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Microstructure and properties of honeycomb composite films containing Eu and Sn
摘要： Honeycomb composite films were prepared by breath figure method via a straightforward, one-step process by doping complex containing Eu or Sn into polystyrene-b-poly(acrylic acid) (PS-b-PAA) solution. Several influencing factors, such as the concentration of the block polymer solution, the relative humidity of the environment and the amount of complexes, were investigated to control micropore size and tune film surface properties. The characteristics of the composite films were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), ultraviolet and emission spectra. Results indicate that composite films containing Eu have excellent optical performance, and micro-patterned bowl-like SnO2 microparticles could be fabricated from composite films containing Sn after being calcined at 600 °C for 5 h. This general approach for the fabrication of honeycomb composite films opens a convenient and effective route to the functional modification of honeycomb films and offers new prospects for the application in miniaturized sensors, micro-reactor and catalysis.
关键词： Complex containing Eu,Breath figure method,Honeycomb composite film,Tin dioxide,Microstructure
更新于2025-09-23 15:21:21
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Magnetic and optical behaviors of SnO2-x thin films with oxygen vacancies prepared by atomic layer deposition
摘要： SnO2-x thin films with different concentration oxygen vacancies were prepared by Atomic Layer Deposition (ALD). Specifically, the oxygen vacancy concentration was controlled by the oxidation pulse time during the ALD process. The crystal structure of the as-prepared thin films was determined by XRD, and the magnetic properties were measured by VSM, while the optical properties were measured by optical transmittance spectrum. The results showed that the oxygen vacancy concentration of the SnO2-x could be controlled by the oxidation pulse time, and the crystal structures, magnetic properties, and optical properties were largely impacted by the concentration of oxygen vacancy.
关键词： microstructure,thin film,magnetic,diffraction,nanocrystal,oxygen vacancy
更新于2025-09-23 15:21:21
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Effects of TiC on the microstructure and properties of TiC/TiAl composite coating prepared by laser cladding
摘要： In order to study the effect of TiC on the microstructure and properties of cladding coatings, TiC/TiAl composite coatings have been prepared by using a laser cladding technique on TiAl alloy, and the microstructure and properties of the resulting composite coatings have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-hardness testing, X-ray stress measurements, friction and wear testing, and an electrochemical workstation. The results showed that when the particle size of TiC is up to micron, the growth of TiC is more developed, the dendrite growth direction is disordered, and the cladding quality is poor. When the particle size of TiC is nanoscale, the morphology of the reinforcement phase TiC is mainly granular and thin rods, which is uniform in the coating and the direction of growth is regular. When the concentration of TiC reaches 20%, the microstructure of the cladding layer grows well and is dense. The microhardness and wear resistance of the coatings prepared by adding nano TiC are better than those of the coatings prepared by micron TiC. When the content of nano TiC in the coatings increases from 10% to 20%, the microhardness and wear resistance of the coatings are obviously improved. The residual stress of the coating is positively related to the crack rate. The residual stress in the coating is tensile stress, and the crack type is the crystal crack in the hot crack. When the particle size of TiC is small and the concentration is high, the coating shows better corrosion resistance.
关键词： TiAl alloy,TiC/TiAl composite coating,Laser cladding,Properties,Microstructure
更新于2025-09-23 15:21:21
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Comparison of the Physicochemical Properties of TiO2 Thin Films Obtained by Magnetron Sputtering with Continuous and Pulsed Gas Flow
摘要： In this paper, a comparison of TiO2 thin ?lms prepared by magnetron sputtering with a continuous and pulsed gas ?ow was presented. Structural, surface, optical, and mechanical properties of deposited titanium dioxide coatings were analyzed with the use of a wide range of measurement techniques. It was found that thin ?lms deposited with a gas impulse had a nanocrystalline rutile structure instead of ?brous-like anatase obtained with a continuous gas ?ow. TiO2 thin ?lms deposited with both techniques were transparent in the visible wavelength range, however, a much higher refractive index and packing density were observed for coatings deposited by the pulsed gas technique. The application of a gas impulse improved the hardness and scratch resistance of the prepared TiO2 thin ?lms.
关键词： optical properties,scratch resistance,thin ?lms,gas impulse magnetron sputtering,microstructure,hardness,surface properties,mechanical properties,TiO2
更新于2025-09-23 15:21:21
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Selected properties of laser cladding coatings shaped using Flow drill technology
摘要： The paper presents the investigations of selected chemical and mechanical properties as well as macro- and microstructure of materials formed using thermal drilling process (Flow drill). The aim of this study was to determine the microstructure of the coatings produced using laser cladding with powder technology. The coatings were produced on the low-carbon steel using 1 kW disc laser. After modification of surface, the thermal drilling process was applied. To produce all coatings, the pure copper powder was used. In this study the laser power equal of 500, 700 and 900 W were used. The microstructure, chemical composition (EDS) and microhardness were investigation. It was found that the surface modification of low carbon steel and next conducted thermal drilling process caused change the surface properties on the hole flange. It was found that surface modification of steel using laser cladding with cooper powder and next Flow drill process contributes to the change in microhardness and chemical composition on hole flange.
