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•Superhydrophobic surface has been investigated on polyurethane coating of GFRP using femtosecond laser texturing.•The contacting models between water droplets and substrates have ...been demonstrated.•Hydrophobicity and anti-icing performance of laser-treated surface have been largely improved at a low temperature.•The superhydrophobic surface has exhibited excellent self-cleaning effect and stability.
Polyurethane coating has been commonly used in aerospace and construction, and enhancing anti-icing capabilities in low temperatures is crucial for preventing mechanical failures and reducing energy consumption. Utilizing a superhydrophobic surface was considered an important option to improve anti-icing performance. In this study, femtosecond laser treatment has applied to polyurethane coating on glass fiber-reinforced plastic (GFRP) to transform from hydrophilic to superhydrophobic. Results have indicated that laser treatment significantly reduced the solid–liquid contact area compared to the original surface. The non-polar groups on the surface contributed greatly to the enhancement of hydrophobicity. In comparison to the original surface, the freezing temperature of droplets on the superhydrophobic surface with improved anti-icing performance was reduced from −4.5 °C to −9.2 °C, while the freezing time was extended from 65 s to 269 s. This improvement was attributed to the reduction of solid–liquid contact area, resulting in a low heat transfer rate and a low heterogeneous nucleation rate. Additionally, the laser-treated surface exhibited excellent self-cleaning effects, along with mechanical and chemical stability.
Surface texturing and solid lubricants have demonstrated the ability to substantially reduce friction and wear under dry conditions. In recent decades, these two technologies have been combined to ...leverage the advantages of both for superior tribological performance. This review article first summarizes the state-of-the-art regarding surface texturing and solid lubricants, including soft metals, polytetrafluorethylene, diamond-like carbon and 2D layered materials. Then, the synergy between surface textures and solid lubricants is discussed, with particular emphasis on the underlying mechanisms. Finally, gaps in the existing understanding of these synergies are identified and opportunities for future research are suggested.
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•This review focuses on the combination of surface textures and solid lubricants.•The limitations of surface textures and solid lubricants for dry sliding are identified.•Soft metals, PTFE, DLC and 2d layered materials as solid lubricants are considered.•Synergistic mechanisms between texturing and solid lubricants are discussed.•Current short-comings and opportunities for future research are identified.
This study investigates the improvement of tribological properties of TB6 (Ti-10V-2Fe-3Al) alloys through laser surface texturing. It examines the effects of laser scanning cycles (LSCs) and dimple ...spacing (DS) on the water contact angle and the coefficient of friction (CoF) under both dry friction and starved-oil lubrication conditions. Dimple-textured surfaces reduce wear and friction by decreasing the actual contact area between the friction pairs, preventing wear particle entrapment, and enhancing oil retention, thereby leading to stable oil films. The optimal LSCs and DSs significantly reduce the CoF by up to 66 % under dry friction conditions and by 61 % under starved-oil lubrication conditions, compared to original surfaces. Surfaces with increased LSCs and decreased DSs become superhydrophobic after octadecyltrichlorosilane modification.
The aim of this work was to show that with the use of the surface roughness parameters S
sk
and S
ku
we can predict tribological behavior of contact surfaces and use these parameters to plan surface ...texturing. This article presents a continuation of our research on virtual texturing and experimental work on surface textures in the form of channels. For this investigation, steel samples were laser surface textured in the shape of dimples with different spacings between the dimples and different dimple depths. The experimental results confirmed that the parameters S
sk
and S
ku
can be used to design the surface texturing, where a higher value of S
ku
and more negative S
sk
lead to lower friction.
