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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., (© 2023. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

Hypothesis: Lateral adhesion forces are a fundamental property of liquid-solid interactions and a key aspect of dynamic droplet mobility. But, commonly applied conventional wetting analysis is limited to static and quasi-static methods and cannot resolve dynamic and spatial liquid-solid interactions. However, droplet mobility is assumed to be affected by chemical and topographic surface inhomogeneities introduced by femtosecond laser treatment., Experiments: In this study, we used a customized droplet adhesion force instrument to determine lateral adhesion forces on various femtosecond laser-structured surface designs to obtain a deeper understanding of the dynamic droplet motion with regard to chemical and topographic surface features., Findings: We show that the droplet motion was highly affected by the chemical and topographical surface design and local inhomogeneities. The droplet mobility on femtosecond laser-structured surfaces could be classified into a static, a transfer, and a kinetic regime, which is essential for designing surfaces with extreme wetting characteristics and a wide range of scientific and industrial processes. Furthermore, with proper tailoring of surface structures and chemical modification, we were able to provoke adhesion forces on self-organized laser microstructures similar to those found on the natural lotus leaves., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

The clinical application of anastomotic instruments improves the efficiency of the digestive tract surgery. However, the stapler with titanium nails implanted is still controversial in terms of anastomotic complications, and further improvement and optimization are needed. The purpose of this study was to explore the optimal microtextured parameters that could enhance the bioactivity of titanium implants in vitro. Laser microtexturing technology was used to construct the groove-type microstructural surfaces with different parameters, and human gastric mucosal epithelial cells (GES-1 cells) and mouse fibroblasts (3T3 cells) were cultured on the surface of the titanium plates in vitro. The data of cell adhesion, cell proliferation and cell activity were obtained and statistically analyzed. The textured titanium plates meet the expected design. GES-1 and 3T3 cell adhesion were better in the surface of titanium plates in microstructural group than that in the polished group. GES-1 and 3T3 cells also showed higher proliferative activity in the microstructural group compared with the polished group. The laser textured titanium plates have good groove-type microstructure, which increase the surface roughness, change the surface wettability, promote the adhesion, proliferating and orderly growth of GES-1 and 3T3 cells, and show good biological properties.

Two distinct surface topographies consisting of micro- and nano-surface were developed using laser texturing (LT) and anodization process respectively and their effect on the surface-related properties of Ti-6Al-4V fabricated using Laser Engineered Net Shaping (LENS) were determined. The topographies developed using laser texturing (25, 50 and 75% overlap) were examined using 3D profilometer, whereas, Field Emission Scanning Electron Microscopy (FE-SEM) was used to analyze Titania NanoTubes (TNT) formed using anodization. Though all the surface modified specimens exhibited hydrophilic behavior, least contact angle values were observed for the specimen surface modified with TNT. 25LT and 50LT specimens offered about 8 fold higher corrosion resistance than TNT specimens. All the surface modified samples exhibited non-toxicity to blood cells as well as to the mesenchymal stem cells (hMSCs) with a higher rate of proliferation and differentiation hMSCs observed on 75LT specimens and TNT specimen., (Copyright © 2019. Published by Elsevier Inc.)

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]

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]

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]

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 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]

Light-trapping structures formed on surfaces of various materials have attracted much attention in recent years due to their important role in many applications of science and technology. This article discusses various methods for manufacturing light-trapping "black" silicon, namely laser, chemical and hybrid chemical/laser ones. In addition to the widely explored laser texturing and chemical etching methods, we develop a hybrid chemical/laser texturing method, consisting in laser post-texturing of pyramidal structures obtained after chemical etching. After laser treatments the surface morphology was represented by a chaotic relief of microcones, while after chemical treatment it acquired a chaotic pyramidal relief. Moreover, laser texturing of preliminarily chemically microtextured silicon wafers is shown to take five-fold less time compared to bare flat silicon. In this case, the chemically/laser-treated samples exhibit average total reflectance in the spectral range of 250–1100 nm lower by 7–10% than after the purely chemical treatment. [ABSTRACT FROM AUTHOR]

In times of societal development, sustainability has become a major concern for many manufacturers in the metal industries. In this context, surface texturing of cutting tools offers a promising approach in terms of reducing energy consumption and material waste. In this work, direct laser interference patterning is utilized for producing periodic line-like structures with spatial periods of 2.0 µm and 5.5 µm on rake-flank faces of cemented tungsten carbide cutting inserts. Structure depths up to 1.75 µm are reached by controlling the applied number of laser pulses. Turning experiments under lubricated conditions carried out on Al 6061 T6 parts with textured and untreated tools are performed to determine their tribological performances. The used textured cutting tools can effectively decrease machining forces up to 17% due to the corresponding improvement in frictional behavior at the tool/chip interface. Furthermore, the laser-processed tools produce thinner chips and decrease the surface roughness by 31% of the aluminum work piece. [ABSTRACT FROM AUTHOR]

Among metallic biomaterials, near-equiatomic NiTi is one of the most promising intermetallic system applicable for biomedical applications, thanks to its high biocompatibility and unique superelasticity (or pseudoelasticity), offering a complete recoverable strain up to 8%. In the prospective uses for bio-devices, the surface processing of NiTi medical components plays a fundamental role for guaranteeing both a Ti oxide passivizing layer for avoiding Ni ion release into the human body and surface morphology for controlling the cell proliferation. Mechanical polishing, thermal, chemical or electro-chemical treatments are typically performed for surface modifications. Recently, laser texturing has been successfully applied for different materials, included NiTi shape memory alloys, and also for tuning the surface properties, such as wettability. In the present work, ultrashort laser surface modification was carried out, through the use of a femtosecond laser, for the surface texturing of commercial superelastic NiTi plates. The main goal is to investigate the correlation among morphology, chemical composition and wettability with the principal process parameters, such as average power and scanning velocity in high power ultrashort laser texturing. Laser patterned surfaces were characterized by means of scanning electron microscopy, 3D-profilometry, XPS analysis and wetting measurements. After the laser treatments, both surface morphology and Ni/Ti ratio were largely modified from the initial surface, depending on the adopted process parameters. The wettability of the laser textured surfaces can be also varied with respect to the initial surface, due to the roughness values and grooves induced by the laser beam scans. The laser texturing process induced a combination between micro and nano structures, depending on the input energy. In details, the surfaces were tuned to lower roughness values (from 0.4 μm to 0.3 μm) with a laser power of 1 W, while it was increased up to 0.65 μm with a laser power of 13 W. The laser surface modification promoted a change of the contact angle from 70° of the untreated condition up to 135° to the surface laser treated with a power of 13 W. [ABSTRACT FROM AUTHOR]

