Surface Microstructure Research Articles

Influence of Finishing Process Parameters of HDF Boards on Selected Properties of Coatings in Modern UV Lines and Their Relation to Energy Consumption

This study analyzes the influence of energy generated by emitters on the adhesive properties of varnish coatings in multilayer UV systems. The experimental material, in the form of a cell board finished with UV varnish products, was prepared on a prototype line under the conditions of Borne Furniture in Gorzów Wielkopolski. The roughness and wettability were measured using a OneAttension tensiometer integrated with a topographic module, taking into account the Wenzel coefficient. The adhesion of the examined systems was verified using the PositiTest AT-A automatic pull-off device. Energy consumption by the prototype production line was compared to the standard line, utilizing mercury emitters and mercury emitters with added gallium. Energy consumption was calculated for selected variants. The influence of the Wenzel coefficient on the wettability angle was observed. Significant differences between contact angles (CA and CAc) were noted for coatings formed with sealers (stages I and II). The largest discrepancies, reaching up to 30 degrees, were recorded at the lowest UVA and UVV doses of 26 mJ/cm2. In adhesion tests, values below 1 MPa were obtained. Insufficient energy doses in the curing process of UV systems led to delamination between the coatings. Five variants were selected where delamination within the substrate predominated (˃90% A) and were characterized by the lowest energy consumption in the processes. Topographic images helped identify the presence of various surface microstructures at different stages of the production cycle. The greatest energy savings, up to 50%, were achieved in stages III and IV of the technological process.

Surface microstructure and corrosion resistance characterization of Mg-based amorphous alloys

Surface microstructure and corrosion resistance characterization of Mg-based amorphous alloys

Densification behavior in compaction for Cu/TiB2 composite under electromagnetic impact

Cu/TiB2 composite combines electrical conductivity and wear resistance, leading to its wide application prospect in electrical contact. In this study, electromagnetic impact was applied to compact Cu/TiB2 powder. The interaction between powder and die under electromagnetic impact was analyzed by observing the surface quality, density, microstructure, and hardness. The results showed that when the energy was less than 21 kJ, the increase in energy could enhance density and tensile strength of the compact. However, when the energy exceeded 21 kJ, the state of compact hardly changed and burr near the edge would be worsened. Besides, the hardness of the upper surface increased gradually from the center to the edge, while the opposite was true for the lower surface, reflecting the spatial distribution of density. With the aid of simulation, it was found that the stress wave propagation influenced the densification behavior and led to the variation of density.

Structurally Colored Photonic Crystal Biomimetic Microstructures for Daytime Radiative Cooling.

Daytime radiative cooling offers a novel solution to the energy crisis, enabling green and efficient thermal management in space. High reflectance in the solar spectrum is essential for passive radiative cooling, rendering dye coloring and similar methods unsuitable for colored coolers. This paper presents a structurally colored photonic crystal biomimetic microstructured radiative cooler. Inspired by natural biological systems, this cooler features a dual-layered microtruncated-cone array structure on the surface and bottom membrane layers. The silver reflector and 3D micrograting surface structure produce continuous iridescent colors through multiple interference effects. Optimized lithographic process enable the fabrication of the ordered dual-layer surface microstructure arrays with precise angular combinations. The dual-layered microtruncated-cone introduces a gradient refractive index, reducing impedance mismatch at the interface. As a result, the radiative cooler achieves high solar spectral reflectance (0.95) and high mid-infrared emissivity (0.95). Notably, the net theoretical cooling power and the subambient temperature drop are 106.9 W m-2 and 7.4 °C, respectively, at an ambient temperature of 40 °C, with a measured average temperature reduction of 6.1 °C under direct sunlight. This performance matches that of advanced radiative coolers, striking a balance between aesthetics and radiative cooling capability.

Facile Formation of Metallic Surface with Microroughness via Spray-Coating of Copper Nanoparticles for Enhanced Liquid Metal Wetting

This paper presents a simple, fast, and cost-effective method for creating metallic microstructured surfaces by spray-coating a dispersion of copper nanoparticles (CuNPs) onto polymethyl methacrylate (PMMA) substrates, enabling the imbibition-induced wetting of liquid metal. The formation of these microstructured patterns is crucial for the spontaneous wetting of gallium-based liquid metals. Traditional techniques for producing such microstructures often involve complex and costly lithography and vacuum deposition methods. In contrast, this study demonstrates that liquid metal wetting can occur with metal microstructures formed through a straightforward spray-coating process. To immobilize the CuNPs on the polymer substrate, an organic solvent that dissolves the polymer surface was employed as the dispersion medium. The effects of various spray-coating parameters, including distance and time, on the uniformity and immobilization of CuNP films were systematically investigated. Under optimal conditions (120 s of spray time and 10 cm spray distance), CuNPs dispersed in dichloromethane (DCM) yielded uniform and stable microstructured surfaces. The spontaneous wetting of gallium-based liquid metal was observed on the fabricated CuNP film. Additionally, liquid metal selectively wet the CuNP patterns formed by stencil techniques, establishing electrical connections between electrodes. These findings underscore the potential of spray-coating for fabricating metallic surfaces to drive the formation of liquid metal patterns in flexible electronics applications.

