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Microstructural Evolution and Microhardness of Direct Laser Clad TiC Dispersed Titanium Aluminide (Ti45Al5Nb0.5Si) Alloy
摘要： In the present study, the effect of TiC additions (10 wt.% and 20 wt.%) on the microstructure and microhardness of direct laser clad Ti45Al5Nb0.5Si based titanium aluminide alloy has been undertaken. Direct laser cladding has been conducted using a high power (3 kW) fiber optic delivered Nd:YAG laser (with a beam diameter of 2 mm) using a 3-axis handling system in a layer by layer fashion to on Ti-6Al-4V substrate to develop a coupon with a dimension of 10 mm x 10 mm x 5 mm. Addition of TiC leads to formation of defect free microstructures under varied parameters, except a few processing conditions. There is formation of complex carbides (Ti2AlC, Ti3AlC2 and Ti2AlC) in addition to TiC phase in the microstructure of duplex phase. There is improvement in microhardness due to TiC addition, which increases with increased quantity of TiC. Laser power and scan speed influences the microhardness, however, powder feed rate did not influence it significantly.
关键词： microstructure,XRD,microhardness,titanium carbide,Titanium aluminide
更新于2025-09-12 10:27:22
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Structural and optical study of CZTS-reduced graphene oxide composite towards photovoltaic device application
摘要： The deficit in obtaining targeted photo conversion efficiency for (Cu2ZnSnS4) CZTS based photovoltaic cell results either from insufficient photo charge carrier generation or e-/h+ pair transportation towards the end of electrodes, which lowers the device Voc and Jsc. On this regard, semiconducting absorber material merged with highly mobile reduced graphene oxide (rGO) as filler form a bridging network within active layer facilitates both improvement in charge carrier separation as well as transportation to electrodes before recombination occurs. A simple solution casting approach for CZTS nanoparticle anchored rGO composite for photovoltaic device application is reported here. The presence and distribution of CZTS nanoparticles over the surface of rGO sheet is confirmed from XRD, Raman, SEM and UV-Visible analysis.
关键词： Raman,XRD,Cu2ZnSnS4 (CZTS),reduced graphene oxide (rGO),SEM,Photovoltaic device
更新于2025-09-12 10:27:22
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Characterization of TiO2 photoanodes and natural dyes (Allamanda Blanchetti and Allamanda Cathartica) extract as sensitizers for dye-sensitized solar cell applications
摘要： In the present work, Dye-Sensitized Solar Cells (DSSC) were fabricated using fabricated TiO2 photoanodes and natural dyes (Allamanda Blanchetti (AB) and Allamanda Cathartica (AC)) as the sensitizers. Initially, TiO2 nanoparticles were synthesized by sol–gel technique and a thin ?lm of TiO2 was formed on the FTO substrate by Doctor Blade technique. Then, they were annealed at 400, 500, and 600 °C to act as the photoanode. X-ray diffraction analysis shows the prepared samples have tetragonal crystal structure with anatase and rutile phase. The average crystallite size was found to be 10–17 nm when the annealing temperature (TA) was increased from 400 to 600 °C. From UV–DRS analysis, the percentage of re?ectance was found to starts at 315 nm. The bandgap analysis shows the transitions were indirect allowed and the bandgap value decreases from 3.6 to 2.8 eV when the TA increases from 400 to 600 °C. From the optical absorption spectra, the absorption of dye and dye-sensitized TiO2 was found to be in the visible region. From PL analysis, the emission peak intensity of Ti4+ ?) vacancies with TA increases from 400 to 600 °C was noted. FESEM analysis shows the synthesized particles were spherical and from EDS the presence of Ti and O was con?rmed. From FTIR analysis, the functional groups presented in the prepared extracts were con?rmed. The Ef?ciency of DSSC was found to be 1.16 and 0.30% for AB sensitized TiO2 (400 °C) and AC sensitized TiO2 (400 °C) as photoanodes. From Electrochemical Impedance Spectroscopic (EIS) analysis, DSSC with AB + TiO2 shows low charge transfer resistance compared with AC + TiO2.
