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Possibilities of Dry and Lubricated Friction Modification Enabled by Different Ultrashort Laser-Based Surface Structuring Methods
摘要： In this contribution we report on the possibilities of dry and lubricated friction modification introduced by different laser surface texturing methods. We compare the potential of Laser-Induced Periodic Surface Structures and Laser Beam Interference Ablation on 100Cr6 steel in a linear reciprocating ball-on-disc configuration using 100Cr6 steel and tungsten carbide balls with load forces between 50 mN and 1000 mN. For dry friction, we find a possibility to reduce the coefficient of friction and we observe a pronounced direction dependency for surfaces fabricated by Laser Beam Interference Ablation. Furthermore, Laser-Induced Periodic Surface Structures result in a load-dependent friction reduction for lubricated linear reciprocating movements. This work helps to identify the modification behaviour of laser generated micro structures with feature sizes of approximately 1 μm and reveals new possibilities for surface engineering
关键词： lubricated friction,smart surfaces,laser surface texturing,laser beam interference ablation,laser-induced periodic surface structures,dry friction
更新于2025-11-21 11:18:25
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Enhancement of substrate-coating adherence of boron-doped diamond electrodes by nanosecond laser surface texturing pretreatment
摘要： To improve the substrate-coating adherence of Nb-based boron-doped diamond (BDD) electrodes, laser surface texturing (LST) pretreatment was investigated. Substrates were textured by a Nd:YAG laser (1.06 μm radiation, 20 ns) with several laser parameters such as single pulse energy and scanning spacing, then coated with a BDD film by hot filament chemical vapor deposition (HFCVD). Characteristics of the substrates and BDD thin film electrodes were investigated. The results revealed that periodic valley-like structures were fabricated on substrate surfaces. LST pretreatment can significantly enhance the substrate-coating adherence of BDD electrode samples, and the laser cleaning step can effectively remove the surface oxide layer generated by laser pretreatment. Single pulse energy is a crucial influencing factor, the proper pulse energy can provide the best adherence property, providing sufficient surface treatment effect, promoting nucleation, release residual stress and promote the mechanical interlock. Suitable scanning spacing can further improve the coating adherence, and the match of scanning spacing and single pulse spacing can effectively avoid the directional peeling.
关键词： Laser cleaning,BDD electrode,Laser surface texturing,Substrate-coating adherence
更新于2025-09-23 15:23:52
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Roles of chemistry modification for laser textured metal alloys to achieve extreme surface wetting behaviors
摘要： Wetting behaviors of structured metal surfaces have received considerable attention due to the wide range of applications for commercial, industrial, and military uses as well as fundamental research interests. Due to its adaptability, precision, and ease of automation, laser-based texturing techniques are desirable platforms to create micro- and nano-structures, including laser-induced periodic surface structures, or hierarchical structures on a metal substrate. However, micro- and nanostructures alone often do not achieve the desired wettability. A subsequent surface chemistry modification method must be performed to attain target extreme wettability for laser textured metal substrates. This review aims to provide a systematic understanding of the interdependence of surface chemistry modification and physical surface structures formed during the laser-based surface engineering methods. The role of surface chemistry on top of the surface structures is presented to decide the final wetting scenario. Specifically, by controlling the surface chemistry of a laser textured surface, wetting can be modulated from extreme hydrophobicity to hydrophilicity, allowing freedom to achieve complex multi-wettability situations. In each section, we highlight the most fruitful approaches and underlying mechanisms to achieve a fitting combination of surface structures and surface chemistry. Durability and stability of the treatd surface is also discussed in corrosive and abrasive environments. Finally, challenges in current studies and prospects in future research directions of this rapidly developing field are also discussed. This review will provide a comprehensive guideline for the design of laser texturing methods and the fabrication of extreme wetting surfaces for metal alloys.
关键词： superhydrophilicity,superhydrophobicity,metal alloy,Laser surface texturing,chemistry modification,silane treatment
更新于2025-09-23 15:21:01
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Investigations in the fabrication of surface patterns for wettability modification on a Zr-based bulk metallic glass by nanosecond laser surface texturing
摘要： Laser texturing has previously been employed to enhance the wettability of metallic alloys. Such studies reported that modifying the wettability of a surface is a result of changes in both its topography and its chemistry. In this paper, an investigation about laser-induced surface wettability modification is also reported but for a less studied type of material in this context. In particular, nanosecond (ns) laser processing was employed to texture two types of surface patterns, i.e. dimples and grooves, on the surface of a Zr-based bulk metallic glass (BMG) known as Vitreloy 105. The specific focus of the research was on understanding the role played by both surface topography and chemistry modifications in changing the wettability of the original surface. Using static contact angle measurements, it was found that groove patterns enhanced the hydrophilicity of the original BMG, while dimple patterns weakened it. Based on the obtained 3D surface measurements and XPS data, it is suggested that the reduced hydrophilicity of dimple-textured surfaces was driven by the decrease of hydrophilic C=O and O=C-O bonds post laser processing. While these bonds were also reduced for groove-textured patterns, the hydrophilicity was still enhanced following laser irradiation as a result of the dominant role that a much larger induced surface roughness should play in this case.
