• A Venkataraman

      Articles written in Bulletin of Materials Science

    • A new combustion route to 𝛾-Fe2O3 synthesis

      A Venkataraman Vijay A Hiremath S K Date S D Kulkarni

      More Details Abstract Fulltext PDF

      A new combustion route for the synthesis of 𝛾-Fe2O3 is reported by employing purified 𝛼-Fe2O3 as aprecursor in the present investigation. This synthesis which is similar to a self propagation combustion reaction, involves fewer steps, a shorter overall processing time, is a low energy reaction without the need of any explosives, and also the reaction is completed in a single step yielding magnetic iron oxide i.e. 𝛾-Fe2O3. The as synthesized 𝛾-Fe2O3 is characterized employing thermal, XRD, SEM, magnetic hysteresis, and density measurements. The effect of ball-milling on magnetic properties is also presented.

    • Dielectric, electrical and infrared studies of 𝛾-Fe2O3 prepared by combustion method

      Vijay A Hiremath A Venkataraman

      More Details Abstract Fulltext PDF

      This paper reports the electrical and spectroscopic investigation of the gamma ferrite synthesized through combustion route. The electrical study and dielectric behaviour showed a typical ferrite nature for the samples. The $\gamma \rightarrow \alpha $ transition is observed from the electrical conductivity data. Infrared spectral study showed the transition of a typical ferrite. The effect of the presence of 𝛼-impurities in 𝛾-Fe2O3 is also explained here.

    • Adsorption study of Pb2+ ions on nanosized SnO2, synthesized by self-propagating combustion reaction

      Arunkumar Lagashetty A Venkataraman

      More Details Abstract Fulltext PDF

      Novel combustion synthetic route for the synthesis of nanosized SnO2 is reported. X-ray, tap and powder densities of SnO2 are calculated. Adsorption of Pb2+ ions on combustion derived nanosized SnO2 is studied. The as synthesized SnO2 and lead ions adsorbed SnO2 are characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM), and infrared spectroscopic (IR) techniques. The eluent is characterized by atomic absorption spectroscopy (AAS) and solution conductivity (SC) to know the reduction in the concentration and increase in conductance of lead solution after adsorption on the SnO2 surface. The potential use of solid adsorbents for the adsorption of heavy metal pollutants is envisaged in the present work.

    • Synthesis of MoO3 and its polyvinyl alcohol nanostructured film

      Arunkumar Lagashetty Vijayanand Havanoor S Basavaraja A Venkataraman

      More Details Abstract Fulltext PDF

      The synthesis of ultrafine MoO3 through a self-propagating combustion route employing polyethylene glycol as fuel is reported. The precursor molybdenum oxalate is employed in this study for the conversion of the precursor to ultrafine MoO3 particles. The solvent casting method is adopted for the synthesis of MoO3 dispersed polyvinyl alcohol nanostructured film (MoO3–PVA). These synthesized MoO3 and their composite samples are characterized for their structure, morphology, bonding and thermal behaviour by XRD, SEM, IR and DSC techniques, respectively. The distribution of MoO3 in polyvinyl alcohol gives a crystalline polymer, a compact structure and an increase in glass transition temperature.

    • Uses of 𝛼-Fe2O3 and fly ash as solid adsorbents

      J Shakhapure H Vijayanand S Basavaraja V Hiremath A Venkataraman

      More Details Abstract Fulltext PDF

      Solid adsorbents have shown great promise for control of particulate and non-particulate matter and as gas sensing devices in recent times. In the present study, adsorption of environmental toxic pollutant such as lead ions on solid adsorbents viz. 𝛼-Fe2O3 and fly ash, are reported. Considerable adsorption was observed on fly ash when compared to 𝛼-Fe2O3 surface. These studies are characterized by employing solid state and solution studies.

