Energy Dispersive Microscopy Research Articles

Zn22Al4Ag ALLOY MICROWIRES CASTING TO RAPID SOLIDIFICATION PROCESS BY ROTATING DRUM

In this work, the Zn22Al4Ag alloy was synthesized by melting in a muffle furnace.The alloy obtained was characterized by Scanning Electron Microscopy Energy Dispersive Spectroscopy and was analyzed by the X-Ray Diffraction technique, where the crystallinity of the material was verified before and after being processed. Likewise, the Differential Scanning Calorimetry technique was used to obtain the temperatures where phase transformations occurin the alloy. These results were fed to the Termocalc®, software to numerically obtain the phase diagram of the alloy. Subsequently, a section of the ingot was taken to the rapid solidification process by rotating drum. The process variables were manipulated: jet stability, nozzle diameter, distance from the nozzle surface to the cooling medium, the delay time of the molten material in the crucible, speed of the rotating drum and jet angle, until obtaining a microwire with a diameter of ~ 160µm. Finally, it was determined that inadequate control of these parameters can result in powders, flakes or blockage of the crucible outlet. Potentially uses within the micro and nanoworld as an analogy to structural elements and electrical conductors, in addition to its current use as a coating anti-corrosive. Key Words: ZnAlAg alloy, Melt spinning process, Microwire, DSC analysis, Thermodynamic simulation

Comparative evaluation of remineralising and adsorption properties of regular cow milk and A2 milk using human enamel discs and hydroxyapatite discs

Depending on the frequency and type of intake, milk can affect caries formation by virtue of its demineralisation- remineralisation properties. The effect of A2 milk on human dentition is still unexplored. Hence,the aim of the present study was to evaluate and compare the remineralising and adsorption properties of regular cow milk and A2 milk using Human Enamel discs and Hydroxyapatite(HA) discs in an in-vitro model. Materials and methods: To evaluate the remineralising properties of milk, 24 human enamel discs and 24 Hydroxyapatite(HA) discs were divided equally into two different milk groups. Subsurface carious lesions were created and they were subjected to remineralisation-demineralisation cycles using twenty-one-day pH-cycling model. Baseline, post-demineralisation and post-remineralisation differences between the groups were studied by microhardness test (Vicker’s Indenter) and surface roughness test (profilometer). Ca:P ratio of the subtrates was analysed using Scanned Electron Microscopy Energy Dispersive X-Ray (SEM-DEX) analysis of five HA discs, out of which two were treated with the different milk types and the remaining three with different controls. Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) based analysis, followed by densitometric evaluation was performed to examine the adsorption of caseins from the two milk types on HA discs.

Effect of multiple dissimilar nanoparticles in Ni–W alloy matrix composite coating and evaluation of surface-mechanical, corrosion, and hydrophobic properties

TiO2 and ZrO2 nanoparticles reinforced Ni–W-based composite coatings were prepared on mild steel substrate via pulse electrodeposition technique under constant operating parameters. During the deposition process, TiO2 content was maintained constant throughout the process whereas, ZrO2 content has been varied. Phase evolution, microstructure, and compositional changes of coatings were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive microscopy, respectively. Microhardness and wear tests were conducted on composite coatings to evaluate the surface mechanical properties. The corrosion behaviour of the composite coatings was studied by potentiodynamic polarization and electrochemical impedance spectroscopy in a 3.5% NaCl solution. The topography of certain composite coatings has been examined by an atomic force microscope (AFM). Besides, a wettability test was conducted to study the hydrophobic properties of composite coatings. Experimental results demonstrated that ZrO2 nanoparticle's addition under fixed TiO2 content in deposition bath play a crucial role to improve the surface-mechanical, corrosion, and hydrophobic properties of the coating. The maximum hardness (1074 HV0.05), wear and corrosion properties were observed in Ni–W-5g/L TiO2-15g/L ZrO2 composite coating.

Non-Invasive Assessment of PVA-Borax Hydrogel Effectiveness in Removing Metal Corrosion Products on Stones by Portable NMR.

