray diffraction (EDX), and atomic force microscopy (AFM). After the ceramic coating is applied and subjected to thermal sintering, the metal–ceramic samples are mechanically tested to assess the adhesion of the ceramic layer. The research findings, illustrated by scanning electron microscopy (SEM) images of the metal structures’ surfaces, indicate that alloy powder particles ranging from 10 to 50 µm were either adhered to the surfaces or present as discrete dots. Particles that exceed the initial design specifications of the structure can be smoothed out using sandblasting or mechanical finishing techniques. The energy-dispersive spectroscopy (EDS) results show that, after sandblasting, fragments of aluminum oxide remain trapped on the surface of the metal structures. These remnants are considered impurities, which can negatively impact the adhesion of the ceramic to the metal substrate. The analysis focuses on the exfoliation of the ceramic material from the deformed metal surfaces. The results emphasize the significant role of the sandblasting method and the micro-topography it creates, as well as the importance of the oxidation temperature in the treatment process. Drawing on 25 years of experience in dental prosthetics and the findings from this study, this publication aims to serve as a guide for applying the ceramic bonding layer to metal surfaces and for conditioning methods. These practices are essential for enhancing the adhesion of ceramic materials to metal substrates. Full article

Limited hardness and corrosion resistance restrict 7050 aluminum alloys in aggressive environments. Cr coatings, applied as single layers or over Ti, Al, or Ni buffer layers, were deposited onto 7050 aluminum alloy by direct-current magnetron sputtering; their microstructure, adhesion, mechanical properties, and corrosion behavior were examined. The results indicate that introducing a buffer layer significantly enhances the bonding strength between a Cr coating and an aluminum alloy substrate, with the Ni buffer layer exhibiting the highest bonding strength, nearly three times that of the Cr coating alone. Furthermore, the buffer layer influences the mechanical properties of the Cr coatings, with Ni/Cr and Al/Cr coatings demonstrating increased hardness and elastic modulus. The Ni/Cr coating achieved the highest values of 3.95 GPa and 62.09 GPa, respectively. Regarding corrosion performance, The Cr coatings containing buffer layers showed markedly better corrosion resistance than the bare 7050 Al alloy. A compact Cr₂O₃ passive film formed on their surfaces, cutting the corrosion current density by roughly two orders of magnitude. Among all samples, the Ti/Cr coating performed best, registering the lowest current density (1.687 × 10⁻⁶ A cm⁻²) and the highest charge-transfer resistance (6090 Ω cm²). Full article

Electrochemical formation of ceria (mixed Ce₂O₃ and CeO₂) coatings on different types of screen-printed carbon electrodes (SPCEs) (based on graphite (C110), carbon nanotubes (CNT), single-walled carbon nanotubes (SWCNT), carbon nanofibers (CNF), and mesoporous carbon (MC)) were studied. Their potential applications as catalysts for various redox reactions and electrochemical sensors were investigated. The ceria oxide layers were electrodeposited on SPCEs at various current densities and deposition time. The morphology, structure, and chemical composition in the bulk of the ceria layers were studied by SEM and EDS methods. XRD was used to identify the formed phases. The concentration, chemical composition and chemical state of the elements on the surface of studied samples were characterized by XPS. It was established that the increase of the concentration of CeCl₃ in the solution and the cathode current density strongly affected the surface structure and concentration (relation between Ce³⁺ and Ce⁴⁺, respectively) in the formed ceria layers. At low concentration of CeCl₃ (0.1M) and low values of cathode current density (0.5 mA·cm⁻²), porous samples were obtained, while with their increase, the ceria coatings grew denser. Full article

Contact resistance between the cathode active material (CAM) and the Al current collector can be reduced by applying carbon coatings to the Al current collector surface. However, this process requires an additional step of carbon layer coating on the current collector, which increases both manufacturing costs and processing time. In the present work, an interlayer of continuous unsized carbon fibers aligned in one direction (CF interlayer), is introduced between the Al current collector and the NMC811 cathode during cathode deposition on the Al current collector. This single-step approach eliminates the need for the additional carbon layer coating on the current collector. Additionally, this approach removes the use of toxic solvents and insulative polymers used for making the carbon coating. The CF interlayer improves the rate capability at higher C-rates. The CF interlayer lowers the contact resistance between the cathode particles and the current collector while improving the activation energy of charge transfer. The peel test showed that the CF interlayer does not affect the adhesion strength of the cathode layer with the current collector. Full article

