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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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Double- and Multi-Femtosecond Pulses Produced by Birefringent Crystals for the Generation of 2D Laser-Induced Structures on a Stainless Steel Surface
摘要： Laser-induced textures have been proven to be excellent solutions for modifying wetting, friction, biocompatibility, and optical properties of solids. The possibility to generate 2D-submicron morphologies by laser processing has been demonstrated recently. Employing double-pulse irradiation, it is possible to control the induced structures and to fabricate novel and more complex 2D-textures. Nevertheless, double-pulse irradiation often implies the use of sophisticated setups for modifying the pulse polarization and temporal profile. Here, we show the generation of homogeneous 2D-LIPSS (laser-induced periodic surface structures) over large areas utilizing a simple array of birefringent crystals. Linearly and circularly polarized pulses were applied, and the optimum process window was defined for both. The results are compared to previous studies, which include a delay line, and the reproducibility between the two techniques is validated. As a result of a systematic study of the process parameters, the obtained morphology was found to depend both on the interplay between fluence and inter-pulse delay, as well as on the number of incident pulses. The obtained structures were characterized via SEM (scanning electron microscopy) and atomic force microscopy. We believe that our results represent a novel approach to surface structuring, primed for introduction in an industrial environment.
关键词： metal surface texturing,2D-LIPSS,femtosecond,micro/nanostructuring,birefringent crystals,double pulses
更新于2025-11-14 14:32:36
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[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI, USA (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Plasma Texturing of Silicon Wafers and Finished Solar Cell for Mass Production
摘要： Standard plasma texturing of silicon wafers are not widely introduced within mass production due to several challenges which have to be overcome before implementation i.e. surface contamination, surface near damaging due to ion bombardment, and surface passivation. Within this contribution we will show our current status to overcome these challenges. We will present that the electrical and optical properties of ICP only plasma textured samples are sufficient for solar cell production. Since in ICP processes the ion bombardment is low we also will discuss our current understanding of the plasma process based on experimental results of the self-masking process. Furthermore, a new plasma texturing approach texturing the SiN layer of finished solar cells is introduced for the first time which overcome all problems introduced by the plasma texturing of bare solar wafers.
关键词： Plasma materials processing,silicon,SiN texturing,Plasma texturing,photovoltaic cells
更新于2025-10-22 19:40:53
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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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Drag reduction effect of ultraviolet laser-fabricated superhydrophobic surface
摘要： Superhydrophobic (SH) surface has been found effective for drag reduction in wall-bounded turbulence for decades, especially the metallic durable SH surfaces are believed very promising for improving the velocity and voyage of marine vehicles. We present stainless steel SH surfaces with U-groove patterns that fabricated by ultraviolet laser texturing and coating modifier treatment. The drag-reducing effects of the SH surfaces are tested by a self-built gravity sliding speed improving evaluation device. The results show that the different drag-reduction performance of the SH surfaces can be achieved by adjusting the line spacing of the crossing U-groove patterns. With the line spacing equalling to 80 μm, the ultraviolet laser textured stainless steel SH surface acquires the static contact angle of 161.5° and the dynamic sliding angle of only 2°, which leads to the maximum speed improving rate of 29.7%.
关键词： drag reduction,Superhydrophobic surface,stainless steel,laser texturing
更新于2025-09-23 15:23:52
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Improvement in Light Extraction Efficiency of InGaN/GaN Blue Light Emitting Diodes Using Sidewall Texturing
摘要： Herein, we reported the effects of the geometric morphology of the sidewall on the extraction ef?ciency of GaN-based light-emitting diodes (LEDs). We performed numerical analysis based on the ray-tracing method. We found that the extraction ef?ciency of the LEDs increased with the texturing of the sidewall. The light output intensity of the LEDs (at an injection current of 100 mA) increased by 13.8% after sidewall texturing. These results con?rmed that the geometric morphology of the sidewall plays an important role in improving the extraction ef?ciency of LEDs.
