Advanced Materials Research Vol. 678

Abstract: Alloy nanostructures formed by magnetic and nonmagnetic components play a significant role in sensor applications due to their unique magnetic properties. In this study cobalt-silver nanomaterial has been synthesized by chemical reduction using sodium borohydride, though Co and Ag are immiscible according to their phase diagram. The materials prepared with different precursor compositions have been analysed to determine the structure and the magnetic properties. It is observed that the alloy samples show room temperature ferromagnetism. The surface morphology of the as prepared samples was studied from the SEM micrographs. This is a simple but an effective method to prepare magnetic Co-Ag nanomaterials in bulk quantities at room temperature.

Abstract: In the present study, the application for the removal of Nickel (II) ion from aqueous solution by using synthetic nano Fe3O4 with the average size of 20 nm was investigated by batch method, as a function of concentration, adsorbent dosage, contact time and pH. The equilibrium adsorption isotherm data are tested by applying both Freundlich and Langmuir isotherm models.

Abstract: The green synthesis is the versatile tool to produce the nano scale materials. The present study deals with the synthesis of gold nanoparticles using the Cassia auriculata flower extract. The complete reduction of gold ions was observed after 45 min of reaction under stirrer condition. The colour changes in reaction mixture (dark red colour) was observed during the reaction period because of the formation of gold nanoparticles in the reaction mixture enables to produce particular colour due to their specific properties (Surface Plasmon Resonance). The formation of gold nanoparticles was confirmed using UV visible spectroscopy, the size of the nanoparticles measured by using particle size analyzer. The morphology of the poly dispersed gold nanoparticles was studied using TEM, This green synthesis method is cost effective; and eco friendly technique to produce large scale production of Nanomaterials

Abstract: In this study, the phonon dispersion curve of dendrite-shaped lead telluride (PbTe), a nano structured material is obtained by shell model and the thermal parameters are calculated and compared with experimental results.

Abstract: Zinc tungstate is a scintillator material with excellent photocatalytic and photoluminescent properties. In the present study, fine sized ZnWO4 powders with monoclinic wolframate structure were prepared by chemical precipitation route assisted with polymer evaporation. DTA/TG and XRD were employed to investigate the thermal behaviour and crystallite size evaluation of ZnWO4 .The particle size and morphology of the powder heat treated at different temperature was observed and characterized by SEM. The FTIR spectrum has been used to study the stretching and bending frequencies of the ZnWO4. The result shows that the process provides a technically simple route for the precipitation of fine sized narrow particle distribution and free dense agglomerate ZnWO4 particles.

Abstract: Abstract Copper particles are prepared at room temperature using a simple chemical method. The method used is capable of giving high yields. In this method sodium borohydride is used as a reducing agent and poly vinly pyrrolidone (PVP) as a capping reagent. The prepared copper particles are characterized by X-ray diffraction method and Energy dispersive x-ray analysis (EDX). The scanning electron microscopy (SEM) images show the formation of dendrite like structures. The transmission electron microscope (TEM) studies also conform the formation of dendrite structures.

Abstract: The thin films of WO₃ were prepared on cleaned microscopic glass substrates by the electron beam evaporation technique. The films were coated at room temperature using pure WO₃ pellets as source. The prepared films were further post heat treated at different temperatures (100°C to 350°C) for about 1hr in air. The optical properties of WO3 thin films were studied in detail. The increase in the density of the film as the annealing temperature increases have been confirmed by the transmittance spectra. The film annealed at 250°C shows a strong photoluminescence peak. The peak intensity is found to be less for all other temperature. The observed results were discussed in terms of crystalline nature of WO₃.

Abstract: Hollow glass microspheres (HGMs) are a unique class of materials with interconnected pores in the microsphere walls, which can adsorb, retain and release hydrogen and other gases. In this study, HGMs was prepared from amber coloured and borosilicate glass frits. The glass frits after the preliminary washing and drying was sized to particles below 120 μm. The hollow glass microspheres were successfully fabricated from the glass powder by flame spheroidisation using air-acetylene flame. Effect of glass feed particle size as well as feed rate, in the formation of HGMs was studied. Glass feed particle size >75 μm and that <45 μm were found to give very poor yield of HGMs, whereas particles 50-75 μm gave very good yield for HGMs. Further study of the process parameters and constant monitoring to regulate the process are being carried out in our laboratory to arrive at a correct figure for the yield of HGMs. Characterisation of the HGMs prepared was done using Image analysing system, SEM, and XRD. The composition of the raw material and the product HGMs were determined using ICP-AES.

Abstract: Vanadium pentoxide thinfilms have been deposited by vacuum evaporation method and the effect of deposition temperatures on the surface morphology of the prepared sample has been analyzed. Structural and morphological were carried out on the prepared samples, using X-Ray Diffractometer (XRD) and Scanning Electron Microscopy (SEM). The samples deposited at elevated temperature showed nanopetal like structures on their surface which were found to be around 100-200 nm. The formation of the V2O5 phase has been confirmed through TG/DTA analysis which shows a sharp peak around 690°C corresponding to the melting point of vanadium pentoxide. The best sample was subjected to gas sensing analysis and the change in the resistance of the sensing element with respect to the test gas concentration was measured by noting down the resistance at each concentration for various time intervals. Sensitivity of the material linearly increased with different concentration of the test gas.