Ti/a-C:Cr multilayer films were deposited on 316L stainless steel (SS316L) substrates using medium-frequency alternating current magnetron sputtering, with a single-layer a-C:Cr film also prepared on a titanium substrate. The influence of sputtering pressure on the film’s structure and properties was systematically investigated. Film morphology and microstructure were analyzed via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). At a pressure of 1.4 MPa, the interfacial contact resistance (ICR) of SS316L bipolar plates (BPPs) coated with the films reached as low as 3.30 mΩ·cm², while that of titanium BPPs was 2.90 mΩ·cm². Under simulated proton exchange membrane fuel cell (PEMFC) cathode conditions (70 °C, 0.6 V vs. SCE, 0.5 M H₂SO₄, 5 ppm HF solution), the corrosion current density, Icorr, reached optimal values of 0.69 μA·cm⁻² for SS316L and 0.62 μA·cm⁻² for titanium. These results demonstrate that parameter optimization enables SS316L BPPs to functionally replace titanium counterparts, offering significant cost reductions for metal BPPs and accelerating the commercialization of PEMFC technology. Full article

In additive–subtractive hybrid manufacturing (ASHM), machining and additive processes are combined in a single operation to merge the benefits of both. This method faces challenges, especially during the machining steps. Parts made through additive manufacturing often have low machinability due to factors like residual stresses and fine, hard microstructures. In ASHM, intermediate heat treatments are not possible, leading to the increased hardness of the printed material. Cutting fluids, typically used to reduce temperature and friction, can contaminate the build environment and impair layer adhesion; therefore, they are not recommended in ASHM. This study investigates soft metallic lubricant coatings in ASHM as substitutes for conventional fluid lubricants during dry machining. The coatings form a lubricating layer between the tool and workpiece, providing an alternative to cutting fluids. This research evaluates their effectiveness in improving the surface integrity of additively manufactured parts and supporting dry machining. The results of our research show a 65% reduction in force, a 50% reduction in tool wear, and a reduction in microstructural changes during machining while maintaining dry machining. Full article

This study presents the optimization of a laser ablation process designed to achieve the precise removal of polyamide coatings from ultra-thin platinum wires. Removing polymer coatings is a critical challenge in high-reliability manufacturing processes such as aerospace thermocouple fabrication. The ablation process must not only ensure the complete removal of the polyamide insulation but also maintain the tensile strength of the wire to withstand mechanical handling in subsequent manufacturing stages. Additionally, the exposed platinum surface must exhibit low surface roughness to enable effective soldering and be free of thermal damage or residual debris to pass strict visual inspections. The wires have a total diameter of 65 µm, consisting of a 50 µm platinum core encased in a 15 µm polyamide coating. By utilizing a UV laser with a wavelength of 355 nm, average power of 3 W, a repetition rate range of 20 to 200 kHz, and a high-speed marking system, the process parameters were systematically refined. Initial attempts to perform the ablation in an air medium were unsuccessful due to inadequate thermal control and incomplete removal of the polyamide coating. Hence, a water-assisted ablation technique was explored to address these limitations. Experimental results demonstrated that a scanning speed of 1200 mm/s, coupled with a line spacing of 1 µm and a single ablation pass, resulted in complete coating removal while ensuring the integrity of the platinum substrate. The incorporation of a water layer above the ablation region was considered crucial for effective heat dissipation, preventing substrate overheating and ensuring uniform ablation. The laser’s spot diameter of 20 µm in air and a focal length of 130 mm introduced challenges related to overlap control between successive passes, requiring precise calibration to maintain consistency in coating removal. This research demonstrates the feasibility and reliability of water-assisted laser ablation as a method for a high-precision, non-contact coating material. Full article