The cleaning of buildings, statues, and artworks composed of stone materials from metal corrosion is an important topic in the cultural heritage field. In this work the cleaning effectiveness of a PVA-PEO-borax hydrogel in removing metal corrosion products from different porosity stones has been assessed by using a multidisciplinary and non-destructive approach based on relaxation times measurement by single-sided portable Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy—Energy Dispersive Spectroscopy (SEM-EDS), and Raman Spectroscopy. To this end, samples of two lithotypes, Travertine and Carrara marble, have been soiled by triggering acidic corrosion of some copper coins in contact with the stone surface. Then, a PVA-PEO-borax hydrogel was used to clean the stone surface. NMR data were collected in untreated, soiled with corrosion products, and hydrogel-cleaned samples. Raman spectroscopy was performed on PVA-PEO-borax hydrogel before and after cleaning of metal corrosion. Furthermore, the characterization of the dirty gel was obtained by SEM-EDS. The combination of NMR, SEM-EDS and Raman results suggests that the mechanism behind the hydrogel cleaning action is to trap heavy metal corrosion products, such as Cu2+ between adjacent boron ions cross-linked with PVA. Moreover, the PVA-PEO-borax hydrogel cleaning effectiveness depends on the stone porosity, being better in Carrara marble compared to Travertine.

Sewage sludge from Taxco de Alarcón wastewater treatment plant as substrate to cultivate Panicum maximum

The management and disposal of the sewage sludge (SS) generated by a wastewater treatment plant (WWTP) as part of the municipal wastewater (MWW) treatment process is one of the main socio-environmental issues faced by this type of system. Taxco de Alarcón, Guerrero, in southern Mexico has had a WWTP operating since 2016, and the SS disposal is a task that must be addressed by the WWTP. Thus, the aim of this work was to evaluate the growth capacity of Panicum maximum, also known as mombaza grass (MG), by using SS generated within the "Taxco de Alarcón wastewater treatment plant" as substrate. To do so, 4 g of MG seeds were scattered over 5 kg (dry basis) of SS. As a control, a commercial compost soil was used, hereafter called pattern soil (PS). The experiment was carried out in triplicates for three months and drinking water (water used for human consumption) was used for crop irrigation. Each month a MG harvest was carried out. The response variables analyzed for MG were germination time (one month after plant emergence), height (HMG), growth rate GrMG, and yield (YMG), whereas in the SS and PS the content of organic matter was analyzed. Furthermore, the chemical composition was analyzed using scanning electron microscopy and X-ray energy dispersion spectroscopy (SEM-EDS) on the MG, SS, and PS. The results showed that MG germinated faster on PS (5 days) than germination on SS (7 days). However, the MG grown on SS reached a considerably higher height (45 cm) compared to the height reached on PS (17 cm). Furthermore, the maximum GrMG over SS was also higher than the maximum GrMG observed on the PS, 3.64 and 1.40 cm∙day-1, respectively. In terms of YMG, it was observed that on SS it reached an average monthly YMG of 416 g∙m-2, whereas in PS it reached a YMG of 72 g∙m-2. The chemical analysis detected P, K, Ca, Mg, and S, considered macronutrients in both substrates. Besides, some micronutrients identified in SS were Cu, Fe, Mn, and Zn, whereas in PS it was also possible to detect micronutrients except Mn and Zn. All the macronutrients detected in the substrates were observed in the harvested MG. However, in the MG harvested in PS, Mn and Zn were not detected. Hence, a feasible disposal strategy for the SS generated by the Taxco de Alarcón WWTP is as a substrate for grass forage MG by its high organic matter content, the significant presence of macro and micronutrients, and the performance shown by MG cultivated in SS. Furthermore, the SS characteristics provide added value and can be considered as organic amendments of agricultural soils.