Dynamic Monitoring the Friction Transmission of Mine Hoist Using Triboelectric Nanogenerators Self‐Powered Sensor Based on Different Surface Structures Embedded in the Friction Lining

The friction lining is a critical component of the friction hoist, serving as the driving force for lifting through its interaction with the wire rope. Monitoring the friction state between the wire rope and the friction lining is crucial as it directly impacts lifting capacity, work efficiency, and overall safety. By employing finite element simulation and creating surface microstructures on triboelectric nanogenerators (TENG) using ultraviolet laser, this study demonstrats that microstructure can improve voltage output. Compared with TENG without morphology, the voltage is increased by nearly seven times, reaching 2.28 V. Moreover, experiments revealed that embedding TENG at the optimal standard point of the friction lining enables effective monitoring of friction transmission under varied conditions, with the voltage signal showing synchronization with friction force. Notably, the voltage reached 520 mV under increasing specific pressures and stabilized around 670 mV with rising sliding speeds. This research represents a significant step toward real‐time monitoring of intelligent mining systems by dynamically observing friction transmission in mine hoists.

3D-Printed Multi-Axis Alignment Airgap Dielectric Layer for Flexible Capacitive Pressure Sensor

Flexible pressure sensors are increasingly recognized for their potential use in wearable electronic devices, attributed to their sensitivity and broad pressure response range. Introducing surface microstructures can notably enhance sensitivity; however, the pressure response range remains constrained by the limited volume of the compressible structure. To overcome this limitation, this study implements an aligned airgap structure fabricated using 3D printing technology. This structure, designed with a precisely aligned triaxial airgap configuration, offers high deformability under pressure, substantially broadening the pressure response range and improving sensitivity. This study analyzes the key structural parameters—the number of axes and pore size—that influence the compressibility and stability of the dielectric material. The results indicate that the capacitive pressure sensor with an aligned airgap structure, manufactured via 3D printing, exhibits a wide operating pressure range (50 Pa to 500 kPa), rapid response time (100 ms), wide limit of detection (50 Pa), and approximately 21 times enhancement in sensitivity (~0.019 kPa−1 within 100 kPa) compared with conventional bulk structures. Furthermore, foot pressure monitoring trials for wearable sensor applications demonstrated exceptional performance, indicating the sensor’s suitability as a wearable device for detecting plantar pressure. These findings advocate for the potential of 3D printing technology to supplant traditional sensor manufacturing processes.

Effect of Alkaline Etching on Formation Behavior and Corrosion Resistance of a Cr-Zr-Ti TCP Conversion Coating on AA2024 Aluminum Alloy

Abstract Trivalent chromium process conversion coating is considered to be the ideal alternative to traditional chromate conversion coating due to its high corrosion resistance and low toxicity. However, achieving a high corrosion resistance trivalent chromium conversion coating on 2xxx aluminum alloys has been a great challenge. Herein, based on a newly developed trivalent chromium conversion solution (CN patent, ZL 202210804263.2), the effect of alkaline etching on the formation behavior and corrosion resistance of the coating on AA2024-T351 aluminum alloy was investigated. It was found that under the same conditions, the mechanically polished sample and the sample alkaline etched for 30 s showed the highest corrosion resistance. When the alkaline etching time was too short or too long, the corrosion resistance of the coating deteriorated. This is ascribed to changes in the surface microstructure of the alloy during alkaline etching, i.e., reduced number of intermetallic particles and formation of a copper enrichment layer. Reducing the number of intermetallic particles on the alloy surface is beneficial for uniform growth of the coating. However, the copper enrichment layer participated in formation of the coating, resulting in doping of copper species in the coating, which is detrimental to the corrosion resistance of the coating.