Platinum wires, known for their excellent electrical conductivity and durability, are widely used in high-precision industries, such as aerospace and automotive. These wires are typically coated with polyamide for protection; however, specific manufacturing processes require the coating to be selectively removed. Although traditional chemical stripping methods are effective, they are associated with high costs, safety concerns, and long processing times. As a result, laser ablation has emerged as a more efficient, precise, and cleaner alternative, especially at the microscale. In this study, ultraviolet nanosecond laser ablation was applied to remove polyamide coatings from ultra-thin platinum wires in a water-assisted environment. The presence of water enhances the process by promoting thermal management and minimizing debris. Key processing parameters, including the scanning speed, overlap percentage, and line distance, were evaluated. The optimal result was achieved at a scanning speed of 1200 mm/s, line distance of 1 µm, and single loop in water-ambient, where coating removal was complete, surface roughness remained low, and wire tensile strength was preserved. This performance is attributed to the effective energy distribution across the wire surface and reduced thermal damage due to the heat dissipation role of water, along with controlled overlap that ensured full coverage without overexposure. A thin, well-maintained water layer confined above the apex of the wire played a crucial role in regulating the thermal flow during ablation. This setup helped shield the delicate platinum substrate from overheating, thereby maintaining its mechanical integrity and preventing substrate damage throughout the process. This study primarily focused on analyzing the main effects and two-factor interactions of these parameters using Analysis of Variance (ANOVA). Interactions such as Speed × Overlap and Speed × Line Distance were statistically examined to identify the influence of combined factors on tensile strength and surface roughness. In the second phase of experimentation, the parameter space was further expanded by increasing the line distance and number of loops to reduce the overlap in the X-direction. This allowed for a more comprehensive process evaluation. Again, conditions around 1200 mm/s and 1500 mm/s with 2 µm line distance and two loops offered favorable outcomes, although 1200 mm/s was selected as the optimal speed due to better consistency. These findings contribute to the development of a robust, high-precision laser processing method for ultra-thin wire applications. The statistical insights gained through ANOVA offer a data-driven framework for optimizing future laser ablation processes. Full article

Coating diamond particle surfaces with a layer of high-temperature resistant nickel, which possesses weldability, effectively enhances the bonding strength between diamond particles and substrates in pre-grinding tools. This improves their stability and strength at high temperatures, thereby enhancing the performance, lifespan, and efficiency of grinding tools. This paper explores the electroless nickel plating process on diamond surfaces, analyzes the working principle of electroless nickel plating on diamond surfaces, and proposes the use of 2 g/L AgNO₃ solution and 2 g/L AgNO₃ + 10 mL/L NH₃·H₂O solution as Pd-free activating solutions. Experimental studies have demonstrated the feasibility of using silver nitrate as an activator, and it has been found that the 2 g/L AgNO₃ + 10 mL/L NH₃·H₂O solution achieves a higher surface plating ratio when used as an activator for electroless nickel plating on diamond surfaces. Based on this, through orthogonal and single-factor experimental methods, the effects of ammonia solution concentration, sodium hypophosphite concentration, plating temperature, and diamond particle size on electroless nickel plating on diamond surfaces were investigated. The optimal process for electroless nickel plating on diamond surfaces was obtained: ammonia solution concentration of 17.5 mL/L, sodium hypophosphite concentration of 33 g/L, and plating temperature of 80 °C. Under this process, using diamond particles with a size of 120/140 for electroless nickel plating, a surface plating ratio of 10.75% electroless nickel-plated diamond can be achieved. Full article

