Search

Polymers are versatile materials widely used in various industries, with significant applications in biomedicine where biofouling on polymer surfaces presents major health and economic challenges. Biofouling, initiated by bacterial adhesion, can be mitigated by modifying surface properties through laser micro- and nano-texturing, an approach that offers advantages over chemical treatments. This study introduces an economical mass production process for textured polymeric components using injection molding to replicate hierarchical textures. Testing revealed that all textured samples significantly reduced bacterial adhesion compared to untextured surfaces across different designs and bacteria types after 24 h of culture. The study examined factors like wettability, nanoscale roughness, and pattern dimensions to explain these outcomes, comparing them with existing studies. Despite all textured samples showing decreased wettability and roughness, these factors alone did not ensure reduced bacterial adhesion. The most effective anti-adhesive performance was observed in surfaces with parallel ridge patterns, which segmented the surface into isolated areas that limited bacterial interaction and hindered micro-colony formation, highlighting the importance of specific surface patterning in combating biofouling. [ABSTRACT FROM AUTHOR]

Highlights Printing polymers on metal surfaces using fused deposition modeling could enhance the versatility of hybrid structures. However, the differences between metals and plastics prevented the effective spreading of molten plastic on metal surfaces, challenging reliable plastic printing on metal substrates. This study employed a nanosecond laser to fabricate laser‐textured grids of varying widths (0.2–0.5 mm) on a 6061 aluminum alloy (6061Al) surface. Carbon fiber reinforced thermoplastic plastic (CFRTP) was printed on 6061Al surface in different printing directions (0°, 45°, and 90°). The influence of laser texturing and printing direction on joint performance was evaluated. The findings indicated the laser‐texturing increased 6061Al surface roughness, enhancing wettability of CFRTP on 6061Al surface. The 45° printing direction provided the best wetting, resulting in a tensile‐shear force of 1631.7 N, 218% higher than at 90°. Optimal performance was achieved with a 0.5‐mm texture width, increasing tensile‐shear force by 180% compared to 0.2 mm and 67% compared to 0.6 mm. Interfacial stress concentration decreased and then increased with the increase of laser‐textured width and the 45° printing direction provided the longest print path and best resin spreading. This research presented a novel approach to metal‐polymer joining, with significant implications for advanced lightweight hybrid structures. Printing carbon fiber reinforced thermoplastic plastic (CFRTP) on 6061 aluminum alloy (6061Al) surface was achieved by fused deposition modeling via laser texturing. The print direction affected the wetting and spreading space of the molten resin. Pinning effect of printed CFRTP/6061Al by laser texturing was studied. The spreading and wetting of resin determined the mechanical properties. [ABSTRACT FROM AUTHOR]

Embossing rolls are used in a variety of sectors to transfer surface textures to a product. Textures on the rolls are typically achieved by material-removal techniques, resulting in craters in the surface of the roll. The wear resistance of the surfaces is improved by additional coating technologies. A novel process offering improved surface design freedom and which negates the need for post-coating techniques is the embedding of micro-meter-sized ceramic particles in the surface of the roll. This can be achieved through micro-additive processing. This work presents and discusses experimental results of surface texturing through locally derived laser-induced melt pools in which ceramic particles are dissolved. This process is termed laser implantation, or laser dispersing. Using this technology, dome-shaped surface structures with significantly increased hardness compared to the bare steel can be achieved. Reported results in the literature focus on implantations with diameters ranging from 150 μ m to 400 μ m and heights ranging from 10 μ m to 30 μ m. However, features with smaller diameters and heights are desired for technology adoption to permit a wider range of surface roughness. This paper presents and discusses the experimental results of implantations with a diameter smaller than 150 µm, with heights between 1 μ m and 15 μ m. For that purpose, a Nd:YAG laser source (focal diameter 70 μ m, pulse durations from 3 to 15 ms, pulse power from 20 to 50 W average) was used to induce a melt pool driving the particle embedding. [ABSTRACT FROM AUTHOR]

Medical stents are vital for treating vascular complications and restoring blood flow in millions of patients. Despite its widespread effectiveness, restenosis, driven by the complex interplay of cellular responses, remains a concern. This study investigated the reactions of vascular cells to nano/microscale wrinkle (nano-W and micro-W) patterns created on laser-textured nitinol (NiTi) surfaces by adjusting laser processing parameters, such as spot overlap ratio and line overlap ratio. Evaluation of topographical effects on endothelial and smooth muscle cells (SMCs) revealed diverse morphologies, proliferation rates, and gene expressions. Notably, microscale wrinkle patterns exhibited reduced monocyte adhesion and inflammation-related gene expression, demonstrating their potential applications in mitigating vascular complications after stent insertion. Additionally, an ex vivo metatarsal assay was utilized to bridge the gap between in vitro and in vivo studies, demonstrating enhanced angiogenesis on laser-textured NiTi surfaces. Laser-textured NiTi exhibits a guided formation process, emphasizing their potential to promote swift endothelialization. These findings underscore the efficacy of laser texturing for tailored cellular interactions on metallic surfaces and offer valuable insights into optimizing biocompatibility and controlling cellular responses, which may pave the way for innovative advances in vascular care and contribute to the ongoing improvement of stent insertion.

Steel-aluminum laminates show promise in industrial manufacturing, yet their utilization is limited by unstable interface bonding. This study investigates the influence of laser texturing on the interface bonding properties of DP600/AA1060 obtained through co-extrusion. White-light interference profilometry (WLIP) and MATLAB algorithms are used to quantify different surfaces. A model is established to predict the shear load with different process angles. Furthermore, energy dispersive spectroscopy (EDS), scanning electron microscope (SEM) and X-ray diffraction (XRD) are utilized to examine the microstructure of interface fractures and DP600/AA1060 alloys. Notably, the laser texturing process (LTP) significantly enhances the interface bonding strength of the DP600/AA1060, yielding a 37% increase in maximum shear strength compared to the original sample. The prediction holds true for the process angle in the range of 0°–45° but failed between 45° and 90° due to the occurrence of tensile/compressive stress in the laser-textured area, leading to unstable bonding caused by oxides and alloy particles. However, the laser-textured surface of DP600 enhances mechanical interlocking and increases the number of micro-protrusions, thereby strengthening the interface bonding and improving the mechanical properties of co-extruded laminates.