Laser-formed nanoporous graphite anodes for enhanced lithium-ion battery performance

Lithium-ion batteries are pivotal in modern energy storage, commonly utilizing graphite anodes for their high theoretical capacity and long cycle life. However, graphite anodes face inherent limitations, such as restricted lithium-ion storage capacity and slow diffusion rates. Enhancing the porosity of graphite and increasing d-spacing in expanded graphite anodes have been explored to improve lithium-ion diffusion and intercalation. Recent advancements suggest that nanoscale modifications, such as utilizing nano-graphite and graphene, can further enhance performance. Laser processing has emerged as a promising technique for synthesizing and modifying graphite and graphene-related materials, offering control over surface defects and microstructure. Here, we demonstrate an industrially compatible one-step laser processing method to transform a nano-graphite and graphene mixture into a nanoporous matrix, significantly improving lithium-ion battery performance. The laser-processed anodes demonstrated significantly enhanced specific capacities at all charge rates, with improved relative performance at higher charge rates. Additionally, long-term cycling at 1 C showed that laser-processed cells outperformed their non-processed counterparts, with specific capacities of 323 and 241 mAh/g, respectively.

Precipitation–Flotation Process for Molybdenum and Uranium Separation from Wastewater

The mining of molybdenum and uranium ores inevitably results in the generation of large volumes of wastewater containing low concentrations of metals, which poses significant threats to the environment. This study presents a novel precipitation–flotation process for the simultaneous separation of molybdenum and uranium from wastewater. A systematic investigation was conducted on the impacts of the type of precipitant, flotation reagent type, and flotation parameters on the experimental results. Ferric salt served better as a precipitant than aluminum salt and humic acid did, and sodium dodecyl sulfate (SDS) was more suitable than sodium dodecyl benzene sulfonate for acting as a surfactant and foaming agent. Under specific conditions, including a pH of 6.6, an Fe3+ dosage of 0.6 mmol·L−1, an SDS dosage of 40 mg·L−1, an air flow rate of 25 mL·min−1, and a flotation time of 10 min, the removal efficiencies of molybdenum and uranium reached 96.6% and 93.6%, respectively. After flotation, the molybdenum concentration, uranium concentration, chemical oxygen demand, and turbidity of the treated water all meet the emission standards. Furthermore, the metal removal mechanisms, including the particle size distribution, functional group structure, surface element composition, microstructure, and element distribution, were elucidated on the basis of characterization of the precipitation–flotation products.

Safety and efficacy of Mg-Dy membrane with poly-L-lactic acid coating for guided bone regeneration

The aim of this study was to evaluate safety and efficacy of a poly-L-lactic acid (PLLA)-coated magnesium (Mg)-Dysprosium (Dy) membrane in guided bone regeneration (GBR) using a rabbit calvarium model. The microstructure of the Mg-Dy membrane surface and thickness of the PLLA coating were examined. In vitro degradation and cytotoxicity test was conducted. The in vivo study used 24 white male rabbits with two 8 mm-diameter defects created on the calvaria; 12 defects were randomly assigned per group: (1) Negative control, (2) positive control, (3) uncoated Mg, and (4) PLLA-coated Mg group. Specimens were harvested at 4, 8, and 12 weeks postoperatively for radiological, histological, and histomorphometric analyses. The PLLA-coated Mg-Dy membrane showed a low degree of degradation, indicating that the coating exerted a protective effect. In the cytotoxicity test, no deformed or degenerated cells were observed. In the in vivo study, radiographic and histomorphometric analyses indicated favorable new bone formation and maintenance of the graft material for PLLA-coated Mg group. PLLA-coated Mg group, compared to the uncoated counterpart, restored the bony contour more completely, without inducing significant inflammatory response. Our results support the safety and efficacy of PLLA-coated Mg-Dy membranes for GBR both in vitro and in vivo.

Research on microscopic fracture mechanism of glass-ceramics grinding surface based on progressive scratch test

Progressive scratch test was carried out on the glass-ceramics to study the continuous micro-fracture mechanism of its surface, which provided an important basis for the research on the grinding mechanism of glass-ceramics. By microimaging of scratch, the continuous material removal process of glass-ceramics from ductility to ductile brittleness to brittleness was observed in micro-view, confirming that there was a ductile brittleness between ductility and brittleness on the surface of glass-ceramics. The critical point for breaking from ductility to ductile brittleness and the critical point for breaking from ductile brittleness to brittleness were measured. The machined critical depth hc1 of the composite domain of ductility and ductile brittleness and the machined critical depth hc2 of the composite domain of ductile brittleness and brittleness for glass-ceramics were further obtained by computational analysis. This study provides valuable insights into the surface machining forming and surface microstructure generating of glass-ceramics material. The research results can also provide reference on determining the critical grinding parameters of glass-ceramics material.