Polymer membranes often face challenges of oil fouling and rapid water flux decline during the separation of oil-in-water emulsions, making them a focal point of ongoing research and development efforts. Coating PVDF membranes with a hydrogel layer equips the developed membranes with robust potential to mitigate oil fouling. However, developing a controllable thickness of a stable hydrogel layer to prevent the blocking of membrane pores remains a critical issue. In this work, atmospheric pressure low-temperature plasma was used to prepare the surface of a PVDF membrane to improve its wettability and adhesion properties for coating with a thin hydrophilic film of an AM-NaA copolymer hydrogel. The AM-NaA/PVDF membrane exhibited superhydrophilic and underwater superoleophobic properties, along with exceptional anti-crude oil-fouling characteristics and a self-cleaning function. The AM-NaA/PVDF membrane achieved high separation efficiency, exceeding 99% for various oil-in-water emulsions, with residual oil content in the permeate of less than 10 mg/L after a single-step separation. Additionally, it showed a high-water flux of 5874 L/m²·h for crude oil-in-water emulsions. The AM-NaA/PVDF membrane showed good stability and easy cleaning by water washing over multiple crude oil-in-water emulsion separation and regeneration cycles. Adding CaCl₂ destabilized emulsions by promoting oil droplet coalescence, further boosting flux. This strategy provides a practical pathway for the development of highly reusable and oil-fouling-resistant membranes for the efficient separation of emulsified oily water. Full article

This study aims to develop a stress-optimized ultra-broadband beam-splitting coating that integrates four spectral bands by analyzing the beam-splitting properties of coatings spanning visible to medium and long-wave infrared regions. A beam-splitting coating was deposited on a Ge substrate using ion-beam-assisted thermal evaporation, employing Ge, ZnS, and YbF₃ as coating materials. The designed coating exhibits high reflectance in the 0.5–0.8 μm and 0.9–1.7 μm wavelength bands while maintaining high transmittance in the 3–5 μm and 8–12 μm bands. The optimal deposition process for a single-layer coating was established, at a 45° incidence angle, the beam-splitting coating achieved an average reflectance (Rave) of 86.6% in the 0.9–1.7 μm band and 93.7% in the 0.9–1.7 μm band, alongside an average transmittance (Tave) of 91.36% in the 3–5 μm band and 91.3% in the 8–12 μm band. The antireflection coating achieved a single-side Tave of 98.5% in the 3–5 μm band and 97% in the 8–12 μm band. The coating uniformity exceeded 99.6%. To optimize the surface profile, a single-layer Ge coating was added to the rear surface, resulting in a root mean square deviation of less than 0.0007 μm, achieved the same precision of the surface profile successfully. The deposited beam-splitting coating possessed high surface profile precision, and successfully achieved high reflectance in the visible to short-wave infrared range and high transmittance in the medium- and long-wave infrared range. The coating demonstrated excellent adhesion, abrasion resistance, and structural integrity, with no wrinkling, cracking, or delamination. Full article

Understanding the competitive adsorption mechanism is essential for the development of adsorptive separation of ethylene (C₂H₄) and ethane (C₂H₆). In this work, density functional theory calculations and molecular dynamics simulations were employed to investigate the adsorption of C₂H₄ and C₂H₆ in two LTA-type zeolites, ITQ-29 and 5A. The results show that the adsorption energies of the gas molecules in zeolite 5A are more negative than in ITQ-29, and the difference in adsorption energy between C₂H₄ and C₂H₆ in zeolite 5A is significantly larger than in ITQ-29, 13.3 versus 6.2 kJ/mol. Zeolite ITQ-29 demonstrates high C₂H₄/C₂H₆ ideal selectivity (43.5 at 5 ns) while exhibiting slow C₂H₄ uptake efficiency due to the small pore windows, hindering C₂H₄ diffusion (1.05 × 10⁻¹⁰ m²/s at 298 K). In contrast, zeolite 5A facilitates the faster diffusion of C₂H₄ molecules (3.25 × 10⁻⁹ m²/s at 298 K) and exhibits a modest C₂H₄/C₂H₆ selectivity of 1.11 at 5 ns in single-gas adsorption and 2.72 in equimolar binary mixture adsorption. To enhance C₂H₄/C₂H₆ selectivity, methyl phosphonic acid is introduced onto zeolite 5A to add a sieving layer that enables the C₂H₄ molecules to preferentially permeate, and the optimal coverage of methyl phosphonic acid is 50%, yielding a C₂H₄/C₂H₆ selectivity of 17.5 at 5 ns in mixture adsorption and preserving the C₂H₄ uptake efficiency. The insights into the competitive diffusion of molecules in the coating layer and inside the zeolites provide a theoretical basis for the rational design of high-performance adsorbents. Full article