• Laser texturing improved the laser actuation performance of nitinol shape memory alloy. • Textured nitinol showed significant improvement in actuation performance due to enhanced optical absorbance. • Influence of single- and two-stage texturing on actuation performance of nitinol was explored. • Improvement in actuation performance was demonstrated for continuous wave fiber and CO 2 lasers. Laser surface texturing of nitinol was performed using a nanosecond fiber laser to modify the surface structure and enhance the laser actuation performance of nitinol. The influence of laser processing parameters on surface morphology and chemical composition was studied in detail. The influence of texturing on the laser actuation behavior was evaluated using a continuous wave fiber laser and a CO 2 laser. Compared to the pristine sample, the textured samples demonstrated better displacements and faster actuation. During laser actuation using a fiber laser, the textured sample showed maximum and minimum displacement enhancements of 65% and 15%, respectively. The actuation performance of the textured sample was approximately twice that of the pristine sample during the irradiation with CO 2 laser. This paper presents the viability of laser surface texturing to enhance the actuation performance of shape memory alloys, and the results indicate that the power required for actuation can be reduced to avoid the use of bulky power and control units. [ABSTRACT FROM AUTHOR]

An asymmetric friction principle is newly proposed for the design of inertial impact piezoelectric actuators. There are two ways to achieve asymmetric frictions: either by tuning the positive pressure or by tuning the friction coefficient. Compared with tuning the positive pressure by an asymmetric structure, the structural parameters can be reduced by employing a symmetric structure and tuning the friction coefficient. In this study, an asymmetric friction inertial impact actuator was developed using a symmetric compliant mechanism (SCM), and the asymmetric frictions were realized by laser texturing of the driving feet at one end of the SCM. Four kinds of microstructures were initially fabricated on the driving feet, and their friction properties were experimentally tested. Accordingly, two kinds of microstructures, namely Ta and Tb microstructures, were selected. Output characteristics of the actuator with these two microstructures were measured and comparatively analyzed. The experimental results indicate that the actuator could achieve stable step motion, and the output characteristics were affected by the fabricated microstructure, as it determined the friction coefficient. The actuator with the Tb microstructure achieved a maximum speed of 2.523 mm/s, a resolution of 188 nm, a vertical loading capacity of 2 N and a horizontal loading capacity of 0.6 N, whereas the actuator with the Ta microstructure had a higher resolution of 74 nm. This study provides a novel idea for the design of asymmetric friction inertial impact actuators by tuning the friction coefficient. [ABSTRACT FROM AUTHOR]

A high volume of wastewater is drained out every year from agriculture and industrial operations. In the present study, Microbial Fuel Cells (MFC) are used to generate electricity from sugarcane wastewater using titanium as an anode material. Besides, three different laser texturing such as linear pattern (LP), sinusoidal pattern (SP), and waviness pattern (WP) are created on titanium surface to enhance the electricity production and has been compared with the un-textured surface (UTS). In addition, water contact angle and roughness are measured on un-textured surface, LP, SP, and WP surfaces which are 60°, 45°, 34°, 20° and 2.9 μm, 10.7 μm, 15.9 μm, and 19.0 μm, respectively. Results show that laser textured surfaces exhibit a higher power density than the un-textured surface. The improvement in power density is 2–3.5 times that in un-textured surfaces. The outcome of this study indicates that laser textured microbial fuel cells can be considered as an efficient technique for generating electricity from the wastewater and also this could be considered as a new technique to offset wastewater treatment plant operating costs. [ABSTRACT FROM AUTHOR]

In this work the influence of picosecond laser (ps) irradiation (PLI) on the properties of black Cr electrodeposited on an SS substrate has been investigated. XPS has shown that black Cr treatment by PLI changes the concentrations of elements on the black Cr coating surface. Furthermore, it diminishes the quantity of CrN compound, while increasing the quantity of metallic chromium (Cro). Full reflectance (RD) of black Cr after treatment with PLI and before treatment in the visible region (300–800 nm) were quite close. Thermal tests at a temperature of 200 oC showed that the adhesion between black Cr treated with PLI and SS is better than that of black chromium not treated with PLI. Thus, such a black Cr absorber may be used in solar water heaters. [ABSTRACT FROM AUTHOR]

