scholarly journals Development of a Monitoring Strategy for Laser-Textured Metallic Surfaces Using a Diffractive Approach

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 53
Author(s):  
Sascha Teutoburg-Weiss ◽  
Bogdan Voisiat ◽  
Marcos Soldera ◽  
Andrés Fabián Lasagni
Keyword(s):  
Current Status ◽  
Textured Surfaces ◽  
Metallic Surfaces ◽  
Optical Images ◽  
Single Scale ◽  
Direct Laser ◽  
Indirect Evaluation ◽  
Optical Configuration ◽  
Surface Patterns ◽  
Direct Laser Interference Patterning

The current status of research around the world concurs on the powerful influence of micro- and nano-textured surfaces in terms of surface functionalization. In order to characterize the manufactured topographical morphology with regard to the surface quality or homogeneity, major efforts are still required. In this work, an optical approach for the indirect evaluation of the quality and morphology of surface structures manufactured with Direct Laser Interference Patterning (DLIP) is presented. For testing the designed optical configuration, line-like surface patterns are fabricated at a 1064 nm wavelength on stainless steel with a repetitive distance of 4.9 µm, utilizing a two-beam DLIP configuration. Depending on the pulse to pulse overlap and hatch distance, different single and complex pattern geometries are produced, presenting non-homogenous and homogenous surface patterns. The developed optical system permitted the successfully classification of different pattern geometries, in particular, those showing single-scale morphology (high homogeneity). Additionally, the fabricated structures were measured using confocal microscopy method, and the obtained topographies were correlated with the recorded optical images.

scholarly journals Subwavelength Direct Laser Nanopatterning Via Microparticle Arrays for Functionalizing Metallic Surfaces

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Jean-Michel Romano ◽  
Rajib Ahmed ◽  
Antonio Garcia-Giron ◽  
Pavel Penchev ◽  
Haider Butt ◽  
...  
Keyword(s):  
Focal Length ◽  
Near Field ◽  
Cost Effective ◽  
Spot Size ◽  
Metallic Surface ◽  
Metallic Surfaces ◽  
Large Area ◽  
Transitional State ◽  
Direct Laser ◽  
Surface Patterns

Functionalized metallic nanofeatures can be selectively fabricated via ultrashort laser processing; however, the cost-effective large-area texturing, intrinsically constrained by the diffraction limit of light, remains a challenging issue. A high-intensity near-field phenomenon that takes place when irradiating microsized spheres, referred to as photonic nanojet (PN), was investigated in the transitional state between geometrical optics and dipole regime to fabricate functionalized metallic subwavelength features. Finite element simulations were performed to predict the PN focal length and beam spot size, and nanofeature formation. A systematic approach was employed to functionalize metallic surface by varying the pulse energy, focal offset, and number of pulses to fabricate controlled array of nanoholes and to study the generation of triangular and rhombic laser-induced periodic surface structures (LIPSS). Finally, large-area texturing was investigated to minimize the dry laser cleaning (DLC) effect and improve homogeneity of PN-assisted texturing. Tailored dimensions and densities of achievable surface patterns could provide hexagonal light scattering and selective optical reflectance for a specific light wavelength. Surfaces exhibited controlled wetting properties with either hydrophilicity or hydrophobicity. No correlation was found between wetting and microbacterial colonization properties of textured metallic surfaces after 4 h incubation of Escherichia coli. However, an unexpected bacterial repellency was observed.

scholarly journals Avoiding Starvation in Tribocontact Through Active Lubricant Transport in Laser Textured Surfaces

Lubricants ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 54 ◽  
Author(s):  
Tobias Stark ◽  
Thomas Kiedrowski ◽  
Holger Marschall ◽  
Andrés Fabián Lasagni
Keyword(s):  
Fluid Transport ◽  
Dynamical Behavior ◽  
Second Step ◽  
Textured Surfaces ◽  
Laser Interference ◽  
Narrow Channels ◽  
Surface Textures ◽  
Direct Laser ◽  
Direct Laser Interference Patterning ◽  
Limited Depth

Laser texturing is a viable tool to enhance the tribological performance of surfaces. Especially textures created with Direct Laser Interference Patterning (DLIP) show outstanding improvement in terms of reduction of coefficient of friction (COF) as well as the extension of oil film lifetime. However, since DLIP textures have a limited depth, they can be quickly damaged, especially within the tribocontact area, where wear occurs. This study aims at elucidating the fluid dynamical behavior of the lubricant in the surroundings of the tribocontact where channel-like surface textures are left after the abrasion wear inside the tribocontact area. In a first step, numerical investigations of lubricant wetting phenomena are performed applying OpenFOAM®. The results show that narrow channels (width of 10 μ m ) allow higher spreading than wide channels (width of 30 μ m ). In a second step, fluid transport inside DLIP textures is investigated experimentally. The results show an anisotropic spreading with the spreading velocity dependent on the period and depth of the laser textures. A mechanism is introduced for how lubricant can be transported out of the channels into the tribocontact. The main conclusion of this study is that active lubricant transport in laser textured surfaces can avoid starvation in the tribocontact.