Temperature and RI sensing based on micro-structured optical fiber surface plasmon resonance

In this paper, we propose a surface plasmon resonance sensor based on micro-structured optical fiber capable of simultaneous sensing of a liquid refractive index and temperature. The fiber structure comprises four large air holes, with side polishing and rectangular groove processing on one side without air holes. Ag film and α-Fe2O3 film are coated inside the rectangular groove for refractive index sensing. Au film is coated on the inner walls of the two side air holes and filled with polydimethylsiloxane (PDMS) for temperature sensing. The results show that the sensor can achieve sensing of two parameters in two polarization directions. With a refractive index ranging from 1.35 to 1.42 and temperature ranging from 10°C to 100°C, the maximum refractive index sensitivity reaches 28225.7 nm/RIU and the maximum temperature sensitivity reaches −3.64nm/∘C. The sensor features simple structure, easy implementation, and high sensitivity, making it applicable in fields such as biosensing, chemical sensing, and environmental monitoring.

Tailoring Interlayer Microenvironment of 2D Layered Double Hydroxides for CO2 Reduction with Enhanced C2+ Production.

Both the physicochemical properties of catalytic material and the structure of loaded catalyst layer (CL) on gas diffusion electrode (GDE) are of crucial importance in determining the conversion efficiency and product selectivity of carbon dioxide reduction reaction (CO2RR). However, the highly reducing reaction condition of CO2RR will lead to the uncontrollable structural and compositional changes of catalysts, making it difficult to tailor surface properties and microstructure of the real active species for favored products. Herein, the interlayer microenvironment of copper-based layered double hydroxides (LDHs) is rationally tuned by a facile ink solvent engineering, which affects both the surface characters and microstructure of CL on GDE, leading to distinct catalytic activity and product selectivity. According to series of in situ and ex situ techniques, the appropriate surface wettability and thickness of porous CL are found to play critical roles in controlling the local CO2 concentration and water dissociation steps that are key for hydrogenation during CO2RR, leading to a high Faradaic efficiency of 75.3% for C2+ products and a partial current density of 275mAcm-2 at -0.8V versus RHE. This work provides insights into rational design of efficient electrocatalysts toward CO2RR for multi-carbon generation.

Impact of surface dielectric barrier discharge cold atmospheric plasma on quality and stability of fresh-cut iceberg lettuce

This study evaluated the impact of cold atmospheric plasma (CAP) on fresh-cut iceberg lettuce (FIL) quality and stability. CAP treatments were performed using a Surface Dielectric Barrier Discharge, applying 6 kV at 23 kHz and exposition times varying from 15 to 60 min. FIL was analysed before and after treatments for polyphenoloxidase (PPO) and peroxidase (POD) activity, microbial contamination, colour, surface microstructure properties, chlorophylls content, polyphenols (TPC), ascorbic acid (AA), and antioxidant activity (AoA). TPC, AA and AoA were evaluated also after storage (4 °C for 5 days). CAP treatments provoked a reduction of PPO and POD activity with a processing time- and ozone-concentration-dependent effect. After treatments, a slight inactivation of mesophilic and psychrotrophic bacteria was observed, while yeast counts remained unaffected. With increasing treatment times, increasing cell damages and colour variations were detected, and a decrease of chlorophylls, TPC, AA, and AoA. After storage, an overall AoA increase was observed due to increased extractability or production by living cells of antioxidant compounds. These findings provide insights into the efficacy of CAP treatment in preserving fresh-cut iceberg lettuce quality. Further investigations are needed to optimize the process conditions and increase microbial inactivation while limiting qualitative damage to the product.

Portable Machine Tools by Small Piezoelectric Robots for Scalable and Waviness‐Adaptive Fabrication of Surface Microstructures

Surface functional microstructures exhibit extensive application requirements in an array of breakthrough areas. One critical problem that restricts their industrial application is the lack of scalable fabrication techniques due to the limitation of conventional machine tools. This study proposes a scalable surface texturing technique using a portable small (30 × 19 × 22 mm) three‐leg robot that walks and works on the workpiece surface. Due to the elliptical tool vibration, microgrooves can be created on the workpiece surface periodically; meanwhile, the machining force drives the robot to walk forward. Surface texturing experiments are conducted on aluminum and copper workpieces to explore the machining performance of the small robot. The robot can reach a maximum moving velocity of 6.3 mm s−1 and can produce microstructures with a spacing of 4–14 μm on workpiece surfaces. Owing to its unique working principle, the small robot can maintain a constant depth of cut, demonstrating its capacity to adapt to the surface waviness of the workpiece. Finally, the motion straightness of the robot is greatly improved by combining it with the auxiliary track, and multiline microstructures are obtained. In short, the developed small robot presents a promising solution to the challenge of scalable surface texturing.