Surface texturing has been frequently used for tribological purposes in the last three decades due to its great potential to reduce friction and wear. Although biological systems advocate the use of ...hierarchical, multi-scale surface textures, most of the published experimental and numerical works have mainly addressed effects induced by single-scale surface textures. Therefore, it can be assumed that the potential of multi-scale surface texturing to further optimize friction and wear is underexplored. The aim of this review article is to shed some light on the current knowledge in the field of multi-scale surface textures applied to tribological systems from an experimental and numerical point of view. Initially, fabrication techniques with their respective advantages and disadvantages regarding the ability to create multi-scale surface textures are summarized. Afterwards, the existing state-of-the-art regarding experimental work performed to explore the potential, as well as the underlying effects of multi-scale textures under dry and lubricated conditions, is presented. Subsequently, numerical approaches to predict the behavior of multi-scale surface texturing under lubricated conditions are elucidated. Finally, the existing knowledge and hypotheses about the underlying driven mechanisms responsible for the improved tribological performance of multi-scale textures are summarized, and future trends in this research direction are emphasized.
Surface texturing to control friction and wear has been the focus of numerous studies in the last few decades. Despite this interest, understanding the underlying causes for surface texturing effects ...under different contact and lubrication conditions remains a subject of continuing controversy. Although there has been progress in the fabrication of precise surface textures and modeling of their influence in specific cases, many conflicting reports still exist concerning the effectiveness of surface texturing under certain contact conditions. This review therefore presents a critical assessment of the common understanding in this rapidly developing research field. First, the effects of surface textures under the operative lubrication regimes in the Stribeck curve, with a clear distinction between conformal- and non-conformal contacts, will be discussed. Finally, the strengths and weaknesses of various fabrication methods will be described, giving a summary of the fabrication methods with respect to their typical feature sizes, costs, and applicable materials. Special attention will be paid to the friction reducing mechanisms and their implications for the wear under different frictional regimes.
•Critical assesment of surface texturing is given.•Effects of surface texturing on different lubrication regimes is presented.•Surface texturing techniques are described and pros as well as cons discussed.
Surface texturing is one of the most efficient surface modification approaches for improving the tribological performance of engineering materials. Several surface texturing techniques have been ...developed in recent years. Among these methods, laser surface texturing (LST) has gained considerable interests due to its high flexibility, superior texturing accuracy, and good controllability. This paper reviews the recent advances and developments of LST for enhanced tribological properties of engineering materials. The process designs of LST by means of direct laser ablation, laser interference, and laser shock processing are discussed. The effects of laser parameters on the texture features are highlighted. The enhanced tribological properties of LST-processed materials and their applications on various fields are reviewed. The current challenges and future directions of LST techniques are discussed.
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•Surface modification by nanosecond laser texturing of biodegradable pure Zn surface is explored.•The energy input can dictate the surface morphology and composition through local ...remelting.•The corrosion mechanism in pseudo-physiological environment is affected by the laser modification.•The formation of different degradation products may improve local cytotoxicity effects and interaction with bone tissues.
The development of bioresorbable metallic alloys, which are being actively researched as materials for temporary medical implants, poses considerable challenges under the processing, metallurgical and corrosion points of view. Their degradation behaviour in physiological environment is strongly connected to their surface topography and chemistry, which shall be carefully addressed in the view of spreading the fielding of such alloys in the biomedical sector.
The present work addresses the possibility of controlling the degradation behaviour of pure Zn though laser surface modification by nanosecond laser texturing. The effect of irradiated energy on the surface topography and the microstructure was studied and the resulting degradation behaviour was investigated. It was found that laser texturing can deeply affect surface roughness and the presence of oxides, due to the rapid remelting induced by the laser pulses in the nanosecond order. Therefore, different degradation behaviours were found to be associated to the surfaces, laser treated at low and high energy, resulting in a diversification of the nature and morphology of the degradation products.
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 treated surface are 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.
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•Laser-induced surface structures and following surface chemistry modification are equally critical for extreme wettability.•Underlaying mechanisms of surface chemistry modification are explained.•Recent progress in durability laser textured extreme wetting surface is addressed.•It provides a comprehensive guidance for fabricating extreme wetting surfaces for metal alloys by laser texturing methods.
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