ОЦЕНКА ДЕФЕКТОВ ПОВЕРХНОСТИ ИЗДЕЛИЙ С ПОМОЩЬЮ ЦИФРОВЫХ ТЕХНОЛОГИЙ

The suggested approach provides an opportunity under the conditions of enterprises to give a comprehensive view of products defects and functional coatings imperfections. The application of the computer program developed in the Microsoft Visual Studio environment, which allows digital image processing of the studied surfaces to estimate the area of external defects of materials, regardless of the nature of the origin of defects and the method of image acquisition, is proved.
 Research methods. Digital images of metal surfaces and coatings obtained by energy dispersive microanalysis, electron and optical microscopy have been tested.
 Research results and novelty. The possibility of using the program for evaluation of surface bands with local chemical and morphological inhomogeneities, determination of the porosity of materials is shown. The possibility of express evaluation of digital images of objects at macro-, meso- and microstructural levels for automated diagnostic control of surface defects within 1-2 seconds is implemented. Disaggregation of brightness, texture and color components of the image significantly increases the speed and efficiency of image processing structures.
 Conclusions: The proposed program is versatile, does not require special user skills and serves as a convenient tool for analyzing and controlling the quality of objects of various physico-chemical nature. The results of the study indicate that the application of the developed computer program makes effective quantitative calculation of the area of local defects, areas of distribution of chemical elements, various inclusions, surface porosity of products and coatings possible.

Electrochemical and biological behaviour of near β Titanium alloy for biomedical implant applications

Pulsed laser deposition technique (PLD) is one of the methods to coat hydroxyapatite on near beta titanium alloys (Ti-13Nb-13Zr) implants which are used in orthopaedics and dentistry applications. In this study, Hydroxyapatite (HA) ceramics in the form of calcium phosphate (Cap) were deposited on nearβ Titanium alloys (Ti-13Nb-13Zr) by the pulsed laser deposition method. The coated thin film was characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) with Energy dispersive spectroscopy (EDS) and atomic microscopy (AFM). The corrosion studies were carried out coated and uncoated samples using potentiodynamic polarisation studies in simulated body fluid (Hanks’ solution). The bioactivity of the Hap-coated samples on nearβ Titanium alloys was evaluated by immersing them in simulated body fluid (SBF) for nine days. XRD and EDS analysis confirmed the presence of hydroxyapatite. The corrosion studies showed that the treated samples have better corrosion resistance compared to uncoated substrates. The formation of apatite on treated samples revealed the bioactivity of the Hap-coated substrates. HA-coated nearβ Titanium alloys provide higher corrosion protection than substrates, which can be used for biomedical implant applications.

Study on long-term thermochemical thermal storage performance based on SrBr2-expanded vermiculite composite materials

Strontium bromide hexahydrate (SrBr2·6H2O) is one of the most promising storage materials of thermochemical energy storage for space heating. In this study, four different SrBr2/expanded vermiculite composites (SrBr2/EVMs) were prepared by the impregnation method. After that, the micro and macro-structural characteristics of those composites were characterized by Scanning Electron Microscopy (SEM) and X-ray Energy Dispersive Analysis (EDX). Moreover, the composites’ dynamical desorption behaviors were tested by Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Meanwhile, the composites’ dynamical adsorption behaviors were investigated in a constant temperature and humidity chamber. Lastly and most importantly, the kinetic models for the adsorption and desorption processes of SrBr2·6H2O were first deduced based on the above experimental data. The results showed that the carrying capacity of SrBr2/EVM composite linearly increased with the concentration of SrBr2 solution. And the composite can likely achieve a higher water uptake amount and better adsorption performance than pure salt. However, the composite loaded with more salt would deliquesce at high humidity and reduce the adsorption performance. It was found that SrBr2·6H2O in the composite could be well desorbed and achieve a reaction enthalpy as high as 644.9 J/g. The developed conversion rate function can reasonably predict the hydration reaction of SrBr2. Besides, six different kinetic equations of the solid-state decomposition were established to calculate the desorption reaction. The findings are useful to the design and operation of the thermochemical energy storage system with SrBr2·6H2O.