Biodegradable metallic alloys are promising materials for the development of temporary medical implants, including cardiovascular and orthopedic devices. The present work explores the surface modification of a biodegradable Fe–20Mn alloy by means of ultrashort laser texturing and the correlation between the laser‐induced surface morphology and the degradation behavior. In detail, the effect of different processing parameters on surface morphology is explored and compared with the unprocessed surface. It is found that laser texturing can tune the degradation rate, selectively inducing positive (+29%) or negative (−31%) change with respect to the untreated surface. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate novel laser-treated structures designed to improve the adhesion performance and corrosion resistance of AA7075-T6 bonded joints. The spacing, position, and surface area parameters of the laser-treated grooves were investigated to understand their role in adhesion performance even under corrosion conditions. Laser-treated surfaces were analyzed using microscopic, topographic, and chemical methods to determine their scientific contribution to adhesion and corrosion performance. Laser-treated adherends were also bonded to mechanically test their bond strength both before and after exposure to corrosion for varying periods of time. Roughness and therefore surface area have a significant effect on adhesion performance; however, it is worth noting that the best adhesion performance both before and after corrosion exposure was achieved when the required surface area was properly designed and, laser treated according to the salt water exposure directions to inhibit its diffusion into the adhesion interface. The performance of the novel laser-treated structures in terms of adhesion performance under corrosive atmosphere was also supported by failure analysis. The mixed failure mode was significantly shifted to the cohesive failure mode, especially for bonded joints with box-type laser-treated structures. [Display omitted] • Reducing groove spacing resulted in an increase in surface area and bond strength. • Novel laser-treated structures resulted in significantly more surface area. • Deeper grooves positively affected the adhesion strength and corrosion resistance. • Direction of the grooves had an important effect on the inhibition of salt water. • Box type structure had an optimum adhesion strength even under corrosion exposure. [ABSTRACT FROM AUTHOR]

It was mainly aimed at the study to make the optimization of laser parameters to obtain dimples with the desired shape and size. Carbon Fiber EPOXY composite (CF-EPOXY) surfaces were ablated by Nd:YAG laser which has a 1064 nm wavelength. Some important laser process parameters such as focus position, pulse energy, duration and number were optimized to achieve maximum aspect ratio, circular shape and minimum thermal defect. In addition, it has been determined that which laser parameters are more effective to obtain the desired quality surface. These different shapes and geometry of dimples could be used to improve some properties such as wettability, friction, etc. The pulse energy with an effective rate of 55.97 % is the most effective parameter to achieve the larger aspect ratio. The focus position is the most effective parameter with the rates of 66.18 % and 47.94 % to obtain both perfect circularity and minimum thermal defects respectively. Confirmation experiments were performed and the highest aspect ratio was found as 1.14, the best circular dimple and the minimum thermal effects outside the spot area were found with the rates of 1.021. These are the optimum results of 9 experiment sets in this study for each output. The results were supported by confirmation experiments and regression analysis. It can be concluded that the Taguchi method is reliable and saves time and materials. [ABSTRACT FROM AUTHOR]

To explore the relationship of morphology and surface roughness on laser textured TC4 titanium alloy, both the process experiment and the numerical simulation approaches were adopted. The physical model of laser texturing pit was established under the condition of single pulse energy of 100, 150 and 200 mJ laser pulses irradiation using the COMSOL Multiphysics software, and the physical process of laser texturing was analysed, which laid a theoretical foundation for subsequent process experiments. A laser diode pumped Nd:YAG laser texturing experimental setup was build up. The process parameters, which are laser pulse energy, pulse width and defocusing amount included, were investigated with the monofactor analysis method. The roughness of laser texturing surface was measured from 0.71 to 13.86 µm, and the effects of these processing parameters on the surface roughness and pits morphology were analysed. Based on the morphological parameters, a mathematical integration algorithm for roughness was designed to simulate the laser texturing surface roughness, and the relationship between pit morphology and surface roughness was built up. After compared the calculated values with experimental results, it was proved that the algorithm can effectively reflect the surface roughness of samples. The experimental results show the guiding significance for the high-quality engineering application of laser texturing on titanium alloys. [ABSTRACT FROM AUTHOR]

Zirconia (ZrO 2) incorporated ceramic coatings were fabricated on biodegradable ZM21 Mg alloy by the PEO coupled with EPD process. Subsequently, the sample surface was modified by laser texturing to improve the corrosion resistance, roughness and cell proliferation and growth properties. The corrosion performance of the fabricated samples along with the substrate was studied by electrochemical measurements under simulated body fluid (SBF) environment. The cell direct contact assay was conducted for the substrate and fabricated samples using L -929 mouse fibroblast cells for 24 h. The phase contrast images of cell direct contact assay revealed that fabricated samples exhibited better contact and response with the fibroblast cells, compared to the substrate. The addition of nanoparticles in the PEO process, called PEO coupled EPD process, resulted in attaining a higher thickness and improved corrosion performance of the samples than the PEO coated samples. Among all the samples, laser surface textured PEO, and PEO-EPD coated samples unveiled enhanced corrosion resistance, cell growth, thereby enabling it as a suitable prototype for biodegradable implant applications. [ABSTRACT FROM AUTHOR]

Ceramics have been widely used in the field of tribology due to their superior corrosion resistance and low friction coefficient. The tribological properties of ceramics can be improved by machining proper surface texture. This work uses a nanosecond laser to process dimples on different ceramic surfaces. The morphology and size of dimples as a function of the number of laser shots and laser power are investigated. A theoretical model relating laser parameters and dimple size is established. In the initial point contact friction test, based on the experimental parameters mentioned in this paper, the existence of surface texture reduces the wear volume of Si 3 N 4 balls in water by 41.5% and the wear volume of ZrO 2 balls in oil by 51%. [ABSTRACT FROM AUTHOR]

• Micro-texture under different texturing direction had different effect on joint. • Stress at the TC4/CFRTP interface was simulated. • Different Micro-texture provided different mechanical resistance during tensile test. Hybrid structure of titanium alloy and carbon fiber reinforced thermoplastic composite (CFRTP) provided a new direction for lightweight and laser had a great prospect for application in joining metal/plastic. In this work, before laser joining TC4 (Ti6Al4V) and CFRTP (PA66), three groove micro-structures in different texturing direction (0°, 45°, 90°) were prepared on the TC4 surface respectively by nanosecond laser. The effect of different groove texturing was studied. Research results showed that the existence of three groove texturing increased the affinity between TC4 and molten CFRTP to the same extent. The resin-carbon fiber mixture adhered to the surface of TC4 after laser texturing increased obviously. However, the groove micro-structure had different impact on the tensile performance of the joint. The maximum tensile shear strength could reach 10.9 MPa, which was increased by 111 % compared with the untreated when the groove micro-texturing direction was perpendicular to the tensile direction (0° texturing) while the 90° textured joint performance was only increased by 42.9 %. The FEA results revealed that micro-texturing provided mechanical resistance for the joint during the tensile process and 0° micro-texturing provided the largest mechanical resistance followed by 45° and 90° micro-texturing. [ABSTRACT FROM AUTHOR]