Load-dependent run-in and wear behaviour of line-like surface patterns produced by direct laser interference patterning

Wear ◽  
2016 ◽  
Vol 368-369 ◽  
pp. 350-357 ◽  
Author(s):  
Andreas Rosenkranz ◽  
Joris C. Pangraz ◽  
Carsten Gachot ◽  
Frank Mücklich
Keyword(s):  
Wear Behaviour ◽  
Laser Interference ◽  
Direct Laser ◽  
Surface Patterns ◽  
Direct Laser Interference Patterning

scholarly journals Stable Superhydrophobic Aluminum Surfaces Based on Laser-Fabricated Hierarchical Textures

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 184
Author(s):  
Stephan Milles ◽  
Johannes Dahms ◽  
Marcos Soldera ◽  
Andrés F. Lasagni
Keyword(s):  
Mechanical Stability ◽  
Processing Parameters ◽  
Contact Angles ◽  
Textured Surfaces ◽  
Water Contact ◽  
Multi Scale ◽  
Static Contact ◽  
Direct Laser ◽  
Direct Laser Interference Patterning ◽  
Microtextured Surfaces

Laser-microtextured surfaces have gained an increasing interest due to their enormous spectrum of applications and industrial scalability. Direct laser interference patterning (DLIP) and the well-established direct laser writing (DLW) methods are suitable as a powerful combination for the fabrication of single (DLW or DLIP) and multi-scale (DLW+DLIP) textures. In this work, four-beam DLIP and DLW were used independently and combined to produce functional textures on aluminum. The influence of the laser processing parameters, such as the applied laser fluence and the number of pulses, on the resulting topography was analyzed by confocal microscopy and scanning electron microscopy. The static long-term and dynamic wettability characteristics of the laser-textured surfaces were determined through water contact angle and hysteresis measurements, revealing superhydrophobic properties with static contact angles up to 163° and hysteresis as low as 9°. The classical Cassie–Baxter and Wenzel models were applied, permitting a deeper understanding of the observed wetting behaviors. Finally, mechanical stability tests revealed that the DLW elements in the multi-scale structure protects the smaller DLIP features under tribological conditions.

scholarly journals Effect of Low Depth Surface Texturing on Friction Reduction in Lubricated Sliding Contact

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 62 ◽  
Author(s):  
Haytam Kasem ◽  
Ori Stav ◽  
Philipp Grützmacher ◽  
Carsten Gachot
Keyword(s):  
Research Work ◽  
Surface Texturing ◽  
Friction Reduction ◽  
Laser Surface Texturing ◽  
Surface Pattern ◽  
Textured Surfaces ◽  
Laser Interference ◽  
Wear Properties ◽  
Direct Laser ◽  
Direct Laser Interference Patterning

Laser surface texturing is an interesting possibility to tailor materials’ surfaces and thus to improve the friction and wear properties if proper texture feature sizes are selected. In this research work, stainless steel surfaces were laser textured by two different laser techniques, i.e., the direct laser interference patterning by using a nanosecond pulsed Nd:YAG laser and additionally by an ultrashort pulsed femtosecond Ti:Sa. The as-textured surfaces were then studied regarding their frictional response in a specially designed linear reciprocating test rig under lubricated conditions with a fully formulated 15W40 oil. Results show that dimples with smaller diameter lead to a significant reduction in the coefficient of friction compared to the dimples with a larger diameter and surfaces with a grid-like surface pattern produced by direct laser interference patterning.

scholarly journals The Role of the Surface Nano-Roughness on the Wettability Performance of Microstructured Metallic Surface Using Direct Laser Interference Patterning

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2737 ◽  
Author(s):  
Alfredo I. Aguilar-Morales ◽  
Sabri Alamri ◽  
Bogdan Voisiat ◽  
Tim Kunze ◽  
Andrés F. Lasagni
Keyword(s):  
Contact Angle ◽  
Steady State ◽  
Contact Angles ◽  
Laser Interference ◽  
X Ray ◽  
Multi Scale ◽  
Single Scale ◽  
Direct Laser ◽  
Scale Structures ◽  
Direct Laser Interference Patterning