关键词： TiO2,Bandgap,Electrical measurements,XRD,Natural Dye,DSSC
更新于2025-09-12 10:27:22
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Fabrication of Interconnected Plasmonic Spherical Silver Nanoparticles with Enhanced Localized Surface Plasmon Resonance (LSPR) Peaks Using Quince Leaf Extract Solution
摘要： Interconnected spherical metallic silver nanoparticles (Ag NPs) were synthesized in the current study using a green chemistry method. The reduction of silver ions to Ag NPs was carried out with low-cost and eco-friendly quince leaves. For the first time, it was confirmed that the extract solution of quince leaves could be used to perform green production of Ag NPs. Fourier transform infrared spectroscopy (FTIR) was conducted to identify the potential biomolecules that were involved in the Ag NPs. The results depicted that the biosynthesis of Ag NPs through the extract solution of quince leaf was a low-cost, clean, and safe method, which did not make use of any contaminated element and hence, had no undesirable effects. The majority of the peaks in the FTIR spectrum of quince leaf extracts also emerged in the FTIR spectrum of Ag NPs but they were found to be of less severe intensity. The silver ion reduction was elaborated in detail on the basis of the FTIR outcomes. In addition, through X-ray diffraction (XRD) analysis, the Ag NPs were also confirmed to be crystalline in type, owing to the appearance of distinct peaks related to the Ag NPs. The creation of Ag NPs was furthermore confirmed by using absorption spectrum, in which a localized surface plasmon resonance (LSPR) peak at 480 nm was observed. The LSPR peak achieved in the present work was found to be of great interest compared to those reported in literature. Field emission scanning electron microscopy (FESEM) images were used to provide the morphology and grain size of Ag NPs. It was shown from the FESEM images that the Ag NPs had interconnected spherical morphology.
关键词： FESEM study,FTIR study,XRD analysis,UV–Vis absorption,quince leave,silver nanoparticles
更新于2025-09-12 10:27:22
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Stress-controlled decomposition routes in cubic AlCrN films assessed by in-situ high-temperature high-energy grazing incidence transmission X-ray diffraction
摘要： The dependence of decomposition routes on intrinsic microstructure and stress in nanocrystalline transition metal nitrides is not yet fully understood. In this contribution, three Al0.7Cr0.3N thin films with residual stress magnitudes of ?3510, ?4660 and ?5930 MPa in the as-deposited state were in-situ characterized in the range of 25–1100 °C using in-situ synchrotron high-temperature high-energy grazing-incidence-transmission X-ray diffraction and temperature evolutions of phases, coefficients of thermal expansion, structural defects, texture as well as residual, thermal and intrinsic stresses were evaluated. The multi-parameter experimental data indicate a complex intrinsic stress and phase changes governed by a microstructure recovery and phase transformations taking place above the deposition temperature. Though the decomposition temperatures of metastable cubic Al0.7Cr0.3N phase in the range of 698–914 °C are inversely proportional to the magnitudes of deposition temperatures, the decomposition process itself starts at the same stress level of ~?4300 MPa in all three films. This phenomenon indicates that the particular compressive stress level functions as an energy threshold at which the diffusion driven formation of hexagonal Al(Cr)N phase is initiated, provided sufficient temperature is applied. In summary, the unique synchrotron experimental setup indicated that residual stresses play a decisive role in the decomposition routes of nanocrystalline transition metal nitrides.
关键词： thin films,AlCrN,phase decomposition,thermal expansion,microstructure,in-situ XRD,residual stress
更新于2025-09-12 10:27:22
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ZnO nano-sized particles preparation by laser ablation in liquids
摘要： In this paper, we used laser ablation in liquids to prepare ZnO nanoparticles. In our experiment, the pulsed laser was focused onto the Zn target submerged in water. We used di?erent laser energy to form the ZnO nanoparticles. The size, structure and photoluminescence spectra of ZnO nanoparticles were displayed by using XRD and AFM. The relationship between diameter of ZnO nanoparticles and laser energy was analyzed. In addition, we also studied the variation of photoluminescence spectra of ZnO nanoparticles with di?erent laser energy.
关键词： Laser ablation in liquids,XRD,ZnO nanoparticles,AFM
更新于2025-09-12 10:27:22
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Blue Luminescent Phosphor Sr <sub/>3</sub> Y <sub/>1?X</sub> (BO <sub/>3</sub> ) <sub/>3</sub> : <sub/>X</sub> Bi <sup>3+</sup> for WLED Applications
摘要： The polycrystalline powder sample of Bi3+-activated strontium yttrium borate phosphor Sr3Y1?x(BO3)3:xBi3+ (x = 3, 4, 5 mole%) is prepared by solution combustion technique. Formation of phosphor in the desired crystalline phase is con?rmed by powder X-ray di?raction characterization and FTIR, SEM images of the synthesized phosphor show the irregular grains with average particle size 2.5 μm. Luminescence properties of the synthesized phosphor are investigated at room temperature. The excitation spectrum consists of a single broad absorption band from 200 to 370 nm with the prominent excitation peak at 336 nm [1S0 to 3P1 of Bi3+ ions] and weak excitation peak at 254 nm [1S0 to 1P1 of Bi3+ ions]. Strongest emission peak of 492 nm wavelength that is of blue light is observed at 336 nm UV light excitation. Sr3Y1?x(BO3)3:xBi3+ phosphor emits blue light. As Bi3+ is sensitive to the surrounding crystal ?eld environment it shows weak excitation peak at 254 nm, which gives emission at 413 nm. Hence, Sr3Y1?x(BO3)3:xBi3+ is new UV excited blue emitting phosphor useful for UV/blue chip WLEDs.