    • Lead adsorption study on combustion derived 𝛾-Fe2O3 surface

      Arunkumar Lagashetty H Vijayanand S Basavaraja N N Mallikarjuna A Venkataraman

      More Details Abstract Fulltext PDF

      New combustion synthetic route for the synthesis of nanosized 𝛾-Fe2O3 by microwave-assisted route is reported. X-ray density, tap density and powder density of prepared 𝛾-Fe2O3 are calculated. Adsorption study of Pb2+ on combustion derived nanosized 𝛾-Fe2O3 is studied by dynamic method. The 𝛾-Fe2O3 structure and lead adsorbed 𝛾-Fe2O3 (Pb-𝛾-Fe2O3) are studied by X-ray diffraction (XRD). Additional lead peaks in Pb-𝛾-Fe2O3 sample pattern confirm the lead adsorption. Morphology of as prepared 𝛾-Fe2O3 and Pb-𝛾-Fe2O3 is studied by scanning electron micrograph (SEM) technique. Varied morphology for Pb-𝛾-Fe2O3 compared to its 𝛾-Fe2O3 is observed. Variation of bonding in Pb-𝛾-Fe2O3 sample due to lead adsorption is viewed by infrared spectroscopic (IR) technique. Energy dispersive X-ray microanalysis (EDX) is scanned for the lead adsorbed 𝛾-Fe2O3 to know the presence of lead on 𝛾-Fe2O3 surface. The eluent lead solution is characterized by atomic absorption spectroscopy (AAS) and solution conductivity (SC). Reduction in the concentration and increase in conductance of eluent lead solution is observed. The potential use of solid adsorbents for the adsorption of heavy metal pollutants is envisaged in the present work.

    • Solvothermal synthesis and characterization of acicular 𝛼-Fe2O3 nanoparticles

      S Basavaraja D S Balaji Mahesh D Bedre D Raghunandan P M Prithviraj Swamy A Venkataraman

      More Details Abstract Fulltext PDF

      Nanometer-sized 𝛼-Fe2O3 particles have been prepared by a simple solvothermal method using ferric acetylacetonate as a precursor. The products were characterized by X-ray diffraction (XRD), energy dispersive X-ray microanalysis (EDAX), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transition electron microscopy (TEM), infrared spectroscopy (IR) and thermal analysis (TG–DTA). XRD indicates that the product is single-phase 𝛼-Fe2O3 with rhombohedral structure. Bundles of acicular shaped nanoparticles are seen in TEM images with an aspect ratio ∼ 12; typically 8–12 nm wide and over 150 nm long. The 𝛼-Fe2O3 nanoparticles posses a high thermal stability, as observed on thermal analysis traces.

    • Barium ferrite nanoparticles prepared by self-propagating low-temperature combustion method and its characterization

      P M Prithviraj Swamy S Basavaraja Vijayanand Havanoor N V Srinivas Rao R Nijagunappa A Venkataraman

      More Details Abstract Fulltext PDF

      The barium ferrite particles were prepared using a self-propagating low-temperature combustion method using polyethylene glycol (PEG) as a fuel. The process was investigated with simultaneous thermogravimetric-differential thermal analysis (TG–DTA). The crystalline structure, morphology and the magnetic properties of the barium ferrite particles were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and SQUID susceptometer. The results show that the ignition temperature of PEG is lower compared with other combustion methods and gives nanocrystalline barium ferrite.

    • Synthesis and characterization of zinc ferrite nanoparticles obtained by self-propagating low-temperature combustion method

      P M Prithviraj Swamy S Basavaraja Arunkumar Lagashetty N V Srinivas Rao R Nijagunappa A Venkataraman

      More Details Abstract Fulltext PDF

      The self-propagating low-temperature combustion method was used to produce nanocrystalline particles of zinc ferrite. The products were characterized for chemical and phase composition, morphology and magnetic properties. The results obtained showed the formation of single-phase zinc ferrite nanoparticles with an average particle size of about 40 nm. As-synthesized powder displayed good magnetic property. Due to the simplicity and low cost of this process, it could also become a valuable starting point for the generation of other mixed and complex ferrites.

© 2017-2019 Indian Academy of Sciences, Bengaluru.