To address the challenges of high grinding force and poor processing quality in grinding zirconia ceramics with traditional grinding wheels, this study explores the use of leaf vein bionic fractal textured diamond grinding wheels. These wheels, designed with fractal angles of 30.0°, 45.0°, and 60.0°, leverage the leaf vein bionic fractal texture's capabilities in reducing drag, guiding flow, heat dissipation, and mass transfer. The effects of the original grinding wheel and the three types of bionic fractal grinding wheels on the surface roughness (Ra), grinding force, and grinding force ratio of zirconia ceramics were compared and analyzed. The results show that the bionic fractal grinding wheels outperform the original grinding wheel. Specifically, compared to the original grinding wheel, the normal grinding force of the bionic fractal grinding wheel is reduced by 12.7% to 55.8%, and the tangential grinding force is reduced by 8.1% to 40.3%. The bionic fractal grinding wheels have not obvious effects on the surface roughness Ra. When the fractal angle is 30.0°, the minimum grinding force ratio is 1.4 to 3.0, and the minimum surface roughness Ra is 1.824 μm.

The surface texture process was done with carbon dioxide laser on dual-phase steel (DP 1180). The effects of the parameters of the carbon dioxide laser on the contact angle, skewness and kurtosis values were investigated, and the laser parameters required for obtaining the highest contact angle, lowest skewness and highest kurtosis have been optimized by the Taguchi method. In addition, the effects of these parameters on contact angle, skewness and kurtosis were calculated. The most effective parameters were laser power with 33.03% for contact angle, overlap ratio with 52.48% for skewness and overlap ratio with 41.34% for kurtosis. In the optimization result to obtain the optimum values, contact angle, skewness and kurtosis were found as 145.45, 0.07 and 3.39, respectively. These results are better than those obtained in the experiments for all three quantities. Since the results of the confirmation experiments performed with the parameters suggested by the Taguchi method are quite close to the expected results, it can be said that the Taguchi method is a reliable method in such studies. The results are supported by main effect plots and regression equations. [ABSTRACT FROM AUTHOR]

This paper analyzes the tribological behavior of the Ti6Al4V ELI alloy subjected to laser texturization for medical purposes. Laser texturing enables one to observe specific patterns of the material surface at established depths. Microtexturing of the samples was performed using a 355 nm picosecond laser. The influence of the microtexturing process (depending on the process parameters) on the geometric parameters of the proposed laser texturing pattern was evaluated. Selected samples were subjected to tribological testing using the ball-on-plate technique in dry and lubricant-sliding methods (in Ringer solution). The wear properties were evaluated by comparing the coefficient friction, wear volumes, and wear ratio. A scanning electron microscope characterized the morphologies of the wear scar and the wear mechanism. The experimental results show that the surface texturing and the changes in microgrooves can reduce wear. The results indicate, that samples after laser texturing were characterized by 15% higher microhardness, compared to those in the initial state. It was found, a 26% reduction in friction coefficient and 29% in the wear volume compared to the smooth, untextured surface samples under lubricated conditions. The decrease in value of the coefficient friction and wear volume for the samples after the laser texturing process is an effect of synergistic of entrapped wear debris in micro-grooves and increased hardness for samples after laser textured. [ABSTRACT FROM AUTHOR]

The relatively poor antibacterial capability of intrinsic hydrophilic zirconia ceramics limits its wide applications in the field of biological implants. To further exploit and enhance the biocompatibility of zirconia ceramics, a facile silicone oil-assisted laser-heat process was developed to prepare the superhydrophobic zirconia ceramic surface with microcolumn array structure and low surface energy. The characterization results indicated that the micro/nano hierarchical structure was induced by laser texturing on the zirconia ceramic surface, and part of the crystal structure was transformed from tetragonal phase to monoclinic phase. The deposition of carbon-containing hydrophobic functional groups and silicon atoms on the surface was accelerated and the surface energy was significantly reduced by silicone oil-assisted heat treatment. The surface wettability was transitioned from hydrophilicity to superhydrophobicity after the silicone oil-assisted laser-heat process. The bacterial adhesion can be effectively blocked due to the air layer trapped by the surface micro/nanostructures, and the surface antibacterial rate was increased by more than 80%. The ionic corrosion was also slowed down under the combination of the air layer and the reduced solid-liquid contact area on the superhydrophobic surface, which improved the corrosion resistance of the surface. The enhanced antibacterial capability and corrosion resistance on the superhydrophobic zirconia ceramic surfaces prepared by the developed process are expected to provide a key avenue for biomedical applications. [Display omitted] • A laser-based process was developed to fabricate superhydrophobic zirconia ceramic. • Superhydrophobic surface was achieved by altering surface structure and chemistry. • The underlying mechanism of surface wettability transition was analyzed. • Surface antibacterial capability can be enhanced due to superhydrophobicity. • Surface corrosion resistance can be improved due to superhydrophobicity. [ABSTRACT FROM AUTHOR]

Copyright of Diamond & Abrasives Engineering is the property of Zhengzhou Research Institute for Abrasives & Grinding and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Surface preparation is an important step in adhesive technology. A variety of abrasive, chemical, or concentrated energy source treatments are used. The effects of these treatments vary due to the variety of factors affecting the final strength of bonded joints. This paper presents the results of an experimental study conducted to determine the feasibility of using fiber laser surface treatments in place of technologically and environmentally cumbersome methods. The effect of surface modification was studied on three materials: aluminum EN AW-1050A and aluminum alloys EN AW-2024 and EN AW-5083. For comparison purposes, joints were made with sandblasted and laser-textured surfaces and those rolled as reference samples for the selected overlap variant, glued with epoxy adhesive. The joints were made with an overlap of 8, 10, 12.5, 14, and 16 mm, and these tests made it possible to demonstrate laser processing as a useful technique to reduce the size of the overlap and achieve even higher load-bearing capacity of the joint compared to sandblasting. A comparative analysis was also carried out for the failure force of the adhesive bond and the failure energy. The results show the efficiency and desirability of using lasers in bonding, allowing us to reduce harmful technologies and reduce the weight of the bonded structure. [ABSTRACT FROM AUTHOR]

