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Manivasakan P.,KS Rangasamy College of Technology | Rajendran V.,KS Rangasamy College of Technology | Rauta P.R.,Dalmia Institute of Scientific and Industrial Research | Sahu B.B.,Dalmia Institute of Scientific and Industrial Research | And 4 more authors.
Journal of the American Ceramic Society | Year: 2010

Nanosized TiO2 was obtained using a simple chemical route from natural ilmenite available in Tamilnadu, India. The nano-TiO2 particles obtained were comprehensively characterized by X-ray diffraction, FTIR, BET surface area, particles size, and transmission electron microscopic analysis. The results observed reveal that the nano-TiO2 show a rutile crystal structure with an average particle size of 50 nm and a specific surface area of 112.64 m2/g with spherical morphology. Different proportions of nanotitania were added in silica brick composition to determine out the amount of tridymite phase transformation. It was observed that the addition of 0.5 wt% nano-TiO2 leads to highest amount of tridymite phase formation. The effect of incorporation of nano-TiO2 in silica refractory was explored in terms of refractory properties such as bulk density, apparent porosity, cold crushing strength, refractoriness under load, creep in compression, and reversible thermal expansion. © 2010 The American Ceramic Society.


Parida K.M.,CSIR - Institute of Minerals And Materials Technology | Sahu N.,CSIR - Institute of Minerals And Materials Technology | Mohapatra P.,Dalmia Institute of Scientific and Industrial Research | Scurrell M.S.,University of Witwatersrand
Journal of Molecular Catalysis A: Chemical | Year: 2010

A series of gold supported mesoporous Fe-TiO2 samples were prepared by the borohydrate reduction method. Fe-TiO2 (1.0, 3.0, 5.0, 7.0 wt%) was prepared by the incipient wetness impregnation method. These catalysts were characterized by TEM, XPS, UV-vis DRS, photoluminescent spectra (PL), TPR/TPD, BET surface area etc. A detail study has been carried out to know the effect of iron on the physico-chemical and catalytic property of gold-titania catalyst. Iron doping influences the surface and electronic properties of Au-TiO2. The activity of these catalysts for CO oxidation was evaluated. We observed higher catalytic activity of gold supported Fe-TiO2 catalysts compared to gold supported TiO2. We found that the catalyst with 5 wt% of Iron was the most active catalyst. The gold supported Fe-TiO2 catalyst does not lose its activity over several hours even at 500 °C, in marked contrast to Au-TiO2. Iron doping enhances the catalytic activity of Au-TiO2 as well as stabilizes the catalyst at high temperature. © 2009 Elsevier B.V. All rights reserved.


Manivasakan P.,KS Rangasamy College of Technology | Rajendran V.,KS Rangasamy College of Technology | Rauta P.R.,Dalmia Institute of Scientific and Industrial Research | Sahu B.B.,Dalmia Institute of Scientific and Industrial Research | Panda B.K.,Dalmia Institute of Scientific and Industrial Research
Powder Technology | Year: 2011

In this study a novel synthetic method for the large-scale production of spherical, high surface area and ultra-fine alumina (Al2O3) powder has been described. Synthetic Bayer liquor was extracted by alkali fusion of raw bauxite with sodium hydoxide. Alumina nanopowders were synthesised through a ball mill-aided precipitation method using the synthetic Bayer liquor and mineral acid precipitants. The powders produced were characterised by X-ray diffraction (XRD), particle size distribution (PSD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller surface area and pore size analysis, energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In this article, the effects of precipitants such as H2SO4, HCl and HNO3 on crystallite and particle size, surface area, pore volume, and pore size and shape are reported. The experimental results prove that precipitation leads to an aggregated particle that is disaggregated by the ball-milling method. The ball milling process strongly influences the formation of uniform-sized spherical particles with a high surface area. It was revealed that nitric acid is an effective precipitant for controlling particle size and textural properties of Al2O3 powder. A nanopowder of γ-Al2O3 with an average crystallite size of 3nm and an average particle size of 58nm with a specific surface area (SSA) of 190m2 g-1 is produced. This article elucidates a new method with a simple reaction scheme for the mass production of Al2O3 nanoparticles from raw bauxite for various commercial applications. © 2011 Elsevier B.V.


Manivasakan P.,KS Rangasamy College of Technology | Rajendran V.,KS Rangasamy College of Technology | Ranjan Rauta P.,Dalmia Institute of Scientific and Industrial Research | Bandhu Sahu B.,Dalmia Institute of Scientific and Industrial Research | Krushna Panda B.,Dalmia Institute of Scientific and Industrial Research
Journal of the American Ceramic Society | Year: 2011