关键词： Texturing,Light Emitting Diodes,Gallium Nitride,Light Extraction Ef?ciency
更新于2025-09-23 15:22:29
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Design of Chemical Surface Treatment for Laser Textured Metal Alloy to Achieve Extreme Wetting Behavior
摘要： Extreme wetting activities of laser-textured metal alloys have received significant interest due to their superior performance in a wide range of commercial applications and fundamental research studies. Fundamentally, extreme wettability of structured metal alloys depends on both surface structure and surface chemistry. However, compared with the generation of physical topology on the surface, the role of surface chemistry is less explored for the laser texturing processes of metal alloys to tune the wettability. This work introduces a systematic design approach to modify the surface chemistry of laser textured metal alloys to achieve various extreme wettabilities, including superhydrophobicity/superoleophobicity, superhydrophilicity/superoleophilicity, and co-existence of superoleophobicity and superhydrophilicity. Microscale trenches are first created on the aluminum alloy 6061 surfaces by nanosecond pulse laser surface texturing. Subsequently, the textured surface is immersion-treated in several chemical solutions to attach target functional groups on the surface to achieve the final extreme wettability. Anchoring fluorinated groups (-CF2- and -CF3) with very low dispersive and non-dispersive surface energy leads to superoleophobicity and superhydrophobicity, resulting in repelling both water and diiodomethane. Attachment of polar nitrile (-C≡N) group with very high non-dispersive and high dispersive surface energy achieves superhydrophilicity and superoleophilicity by drawing water and diiodomethane molecules in the laser textured capillaries. At last, anchoring fluorinated groups (-CF2- and -CF3) and polar sodium carboxylate (-COONa) together lead to very low dispersive and very high non-dispersive surface energy components. It results in the co-existence of superoleophobicity and superhydrophilicity, where the treated surface attracts water but repels diiodomethane.
关键词： Design,chemical modification,laser texturing,superhydrophilicity,superoleophobicity,superhydrophobicity
更新于2025-09-23 15:21:01
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Experimental study of laser dissimilar joining for Usibor 2000 and Al-T7075 with Tepex 102
摘要： Due to the needs of weight reduction in the automobile structures and of time reduction in the Body-In-White (BIW) manufacturing stage, effective and accurate dissimilar joining is demanded to take advantage of metal-polymer structures. Automotive industry is highly interested in the combination of metal alloys and composite materials; however, dissimilar joining of this type of materials without using mechanic or adhesive joining is a challenge. As an alternative to the classical joining techniques, laser technology can be used to join dissimilar materials. In laser direct joining, a laser beam is used to heat the metal and by conduction to heat the polymer up to melting temperature in the interface without reaching degradation temperature. In this work, an experimental procedure is proposed to set the basis of dissimilar joining between metal and composite parts for the automobile industry. To do that, laser texturing on metallic parts was studied and a wide battery of experimental test were performed to obtain the proper joining process parameters for dissimilar joining between Usibor 2000 and Al-T7075 with Tepex 102. Results show that is possible to reach over 17 MPa in lap shear adhesion test which is similar to the performance of typical adhesives used in automotive industry.
关键词： direct joining,texturing,Laser,dissimilar
更新于2025-09-23 15:21:01
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Reinforcement of a laser-textured 316L steel with CuCoBe-diamond composites through laser sintering
摘要： The aim of this work was the production and the characterization of a laser textured 316L stainless steel reinforced with CuCoBe-diamond composites by laser sintering. The composites were obtained from CuCoBe and synthetic diamond with different particle sizes by mechanical alloying. The influence of the reinforcement on the physical, chemical and surface properties was analyzed. The results showed that the textured pattern consisted of square pyramids with a machined area of approximately 80%. The interfaces between the steel and the reinforcement after sintering are well defined and sharp. A good adherence of the diamond particles to the CuCoBe matrix was achieved. The laser sintering process did not induce any phase transformations or oxidation of the reinforcement. The steel reinforced with the biggest diamond particles exhibited substantially better surface performance than the untextured material.
关键词： composites,sintering,diamond,steel,Mechanical,316L,CuCoBe,alloying,texturing,laser
更新于2025-09-23 15:21:01
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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