The article is aimed at identifying the influence of laser texturing and subsequent coating with a hard, wear-resistant coating AlCrSiN (nACRo®) on selected tribological properties of the analyzed tool steels for cold work, produced by conventional and powder metallurgy. The substrate from each steel was heat treated to achieve optimal properties regarding the chemical composition and the method of production of the material. Böhler K100 and K390 Microclean® steels were used. These are highly alloyed tool steels used for various types of tools intended for cold work. The obtained results show that the coefficient of friction is increased by coating, but the wear rate is lower compared to the samples which were only textured. [ABSTRACT FROM AUTHOR]

Laser texturing enables site-selective tailoring of wetting characteristics of metallic surfaces, converting the surfaces into hydrophilic or hydrophobic ones. In this study, selective wettability transition of 6061 aluminum alloy (Al 6061) surface is demonstrated by using a nanosecond fiber laser. The conversion of initial wettability of pristine Al 6061 into a near-superhydrophobic surface is achieved through laser irradiation of an Al 6061 plate and the following low-temperature thermal annealing. The wettability change is studied by measuring the water contact angle, and a significant increase in the angle (approximately, from 63.9° of pristine Al 6061 to 146.8°) is observed. Furthermore, the laser-textured hydrophobic surface is transformed into a hydrophilic surface by irradiating the surface again with the laser beam, resulting in superwetting ability. These wettability transitions are site-selectively obtained by exploiting the capability of direct laser writing, showcasing a promising potential in various applications. [ABSTRACT FROM AUTHOR]

A flexible and efficient solution is developed to enhance the performance and extend the service life of a Ti6–Al4–V titanium alloy. This solution combines a commercially available nanosecond laser-based metalsurface patterning technique with a self-assembled molecular-film modification. The surface of the titanium alloy is patterned with periodic dimple arrays of varying densities and depths using the laser processing. The surface morphology, roughness and chemical composition of our samples are analyzed using a scanning electron microscopy and a confocal microscopy. Moreover, the wettability of the modified titanium-alloy surface is assessed with a contact-angle meter, yielding in a maximum contact angle as large as 153.2°. The coefficient of friction is measured using a tribometer and the wear mechanism is analyzed with a study of surface morphology. Under dry-sliding and water-lubrication conditions, the average coefficient of friction is reduced respectively by over 20% and 60%, when compared to the value typical for the original surface. This reduction is attributed to changed surface roughness and wettability. Our method offers a practical and efficient means of enhancing the wettability and the tribological performance of the titanium-alloy surfaces. [ABSTRACT FROM AUTHOR]

Zirconia-based dental implants are in direct contact with living tissues and any improvements in their bioactivity and adhesion to the tissues are highly welcome. In this study, different ratios of barium titanate (BT) were added to 3 mol% yttria-stabilized zirconia (3YSZ) through conventional sintering. The laser-texturing technique was also conducted to improve the biological performance of 3YSZ ceramics. The composition and the surface of the prepared composites were characterized by X-ray diffraction and scanning electron microscopy (SEM), respectively. The roughness and surface wettability of the composites were also measured. Furthermore, MC3T3-E1 pre-osteoblast cells were used for the in vitro experiments. Cell viability was evaluated using a commercial resazurin-based method. Morphology and cellular adhesion were observed using SEM. Based on the results, the laser texturing and the barium titanate content influenced the surface characteristics of the prepared composites. The laser-textured 3YSZ/7 mol% BT composites showed a lower water contact angle compared to the other samples, which indicated superior surface hydrophilicity. The cell viability and cell adhesion of 3YSZ/BT composites increased with the rise in the barium titanate content and laser power. An elongated cell morphology and apatite nucleation were also observed by the BT content. Overall, the laser-treated 3YSZ/5 and 7 mol% BT composites may be promising candidates in hard tissue repair due to their good cell response. [ABSTRACT FROM AUTHOR]

The rapid advancement of engineering systems has spurred the search for innovative thermal management solutions. Boiling, as a phase‐change heat transfer method, has shown promise in heat dissipation, but non‐functionalized surfaces struggle with increasing cooling demands. To improve heat dissipation efficiency across different heat loads, functionalized surfaces with tailored wettability have been proposed. Separately, superhydrophilic and superhydrophobic surfaces each offer benefits and drawbacks in boiling applications but combining them on a single "biphilic" surface simultaneously harnesses their advantages. In this study, laser‐functionalized copper surfaces with spatially tailored wettability are developed by combining two‐step laser texturing with a self‐assembled monolayer coating, while focus is placed on the impact of the size and pitch of superhydrophobic spots. The developed functionalized surfaces exhibit exceptional boiling performance with heat transfer coefficients up to 299 kW m−2 K−1, a 434% enhancement over untreated surfaces. Optimal ratios of superhydrophilic and superhydrophobic areas and optimal spot pitch are identified. Additionally, varying behavior at different heat flux levels is observed, emphasizing the importance of considering thermal loads when determining the optimal surface pattern. This advancement in performance, along with the rapid and cost‐effective functionalization process, represents a significant breakthrough for enhanced thermal management applications. [ABSTRACT FROM AUTHOR]