Introduction of Chalcogenide Glasses to Additive Manufacturing: Nanoparticle Ink Formulation, Inkjet Printing, and Phase Change Devices Fabrication

Chalcogenide glasses are one of the most versatile materials that have been widely researched because of their flexible optical, chemical, electronic, and phase change properties. Their application is usually in the form of thin films, which work as active layers in sensors and memory devices. In this work, we investigate the formulation of nanoparticle ink of Ge–Se chalcogenide glasses and its potential applications. The process steps reported in this work describe nanoparticle ink formulation from chalcogenide glasses, its application via inkjet printing and dip-coating methods and sintering to manufacture phase change devices. We report data regarding nanoparticle production by ball milling and ultrasonication along with the essential characteristics of the formed inks, like contact angle and viscosity. The printed chalcogenide glass films were characterized by Raman spectroscopy, X-ray diffraction, energy dispersive spectroscopy and atomic force microscopy. The printed films exhibited similar compositional, structural, electronic and optical properties as the thermally evaporated thin films. The crystallization processes of the printed films are discussed compared to those obtained by vacuum thermal deposition. We demonstrate the formation of printed thin films using nanoparticle inks, low-temperature sintering and proof for the first time, their application in electronic and photonic temperature sensors utilizing their phase change property. This work adds chalcogenide glasses to the list of inkjet printable materials, thus offering an easy way to form arbitrary device structures for optical and electronic applications.

Evaluation of the hybrid system combining electrocoagulation, nanofiltration and reverse osmosis for biologically treated textile effluent: Treatment efficiency and membrane fouling

The efficiency of the hybrid electrocoagulation–nanofiltration–reverse osmosis (EC–NF–RO) system for the treatment of biologically treated textile effluent was investigated. The treatment performances and membrane fouling behaviours of nanofiltration (NF) and hybrid EC–NF systems were compared. EC process was evaluated concerning mitigate the membrane fouling and increasing the removal efficiencies. Besides, the treated wastewater with the hybrid EC–NF process was finally processed using RO process for reuse purpose in the textile industry. The EC treatment was applied using Fe and Al electrodes at various conditions; pH:4–10, current density:0.5–17 mA/cm2 and operating time:30–180 min. Fe electrode showed better performance in terms of higher removal efficiencies (76% COD, 96% DFZ436), lower energy (21.1 kWh/m3) and electrode consumptions (3.7 kg/m3) for the optimum conditions. Scanning Electron Microscopy–Energy Dispersive Index (ESEM-EDX) and Fourier–Transform Infrared Spectroscopy (FTIR) analyses were carried out for EC sludge samples obtained with Fe and Al electrodes. Desal 5 DL and NF 270 membranes were tested in terms of removal efficiency and membrane fouling for NF and hybrid EC–NF process of textile wastewater. Membrane fouling was evaluated with flux values, resistance-in-series model results as well as Atomic Force Microscopy (AFM), FTIR and contact angle measurements. NF 270 membrane achieved better chloride (28%) and conductivity (41%) removal efficiencies for NF treatment. EC pretreatment did not result in any noticeable improvement in rejections except for chloride (48%) and conductivity (59%) for the hybrid EC–NF process with NF 270. The ratios of Rc decreased to 40% for NF 270 and 42% for Desal 5DL after EC pretreatment. NF270 membrane indicated high permeate flux and low membrane fouling considering cake resistance distribution, surface roughness, hydrophilicity and chemical structure variation. >93% COD, 99% conductivity, 97% chloride, and 91% TDS removal efficiencies were obtained with the hybrid EC–NF–RO process. Finally, the obtained high quality water by RO after the EC + NF 270 hybrid process could be used for all textile finishing process.

WITHDRAWN: Effect of bonding time and boron carbide percentage on diffusion bonding characteristics for copper/copper matrix composites (Cu + Cu%B4C)

Abstract In this study, the Joining characteristics of pure copper (Cu) and copper matrix composites reinforced by 2.5, 5.0, 7.5 wt% of Boron Carbide (B4C), were investigated. The diffusion bonding (DB) process was prepared at a temperature of 800 °C, and different holding times of 30, 45, and 60 min. During DB, a uniaxial load of 2 MPa was applied. The dissimilar materials joining quality was studied to determine the influences of diffusion time and B4C particulates on bonding properties. Scanning electron microscopy SEM assays and energy dispersion spectrophotometry EDS element analyzes were performed to determine joint interface properties and to determine mechanical characterization with shear strength SS measurements.