[Display omitted] • The friction-assisted joining technique was adopted to join the AA7075 sheet to the PEEK sheet. • Different laser surface treatments were carried out to increase joint strength. • Laser cleaning enabled the jointing of AA7075 to PEEK. • Laser texturing significantly increases the adhesion strength (+30%). • The two-step laser treatment, texturing + cleaning, results in a further increase in strength (+39%). The present study investigates the adoption of laser surface treatments to improve the bonding strength of dissimilar material hybrid structures made by the thermomechanical joining process. Aluminium AA7075 alloy was joined to Polyether-ether-ketone through a friction-assisted joining process. For the surface treatment, a two-step laser treatment was adopted. The latter consists of a first phase, called laser texturing, where a deep square grid texture is obtained by adopting high pulse energy and repetitions, followed by a further laser treatment, called cleaning, carried out with lower energy content, and applied over the overall adhesion surface. Two textures characterised by different grid sizes (200 and 300 µm) were realised. As received, uncleaned, and only cleaned samples were adopted as reference treatments. The results indicated that laser cleaning performed after laser texturing enabled a significant improvement of adhesion irrespective of the previous laser texturing strategy. This was also confirmed by the higher amount of polymer trapped within the laser-texturized paths. The only laser cleaning treatment enabled the successful joining of the substrates with an average shear strength of 12 MPa. On the other hand, when texturing with a hatch distance of 200 μm, laser cleaning performed after texturing increased the shear strength from 18.4 MPa to 25.2 MPa corresponding to an increase of 37%. The increased adhesion between the PEEK and the aluminium was also indicated by the change in the failure mode of the joints. The texturized samples with a hatch distance of 200 μm failed by pull-out; when the laser cleaning was performed on these samples, they failed by cohesive failure. [ABSTRACT FROM AUTHOR]

• Laser welding of TC4 to CFRTP was assisted by surficial micro-arc oxidation and mirco-texture. • Micro-arc oxidation and mirco-texture improved wettability of CFRTP on Ti surface. • Support Vector Regression model was adopted to optimize welding parameters. Laser texturing and MAO (micro-arc oxidation) hybrid process was adopted to enhance the tensile-shear strength of laser welded CFRTP/TC4 joint. Introduction of porous MAO coating enhanced wetting ability of molten peek from CFRTP and increased surface roughness. Porous structure could also provide a mechanical interlocking effect in CFRTP/TC4 interface and improve the resistance to tensile-shear load. Highest tensile-shear force of 1587 N was obtained when 2.3 μm MAO coating was prepared. Based on this, influence of various laser texturing patterns with different MAO coating thickness on the tensile-shear forces was clarified by combination of experiment and reasonable SVR (Support Vector Regression) model. Maximum predicated surface roughness of 3.075 mm was produced at texturing width of 0.327 mm, texturing depth of 100.54 μm and MAO duration of 1.667 min. Furthermore, highest predicated tensile-shear force of 2995.1 N was achieved at texturing width of 0.331 mm, texturing of depth of 100.6 μm and MAO duration time of 1.718 min. [ABSTRACT FROM AUTHOR]

This paper deals with an experimental investigation of roughness influence on contact angle measurements and proposes a genetic algorithm to identify an empirical regression model to combine roughness and contact angles. A ns-pulsed laser was adopted to ablate different patterns on the surfaces of AISI 304 samples. During the tests, number of repetitions, hatch distance, laser scan speed and laser scanning strategy were changed. To assess the effect of these parameters on the wettability, a multilevel factorial design was developed and tested. The analysis of variance was adopted to determine which and how the laser parameters influence the roughness and the contact angle. A significant change in the wettability is due to the produced textures on the sample surfaces, with contact angles in the range 30–110°. The optimal regression model based on genetic algorithms was able to relate inputs and outputs with a mean error lower than 5%. [ABSTRACT FROM AUTHOR]

Abrasive flow finishing (AFF) is an advanced finished process which finds many applications for nano-finishing of many industrial components, but it has many disadvantages which restrict its applications. While finishing the gears, it creates a lay pattern which is along the lay already generated by a gear machining process. This deteriorates performance and service life of the AFF finished gears. This paper reports on laser texturing of flank surfaces of helical and straight bevel gears to enhance finishing performance of AFF process. Fiber laser of 1064 nm wavelength was used to create homothetic texture across the lay profile generated by gear manufacturing process on flank surface of helical and straight bevel gears using identified optimum combination of focal length, laser power, and number of passes. Laser textured and untextured and helical and straight bevel gears were finished by AFF for different values of the finishing time and using previously optimized values of AFF process parameters. Enhancement in finishing performance of AFF was assessed by comparing microgeometry errors, surface roughness, morphology, microhardness, and wear characteristics of the laser textured helical and straight bevel gears with that of the untextured gears. It revealed that laser texturing helped AFF in enhancing microhardness, wear resistance, material removal rate, and percentage reductions in microgeometry errors and surface roughness of the textured gears than the untextured gears. Surface morphology of AFF finished laser textured gears was smoother than the corresponding untextured gears. This study proves that laser texturing is an effective, simple, and economical method to enhance performance of AFF for finishing different types of gears without any modifications in the existing system. [ABSTRACT FROM AUTHOR]