Glass surfaces tend to be hydrophilic when exposed to water resulting in a low water contact angle and high adhesion. Fabrication on a glass surface with low water adhesion can minimize the droplet's adhesion conduct self-cleaning, and improve the cleanliness of the glass surface. This paper presents surface texturing of the soda-lime glass surface by laser processing three different patterns to improve water contact angle with low water adhesion on the modified glass surface. A design experiment method was developed to determine the effects of laser parameters on the glass surfaces. The laser parameters used are laser power between 0.45 and 1.05W and scanning speeds of 210, 420, and 600 mm/min. The effects of laser parameters on surface morphology, water contact angle measurement, and average surface roughness, Ra were investigated. The characterization was conducted for surface morphology, two-dimensional surface roughness profile, and water contact angle. The results show that the highest water contact angle obtained after laser texturing is up to 125.29° compared to the as-received surface with a contact angle of 32.35°. The highest water contact angle resulted from 420 mm/min scanning speed and 0.45 W of laser power, responding to the surface with a minimum range of Rax and Ray of 0.96 and 1.5 µm. These findings are significant for designing surface modification of self-cleaning glass surface applications like the automotive windscreens, and window panels for high-rise buildings. [ABSTRACT FROM AUTHOR]

Slagging and fouling of boilers are typical technological problems in the combustion of solid fuels (especially coal and biomass). This study proposes a novel approach based on laser texturing of the near-surface layer of steel used to make heating surfaces of coal-fired boilers. This approach is aimed at improving the resistance of metal surfaces to slagging. The formation of slag deposits on the surfaces of AISI 310 S steel modified by laser radiation has been experimentally studied. The formation of slag melt was analyzed on the surface of modified and polished steel plates during heating to 1400 °C. High-temperature heating and interaction with slag led to a change in the chemical composition of the steel. A significant increase in the chromium content (up to 47%) of the steel surface and the transformation of its texture with the formation of grains up to 2.5 µm in size were established. Laser surface treatment significantly increased the resistance of the steel to such changes and also reduced the grain size to 1.5 µm. As a result of laser modification of surfaces, the temperature of slag formation shifts to higher values (higher by 60–75 °C compared to the unmodified polished surface). The anisotropic texture (cauliflower type) contributed to a decrease in the size of the slag spreading front, and also had by self-cleaning properties from the mineral melt. The latter allows to increase the reliability and energy efficiency of boiler equipment. [Display omitted] [ABSTRACT FROM AUTHOR]

Prior studies have evidenced the potential for enhancing boiling heat transfer through modifications of surface or fluid properties. The deployment of nanofluids in pool boiling systems is challenging due to the deposition of nanoparticles on structured surfaces, which may result in performance deterioration. This study addresses the use of TiO2–water nanofluids (mass concentrations of 0.001 wt.% and 0.1 wt.%) in pool boiling heat transfer and concurrent mitigation of nanoparticle deposition on superhydrophobic laser-textured copper surfaces. Samples, modified through nanosecond laser texturing, were subjected to boiling in an as-prepared superhydrophilic (SHPI) state and in a superhydrophobic state (SHPO) following hydrophobization with a self-assembled monolayer of fluorinated silane. The boiling performance assessment involved five consecutive boiling curve runs under saturated conditions at atmospheric pressure. Results on superhydrophilic surfaces reveal that the use of nanofluids always led to a deterioration of the heat transfer coefficient (up to 90%) compared to pure water due to high nanoparticle deposition. The latter was largely mitigated on superhydrophobic surfaces, yet their performance was still inferior to that of the same surface in water. On the other hand, CHF values of 1209 kW m−2 and 1462 kW m−2 were recorded at 0.1 wt.% concentration on both superhydrophobic and superhydrophilic surfaces, respectively, representing a slight enhancement of 16% and 27% compared to the results obtained on their counterparts investigated in water. [ABSTRACT FROM AUTHOR]

Skin-pass rolls are used for setting the final sheet thickness and surface texture. For sheet metal that is produced for forming, textured skin-pass rolls featuring a high-low structure are used in order to improve the formability and paint adhesion of the sheet. In this paper, new textures for skin-pass rolls generated by high-speed laser melt injection (HSLMI) are presented and characterized. Furthermore, it is studied how the texture of the roll is transferred to steel and aluminum sheets. With HSLMI, metal matrix composite (MMC) layers featuring spherical fused tungsten carbide (SFTC) particles with a high hardness could be produced on skin-pass rolls. For generating an increased high-low structure, laser ablation and electrolytic etching were carried out after HSLMI and grinding of the rolls. An analysis of the topography showed that different protruding heights between SFTC particles and matrix can be set. The textures generated by laser ablation showed a topography featuring two homogeneous height levels, whereas a texture with spherically shaped particles could be generated by electrolytic etching. Furthermore, it was found that all textures were transferred from the roll to both steel and aluminum sheets. The transfer of the textures mainly depended on the protruding height of the SFTC particles and the SFTC particle content of the roll. [ABSTRACT FROM AUTHOR]

This study explores the nuanced interplay between surface wettability and morphology in nucleate boiling heat transfer. Surfaces with identical microstructures but varying wettability are created on copper substrates using laser texturing and a hydrophobic agent. The spacing between laser-etched microchannels is adjusted to achieve different contact angles and percentages of laser-textured areas. Boiling performance is assessed with variations in channel spacing and surface coverage, revealing significant differences between hydrophilic and hydrophobic surfaces. The critical heat flux (CHF) enhancement mechanisms are identified, emphasizing either enhanced liquid replenishment or separate boiling and liquid-supply regions. A critical laser line spacing of 100 μm is determined, where hydrophobic and hydrophilic variants exhibit similar CHF. Interestingly, hydrophilic surfaces show a weak correlation between the heat transfer coefficient (HTC) and contact angle, while hydrophobic surfaces demonstrate a strong correlation. This separation of surface morphology and wettability confirms that lower wettability promotes early nucleate boiling and high HTC, whereas hydrophilic variants contribute to enhanced CHF with lower HTC. These distinctions are most prominent at high coverage with laser-textured areas and diminish as coverage decreases. The findings provide valuable insights into optimizing surface properties for efficient boiling heat transfer applications.

