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Bioinspired photothermal conversion coatings with self-healing superhydrophobicity for efficient solar steam generation
摘要： Photothermal conversion materials are prone to contamination caused by microorganisms and mud in water and to damages caused by oxidative substances, corrosive liquids and ultraviolet light, thereby greatly limiting the practical application of solar steam generation. Inspired by lotuses, in this study, scalable, chemically and mechanically stable, and conductive photothermal conversion coatings with self-healing superhydrophobicity are fabricated by spraying a mixture of beeswax, multiwalled carbon nanotubes and polydimethylsiloxane. The resulting photothermal conversion coatings exhibit broadband light absorption ability and can thus efficiently generate steam under sunlight irradiation. The integration of superhydrophobicity provides the photothermal conversion coatings with a self-cleaning ability that can prevent the reduction of steam generation efficiency induced by microorganisms and mud in water. In addition, the photothermal conversion coatings are capable of healing damage to their superhydrophobicity through the migration of beeswax, providing long-lasting protection. Furthermore, the photothermal conversion coatings possess an electric steam generation ability, which allows the coatings to continuously generate steam when sunlight is not available. Considering their low maintenance requirement, simple preparation process and high cost effectiveness, photothermal conversion coatings with self-healing superhydrophobicity may be suitable to provide fresh water for remote/disaster areas.
关键词： self-healing,coatings,photothermal conversion,solar steam generation,superhydrophobicity
更新于2025-09-19 17:15:36
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Influence of Al2O3 addition on the hardness and in vitro corrosion behavior of laser synthesized Ti-Al2O3 coatings on Ti-6Al-4V
摘要： Titanium alloy (Ti-6Al-4V) has been mostly used for medical implants due to its good chemical and mechanical properties. However, this alloy has tendency to emanate toxic V and Al due to its low corrosion resistance in body conditions. In this work, an experimental study of laser cladding Ti-Al2O3 coatings with different Al2O3 fractions (5 wt.% Al2O3, 8 wt.% Al2O3, and 10 wt.% Al2O3) was carried out to establish a coating which could improve the hardness and corrosion resistance of Ti-6Al-4V alloy. Laser parameters of 900 W power, 0.6 m/min laser scan speed, and 2 l/min powder feed were used in this research. The microstructure, phase constituents, microhardness, and corrosion of the resultant coatings were characterized by scanning electron microscope (SEM), optical microscope (OPM), X-Ray Diffractometer (XRD), Vicker hardness tester, and potentiostat respectively. Results showed that a defect free coating was achieved at a coating with less Al2O3 content. Increase in Al2O3 addition resulted in increment of hardness with Ti-10 wt.% Al2O3 coating achieving an optimum hardness of about 2.2 times greater than that of the substrate. Moreover, considerable increment in corrosion resistance of Ti-6Al-4Valloy was achieved after laser deposition of various Ti-Al2O3 admixed coatings. An optimal corrosion rate reduction of about 81% and polarization resistance increment of 709% over the substrate were achieved at Ti-5 wt.% Al2O3 due to low porosity within the coating layer. It has been established that fabricating Ti-Al2O3 on Ti6Al4V through laser could be used in improving the surface hardness values and corrosion resistance.
关键词： Ti-Al2O3 coatings,Corrosion behavior,Laser cladding,Hardness properties,Ti-6Al-4Valloy
更新于2025-09-19 17:15:36
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Nonstoichiometric amorphous silicon carbide films as promising antireflection and protective coatings for germanium in IR spectral range
摘要： A technology for preparation of amorphous nonstoichiometric hydrogenated silicon carbide (a-SixC1-x:H) films using the PE-CVD method has been developed. Such films with refractive index n = 1.8–2.1 are suitable to obtain antireflection effect on germanium in the IR spectral region. Single- and two-sided antireflection coatings of Ge enabled to increase its optical transmission up to 65% and 96% in the maximum transmission, respectively. The obtained films have good mechanical properties (H > 12 GPa, E = 100 GPa). Presence of Si-C bonds in the a-SixC1-x:H films restricts their range of application to the spectral interval 2.5–10 μm. The prepared films are uniform in composition and have high adhesion to the substrate. Variation of deposition conditions makes it possible to obtain a-SixC1-x:H films having high hardness and Young's modulus. High deposition rate, optimal optical properties of the a-SixC1-x:H films and good combination of mechanical properties for the Ge/a-SixC1-x:H film structures make them to be promising for practical application as antireflection and protective coatings for germanium.