Laser texturing of the surface of 304 stainless steel is carried out under the high pressure N2 assisting gas. Morphology, elemental composition and wetting state of the surface are analysed using the analytical tools. Free energy of the laser textured surface is measured using the droplet method. The influence of environmental dust particles on the laser textured surface in a humid air ambient is examined. It is found that laser texturing results in micro/nanopillars with presence of nitride compounds at the surface and the formation of micro/nanopillars changes the wetting state of the surface from hydrophilic to hydrophobic. The dust particles possess alkaline (Na, K) and alkaline earth (Ca) metals and their compounds dissolve in water while forming chemically active liquid on the laser textured surface. The liquid solution wets the entire textured surface and once it dries and forms crystal structures and strongly adheres to the surface. The tangential force required to remove the dried solution from the laser textured surface is almost three-times of the frictional force. The liquid solution results in small and shallow pit sites on the as-received surface; however, this behavior is not observed for the laser textured surface. [ABSTRACT FROM AUTHOR]

This article aims to investigate tribological properties of a surface modified by laser texturing under full oil lubrication as well as the effect of laser texturing on the abrasion resistance properties. Laser texturing was carried out to fabricate a spherical bulge texture on the surface of GCr15 bearing steel using an SPI fiber laser. Rriction and wear tests were performed to simulate the actual situation of sliding friction under full oil lubrication. Mechanical properties of the micro bulge and substrate region were detected and analyzed using an optical microscope, microhardness tester, and residual stress detector. Friction and wear tests showed that under full oil lubrication, the friction coefficient (FC) of bulge-textured samples is positively correlated with texture density. Compared with a smooth sample, the FC of the sample with 50.2% texture density decreased by 64.4%. The sample with 28.2% texture density had a minimal wear volume (1.35 × 108 μm3), which was diminished by 87.6% versus the smooth sample. The microstructure of the heat-affected zone is transformed into austenite by a large amount of heat and finally became acicular martensite when cooled. The microhardness of the bulge was increased to 419 and 331% of that of the substrate in vertical and radial directions, respectively. In addition, the surface of the micro bulge mainly revealed 20–35 MPa of residual tensile stress. The research proved that the surface wear resistance and antifriction effect of the sliding friction pair can be greatly improved by laser texturing, which shows favorable prospects for engineering applications such as bearings, guide rails, and mold formation. [ABSTRACT FROM AUTHOR]

The present study is directed to reveal the effect of density and shape of the dimples on the friction and wear characteristics of textured bearing steel (100Cr6) under dry sliding conditions. One untextured and four laser-textured disks of 100Cr6 steel with circular and bi-triangular dimples having 7 and 20% density, respectively, in the spiral layout were tested using a pin-on-disk unidirectional tribometer against a 100Cr6 pin having a flat surface with rounded corners under flat-on-flat configuration. The tests were carried at different speeds of 0.2, 0.6, and 1 m/s at a constant load of 15 N. The results indicate that a higher density of bi-triangular dimples had less wear and a lower coefficient of friction compared to untextured disk or disk with circular dimples, particularly at a relatively higher speed. This has been attributed to a relatively higher number of dimples in the contact zone in case of a spiral array, which increases the entrapment of more wear particles leading to a reduction in wear. The friction coefficient had a relatively higher value at a relatively lower speed but decreased at the highest speed of 1.0 m/s used in the present study. The results suggest that dimples may not be too effective under dry contact because they lose their effectiveness to trap wear debris after getting filled. [ABSTRACT FROM AUTHOR]

As the most common protective layer in car body protection, the paint layer is an effective barrier against corrosion of the material matrix. The adhesion between the paint layer and the substrate is an important factor in ensuring the long-term and effective protection of the paint layer. On the 5083 aluminium alloy substrate, a series of laser micro-texture with varying depths are produced by laser texturing, with the aspect ratio ranging from 0.12 to 1.76. The adhesion test of standard GB/T 5210–2006 was used to investigate the effect of different texturing depths on the adhesion strength of the paint layer. The cross-sectional microstructure and fracture morphology of the paint layer were analysed and characterized to study the deposition and fracture mechanism of the paint layer. The results show that the presence of laser micro-texture significantly enhances the adhesion of the paint layer, and the influence of laser micro-texture of different depths and dimensions on the adhesion of the paint layer is different. And found that the optimal depth size affecting the size of adhesion is around 0.67. By analyzing the cross-sectional microstructure and fracture morphology of the paint layer, it is found that the change in paint adhesion is the result of the change of developed interfacial area ratio (Sdr), the bonding condition of the paint layer and the substrate surface, and the bubble defect. At the same time, the process of the paint layer flowing on the substrate surface, filling the micro-texture, and forming bubbles was analysed. • Laser texturing produces a range of microfibres in depth-to-width ratio. • Significant improvement in surface roughness and specific surface area with laser texturing. • The gas recoil pressure created by gasifying the material is the main factor in forming laser microfabrics. • The depth-to-width of the micro-texture is most conducive to paint adhesion when the aspect ratio is around 0.67. [ABSTRACT FROM AUTHOR]

Laser-based surface texturing provides highly controlled interference fit between two parts. In this work, artificial intelligence-based models were used to predict the surface properties of laser processed stainless steel 316 samples. Artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) were used to predict the characteristics of laser surface texturing. The models based on feedforward neural network (FFNN) were developed to examine the effect of the laser process parameters for surface texturing on 316L cylindrical pins. The accuracy of the models was measured by calculating the root mean square error and mean absolute error. The reliability of the ANFIS and FFNN models for the output prediction of the laser surface texturing (LST) system were investigated by using the data measured from experiments based on a 3^3 factorial design, with main processing parameters set as laser power, pulse repetition frequency, and percentage of laser spot overlap. The relative assessment of the models was performed by comparing percentage error prediction. Finally, the impact of input data was examined using predicted response surface plots. Results showed that ANFIS prediction was 48% more accurate compared with that provided by the FFNN model. [ABSTRACT FROM AUTHOR]