关键词： Surface topography,Bulk metallic glass,Nanosecond laser surface texturing,Surface chemistry.,Wettability
更新于2025-09-23 15:19:57
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Effect of laser texturing on the performance of ultra-hard single-point cutting tools
摘要： This paper investigates the cutting performance and anti-adhesive properties of textured single-point polycrystalline diamond (PCD) cutting tools in machining Aluminium 6082 alloys. The micro/nano textures were first milled using a fibre laser (1064-nm wavelength) at different power intensities, feed speeds and pulse durations, and finally characterised using scanning electron microscopy, white light interferometry and energy dispersive X-ray spectroscopy. The effect of different textures on the cutting performance was investigated in turning tests under dry cutting conditions. The test was stopped at regular lengths of cut to allow analysis of height of adhesion through 3D white light interferometry. The data processing of the cutting forces and the microscopical characterisation of the tested cutting tools enabled the evaluation of the effects of texture design, friction coefficient and adhesive properties. The results indicated that feed force in tools with grooves perpendicular to the chip flow direction (CFD) was more stable (20–40 N) than the benchmark (6–41 N). Similarly, the thrust force for tools with grooves parallel to CFD and grooves perpendicular to CFD showed a homogeneous trend fluctuating between 60 and 75 N as compared with the benchmark (ranging between 73 and 90 N). For texture depth in the order of 260 nm and post process roughness in the order of tens of nanometers, a reduction of average friction coefficient (0.28 ± 0.14) was reported when using lasered inserts with grooves parallel to the chip flow direction compared with the benchmark tools (0.34 ± 0.26) corroborated by reduced stiction of workpiece material on the rake face. In machining via textured tools with grooves perpendicular to CFD, the cutting forces were reduced by 23%, and the surface quality of the machined workpiece was improved by 11.8%, making this geometry the preferred choice for finishing applications. Using grooves parallel to CFD reduced the cutting forces by 11.76%, adhesion by 59.36% and friction coefficient by 14.28%; however, it increased the surface roughness of the machined workpiece, making this geometry suitable for roughing operations. For the first time, laser manufacturing is proposed as a flexible technique to functionalise the geometrical and wear properties of PCD cutting tools to the specific applications (i.e. roughing, finishing) as opposed to the standard industrial approach to use microstructurally different PCDs (i.e. grain size and binder %) based on the type of operation.
关键词： Adhesion,Dry cutting,Nanosecond pulse,Laser milling,Polycrystalline diamond insert,Laser surface texturing,Cutting forces
更新于2025-09-16 10:30:52
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[Laser Institute of America ICALEO?? 2016: 35th International Congress on Applications of Lasers & Electro-Optics - San Diego, California, USA (October 16a??20, 2016)] International Congress on Applications of Lasers & Electro-Optics - Optimized strategies for seamless stitching with synchronized galvo scanner and linear axis
摘要： Laser surface texturing using ultra short pulsed lasers in combination with galvo scanners is limited to the scan field of the galvo scanner which is typically 65x65 mm using a 160 mm objective. By combine the galvo scanner with an additional high precision linear axis, it is possible to enhance the working field. Increased surface roughness and visible seams in the intersection region have to be avoided to preserve the high quality achieved by using ultra short pulsed laser systems. Strategies to minimize this influence are developed by using a system with a synchronized galvo scanner and by working with b/w bitmaps in a raster scanning mode. This allows splitting an image into two sub-images and compare different strategies for its recombination on the sample. For these tests always the whole image is scanned but with laser switched off alternating for the left and the right sub-image. This setup offers the possibility to evaluate different stitching strategies for the combination of two sub-images without influence of the exact alignment of the linear axis to the galvo scanner. Transferring the stitching strategy to a system including one or two linear axes needs a perfect alignment of the two coordinate systems to preserve the high accuracy. Therefore, a solution for aligning the two coordinate systems with highest accuracy will be presented as well.