关键词： Germanium,Antireflection coatings,Elements of IR optics,Nonstoichiometric SiC films
更新于2025-09-19 17:15:36
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Fluorolytic Sol–Gel Synthesis of Nanometal Fluorides: Accessing New Materials for Optical Applications
摘要： The potential of fluorolytic sol–gel synthesis for a wide variety of applications in the field of optical materials is reviewed. Based on the fluorolytic sol–gel synthesis of nanometal fluorides, sols of complex fluorometalates have become available that exhibit superior optical properties over known classical binary metal fluorides as, for instance, magnesium fluoride, calcium fluoride, or strontium fluoride, respectively. The synthesis of transparent sols of magnesium fluoroaluminates of the general composition MgxAlFy, and fluoroperovskites, [K1?xNax]MgF3, is reported. Antireflective coatings fabricated from MgF2, CaF2, MgxAlFy, and [K1?xNax]MgF3 sols and their relevant properties are comprehensively described. Especially the heavier alkaline earth metal fluorides and the fluorperovskites crystallizing in a cubic crystal structure are excellent hosts for rare earth (RE) metals. Thus, the second chapter reflects the synthesis approach and the properties of luminescent systems based on RE-doped alkaline earth metal fluorides and [K1?xNax]MgF3 phases.
关键词： nanometal fluorides,antireflective coatings,sol–gel synthesis,luminescent materials
更新于2025-09-19 17:15:36
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Structure, thermal stability and chromaticity investigation of TiB2 based high temperature solar selective absorbing coatings
摘要： Transition metal titanium diboride (TiB2) is a promising material for the solar selective absorbing coatings due to its favorable spectral selectivity and thermal stability. In this research, spectrally selective TiB2/Al2O3 tandem absorber is deposited on stainless steel (SS), which exhibits a high solar absorptance (αs = 0.93) and a low thermal emissivity (ε = 0.11). In this tandem absorber, the TiB2 acts as the main absorber layer and the Al2O3 acts as an antire?ection layer. The tandem absorber coating is systematically characterized by ultra-high resolution scanning electron microscope (SEM), UV–vis-NIR spectrophotometer, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Micro-Raman techniques. The thermal stability in vacuum of the SS/TiB2/Al2O3 tandem absorber coatings is investigated in the temperature range of 400–800 °C for 2 h and 100 h, respectively. SEM and Raman spectra indicate that the change of surface morphology and chemical composition for the coating result in the degradation of optical performance. With the di?erent annealed temperature, the SS/TiB2/Al2O3 tandem absorber coatings exhibit di?erent color, which is further investigated using chromaticity diagram.
关键词： Chromaticity,Titanium boride,Structure,Thermal stability,Solar selective absorbing coatings
更新于2025-09-19 17:15:36
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Tackling conservation challenges using erbium lasers: case studies at the British Museum
摘要： Research was conducted at the British Museum to investigate the potential of Er:YAG lasers to address challenging conservation problems where traditional conservation methods had failed. The approach followed was to perform laser tests on model samples and unregistered objects to determine the laser alteration threshold fluence on each substrate and the ability of the laser to remove contaminants, such as inorganic crusts and organic coatings. The effects of the laser were assessed by means of optical microscopy, scanning electron microscopy and colour measurements. If tests were successful on the samples and unregistered objects, the laser was then used on artefacts from the collection of the British Museum. This article details the successful results obtained using Er:YAG lasers for the removal of corrosion from metals, remains of old adhesives from ceramics and shells, mould from polychromed limestone and terracotta, modern overpainting and varnish from a fresco painting.