Drop splashing is a very common phenomenon when liquid drops impact on solid surfaces. In this study, picosecond laser fabricated hybrid superhydrophobic/-philic (SH/SHL) surfaces with designed patterns are successfully applied to control drop splashing on solid surfaces. Using high-speed imaging, the water drop impact behaviors on differently patterned hybrid SH/SHL surfaces were investigated. The experimental results show that the water drop splashing could be restrained greatly on patterned hybrid SH/SHL surfaces, compared with SH or SHL surfaces. On a hybrid SH/SHL surface with a 2 mm diameter circular SH pattern, the drop splashing for a Weber number up to 600 (the corresponding impact velocity is 4.2 m/s) can be totally suppressed. Moreover, we found that the oriented distribution of splashing can be regulated by the shape and size of SH patterns. These results suggest that patterned hybrid SH/SHL surfaces could be a practical approach to regulate or control drop splashing. • Patterned superhydrophobic/-philic surfaces are first proposed to control drop splashing on solid surfaces. • Picosecond laser is a facile and efficient tool to regulate the size and shape of superhydrophobic patterns on superhydrophilic surfaces. • Superhydrophobic surfaces are beneficial for suppressing the splashing generated at the early stage of drop impact. • Oriented distribution of splashing can be regulated by the shape and size of superhydrophobic patterns. [ABSTRACT FROM AUTHOR]

Surface texturing of metals and alloys has recently been identified as an environmentally friendly alternative to the use of high-performance lubricants with complex formulations. Adding micro-scale textures to one or both sliding surfaces of mechanical components can reduce friction and wear compared to conventional/untextured surfaces. This study investigates the effect of laser textured surfaces on the tribological behavior of titanium Ti6Al4V. Multiple texture types were created by varying the energy density of pulse and scanning speed of the laser. These variations modify the outer layers of the alloy, rising the generation of specific topographies and changing the initial properties by means of microstructural modifications and oxidation processes. The performance of these surfaces was evaluated using a ceramic ball in a ball-on-flat reciprocating tribometer under lubricated conditions. Wettability of the tribological system was examined by measuring the contact angle of the oil used on textured and conventional surfaces. Tribological performance of textured surfaces was found to strongly depend on the laser patterning parameters. Replacing conventional surfaces with textured surfaces reduced friction up to 62% and wear up to two orders of magnitude. Wear mechanisms are discussed from optical microscopy and SEM/EDS observation of wear tracks on titanium disks and ceramic balls. [ABSTRACT FROM AUTHOR]

In this work, a mathematical relationship has been formulated between laser texturing process variables and the Ultimate Tensile Strength (UTS) of the AZ31B Mg alloy joints made by Cold Metal Transfer welding (CMTW) process. The nominal depth (D), diameter (Ø) and separation distance (SD) were the input parameters and three-factor and two-level central composite design (CCD) was applied to build up the experimental design matrix. By fixing the already optimized parameters of CMTW viz: current intensity 60A, Welding Speed 6 mm/sec, Gas flow rate 14 L/min and Nozzle to Plate Distance 6 mm and with the experimental matrix using laser texturing process variables, twenty joints were produced using CMTW process. The UTS was measured by standard ASTM procedure. The ANOVA was performed to find out the most significant main and interaction parameters and empirical relationship was determined. The laser texturing process (LST) variables were optimized by making response graphs and contour plots using Minitab software. The formulated mathematical relationship would be useful to forecast the UTS of CMT welded AZ31B joints for stipulated confidence limit. The contour plots will be helpful to acquire the optimal conditions of LST process variables. [ABSTRACT FROM AUTHOR]

This paper reports on study of laser texturing assisted abrasive flow finishing (LT-AFF) process of the hobbed spur gear (HSG) to further improve their microgeometry, surface finish, micohardness, microstructure, wear resistance, and material removal rate (MRR) as compared to AFF process. Preliminary experiments were conducted to identify optimum values of power and focal length of the continuous fiber laser of 1064-nm wavelength, and number of passes for laser texturing of the HSG made of 20MnCr5 alloy steel. Identified optimum values were used to produce homothetic texture on flank surfaces of HSG in a direction perpendicular to the lay profile generated by hobbing. Influence of laser texturing was studied by comparing deviations in microgeometry, average and maximum surface roughness values, microhardness, wear resistance, and MRR of HSG directly finished by AFF and laser-textured hobbed spur gears (LTHSG) finished by AFF. Previously optimized value of viscosity of AFF medium was used during finishing of HSG and LTHSG. Deviations in total profile, total lead and total pitch, and radial runout were used to indicate deviation in microgeometry of the spur gears. Results reveal that AFF of LTHSG reduced surface roughness and errors in microgeometry and improved microhardness, microstructure, wear resistance, and MRR than direct of AFF of HSG. Improved microgeometry and surface quality of spur gears will lead to their increased operating performance and service life thus reducing their running noise and vibrations and preventing their premature and failures. This research proves that productivity of AFF process can be improved significantly by laser texturing for finishing the spur gears. [ABSTRACT FROM AUTHOR]

Substrate preparation plays an important role in the performance of thermal spray coating, especially on softer materials like magnesium and aluminium alloys. Conventional substrate preparation methods such as grit blasting may not be the most suitable choice due to grit embedding, lower coating adhesion strength and environmental concerns. Laser texturing can be an attractive alternative to the grit blasting method for such materials. AZ91D substrate was prepared for thermal spray coating using grit blasting and laser texturing techniques. WC-12Co powder was thermally sprayed on AZ91D magnesium alloy using the high-velocity oxygen fuel technique. The adhesion strength of the coating, thus produced, was determined using the ASTM 633C adhesion strength test. Scanning electron microscopy was used to investigate substrate morphology and to qualitatively analyse substrate and coating interface. X-ray diffraction was used to identify phase compositions. The coating was characterised for roughness, porosity, micro-hardness and fracture toughness. Laser texturing as a substrate preparation technique has been able to produce well-adhered coatings, with adhesion strength of 45.6 MPa, and comparable coating characteristics with those of the grit blasting technique. [ABSTRACT FROM AUTHOR]