Effects of addition of Titanium Diboride and Graphite Particulate Reinforcements on Physical, Mechanical and Tribological properties of Al6061 Alloy based Hybrid Metal Matrix Composites

ABSTRACT The present study is aimed at fabricating and determining the physical, mechanical, and tribological properties of Al6061 alloy reinforced with Titanium Diboride and Graphite particles. The different weight percentages of hybrid particles (Titanium Diboride – Graphite) dispersed in the Al6061 matrix for fabricating hybrid metal matrix composites (HMMCs) using a stir casting method. The amount of titanium diboride reinforcement addition in the Al6061 matrix was in the range from 0 to 6 wt% whereas the fixed graphite reinforcement of 4 wt% was added. Optical Microscopy, Scanning Electron Microscopy and Energy Dispersive Microscopy studies were used to investigate the microstructure of the developed composite materials. The uniform distribution of reinforcement particulates in the matrix was observed. The addition of particulate reinforcements results in the enhancements of the mechanical properties such as density, hardness, with the expense of elongation. The tribological dry sliding wear experiments were carried out using a pin-on-disc tribometer. The Al6061-6%TiB2-4%Gr HMMCs reinforced composites exhibited the highest hardness and ultimate tensile strength and the lowest percentage elongation. Also, Al6061-6 percent TiB2-4%Gr samples had the best wear resistance. The increase in bonding by adding the optimum weight percentages of hybrid particles in the matrix could be the reason for this. The pristine Al6061 matrix exhibited the opposite trend.

Experimental study on microstructural evolution, mechanical property, and corrosion behaviour of laser additive manufactured (LAM) titanium alloy grade 5

Additive manufacturing technique has become one of the more prominent manufacturing techniques over the years. The applications of this manufacturing technique are boundless as new process parameters of the operation affect the new structure of the components and give extended applications. The study experimentally investigates the effects of Ytterbium Laser System process parameters on the resultant microstructure of Ti-6Al-4V grade 5 alloy and reinforcement powders. The deposition process was conducted employing a 3 kW (CW) Ytterbium Laser System (YLS-2000-TR) machine, co-axial to the reinforcement powder. The laser scanning speed and power were varied between the intervals of 0.8–1.0 m/min and 900–1000 W. All other parameters kept constant were the rate of gas flow, the spot diameter, and the rate of powder flow. The composites (Ti-6Al-4V/Ti-Al-Si-Cu) produced by the DLMD technique were analysed using investigative techniques, namely, optical microscopy (OPM), scanning electron microscopy (SEM) aided with energy dispersive microscopy (EDS), X-ray diffraction analysis (XRD), microhardness testing, and corrosion rate analysis. From the analysis of the physical properties, the findings show that the geometric properties such as heat affected zone (HAZ) and dilution ratio of the composite samples were greatly impacted by the increase of the laser power of the DLMD technique, showing an increase in these attributes brought about by the interaction between the laser and the material. The addition of the copper (Cu) element enabled the movement of the copper (Cu) into the titanium (Ti) lattice structure resulting in the formation of beta titanium (β-Ti) microstructure. Increment 54.94% is associated with sample 5A which has the most enhanced microhardness of 770 HV1.0. Sample 6A had shown the most corrosion resistance improvement with 0.00062 mm/year equivalent to 31%.

