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Development of Picosecond Laser Writing for Heat Resistant FBG Sensors and Adhesion Technique for High Temperature Industrial Plants; ?????3?§??????????????·￥?????????è????±FBG ?????3??μè￡??????¨é???????￡?￥-??¨????????3???????????￥???;
摘要： Pulse laser processing point by point method is applied for heat resistant Fiber Bragg Grating structure. In order to fabricate fine FBG, a close packaged picosecond laser system is used with a CCD camera microscopy. An optical fiber is mounted on a precision translation stage. The stage speed is controlled by the current position and the corrector output. In order to contact the FBG on a metal surface, nano-size colloidal silver adhesive is used under temperature monitoring. Heat expansion of SUS plate can be successfully monitored by strain gauge of the heat resistant FBG. It can be available for monitoring the structural integrity of high temperature industrial plant. Complex coolant piping systems of liquid sodium and molten salt are facing the risk of coolant leakage, which is the most promising usage.
关键词： Structural Health Integrity,Picosecond Laser Processing,Adhesion,High Temperature,FBG
更新于2025-09-23 15:19:57
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Laser-assisted glass-based sealing of polished porcelain stoneware tile surface to increase stain resistance
摘要： This study aims to develop a new approach for the permanent sealing of surface pores on polished porcelain stoneware tiles, using ceramic frits for the filling pores, followed by laser-sealing to ensure the fixation of the applied material. The laser-sealing parameters compatible with the ceramic substrate were focus height (z) of 105 mm, scan speed (v) of 2640 mm.min-1, and power values of 750, 800, and 850 W. In order to define the working parameters, three ceramic frits with 30, 50, and 70 wt.% solid contents were tested by sealing at the mentioned powers. High stain resistant polished stoneware tiles were obtained using frit 1 and frit 3 with 50 and 70 wt.% solid contents, respectively, and the proposed procedure. High ease of cleaning is obtained related to the current treatment, demonstrating its suitability for improving the stain resistance for meeting the ISO 13006:2012 requirements.
关键词： Ceramic frits. Laser Processing. Porcelain Tile. Porosity. Stain Resistance.
更新于2025-09-23 15:19:57
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Single-step maskless nano-lithography on glass by femtosecond laser processing
摘要： Femtosecond laser processing is widely adopted today for microfabrication because of its ability to make rapid processing on almost all types of materials in ambient environment. However, it is challenging to apply femtosecond lasers for high-speed large-scale subwavelength nanofabrication, particularly, for two-dimensional nanopatterning on transparent dielectric materials due to their low light absorption. Previous demonstrations of femtosecond laser two-dimensional nanofabrication on dielectrics typically lack structural quality and long-range uniformity. In this work, we report a maskless laser nano-lithographic technique to fabricate high-quality two-dimensional periodic nanodomes on glass. The glass sample is first coated with a thin copper film and then irradiated by femtosecond laser pulses. We show that the period and size of the nanodomes can be controlled using a multi-fluence process. More importantly, a single-fluence technique is developed here, for the first time, for high-quality nanopatterning on glass. The nanopatterning formation mechanism is studied by dynamics experiments and numerical simulations. This introduced technique will provide a simple but highly effective way for dielectrics nanofabrication.
关键词： copper film,nanofabrication,nanodomes,femtosecond laser processing,glass
更新于2025-09-23 15:19:57
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Temperature Effect on Capillary Flow Dynamics in 1D Array of Open Nanotextured Microchannels Produced by Femtosecond Laser on Silicon
摘要： Capillary ?ow of water in an array of open nanotextured microgrooves fabricated by femtosecond laser processing of silicon is studied as a function of temperature using high-speed video recording. In a temperature range of 23–80°C, the produced wicking material provides extremely fast liquid ?ow with a maximum velocity of 37 cm/s in the initial spreading stage prior to visco-inertial regime. The capillary performance of the material enhances with increasing temperature in the inertial, visco-inertial, and partially in Washburn ?ow regimes. The classic universal Washburn’s regime is observed at all studied temperatures, giving the evidence of its universality at high temperatures as well. The obtained results are of great signi?cance for creating capillary materials for applications in cooling of electronics, energy harvesting, enhancing the critical heat ?ux of industrial boilers, and Maisotsenko cycle technologies.
关键词： Maisotsenko cycle,cooling of electronics,silicon,open capillary microchannels,microstructures,nanostructures,femtosecond laser processing,capillary flow
更新于2025-09-23 15:19:57
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Microstructure and mechanical properties of a MoSi2-Mo5Si3 eutectic composite processed by laser surface melting
摘要： Laser surface melting (LSM) of a single-crystal substrate of a MoSi2-Mo5Si3 eutectic composite has been performed to check the feasibility of mechanical property improvement through microstructure re?nement and seeded growth of the eutectic composite on top of the seed composite single crystal by additive manufacturing processes using scanned laser beam. LSM is proved to be capable of obtaining a eutectic composite maintaining the eutectic script-lamellar microstructure as well as crystallographic orientations of the substrate single crystal. The eutectic script-lamellar microstructure is considerably re?ned from several micrometers (the substrate) to several tenths nanometers (43 ± 7 nm) after LSM processing while maintaining the orientation relationship. Due to the microstructure re?nement, the hardness increases by about 38% from 11.60 ± 0.04 GPa (substrate) to 15.96 ± 0.42 GPa (LSMed region) and the fracture toughness increases by about 34% from 3.8 ± 0.3 MPa m1/2 (substrate) to 5.1 ± 1.5 MPa m1/2 (LSMed region).