Superhydrophobic natural surfaces usually have multiple levels of structure hierarchy, particularly microstructures covered with nano-roughness. The multi-scale nature of such a surface reduces the wetting of water and oils, and supports self-cleaning properties. In this work, in order to broaden our understanding of the wetting properties of technical surfaces, biomimetic surface patterns were fabricated on stainless steel with single and multi-scale periodic structures using direct laser interference patterning (DLIP). Micropillars with a spatial period of 5.5 µm and a structural depth of 4.2 µm were fabricated and covered by a sub-micro roughness by using ultrashort laser pulses, thus obtaining a hierarchical geometry. In order to distinguish the influence of the different features on the wettability behavior, a nanosecond laser source was used to melt the nano-roughness, and thus to obtain single-scale patterns. Then, a systematic comparison between the single- and multi-scale structures was performed. Although, the treated surfaces showed hydrophilic behavior directly after the laser treatment, over time they reached a steady-state hydrophobic condition. However, the multi-scale structured metal showed a contact angle 31° higher than the single-scale geometry when the steady-state conditions were reached. Furthermore, the impact of the surface chemistry was investigated by energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) analyses. Finally, a hydrophobizing agent was applied to the laser treated samples in order to further enhance the water contact angles and to determine the pure contribution of the surface topography. In the latter case, the multi-scale periodic microstructures reached static contact angles of 152° ± 2° and a contact angle hysteresis of only 4° ± 2°, while the single-scale structures did not show superhydrophobic behavior. These results definitely suggest that multi-scale DLIP structures in conjunction with a surface chemistry modification can promote a superhydrophobic regime.

scholarly journals Structuring and functionalization of non-metallic materials using direct laser interference patterning: a review

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lucinda Mulko ◽  
Marcos Soldera ◽  
Andrés Fabián Lasagni
Keyword(s):  
Sample Surface ◽  
Metallic Materials ◽  
Laser Interference ◽  
Metallic Surfaces ◽  
Industrial Manufacturing ◽  
Industrial Sectors ◽  
Aluminium Copper ◽  
Developed Surface ◽  
Direct Laser ◽  
Direct Laser Interference Patterning

Abstract Direct laser interference patterning (DLIP) is a laser-based surface structuring method that stands out for its high throughput, flexibility and resolution for laboratory and industrial manufacturing. This top–down technique relies on the formation of an interference pattern by overlapping multiple laser beams onto the sample surface and thus producing a periodic texture by melting and/or ablating the material. Driven by the large industrial sectors, DLIP has been extensively used in the last decades to functionalize metallic surfaces, such as steel, aluminium, copper or nickel. Even so, DLIP processing of non-metallic materials has been gaining popularity in promising fields such as photonics, optoelectronics, nanotechnology and biomedicine. This review aims to comprehensively collect the main findings of DLIP structuring of polymers, ceramics, composites, semiconductors and other non-metals and outline their most relevant results. This contribution also presents the mechanisms by which laser radiation interacts with non-metallic materials in the DLIP process and summarizes the developed surface functions and their applications in different fields.

scholarly journals Microfabrication and Surface Functionalization of Soda Lime Glass through Direct Laser Interference Patterning

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 129
Author(s):  
Marcos Soldera ◽  
Sabri Alamri ◽  
Paul Alexander Sürmann ◽  
Tim Kunze ◽  
Andrés Fabián Lasagni
Keyword(s):  
Laser Radiation ◽  
Surface Functionalization ◽  
Incident Light ◽  
Chemical Properties ◽  
Visible Spectrum ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Textured Surfaces ◽  
Aspect Ratios ◽  
Direct Laser

All-purpose glasses are common in many established and emerging industries, such as microelectronics, photovoltaics, optical components, and biomedical devices due to their outstanding combination of mechanical, optical, thermal, and chemical properties. Surface functionalization through nano/micropatterning can further enhance glasses’ surface properties, expanding their applicability into new fields. Although laser structuring methods have been successfully employed on many absorbing materials, the processability of transparent materials with visible laser radiation has not been intensively studied, especially for producing structures smaller than 10 µm. Here, interference-based optical setups are used to directly pattern soda lime substrates through non-lineal absorption with ps-pulsed laser radiation in the visible spectrum. Line- and dot-like patterns are fabricated with spatial periods between 2.3 and 9.0 µm and aspect ratios up to 0.29. Furthermore, laser-induced periodic surface structures (LIPSS) with a feature size of approximately 300 nm are visible within these microstructures. The textured surfaces show significantly modified properties. Namely, the treated surfaces have an increased hydrophilic behavior, even reaching a super-hydrophilic state for some cases. In addition, the micropatterns act as relief diffraction gratings, which split incident light into diffraction modes. The process parameters were optimized to produce high-quality textures with super-hydrophilic properties and diffraction efficiencies above 30%.

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