Comparing with pure laser irradiation, the hybrid fabrication using laser ablation and chemical modification is one of the widely used techniques to obtain bio-inspired super-hydrophobic surface. Nevertheless, conventional surface chemical modification techniques have faced challenges including the detachment of micro-nano structures and the instability of super-hydrophobic surfaces. This research introduces an innovative method for creating extremely stable super-hydrophobic surfaces on NiTi alloy through a combination of laser exposure, carbon ion implantation, and modification with fluoroalkylsilane (FAS). Surface morphology and chemical component were systematically investigated to reveal the formation mechanism of super-hydrophobicity. Besides, its abrasion stability, thermal stability and corrosion resistance stability of this kind of super-hydrophobic surface were also investigated. And the corresponding stability improvement mechanisms were further revealed.

This paper presents the main texturing methods of metal surfaces, from the perspective of existing studies. This article explores different surface texturing methods and techniques, with an emphasis on using them to improve mechanical and tribological properties. Through a comprehensive analysis, the article addresses traditional texturing techniques as well as emerging technologies. In addition, the benefits and limitations of each method are highlighted, and recent articles in the field are reviewed to provide a complete picture of current developments in surface texturing

Femtosecond ultra-short laser pulses can induce various micro- and nanostructural changes in the surface of stainless steel, paving the way for new functionalities in the application of these materials. In this work, UV, visible, and IR femtosecond laser pulses have been utilized on ferritic stainless steel under differing conditions of fluence, pulses per spot and hatch distance. These variables resulted in various compositional and micro- and nanostructural changes on the steel surfaces. The texturing processes which originate these changes can be meticulously designed by selecting the appropriate strategy and laser parameters, leading to Laser-Induced Periodic Surface Structures (LIPSS) and other potential morphologies. A significant problem to consider during the laser treatment of stainless-steel surfaces is the effect that these microstructural modifications, induced by the ultra-short pulses, can have on the corrosion behavior and the brightness of the surface. On one hand, a detailed study of the effect that these treatments can have on the corrosion resistance of the stainless steel under investigation has been conducted. The study shows that under specific conditions, treatments with ultra-short laser pulses maintain the corrosion resistance of the surfaces. On the other hand, the study of the surface brightness after laser treatments, as measured by the Light Reflectance Value (LRV), shows that brightness is only slightly decreased (less than 10 %) for samples where Surface Density of Applied Energy (SDAE) is lower than 2 J/cm2. Furthermore, the diffuse LRV is increased in every textured sample due to the presence of ripples.

Laser texturing is a promising technology with wide-ranging applications in surface processing. In this study, a nanosecond laser was used to ablate the surface of Q355 steel, creating grooves of varying depths by different processing times. Satisfactory Al/Steel joints were obtained under different groove depths (0 μm, 6 μm, 26 μm and 56 μm). Interfacial microstructure evolutions were investigated and the observed results indicated that introduction of texture would enhance interfacial specific surface area, promote degree of atomic diffusion, thicken interfacial IMCs (intermetallic metallic compounds) while maintain interfacial reaction (η-Fe2(Al,Si)5 + θ-Fe(Al,Si)3). Numerical simulations results illustrated that existence of texture would reduce interfacial peak residual stress, homogenize residual stress distribution and induce compressive stress in the groove. Highest strength of 111 MPa with the fracture mode of tough-brittle compound fracture was produced in the joint when laser texturing processing times were 20, which was nearly 40 % higher compared to the untreated joint (80 MPa). This study provides a novel method to improve joints mechanical properties for laser welding-brazing of Al/Steel system, which may also provide a theoretical reference for the application of other dissimilar metal systems.

The adoption of lightweight materials in engineering applications has become more popular over recent years, with adhesives replacing traditional joining methods such as bolts and rivets. Adhesion science and related technologies are arising as cleaner options for sustainable production in modern industry, with adhesive-bonded joints increasingly being used as design solutions in complex products and assemblies. However, the use of structural adhesives has several significant drawbacks, most of which are related to environmental impact, linked to the nature of the adhesive substance, as well as product disassembly/disposal deriving from the fact that adhesive joints are usually irreversible. Within this context, the goal of this paper is to study adhesive joints in mechanical assemblies from a life cycle perspective, offering more comprehensive analysis tools and assembly solutions suitable for industries such as automotive, aerospace, and assembly/packaging machinery. A methodological framework for the comprehensive characterization of bonded joints using effective surface activation techniques has been created and tested. The first phase encompasses the production of samples for mechanical testing under static and fatigue loading conditions. The second includes the characterization of inputs/outputs (life cycle inventory—LCI) for life cycle assessment (LCA) of mechanical assemblies employing adhesive joints and innovative surface activation techniques. The final phase provides a set of eco-design actions based on a critical analysis of the obtained results. The outcomes demonstrate how it is possible to achieve optimal adhesive-bonded joint properties under specific working conditions (e.g., static or fatigue loading) while maintaining a low environmental load using novel surface pre-treatments such as laser and plasma technologies. These outcomes are supported by a case-study in which adhesive joints are applied to the mechanical assembly of a bottle gripper for a food packaging machine. The adoption of eco-design rules in adhesive joint applications will help designers in the development of suitable solutions for lightweight applications from a complete life cycle perspective. [ABSTRACT FROM AUTHOR]

Rendering transparent materials extreme wettability, for example, superhydrophobicity or superhydrophilicity, has received considerable attention during the past decades. While fabrication of superhydrophobic glass with high processing efficiency and low production cost has always been a challenge. In this work, a laser‐based surface functionalization process that combines ultraviolet (UV) nanosecond laser texturing and silicone oil‐assisted heat treatment was employed to render glass superhydrophobicity with high process throughput. The wettability transition is attributed to the combined effects of laser texturing that induces hierarchical surface micro/nanostructures and silicone oil‐assisted heat treatment that alters surface chemistry and lowers surface energy. The surface transmittance of the laser‐based surface functionalized glass samples in the visible spectrum was experimentally measured and analyzed. The laser‐based surface functionalized glass sample also exhibited long‐term stability in air, mechanical robustness and good self‐cleaning property. More importantly, the developed process shows both high process efficiency and cost effectiveness and has potential for applications where superhydrophobic glass is required. [ABSTRACT FROM AUTHOR]