Laser texturing of Inconel 718 alloy surface under high nitrogen gas pressure is considered and the resulting surface morphology and wetting state are examined. Analytical tools are used to characterize the laser textured surface. Environmental dust particles and liquid solution formed from the water condensate on the dust particles in humid air ambient are analyzed. The tangential force required to remove the dried liquid solution from the laser textured and as received surfaces are measured incorporating the micro-tribomoter. It is found that laser treatment results in micro/nano size pillars on the textured surface and forms nitride compounds on the surface. This, in turn, modifies the wetting state of the workpiece surface from hydrophilic to hydrophobic. A liquid solution is formed due to the dissolution of alkaline and alkaline earth metals of the dust particles into the water condensate in humid air ambient. The liquid solution has high pH and forms different sizes of crystals on the surface upon drying. The liquid solution spreads on the textured surface while forming a film. It adheres strongly to the surface upon drying; in which case, the tangential force required removing the dried liquid from the surface remains high, which is more pronounced for the as receive surfaces. [ABSTRACT FROM AUTHOR]

This research investigates the slurry and cavitation erosion resistance of a polytetrafluoroethylene (PTFE) top-coat applied to standalone high velocity oxy-fuel (HVOF) sprayed and laser textured Vanadium Carbide (VC) coating over SS316 steel. The static contact angle, microstructural characterization, EDS mapping, microhardness, fracture toughness, elastic modulus, slurry erosion, and cavitation erosion of all the samples namely SS316, HVOF sprayed VC, Laser textured VC, and PTFE modified VC were evaluated. Results demonstrate that the inclusion of a PTFE top-coat significantly enhances the erosion resistance over HVOF sprayed and laser textured VC coatings. Further, the laser textured VC surface was also found to be successful in reducing the slurry and cavitation erosion of SS316 steel, which could be attributed to its higher microhardness, presence of circular textures, and higher H/E ratio. When the failure mechanism was examined using SEM images, it was found that brittle failure occurred on hard surfaces while ductile failure occurred on soft surfaces. [Display omitted] • Significant improvement in erosion resistance with PTFE top-coat on HVOF sprayed and laser textured VC coatings. • Higher microhardness, circular textures, and higher H/E ratio contribute to improved erosion resistance. • Brittle failure observed on hard surfaces, while ductile failure observed on soft surfaces. [ABSTRACT FROM AUTHOR]

[Display omitted] • Laser texturing enhances slurry erosion resistance of coated and uncoated samples. • HVOF spraying combined with laser texturing creates superhydrophobic surfaces. • Influence of impact angle; maximum mass loss for VC + TiC at 90°, VC-TiC + 50%CuNi-Cr and CuNi-Cr at 30°. Laser texturing method was used in the current study to create a micro-textured surface over SS316 steel with HVOF (High Velocity Oxy-fuel) sprayed VC-TiC and CuNi-Cr based coatings. The static contact angle, cross-sectional characterization, hardness, EDS mapping, surface roughness, porosity percentage, XRD analysis, bond strength and slurry erosion resistance of textured and non-textured surfaces were measured. Slurry erosion experiments were carried out in accordance with ASTM G-73 standards. According to the findings, laser texturing was found as an effective technique for increasing the static contact angle of the surfaces, which in turn increases the slurry erosion resistance of the surfaces. SEM images were used to analyze the failure mechanism, and it was discovered that hard surfaces experienced a brittle mode of failure, whereas soft surfaces experienced a ductile mode of failure. [ABSTRACT FROM AUTHOR]

The present investigation aimed to determine the influence of the texturing strategy on the mechanical behavior of metal-polymer hybrid joints made by friction-assisted joining. An experimental campaign was conducted on AA7075 aluminum alloy and PolyEther Ether Ketone (PEEK). Laser texturing was performed on the aluminum surface before joining to improve the mechanical interlock between the substrates. Different laser texturing conditions were used by varying the number of scans and the distance between consecutive laser tracks. Microscopic analysis was conducted on the treated samples to determine the main geometrical characteristics. Single-lap shear tests were performed to determine the mechanical behavior of the produced connections. Fracture surface analysis was also performed to establish the main failure mechanisms. According to the achieved results, the laser texturing strategy significantly influenced the mechanical behavior of the joints, the peak force, the absorbed energy, and the failure mode. The density of the laser texturing affected the stress on the aluminum protrusions and the mechanical behavior. Adopting a higher number of scans improved the mechanical interlock and, consequently, the mechanical behavior of the joints. [ABSTRACT FROM AUTHOR]

The effects of laser texturing technology on the tribological performance of tapered roller bearings in terms of fatigue life, friction, and wear are studied for the first time. The influence of diameter, height and density of the circular-shaped dimples is thoroughly analyzed, first on flat samples, and the most encouraging results are upscaled to components. This research demonstrates the advantages that surface texturing can bring to the most demanding applications involving rolling surfaces under lubrication regime. The experiments show a torque reduction up to 18% and very promising results in fatigue life tests. • Textures have been successfully manufactured on laboratory specimens and finished bearings by ultra-short pulse laser. • Dimple design affects the final tribological performance, being height the most critical feature: the lower height the worse. • A tribological improvement up to ∼18% and ∼8% at variable low speed & load, respectively, was achieved. • A ∼18% improvement in high-speed friction test has been achieved compared to untextured finish product. • Promising behavior on fatigue life was observed, producing a life enhancement under high-demanded test conditions. [ABSTRACT FROM AUTHOR]