关键词： Er:YAG laser cleaning,coatings,overpainting,mould,alteration threshold,corrosion
更新于2025-09-19 17:13:59
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Scaling Resistance in Nanophotonics-Enabled Solar Membrane Distillation
摘要： This study compares the scaling behavior of membrane distillation (MD) with that of nanophotonics-enabled solar membrane distillation (NESMD). Previous research has shown that NESMD, due to its localized surface heating driven by photothermal membrane coatings, is an energy-efficient system for off-grid desalination; however, concerns remained regarding the scaling behavior of self-heating surfaces. In this work, bench-scale experiments were performed, using model brackish water, to compare the scaling propensity of NESMD with MD. The results showed NESMD to be highly resistant to scaling; a three times higher salt concentration factor (c/c0) was achieved in NESMD compared to MD without any decline in flux. Analyses of the scaling layer on NESMD membranes revealed that salt deposition was 1/4 of that observed for MD. Scaling resistance in NESMD is attributed to its lower operating temperature, which increases the solubility of common scalants and decreases salt precipitation rates. Precipitation kinetics measurements revealed an order of magnitude faster precipitation under heated conditions (62 °C, k = 8.7 × 10?2 s?1) compared to ambient temperature (22 °C, k = 7.1 × 10?3 s?1). These results demonstrate a distinct advantage of NESMD over MD for the treatment of high scaling potential water, where scaling is a barrier to high water recovery.
关键词： nanophotonics-enabled solar membrane distillation,photothermal membrane coatings,scaling resistance,desalination,membrane distillation
更新于2025-09-19 17:13:59
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Damage Evaluation of TBC by Rapid Thermal Cycling Test Utilizing a Laser Irradiation
摘要： Thermal barrier coating (TBC) is deposited onto the gas turbine blade surface in order to protect the substrate from high-temperature combustion gas. Cracks and delamination of the ceramic coating which come from high heat flux loading are serious problem in TBC. In this study, the rapid thermal cycling device utilizing laser irradiation was developed. It was then investigated how the damage progresses in the ceramic coating exposed to cyclic rapid thermal loading. As a result, a sintering layer was formed in the surface of the ceramic coating, although such phenomenon was not recognized in TBC sample tested by the conventional thermal cycling test using an electric furnace. It was also revealed from the cross-sectional observation that the vertical crack was initiated at the surface of TBC and propagated into sintering layer. Finally, mechanical factors of those damages from finite element analysis using the TBC model including sintering progress was discussed.
关键词： Thermal Barrier Coatings,Gas Turbine,Finite Element Analysis,Laser irradiation
更新于2025-09-16 10:30:52
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Surface Design Using Laser Rapid Manufacturing for Ti64-Hopeite Orthopedic Implants
摘要： Although hopeite bioceramic coatings have already proven effective for achieving better osseointegration and antibacterial character, but the detachment of hopeite coatings during implanting of coated implants can negatively affect the hopeite bioactivity in the physiological environment. To overcome this issue, the present research work proposes a new process route of laser rapid manufacturing (LRM) for depositing hopeite coatings with the metallurgical bond. Microstructure, phase composition, microhardness, antibacterial efficacy, and bioactivity were evaluated using scanning electron microscope, X-ray diffraction, Vickers microhardness tester, fluorescence-activated cell sorting technique, simulated body fluid immersion test respectively. The promising results obtained from these characterizations and testing establishes a new process route LRM as an effective alternative to deposit multifunctional hopeite coatings on metallic prosthetic–orthopedic implants.
关键词： Hopeite,Multifunctional orthopedic coatings,Laser rapid manufacturing,Implant,Laser surface modification,Titanium alloy
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing XLIII ACADEMIC SPACE CONFERENCE: dedicated to the memory of academician S.P. Korolev and other outstanding Russian scientists – Pioneers of space exploration - Moscow, Russia (28 January–1 February 2019)] XLIII ACADEMIC SPACE CONFERENCE: dedicated to the memory of academician S.P. Korolev and other outstanding Russian scientists – Pioneers of space exploration - Laser shock peening with low-energy laser sources: Techniques and prospects
摘要： The first part of the article considers practical prospect of using laser shock peening technology. There are presented prerequisites of solving several technological tasks related to local impact with laser shock processing. The second part of the article is devoted to analysis and parameter optimization that permit to apply low-energy sources for laser shock processing. The influence of various absorbing and tamping coatings used in the process of laser shock peening on the properties of the processed material was researched. Physical and technological properties of viewed coatings were evaluated. The results were evaluated by the treated material microhardness, due to its linear relationship with the stresses in material. Conducted research enables the selection of the optimal environments combination to achieve the most effective results in the process of laser shock peening.
关键词： laser shock peening,surface modification,low-energy laser sources,tamping coatings,absorbing coatings,microhardness
更新于2025-09-12 10:27:22