In this work, zinc oxide–based piezoelectric nanogenerator (PENG) over the flexible Kapton polyimide (PI) substrate is developed. The device performance is improved by laser texturing of PI substrate, which increases the effective surface area of PI and adhesivity of ZnO thin film with PI substrate to improve the reliability and life span of the device. The untextured PI‐based PENG generates a peak‐to‐peak output voltage, current, and power of 6 V, 420 nA, 2.42 μW, respectively, which increases to 15.8 V, 790 nA, and 12.51 μW, respectively, on using textured PI obtained by 60% laser spot overlap. On further increasing the laser spot overlap to 80%, the peak‐to‐peak output voltage, current, and power improve to 22.2 V, 1210 nA, and 26.88 μW, respectively. Therefore, as compared to the untextured‐PI‐based PENG, laser‐textured‐PI‐based PENG is a promising candidate for energy‐harvesting applications. [ABSTRACT FROM AUTHOR]

This study investigates the use of a CuBr vapor nanosecond laser with a 510 nm/578.2 nm wavelength for the surface treatment of 1050 aluminum and 2219 aluminum alloys. Laser-induced periodic surface structuring was used to optimize processing parameters to achieve hydrophobic and hydrophilic properties on the surface. The wetting properties were measured and the roughness results (Ra, Rz, Rq) evaluated. Prior to and after laser treatment, surface wetting and roughness changes were investigated. The wetting study showed that the maximum contact angle between a droplet of deionized water and the treated surface can be reached between more than 140 degrees and less than 10 degrees, which, respectively, is a superhydrophobic and superhydrophilic surface. Compared with the untreated surface, wetting increased by more than 2 times and decreased by more than 8 times. Overall, experiments show the dependence of wetting properties on laser input parameters such as scan speed and scan line distance with different delivered energy amounts. This study demonstrates the possibility of laser parameter optimizations which do not require auxiliary gases and additional processing of the resulting surfaces to obtain different wetting properties on the surface. The findings described in this article suggest that the CuBr laser surface treatment method is a promising method for industrial applications where surfaces with special wetting and roughness properties are required, for example, the laser marking of the serial number of parts used in wet environments such as aerospace, shipbuilding, and defense industries. [ABSTRACT FROM AUTHOR]

Embossing rolls are used in a variety of sectors to transfer surface textures to a product. Textures on the rolls are typically achieved by material-removal techniques, resulting in craters in the surface of the roll. The wear resistance of the surfaces is improved by additional coating technologies. A novel process offering improved surface design freedom and which negates the need for post-coating techniques is the embedding of micro-meter-sized ceramic particles in the surface of the roll. This can be achieved through micro-additive processing. This work presents and discusses experimental results of surface texturing through locally derived laser-induced melt pools in which ceramic particles are dissolved. This process is termed laser implantation, or laser dispersing. Using this technology, dome-shaped surface structures with significantly increased hardness compared to the bare steel can be achieved. Reported results in the literature focus on implantations with diameters ranging from 150 μm to 400 μm and heights ranging from 10 μm to 30 μm. However, features with smaller diameters and heights are desired for technology adoption to permit a wider range of surface roughness. This paper presents and discusses the experimental results of implantations with a diameter smaller than 150 µm, with heights between 1 μm and 15 μm. For that purpose, a Nd:YAG laser source (focal diameter 70 μm, pulse durations from 3 to 15 ms, pulse power from 20 to 50 W average) was used to induce a melt pool driving the particle embedding.

The article is aimed at identifying the influence of laser texturing and subsequent coating with a hard, wear-resistant coating AlCrSiN (nACRo®) on selected tribological properties of the analyzed tool steels for cold work, produced by conventional and powder metallurgy. The substrate from each steel was heat treated to achieve optimal properties regarding the chemical composition and the method of production of the material. Böhler K100 and K390 Microclean® steels were used. These are highly alloyed tool steels used for various types of tools intended for cold work. The obtained results show that the coefficient of friction is increased by coating, but the wear rate is lower compared to the samples which were only textured.

Si is a highly promising anode material due to its superior theoretical capacity of up to 3579 mAh/g. However, it is worth noting that Si anodes experience significant volume expansion (>300%) during charging and discharging. Due to the weak adhesion between the anode coating and the smooth Cu foil current collector, the volume-expanded Si anode easily peels off, thus damaging anode cycling performance. In the present study, a femtosecond laser with a wavelength of 515 nm is used to texture Cu foils with a hierarchical microstructure and nanostructure. The peeling and cracking phenomenon in the Si anode are successfully reduced, demonstrating that volume expansion is effectively mitigated, which is attributed to the high specific surface area of the nanostructure and the protection of the deep-ablated microgrooves. Moreover, the hierarchical structure reduces interfacial resistance to promote electron transfer. The Si anode achieves improved cycling stability and rate capability, and the influence of structural features on the aforementioned performance is studied. The Si anode on the 20 μm-thick Cu current collector with a groove density of 75% and a depth of 15 μm exhibits a capacity of 1182 mAh/g after 300 cycles at 1 C and shows a high-rate capacity of 684 mAh/g at 3 C. [ABSTRACT FROM AUTHOR]

Superhydrophobic surfaces are highly desirable due to their remarkable water-repellent behavior. Laser texturing with subsequent low surface energy modification is a versatile strategy for creating such surfaces. In this study, via synergistic laser texturing and low temperature annealing, superhydrophobicity was first attempted to be achieved on the FeCoCrMnNi surface. By optimizing the laser parameters, the arrays with large depth-to-width ratios were constructed. Subsequently, by annealing at a low temperature, the transition process from superhydrophilicity to superhydrophobicity was successfully achieved on the FeCoCrMnNi surface. The effects of the hatching interval on the wettability were investigated, and the mechanism of wettability transition for FeCoCrMnNi was discussed. According to the experimental results and analysis, the textured surfaces exhibited excellent superhydrophobicity at different hatching intervals and a maximum contact angle of 165° was obtained. Furthermore, the created superhydrophobic surfaces possessed good liquid capture and self-cleaning capabilities and enabled magnification for optical imaging. The wettability transition after low temperature annealing was attributed to the absorption of airborne organic compounds. This study provides an efficient, clean, and versatile strategy to achieve superhydrophobicity of the FeCoCrMnNi surface by laser processing. [ABSTRACT FROM AUTHOR]