Synergetic effect of in-situ TiB2 reinforcement and nano precipitation on wear behavior of ZE41 magnesium matrix composite

The rise in carbon dioxide pollution and energy consumption has increased the demand for lightweight materials such as magnesium in automotive and aerospace industries. However, magnesium alloys face challenges like poor wear resistance and mechanical strength. To overcome these limitations, a promising approach involves developing heterogeneous hybrid microstructures through reinforcement addition and microstructural engineering. This study focuses on the tribological performance of a newly developed in-situ sub-micron sized TiB2/ZE41 composite under various microstructural conditions, comparing it to the unreinforced ZE41 Mg alloy. Wear experiments were conducted using a pin-on-disc tribometer under normal loads of 10, 20, 40, and 60 N at a sliding velocity of 1 m/s. Scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) was used to analyze the worn surfaces in order to identify damage types and surface distortions. By correlating worn surface microstructures with test parameters, predominant wear mechanisms for each material condition under specific loads were determined. Results consistently showed that the presence of in-situ TiB2 reinforcements, β-phase, and rare-earth precipitates enhanced wear resistance regardless of the load conditions. Additionally, the study established a scientific understanding of the wear behavior of ZE41 Mg alloy, with and without in-situ TiB2 particles and precipitates, through analysis of dominant wear mechanisms, wear-induced subsurface deformation mechanisms, kernel average misorientation, grain orientation spread, and microhardness evaluation.

Evolution of Graded Surface Microstructure and Property of Ti6Al4V Threads Processed by Surface Rolling

The surface rolling process is important for the forming property of titanium alloy bolts. This study systematically investigated the evolution of the surface microstructure and property of Ti6Al4V threads induced by surface rolling processes with different feeding times. Gradient surface microstructure and property, as characterized by the depth-dependent variations of refined and deformed grains and hardness, were revealed. A comparative analysis of the microstructure and property of the topmost and subsurface layers in different characteristic areas (root, flank, and crest) of the thread was specifically carried out. The surface microstructure and properties are highly heterogeneous in different areas of the rolled thread. Meanwhile, a gradient microstructure and hardness along the depth from the surface was revealed in the surface layer. Our results showed that the highly heterogeneous surface microstructure and property can be attributed to the close correlation between the different stress/strain levels at different depths from the surface and the different deformation mechanisms in the characteristic surface areas of the thread. The present study has indicated that the distinctive microstructure and property in the different characteristic areas of the rolled thread should be featured by those of surface layers at different depths.

Experimental simulation of the ancient production of gold granules

Granulation is an ancient and sophisticated decorative technique. The production of granules is a crucial part of this process but has rarely been studied. The present study employed three techniques—pouring method, heating method, and crucible method—to produce gold granules. The success ratio of granule formation, granule surface morphology, microstructure, and formation were analyzed to identify the techniques used in archaeological objects. The cooling medium significantly influenced small granule formation, microstructure, and grain size. Both heating and crucible methods could control the granule formation, but these methods produced distinct microstructures. Based on these experimental granules, the probable production methods of ancient gold balls were identified. The present study provided microscopic information for determining ancient gold granule production techniques.

A Biomimetic Chip with Dendrimer-Encapsulated Platinum Nanoparticles for Enhanced Electrochemiluminescence Detection of Cardiac Troponin I

The measurement of cardiac troponin I (cTnI) is of vital importance for the early diagnosis of acute myocardial infarction. In this study, an enhanced electrochemiluminescent immunoassay for the highly sensitive and precise determination of cTnI was reported. A biomimetic chip with nepenthes peristome surface microstructures to achieve single-layer microbead arrays and integrated microelectrode arrays (MEAs) for ECL detection was microfabricated. Ru@SiO2 nanoparticles were prepared as signal amplificators labeling immunomagnetic beads. Dendrimer-encapsulated platinum nanoparticles (Pt DENs) were electrochemically modified on ITO MEAs. The resulting Pt DEN-modified ITO MEAs preserved good optical transparency and exhibited an approximately 20-fold ECL signal amplification compared to that obtained from bare ITO. The method made full use of the biomimetic chip with Pt DENs to develop single-layer immunomagnetic bead arrays with increasingly catalyzed electrochemical oxidation of the [Ru(bpy)3]2+–TPA system. Consequently, a limit of detection calculated as 0.38 pg/mL (S/N = 3) was obtained with excellent selectivity, demonstrating significant potential for the detection of cTnI in clinical diagnostics.