Carbon-based cathodes degradation during electro-Fenton treatment at pilot scale: Changes in H2O2 electrogeneration

Autopsy of carbon-PTFE cathodes was performed by addressing their degradation in a commercial plate-and-frame cell equipped with a Nb-BDD anode. Cell is arranged within an electrochemical pilot plant designed for treating wastewaters by electrochemical Fenton-like processes, thus an efficient electrocatalytic production of H2O2 is necessary to guarantee Fenton’s reaction. Significant decrease in H2O2 electrogeneration occurred during pilot plant operation, hindering the efficient performance of Fenton-like processes. Two cathodes were studied, first was operated at pH 3 and second at neutral pH by using EDDS as complexing agent to maintain iron in solution. Electrogenerated H2O2 decreased from 43 mg L−1 to 16 mg L−1 in the first cathode after 50 h of operation and from 49 mg L−1 to 24 mg L−1 in the second one after 26 h of operation. Both were cleaned with 30% (v/v) solution of HCl/water for 24 h and H2O2 production was recovered only in the second cathode (able to generate 39 mg L−1). Autopsy of the cathodes was tackled by scanning electron microscopy (SEM) and X-ray energy dispersive (EDX), evidencing a strong degradation of first cathode surface and iron oxide inlays in second one due to the decomposition of Fe3+:EDDS and consequent iron precipitation at neutral pH.

Efficient Photocatalytic and Antimicrobial Behaviour of Zinc Oxide Nanoplates Prepared By Hydrothermal Method

In this project, the prime focus was to synthesize zinc oxide nanoplates (ZnO-Nps) by a reliable, simple, and low cost facile hydrothermal method. Zinc acetate was used as major precursors; the synthesis was standardized in a 100 mL autoclave, at 180 °C for 24 h which results in nanoplates with 150–300 nm width and thickness 10–60 nm size and mesoporous nature with a specific surface area 126 cm2 g−1. The prepared sample was characterized by X-ray powder diffraction (XRPD), scaning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive microscopy (EDS), Fourior transfer infrared (FTIR) spectroscopy, X-ray photo electron microscopy (XPS), Brunauer–Emmett–Teller (BET), Photoluminance (PL), and Electrochemical impedance spectroscopy (EIS) techniques. For application purposes, photocatalytic and antimicrobial activities of ZnO-Nps were studied systematically. The material was made photo-active under visible light irradiation for the degradation of the Methyl orange dye in aqueous media. The antimicrobial activity of ZnO-Nps was checked by time kill method, presented the inhibition of growth against clinical isolates of Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli) after 24 h. However, 12.5 and 6.25 µg is minimal inhibitory concentration (MIC) and 25 and 12.5 µg minimal bactericidal concentration (MBC) of ZnO-Nps against MRSA and E. coli respectively.

Analisis Pola Struktur Kalsium Karbonat (CaCO3) Pada Cangkang Kerang Darah (Anadara granosa) Di Bukit Kerang Kabupaten Aceh Tamiang

Characterization of material on cockle shell has been wiped out the shells hills of the Bendahara district of Aceh Tamiang district, with the aim of knowing the basic content and diffraction patterns of the cockle shell to plain CaCO3 aragonite. The research method begins with sampling the cockle shell from the Kerang hill. Firstly, preparation cockle shell. Then, characterized by X-Ray Fluorescence (XRF) examining to work out the basic content within the cockle shell, then doing Scanning Microscopy Energy Dispersive X-Ray (SEM-EDX), and X-ray diffraction ( XRD) testing. The characterization leads to XRF testing showed that the content of the constituent elements of the CaCO3 compound was dominated by CaO of 98.93% at station I and at station II, CaO was obtained the maximum amount as 98.73%. In SEM analysis, the cockle shell have a rod-like morphological structure within the sort of aragonite crystals. The results of EDX at station I, obtained CaO elements is 58.18% and at station II CaO is 36.76%. The results of XRD analysis, the cockle shell have an aragonite phase with an orthorombic crystal structure. the very best phase that appears at 2θ at station I is 26,220, and station II is 26,280.