The relevance. The development of fundamentally new strategies and technical solutions leading to an increase in energy efficiency and resource saving of cooling systems for energy-saturated equipment is impossible without the creation of new structural materials with targeted functional properties. Promising cooling systems of heat-loaded equipment, for example, 5G communication devices emitting high-density heat fluxes (up to 1000 W/cm2), include systems based on drip irrigation. Such cooling makes it possible to increase the intensity and uniformity of heat removal, and significantly reduce the coolant consumption. However, the results obtained so far show that the use of traditional approaches (the use of surfaces made of steel, copper, aluminum and their alloys, processed by grinding or polishing) does not allow solving the problem of intensive cooling of surfaces that release high-density heat fluxes. Laser strategies for processing heat transfer surfaces are one of the most effective ways to intensify evaporation and boiling. In relation to the development of laser systems in the last decade, financially sound technologies for creating targeted, functional surface properties of metals have become available. The practical use of laser-modified heat-transfer surfaces of cooling systems can solve a number of problems associated with meeting the growing global demand for energy resources, in particular, when intensifying the removal of high-density heat fluxes from elements of energy-saturated equipment by shifting the heat transfer crisis of the 2nd kind to higher temperatures. The purpose is to assess the possibility of shifting the heat transfer crisis (Leidenfrost effect) to higher temperatures by modifying heat transfer heating surfaces with nanosecond laser radiation. Methods. Using nanosecond laser processing, unique textures with specified geometric characteristics were created on typical materials used in practice in the design of heat transfer surfaces for heating cooling systems. Texture characteristics were determined using confocal and electron microscopy equipment. The Leidenfrost effect was recorded using a specially made setup with equipment for the shadow optical method and high-speed video recording of fast physical processes. Results. The modes of a single nanosecond laser pulse action on the stainless steel and aluminum surfaces were detected. These modes guarantee the formation of an ablation crater. We showed the possibility to apply the graphic-analytical technique for the formation of a given microtexture during the treatment of metal surfaces with nanosecond laser radiation. Laser treatment of metal surfaces with pulse energy up to 0,6 mJ makes it possible to control the boiling crisis characteristics (2nd kind), in particular, the Leidenfrost temperature, over a wide range of values by more than 110 °C on aluminum surface and by more than 45 °C on stainless steel surface in atmospheric conditions when using distilled deaerated water as a heat carrier due to the formed texture and superhydrophilic properties.

In this study, a scatterometry-based monitoring system designed for tracking the quality and reproducibility of laser-textured surfaces in industrial environments was validated in off-line and real-time modes. To this end, a stainless steel plate was structured by direct laser interference patterning (DLIP) following a set of conditions with artificial patterning errors. Namely, fluctuations of the DLIP process parameters such as laser fluence, spatial period, and focus position are introduced, and also, two patterning strategies are implemented, whereby pulses are deliberately not fired at both deterministic and random positions. The detection limits of the system were determined by recording the intensities of the zero, first, and second diffraction order using a charge-coupled device (CCD) camera. As supported by topographical measurements, the system can accurately calculate spatial periods with a resolution of at least 100 nm. In addition, focus shifts of 70 µm from the optimum focus position can be detected, and missing patterned lines with a minimum width of 28 µm can be identified. The validation of this compact characterization unit represents a step forward for its implementation as an in-line monitoring tool for industrial laser-based micropatterning.

Surface preparation is an important step in adhesive technology. A variety of abrasive, chemical, or concentrated energy source treatments are used. The effects of these treatments vary due to the variety of factors affecting the final strength of bonded joints. This paper presents the results of an experimental study conducted to determine the feasibility of using fiber laser surface treatments in place of technologically and environmentally cumbersome methods. The effect of surface modification was studied on three materials: aluminum EN AW-1050A and aluminum alloys EN AW-2024 and EN AW-5083. For comparison purposes, joints were made with sandblasted and laser-textured surfaces and those rolled as reference samples for the selected overlap variant, glued with epoxy adhesive. The joints were made with an overlap of 8, 10, 12.5, 14, and 16 mm, and these tests made it possible to demonstrate laser processing as a useful technique to reduce the size of the overlap and achieve even higher load-bearing capacity of the joint compared to sandblasting. A comparative analysis was also carried out for the failure force of the adhesive bond and the failure energy. The results show the efficiency and desirability of using lasers in bonding, allowing us to reduce harmful technologies and reduce the weight of the bonded structure.

Prior studies have evidenced the potential for enhancing boiling heat transfer through modifications of surface or fluid properties. The deployment of nanofluids in pool boiling systems is challenging due to the deposition of nanoparticles on structured surfaces, which may result in performance deterioration. This study addresses the use of TiO2–water nanofluids (mass concentrations of 0.001 wt.% and 0.1 wt.%) in pool boiling heat transfer and concurrent mitigation of nanoparticle deposition on superhydrophobic laser-textured copper surfaces. Samples, modified through nanosecond laser texturing, were subjected to boiling in an as-prepared superhydrophilic (SHPI) state and in a superhydrophobic state (SHPO) following hydrophobization with a self-assembled monolayer of fluorinated silane. The boiling performance assessment involved five consecutive boiling curve runs under saturated conditions at atmospheric pressure. Results on superhydrophilic surfaces reveal that the use of nanofluids always led to a deterioration of the heat transfer coefficient (up to 90%) compared to pure water due to high nanoparticle deposition. The latter was largely mitigated on superhydrophobic surfaces, yet their performance was still inferior to that of the same surface in water. On the other hand, CHF values of 1209 kW m−2 and 1462 kW m−2 were recorded at 0.1 wt.% concentration on both superhydrophobic and superhydrophilic surfaces, respectively, representing a slight enhancement of 16% and 27% compared to the results obtained on their counterparts investigated in water.