关键词： microhardness,microstructure,laser cladding,chemical composition,Flow drill technology
更新于2025-09-23 15:21:21
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Laser polishing of additively manufactured Ti-6Al-4V: Microstructure evolution and material properties
摘要： Laser polishing of metals consists of irradiating the part’s surface with a laser beam, thus generating a molten layer that is redistributed and resolidified to create a surface with reduced roughness. However, the process is also characterized by an instantaneous formation of heat-affected zones with consequent microstructural changes that influence the mechanical properties. In order to understand the microstructural evolution during laser polishing of Ti-6Al-4V laser-based powder bed fusion samples, a thermal model is applied in the current study to predict the dimensions of the melted zones and the heat-affected areas. Furthermore, the results obtained through simulations are discussed and compared to the experimental data, thereby establishing the validity of the process models. Finally, the experimental studies also include the evaluation of material hardness and residual stresses after laser polishing.
关键词： laser polishing,thermal model,material properties,additive manufacturing,microstructure evolution
更新于2025-09-23 15:21:01
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Photovoltaic Characteristics of CH3NH3PbI3 Perovskite Solar Cells Added with Ethylammonium Bromide and Formamidinium Iodide
摘要： Photovoltaic characteristics of solar cell devices in which ethylammonium (EA) and formamidinium (FA) were added to CH3NH3PbI3 perovskite photoactive layers were investigated. The thin films for the devices were deposited by an ordinary spin-coating technique in ambient air, and the X-ray diffraction analysis revealed changes of the lattice constants, crystallite sizes and crystal orientations. By adding FA and EA, surface defects of the perovskite layer decreased, and the photoelectric parameters were improved. In addition, the highly (100) crystal orientations and device stabilities were improved by the EA and FA addition.
关键词： perovskite solar cells,ethlammonium,microstructure,formamidinium
更新于2025-09-23 15:21:01
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Densification behavior, microstructure evolution, and tensile properties of selective laser melting additive manufactured TiB <sub/>2</sub> /AlSi10Mg composite
摘要： The fabrication of TiB2/AlSi10Mg composites by selective laser melting (SLM) additive manufacturing has been conducted. The influence of laser processing parameters on the densification behavior, microstructure evolution, and tensile properties of the SLM-processed composites is addressed. With the increase in laser volume energy density, the densification rate increased and reached 99% at a laser speed of 1000 mm/s. Meanwhile, the TiB2 particles underwent a partial melting behavior with the formation of an irregular pattern in the solidified part and complete melting with the smooth surface of the reinforcing particles as the laser volume energy increased. The cellular-dendritic microstructure and the width of the eutectic phase of the as-fabricated composites were significantly refined due to the high cooling rate and complete melting of the reinforcing particles as the nucleation sites using the laser energy density of 117 J/mm3. Therefore, the micro-hardness, ultimate tensile strength, yielding strength, and elongation of the as-fabricated TiB2/AlSi10Mg composites obtained in this process condition were 131.3 HV0.2, 375 MPa, 260 MPa, and 3.1%, respectively, which were significantly higher than those of the unreinforced AlSi10Mg alloy.
关键词： tensile properties,aluminum-based composite,selective laser melting,microstructure evolution
更新于2025-09-23 15:21:01
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Comparative Study on Microstructure and Aluminum Distribution Between Laser Beam Welding and Electron Beam Welding of Tia??6Ala??4V Alloy Plates
摘要： Ti–6Al–4V alloy plates with a thickness of 4 mm were joined by electron beam welding (EBW) and laser beam welding (LBW). The comparison of LBW and EBW was performed according to grain morphology, microstructure, aluminum distribution, and microhardness of the joints. Results indicate that compared with LBW joint, more equiaxed grains are observed around the central zone of the EBW joint. The microstructure in fusion zone (FZ) of EBW joint presents more uneven with obviously coarser acicular martensite α′. Moreover, the aluminum element content of EBW joint is substantially lower, which demonstrates a more significant burning loss behavior in EBW process. The lower aluminum content in the upper center areas of the joints is attributed to the more significant element burning loss caused by higher temperature, whereas more uniform aluminum distribution in the upper part of the joints is ascribed to stronger convection form within the upper part of the joint. In addition, the characteristics of convection and thermal field within the molten pool are recognized as vital factors influencing the aluminum distribution. The lower microhardness profile in FZ of the EBW joint is principally attributed to coarser acicular martensite α′ and lower aluminum element in EBW joint.
关键词： Electron beam welding,Microhardness,Microstructure,Burning loss,Titanium alloy,Laser beam welding
更新于2025-09-23 15:21:01
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Effect of laser parameters on microstructure and phase evolution of Ti-Si-C composites prepared by selective laser melting
摘要： In this paper, blended Ti/SiC powder was processed by selective laser melting (SLM) method to prepare a novel kind of Ti-Si-C composite. Microstructure, elements distribution and phase evolution of Ti-Si-C composites fabricated by SLM were studied. SEM, EDS, TEM and XRD were performed to evaluate the microstructure and phase evolution during the SLM process. The results showed that processing parameters significantly affected the microstructure and element distribution of the samples. It was found that higher laser energy density could promote the densification process and hence suppress balling phenomenon of Ti-rich phases. At the micro-level, the microstructure could be classified into the dense area and the porous area, which was closely related to the redistribution of elements. The phases obtained by the SLM process were composed by TiCx, TiSi2, Ti5Si3, and Ti5Si4, which appeared in different microstructures. The results indicated that composites with different phases and microstructure could be obtained by merely modifying laser processing parameters, which could give experimental guidance for the fabricating of gradient Ti-Si-C composites by selective laser melting without additional apparatus on powder feeding.
关键词： Microstructure evolution,Phase evolution,Ti-Si-C composite,Selective laser melting
更新于2025-09-23 15:21:01