关键词： galvo scanners,laser surface texturing,ultra short pulsed lasers,stitching strategies,linear axis
更新于2025-09-16 10:30:52
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Novel laser textured surface designs for improved zirconia implants performance
摘要： The development of new surface designs to enhance the integration process between surgically placed implants and biological tissues remains a challenge for the scientific community. In this way and trying to overcome this issue, in this work, laser technology was explored to produce novel textures on the surface of green zirconia compacts produced by cold pressing technique. Two strategies regarding line design (8 and 16 lines design) and different laser parameters (laser power and number of laser passages) were explored to assess their influence on geometry and depth of created textures. The produced textures were evaluated with Scanning Electron Microscopy (SEM) and it was observed that well-defined textured surfaces with regular geometric features (cavities or pillars) were obtained by laser combining different strategies lines design and parameters. The potential of proposed textures was also evaluated regarding surface wettability, friction performance (static and dynamic coefficient of friction evolution) against bone, aging resistance and flexural strength. Results demonstrated that all the produced textures display a super hydrophilic or hydrophilic behavior. Regarding the friction behavior, it was experimentally observed a high initial static coefficient of friction (COF) for all produced textures. Concerning the aging resistance, all the textured surfaces revealed a low monoclinic content, less than 25% after 5?h of hydrothermal aging. The flexural strength results showed that the mechanical resistance of zirconia was not significantly compromised with the laser action. Based on the obtained results, it is possible to prove that the processing route used for manufacturing the new and different surface designs (cold pressing technique followed by laser texturing) showed to be particularly effective for the production of zirconia implants with customized surface designs according to the properties required in a specific application. These new surface designs besides to enhance the surface wettability and also to improve the fixation at the initial moment of the implantation, do not significantly compromise the resistance to aging and the mechanical performance of zirconia. Hence, a positive impact on the long-term performance of the zirconia implants may be expected with the proposed novel laser textured surface designs.
关键词： Flexural strength,Aging resistance,Zirconia,Surface wettability,Coefficient of friction,Laser surface texturing
更新于2025-09-12 10:27:22
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Laser surface texturing of titanium with thermal post-processing for improved wettability properties
摘要： The use of lasers to create microstructures on metal surfaces in order to change the wettability properties a material has been widely explored, mainly using ultra-short pulsed lasers working in the femto and picosecond regime. In order to explore a more robust industrial method for the creation of super-hydrophobic surfaces, a fibre based nanosecond pulsed laser has been used to process polished Ti6Al4V samples to produce customised topography. The samples then received a low temperature annealing post-treatment. This, decrease the time needed for reaching the super-hydrophobic point considerably. The nanosecond pulsed laser provides a thermal component in the surface, helping with the creation of micro pillars in the surface morphology. The use of scanning electron microscopy (SEM) with energy dispersive X-Ray analysis (EDX), white light optical profiling, and contact angle measurements were used to characterize and quantify the effects of the surface modification on the wetting properties of the material.
关键词： laser surface texturing.,superhydrophobic,Nanosecond laser,thermal post-processing
更新于2025-09-12 10:27:22
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Effects of laser processing conditions on wettability and proliferation of Saos-2 cells on CoCrMo alloy surfaces
摘要： Any processing disturbances in laser surface texturing (LST) could compromise the resulting surface topography and their desired functional response. Disturbances such as focal plane offsets and beam incident angle variations are always present in LST processing of 3D parts and can affect the surface morphology. In this research the effects of these laser processing disturbances in producing laser induced surface structures (LIPSS) on CoCrMo alloy substrates were investigated. In particular, these two disturbances were considered as laser processing variables to determine their effects on functional responses of LIPSS treated surfaces, i.e. surface wettability and the proliferation of Saos-2 osteoblast-like cells were evaluated. It was found that the changes of laser processing conditions led to a decrease in surface wettability and Saos-2 cells proliferation. In addition, a correlation between surface wettability and cell proliferation on LIPSS treated surface was identified and conclusions made about the effects of investigated process disturbances on the functional response of LIPSS treated CoCrMo substrates.
关键词： cobalt chrome molybdenum,surface functionalization,laser induced periodic surface structures,osseointegration,laser surface texturing
更新于2025-09-11 14:15:04
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Influence of Femtosecond Laser Surface Nanotexturing on the Friction Behavior of Silicon Sliding Against PTFE
摘要： The aim of the present work was to investigate the influence of laser-induced periodic surface structures (LIPSS) produced by femtosecond laser on the friction behavior of silicon sliding on polytetrafluoroethylene (PTFE) in unlubricated conditions. Tribological tests were performed on polished and textured samples in air using a ball-on-flat nanotribometer, in order to evaluate the friction coefficient of polished and textured silicon samples, parallel and perpendicularly to the LIPSS orientation. In the polished specimens, the friction coefficient decreases with testing time at 5 mN, while it increases slightly at 25 mN. It also decreases with increasing applied load. For the textured specimens, the friction coefficient tends to decrease with testing time in both sliding directions studied. In the parallel sliding direction, the friction coefficient decreases with increasing load, attaining values similar to those measured for the polished specimen, while it is independent of the applied load in the perpendicular sliding direction, exhibiting values lower than in the two other cases. These results can be explained by variations in the main contributions to friction and in the wear mechanisms. The influence of the temperature increase at the interface and the consequent changes in the crystalline phases of PTFE are also considered.
关键词： silicon,laser surface texturing,friction,LIPSS,PTFE,laser-induced periodic surface structures
更新于2025-09-11 14:15:04