Ti alloys are widely used in severe corrosion environments where corrosion resistance is required, as biomedical industry. Additive manufacturing produces customized and complexes products. Laser texturing is a process of structuring surfaces using laser pulses, that allows the creation of periodic patterns on the surfaces of materials, to modify them, functionally and/or aesthetically, in a precise and direct way, allowing parameterization, versatility and repeatability. Consequently, bringing together metallic additive manufacturing with laser texturing process could be an alternative to obtain parts with functional hydrophilic surfaces, which improves osteointegration and reduces bacteria adhesion. Thus, the aim of this work is to characterize and evaluate the influence of LASER parameters in as-built additive manufactured potential biomedical components. Ti6Al4V specimens were produced by L-PBF, using Ytterbium LASER with maximum power of 500 W, varying the laser power from 61 W to 244 W. The samples were characterized by SEM, Microhardness, and wettability. After that, some specimens were Laser textured using an Ytterbium optical fiber laser, and then evaluated by SEM, wettability, and 3D roughness. It was possible to observe that the surface of all studied samples was flattened after Laser texturing in comparison with as-built condition, due to the melting of the powder particles.

Shallow Hilbert curve patterns with easily programmable texture density were selected for laser texturing of stainless steel substrates. Two different texture path segment lengths (12 and 24 µm) and four different laser power percentages (5%, 10%, 15%, and 20%) were investigated. The textured and smooth substrates were coated with thin polydopamine/polytetrafluoroethylene (PDA/PTFE) coatings for tribological property assessment. The effects of texture density (texture area coverage) and laser power on the durability and friction of the coated surfaces were studied. Laser texturing the substrates improved the coating durability up to 25 times, reduced the friction coefficient, and prevented coating global delamination. The textures fabricated with a laser power of 15% and a texture path segment length of 12 µm yielded the best coating durability. The textures provided the interlocking for the PTFE coating and thus prevented its global delamination. Furthermore, the PTFE inside the texture grooves replenished the solid lubricant worn away in the wear track and prolonged the coating wear life. [ABSTRACT FROM AUTHOR]

This paper presents the main texturing methods of metal surfaces, from the perspective of existing studies. This article explores different surface texturing methods and techniques, with an emphasis on using them to improve mechanical and tribological properties. Through a comprehensive analysis, the article addresses traditional texturing techniques as well as emerging technologies. In addition, the benefits and limitations of each method are highlighted, and recent articles in the field are reviewed to provide a complete picture of current developments in surface texturing. [ABSTRACT FROM AUTHOR]

According to the literature data graphene oxide cannot be easily used as an anti-corrosion barrier on metals and alloys, especially on carbon steel. This article shows that the oxidised form of graphene can improve the electrochemical corrosion parameters of carbon steel, if necessary modifications on the surface structure and wettability of steel are made prior to the coating step. In this study, the effects of surface roughness and hydrophilicity of carbon steel on the anti-corrosion performance of the electrophoretically deposited graphene oxide were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. The results showed that increasing the roughness and hydrophilicity of the bare steel surface promotes the mechanical interlocking/adhesion between the graphene oxide and steel and this improves the protective performance of the deposited graphene oxide barrier on steel. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the effects of laser texturing of coated textile materials on their cut resistance. The investigated material was an aramid knitted fabric coated with a polymer layer made of an acrylic-styrene dispersion functionalized with particles of silicon carbide (SiC). The distribution of SiC particles in the coating microstructure was assessed on the basis of microscopic observations (scanning electron microscopy). The coating was laser textured, and then the cut resistance of the assembly was determined using a rectangular blade. The findings showed that laser texturing improved the cut resistance of the tested materials, causing a fourfold increase in that parameter as compared to non-modified textile materials. This fact may improve the safety of workers wearing protective gloves in terms of cut protection. [ABSTRACT FROM AUTHOR]

Chemical modification is usually utilized for preparing superhydrophobic SiC surfaces, which has the problems of long processing time, high environmental contamination risk, and high cost. To enhance the condensation heat transfer efficiency of SiC, the superhydrophobic SiC surface was fabricated through laser texturing and heat treatment. In this study, the SiC surface was processed by laser texturing with a nanosecond laser, followed by heat treatment. Surface microstructures and compositions were investigated with SEM and XPS, and the heat transfer coefficient of the superhydrophobic SiC surface was tested. The results indicated that the laser-textured SiC surface had a super hydrophilic contact angle of 0°; after heat treatment, SiC ceramic became superhydrophobic (surface contact angle reaches 164°) because organic contamination on the original SiC surface could be cleaned by using laser texturing, which caused a chemical reaction and the formation of SiO2 on the surface. Moreover, the distribution of relatively low-energy SiOX was formed after heat treatment; then, SiC ceramic became superhydrophobic. Due to the formation of nanoscale sheet-like protrusion structures by heat treatment, the SiC superhydrophobic surface exhibited typical dropwise condensation, and the condensation heat transfer coefficient reached 331.8 W/(m2·K), which was 2.3 times higher than that of the original surface. [ABSTRACT FROM AUTHOR]

Abstract Shallow Hilbert curve patterns with easily programmable texture density were selected for laser texturing of stainless steel substrates. Two different texture path segment lengths (12 and 24 µm) and four different laser power percentages (5%, 10%, 15%, and 20%) were investigated. The textured and smooth substrates were coated with thin polydopamine/polytetrafluoroethylene (PDA/PTFE) coatings for tribological property assessment. The effects of texture density (texture area coverage) and laser power on the durability and friction of the coated surfaces were studied. Laser texturing the substrates improved the coating durability up to 25 times, reduced the friction coefficient, and prevented coating global delamination. The textures fabricated with a laser power of 15% and a texture path segment length of 12 µm yielded the best coating durability. The textures provided the interlocking for the PTFE coating and thus prevented its global delamination. Furthermore, the PTFE inside the texture grooves replenished the solid lubricant worn away in the wear track and prolonged the coating wear life.