关键词： white light,photoluminescence,XRD,borate phosphor
更新于2025-09-11 14:15:04
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Precipitation of Silver Nanoparticles in Borate Glasses by 1064?nm Nd:YAG Nanosecond Laser Pulses: Characterization and Dielectric Studies
摘要： This work aims to present a modern process to synthesis nanoparticles in a glassy matrix. Borate glasses doped by silver nitrate (AgNO3) via the melt annealing technique were irradiated by a (1064 nm wavelength) Nd:YAG (Neodymium–doped Yttrium Aluminum Garnet) laser to yeild precipitation of silver nanoparticles (AgNPs) in borate glasses. The characterization of the irradiated glasses was investigated using ultraviolet/visible (UV/Vis.), x-ray diffraction (XRD), high resolution-transmission electron microscopy (HR-TEM), ?eld emission-scanning electron microscopy (FE-SEM), and dielectric properties. XRD patterns depict the presence of sharp diffraction peaks at 111 and 200 planes that can be attributed to the precipitated AgNPs in the borate glass sample after laser irradiation. A signi?cant change in color was observed within the borate glass after laser irradiation, which was attributed to the appearance of surface plasmon resonance and con?rmed the presence of AgNPs in the borate glass. The morphological properties and the distribution of the observed AgNPs inside the sample were performed via HR-TEM and FE-SEM. The behavior of dielectric constant and dielectric loss progressively decreased as the frequency increased. The values of AC conductivity increased as the temperature of the borate glass matrix increased.
关键词： Borate,UV/Vis.,Nd:YAG,dielectric properties,AgNPs,XRD,FE-SEM,HR-TEM
更新于2025-09-11 14:15:04
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Erbium doped anatase TiO2 nanoparticles for photovoltaic applications
摘要： Doping of rare earth metal erbium (Er) into the nanocrystalline titanium dioxide (TiO2) was identified to enhance the performance of photocatalytic and photovoltaic applications. Herein, TiO2 was doped with different concentrations of erbium through hydrothermal method and then employed to photocatalytic and photovoltaic applications. XRD, FT-IR, TEM, AFM, UV–visible DRS and photocatalytic measurements were carried out to examine the impact of erbium doping on TiO2. The photovoltaic study revealed that the Er doped TiO2 exhibited the better power conversion efficiency with high short-circuit current density (Jsc) and open-circuit voltage (Voc). This enhancement may be due to the reduced charge recombination, increased dye absorption ability and fast photoelectron injection.
关键词： TEM,Photovoltaic,XRD,FT-IR,Er doped TiO2,Photocatalytic
更新于2025-09-11 14:15:04
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Performance Enhancement of Chitosan Filled Silver Vanadate Nano-rods
摘要： Silver vanadate nanorods synthesized via chemical precipitation route at room temperature were characterized using UV/Vis. optical electronic spectra, fourier transform infrared (FTIR) spectroscopy, transmission and scanning electron microscopy (TEM, SEM), Zeta potential and X-ray diffraction (XRD). XRD indicates the presence of both β and α phases of silver vanadate. Chitosan samples filled with pre-calculated amounts of synthesized silver vanadate nano-rods were prepared via ordinary casting route. XRD of the prepared polymeric samples reveals amorphous nature and indicating a homogenous distribution of inorganic filler within the matrix without any tendency for crystallization. FTIR shows maintenance of chitosan characteristic bands in all samples. Optical energy gap for both direct and indirect transitions generally indicates a gradual decrease with increasing inorganic filler content. The biological activity against two-gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis), two gram-negative bacteria (Escherichia coli, Pseudomonas aeuroginosa) in addition to one fungus (Candida albicans) were also studied and correlated with both optical energy gap and nanoparticle dopant concentration.
关键词： UV/Vis.,Zeta Potential,Silver vanadate,FTIR,Chitosan,XRD
更新于2025-09-11 14:15:04