Assessment of the Corrosion Behavior of FeAl Based Intermetallics in NaCl Solution

The corrosion assessment of intermetallic based-FeAl alloys with Ag and Li (3 at. %) produced by casting in induction furnace was realized. The corrosion study of intermetallic alloys immersed in a NaCl aqueous dissolution was done by electrochemical characterizations using the cyclic voltammetry and electrochemical impedance spectroscopy techniques. According to the results of the microstructural characterization, the base alloy was composed for the Fe3Al minority phase homogeneously distributed in the FeAl matrix phase. Additionally, the addition of Li and Ag promoted the modification of microstructure morphology and the quantity of the observed minority phase. The CV results showed an active oxidation behavior and a partially passive region between the oxidation potential values. The EIS results suggest the presence of an active corrosion behavior associated with a localized corrosion mechanism. The electrochemical results were complemented by microstructural and chemical characterization by the use of scanning electron microscopy and X-ray energy dispersion.

Aluminide Thermal Barrier Coating for High Temperature Performance of MAR 247 Nickel Based Superalloy

In this paper, mechanical properties of the as-received and aluminide layer coated MAR 247 nickel based superalloy were examined through creep and fatigue tests. The aluminide layer of 20 µm was obtained through the chemical vapor deposition (CVD) process in the hydrogen protective atmosphere for 8 h at the temperature of 1040 °C and internal pressure of 150 mbar. A microstructure of the layer was characterized using the scanning electron microscopy (SEM) and X-ray Energy Dispersive Spectroscopy (EDS). It was found that aluminide coating improve the high temperature fatigue performance of MAR247 nickel based superalloy at 900 °C significantly. The coated MAR 247 nickel based superalloy was characterized by the stress amplitude response ranging from 350 MPa to 520 MPa, which is twice as large as that for the uncoated alloy.

Люминесцентные свойства коллоидных квантовых точек Ag-=SUB=-2-=/SUB=-S для фотокаталитических приложений

The structural and optical properties of colloidal Ag2S quantum dots in various environments are investigated. With the help of transmission electron microscopy, X-ray diffraction and X-ray energy dispersion analysis, the formation of colloidal Ag2S quantum dots with an average size of 2-3 nm with a monoclinic crystal lattice, and Ag2S/SiO2 core-shell systems based on them, has been established. The change in the luminescence quantum yield of quantum dots with the change of the surface environment state is shown. The decoration of TiO2 nanoparticles of 10-15 nm in size with Ag2S quantum dots was performed and the influence of the structure of the interfaces of quantum dots and their environment (2-mercaptopropionic acid, water, ethylene glycol, SiO2 dielectric shell with a thickness of 0.6 nm and 2.0 nm) on the formation of TiO2-Ag2S heterosystems was analyzed. For Ag2S quantum dots passivated with 2-mercaptopropionic acid, signs of charge phototransfer after adsorption on TiO2 nanoparticles surface have been established. Signs of reactive oxygen species appearance due to charge phototransfer in heterosystem are enstablished, based on methylene blue photobleaching under excitation of heterosystem outside of TiO2 fundamental absorption region,

Synthesis and Characterization of Nano-TiO2 using Aqueous Extract of Erythrina variegata Leaves

In present work, the Erythrina variegata leaves extract acts as a reducing agent for the green synthesis of titanium dioxide (TiO2) nanoparticles. The characterization of the extracted TiO2 nanoparticles were confirmed by ultraviolet spectral studies (UV-Vis), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDAX) and scanning electron microscopy (SEM). The UV-Vis absorption spectrum exhibited maximum absorbance peak at 317.6 nm,w hich supports the formation of TiO2 nanoparticles. The optical band gap energy value has been determined as 2.35 eV. Further characterization by XRD supports the crystallinity and the incidence of peak at 25.28 ºC corresponds to 101 anatase form. The anatase phase TiO2 sample having tetragonal structure with mean crystalline size was found to be 7.91 nm. Scanning electron microscope image supports the shape of the nanoparticles. These nanoparticles are having effective dye degradation ability with various time intervals. The green synthesized TiO2 nanoparticles exhibits interesting photocatalytic efficacy on methylene blue dye under UV irradiation (using multi-lamp photo reactor) and antibacterial activity against pathogenic organisms like Streptococci, Staphylococci, E. coli and Pseudomonas aeruginosa.