关键词： Mechanical properties,Microstructure,Molybdenum silicides,Laser processing,Eutectic composites
更新于2025-09-23 15:19:57
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Experimental X-ray investigations of changes at the “solid-solid interface” boundary after pulsed focused laser irradiation
摘要： Investigated in this work were plates of Zerodur connected to a solid monolith block with the aluminum nanolayer of the 100-nm thickness. The object of the study was this nanolayer that changed its optical transparency under action of pulsed laser radiation. Zerodur plate located on the back side after ablation was step-by-step thinned by grinding and polishing up to the boundary with aluminum nanolayer. After each thinning step, we performed the X-ray phase analysis by using the diffractometer Philips X’Pert PRO – MRD. Used in this study was Cu Kal emission line with the wavelength k = 0.15405980 nm). The anode potential was 45 kV, and current – 40 mA. It has been ascertained that the changes in phase composition are present within the region of 50(cid:1) (cid:1) (cid:1)100 nm from the aluminum nanolayer boundary. It has been found the appearance of the weak but sharp peak at 28.4(cid:1) that corresponds to the re?ection (1 1 1) of cubic silicon nanoparticles. Their size is approximately 12 nm. It was revealed the weakly pronounced but clear peak at 44.78(cid:1) that corresponds to the re?ection (2 0 0) attributed to cubic aluminum.
关键词： Zerodure,Nanoparticles,X-ray techniques,Laser ablation,Thin ?lms,Laser processing
更新于2025-09-19 17:13:59
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Engineering black titanium dioxide by femtosecond laser filament
摘要： We propose an approach, by utilizing the propagation of femtosecond laser pulses in the filamentation region in air, to achieve black titanium dioxide (TiO2), a promising material for efficient photocatalysis. It is found that the black TiO2 engineered by femtosecond laser filament in both solution and air environments shows significantly improved absorption in a broad spectral range from 400 to 2500 nm. In addition, the engineered black TiO2 shows a certain degree of enhanced absorption in the microwave range. The structural and elemental analysis of the processed TiO2 suggest that the absorption enhancement is mainly ascribed to the filament-induced disorder and dopant impurity in the surface layer of crystalline TiO2. Our technique provides an alternative way to engineer black TiO2 with the capability of absorbing the solar energy across a broad spectrum that can be useful for various applications in optoelectronics and photochemistry.
关键词： femtosecond laser filamentation,disordered surface,solar energy,titanium dioxide,absorption enhancement,laser processing
更新于2025-09-19 17:13:59
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Improvement of ablation capacity of sapphire by gold film-assisted femtosecond laser processing
摘要： Sapphire is widely used in civilian and military equipment owing to its superior optical and mechanical properties. Femtosecond laser has been demonstrated to be an effective tool to process sapphire material. However, the direct processing of sapphire by femtosecond laser still meets some challenges, such as poor ablation morphology and low laser energy absorption. In this work, femtosecond laser processing of sapphire coated with a 12-nm-thick gold film (Au-coated sapphire) has been investigated. The experimental results have revealed that the ablation morphology of Au-coated sapphire has been improved, featuring fewer molten materials and thermal cracks, as well as regular crater shape and uniform periodic surface structures. It has also been found that, under 100 shots condition, the threshold fluence of Au-coated sapphire is reduced by about 56% compared to that of uncoated one. Meanwhile, the incubation effect of Au-coated sapphire is stronger than that of uncoated one. We also illustrate that the material removal rate of Au-coated sapphire is increased up to about two times higher than that of uncoated one. In order to reveal the effective mechanism of the gold film in the laser processing of sapphire, the energy transfer process among incident photons, free electrons and sapphire lattice phonons was studied. Our study provides a guidance for improving the laser ablation capacity of sapphire.
关键词： Gold film,Sapphire,Material removal rate,Ablation morphology,Femtosecond laser processing
更新于2025-09-19 17:13:59
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Spectral absorption control of femtosecond laser-treated metals and application in solar-thermal devices
摘要： Direct femtosecond (fs) laser processing is a maskless fabrication technique that can effectively modify the optical, electrical, mechanical, and tribological properties of materials for a wide range of potential applications. However, the eventual implementation of fs-laser-treated surfaces in actual devices remains challenging because it is difficult to precisely control the surface properties. Previous studies of the morphological control of fs-laser-processed surfaces mostly focused on enhancing the uniformity of periodic microstructures. Here, guided by the plasmon hybridisation model, we control the morphology of surface nanostructures to obtain more control over spectral light absorption. We experimentally demonstrate spectral control of a variety of metals [copper (Cu), aluminium (Al), steel and tungsten (W)], resulting in the creation of broadband light absorbers and selective solar absorbers (SSAs). For the first time, we demonstrate that fs-laser-produced surfaces can be used as high-temperature SSAs. We show that a tungsten selective solar absorber (W-SSA) exhibits excellent performance as a high-temperature solar receiver. When integrated into a solar thermoelectric generation (TEG) device, W-SSA provides a 130% increase in solar TEG efficiency compared to untreated W, which is commonly used as an intrinsic selective light absorber.
关键词： spectral light absorption,plasmon hybridisation model,selective solar absorbers,solar thermoelectric generation,broadband light absorbers,femtosecond laser processing
更新于2025-09-19 17:13:59
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Improving processing quality and tribological behavior of laser surface textures using oil layer method
摘要： The study proposes an effective oil layer method for improving the processing quality and the tribological behavior of laser textured surface. Experimental results suggest the oil layer method has the reduction effect on the coverage area of metallic oxide and the height of rim ridges/burrs of textures. Possible mechanisms are mainly attributed as: i) the cooling down effect of oil flow; ii) the protecting of oil film to reduce oxidation and adhesion of laser-ablated melt on metal surface. Moreover, tribological tests confirm the favorable effect of textures laser-irradiated using the oil layer method on reducing friction coefficient.
关键词： surface textures,oil layer method,tribological behavior,laser processing
更新于2025-09-19 17:13:59