To investigate the synergetic effects of laser texturing and super-hydrophobic coatings on tribological performances, we prepare micro-grooves on steel substrates by femtosecond laser and then deposit super-hydrophobic coatings in the micro-grooves to obtain coated groove-textured surfaces (CGSs). The tribological behaviors of polished steel surfaces (PSSs), groove-textured surfaces (GSs), and CGSs under water lubrication are examined. Compared with PSSs and GSs, CGSs show significant anti-friction and wear-resisting properties under a relatively low load. With increasing the texture density, the wear resistance of CGSs decreases. When a load of 0.5 N is applied on the CGSs with a texture density of 10%, the friction coefficient and wear loss are reduced by 22.3% and 73.5%, respectively, compared with PSSs. [Display omitted] • The synergetic effect of laser texturing and super-hydrophobic coatings filled in the laser-ablated textures is investigated. • Wear loss can be reduced by 73.5% through the synergetic effects. • Super-hydrophobic coatings can reduce the friction and wear of laser-textured surfaces by improving hydro-dynamic pressure. [ABSTRACT FROM AUTHOR]

The low hardness and poor tribological properties of titanium and its alloys significantly hinder their practical engineering applications, so surface nitriding or texturing is widely employed to improve the surface performances. However, previous studies mainly used the single method (surface nitriding or texturing), and simultaneous nitriding and texturing are rarely reported. Therefore, their combined effects on the surface mechanical and tribological properties are rarely investigated as well. In this study, by nanosecond pulse laser irradiation in nitrogen atmosphere, simultaneous nitriding and texturing of the Ti6Al4V surface were achieved. The effects of laser parameters including laser power, laser overlap rate, and number of scanning cycles, on the surface hardness and tribological properties of laser irradiated surfaces were comparatively studied. The experimental results showed that after simultaneous laser nitriding and texturing, the surface hardness of Ti6Al4V surface was increased by 50%~95%, and the coefficient of friction (COF) was reduced by 70%~80%. Furthermore, the laser processed surfaces obtained under various irradiation parameters presented quite different scratching characteristics, and the corresponding deformation mechanisms during scratching were analyzed. This study provides a simple and effective method by simultaneous laser nitriding and texturing for improving the surface properties of Ti6Al4V, which would be meaningful for its practical engineering applications. • Simultaneous laser nitriding and texturing were achieved on the Ti6Al4V surface. • Their combined effects on surface mechanical and tribological properties were investigated. • The hardness of laser irradiated surfaces was increased by 50%~95%. • The COF of laser irradiated surfaces was reduced by 70%~80%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Superhydrophobic brass surfaces with tunable water adhesion were prepared. • Water adhesion is tuned by solid-water interfacial area fractions. • Anti-corrosion ability of brass was improved after achieving superhydrophobicity. • Low-adhesion surface has better anti-corrosion ability than high-adhesion surface. Superhydrophobic metallic surfaces with tunable water adhesion have gained increasing interest due to their significance in both fundamental researches and practical applications. However, the relationship between the water adhesion and the anti-corrosion ability of the superhydrophobic metallic surfaces has been seldom studied. In this work, superhydrophobic brass surfaces with tunable water adhesion were fabricated by laser texturing followed by heat treatment, and the anti-corrosion ability of these surfaces was studied by performing electrochemistry tests. The analyses of surface structures and compositions revealed that the observed superhydrophobicity results from the micro/nanostructures produced by the laser texturing and the adsorption of organic matter from ambient air during the heat treatment; the different water adhesions of these superhydrophobic surfaces are attributed to their different solid–liquid interfacial area fractions. The results of the electrochemistry tests revealed that the anti-corrosion abilities of the investigated surfaces are the following order: the superhydrophobic surface with low water adhesion > the superhydrophobic surface with high water adhesion > the bare brass surface, which stems from the different solid-electrolyte interfacial area fractions of these surfaces. [ABSTRACT FROM AUTHOR]

Surface laser texturing is used to ensure mechanical anchoring and strengthen adhesion between the interfaces of bond coatless thermal barrier coating system. To anticipate a possible loss of mechanical properties and to adapt to the perpetual evolutions of chemical compositions of the system, we analyzed the microstructural evolutions of different Ni-based single crystal superalloys, induced during infrared nanosecond laser ablation. Localized asperities composed of a melted, re-solidified matter, with a different microstructure from that of the bulk material, were generated. Regarding asperity morphologies, recrystallization within the latter could be avoided. Then, to compare different Ni-base single crystal superalloys, the thermal-affected volumes were characterized for two patterns textured under different energetic conditions. It seems that all the studied single crystal superalloys behaved quite similarly during nanosecond laser ablation. Finally, according to these results, ablation kinetics between the γ and γ′ phases of Ni-based superalloys could not be homogeneous. [ABSTRACT FROM AUTHOR]

Abstract: Laser texturing is a novel technique that may be used to texture a cold roller in the process of manufacturing high quality steel sheets. With the aim of improving the quality of the textured roller by using a CO2 laser, a new laser beam modulating device is proposed. An optical beam expander with a fast rotating chopper system is designed. The laser pulse is split into two parts by the chopper blades; one is the preheating pulse that is reflected onto optical loop mirrors; the other is the directly transmitted pulse that creates the craters at the preheated spots. The preheating beam focus spot size and position can be adjusted. The focusing characteristics and optical parameter compensation for the flying optics are investigated. The heat transfer and melt process of laser texturing are numerically simulated. The effects of the double pulses on the texturing are analyzed. The effect of preheating the sample ahead of the laser texturing pulse is examined. The surface profile and bump hardness show improvements by using this approach. [Copyright &y& Elsevier]