Zirconia (ZrO2) nanoparticles with nonstabilized monoclinic and sodium-stabilized cubic phase were produced from zircon sand using the ball mill-aided precipitation route. Characterization and a comprehensive study of nanocrystalline ZrO2 particles were expressed by X-ray diffraction, particle size distribution (PSD), Fourier transform infrared spectroscopy, thermal analysis, Brunauer-Emmett-Teller surface area and pore size analysis, X-ray fluorescence spectrometry, scanning electron microscopy, and transmission electron microscopy. In this article, the influence of the processing parameters on the crystalline phase, particle size, PSD, aggregation, and morphology are reported. The experimental results prove that the precipitation leads to aggregated particles, which are disaggregated by the ball-milling process. The ball-milling process strongly influences the formation of uniform-sized spherical particles with a high surface area. Fully crystalline monoclinic ZrO2 nanoparticles with an average particle size of 64 nm (d 50) and the specific surface area of 126 m2/g were obtained. In addition, the sodium-stabilized cubic ZrO2 nanoparticles with an average particle size of 39 nm (d50) and the specific surface area of 227 m2/g were obtained with the help of the ball-milling process. In the present process, a simple reaction scheme is developed for the large-scale production of stabilized and nonstabilized ZrO2 nanoparticles using inexpensive precursor obtained from zircon sand. © 2011 The American Ceramic Society.


Rauta P.R.,Dalmia Institute of Scientific and Industrial Research | Sahoo N.,Dalmia Institute of Scientific and Industrial Research
2015 International Conference on Nascent Technologies in the Engineering Field, ICNTE 2015 - Proceedings | Year: 2015

Nanotechnology is the design, characterization, production and application of structures, devices and systems by controlled manipulation of size and shape at nanometer scale. One particular subsection of nanotechnology can be distinguished as nano structured materials i.e., materials in which certain elements of material structure exist at their nano scale. Generally nanotechnology deals with structures sized between 1 to 100 nanometer in at least one dimension, and involve developing or modifying materials or devices within that size. Nano materials have high surface to volume ratio, which make it more chemically reactive resulting properties like heat resistance and unique electronic, magnetic, optical and catalytic properties. The advancements in nanotechnology have an impact almost in all fields such as materials, instrumentation, electronics, healthcare, defense, sensors, energy, manufacturing and environments. The other major technological areas of nano metal oxides and their composites are in advanced composite materials, catalysts, high energy batteries, automobile and aerospace components, optical devices, radiation shielding and energetic materials. The application of nanotechnology in refractory material is very limited. In the author's laboratory, nano TiO2, ZrO2 and MgO have been prepared by spray pyrolyser route. These nano materials have been used in refractory composition. Incorporation of nano materials improves the corrosion, erosion & high temperature mechanical properties of refractory bricks. © 2015 IEEE.


Goswami G.,Dalmia Institute of Scientific and Industrial Research | Mohapatra B.N.,Dalmia Institute of Scientific and Industrial Research | Panigrahy P.K.,Dalmia Institute of Scientific and Industrial Research
ZKG International | Year: 2015

The main features of a cement quality control system involve raw mix composition, burning of the cement clinker, fineness and finally the strength of the cement produced. The ultimate quality of cement primarily depends on the quantity and characteristics of different mineral phases present in it, which in turn are controlled by the raw mix composition and burning process. Identical raw mix compositions even with a more or less similar burning process may not be expected to produce the same mineral assemblages. Both microscopy and XRD are widely used for physical estimation of clinker phases and clinker microscopy has already been in use for characterization of the clinker burning condition and prediction of cement strength.


Behera S.K.,National Institute of Technology Rourkela | Mishra B.,Dalmia Institute of Scientific and Industrial Research
Ceramics International | Year: 2015

Expanded graphite, fabricated by microwave irradiation of acidified flaky graphite, was used to partially replace graphite and carbon black in a commercial Al2O3-C refractory slide gate plate composition. The developed refractories exhibited enhanced cold and hot strength, as well as oxidation resistance. X-ray diffraction indicated the formation of SiC phase even at temperatures lower than the melting point of Si. Field emission scanning electron microscopy exhibited homogeneous formation of three dimensionally oriented nanostructured SiC whiskers in the samples fabricated with expanded graphite. The formation of the thicker primary whiskers and thinner secondary whiskers in the inter-aggregate space bridging two particles was observed frequently for the expanded graphite fortified samples. Whisker reinforcement of this nature has rarely been observed in refractory systems, which is credited for a considerable improvement in the hot modulus of rupture of the new compositions. © 2014 Elsevier Ltd and Techna Group S.r.l.


Goswami G.,Dalmia Institute of Scientific and Industrial Research | Sanu P.,Dalmia Institute of Scientific and Industrial Research | Panigrahy P.K.,Dalmia Institute of Scientific and Industrial Research
InterCeram: International Ceramic Review | Year: 2015

The paper examines the possibility of estimation of Thermal Expansion (TE) of silica refractory up to 1000 °C, based on its mineral contents, particularly SiO2polymorphs. For that purpose a very accurate quantitative X-ray diffractometric (QXRD) method for estimation of quartz, cristobalite, and tridymite and an optical method for Si glass were standardized in the authors' laboratory. The total TE caused by these Si polymorphs up to 1000 °C was found to be almost equal to that estimated by the conventional dilatometric method showing differences in the third decimal place only. The method is much quicker than the dilatometric method.


Sahani P.,National Institute of Technology Rourkela | Karak S.K.,National Institute of Technology Rourkela | Mishra B.,Dalmia Institute of Scientific and Industrial Research | Chakravarty D.,International Advanced Research Center for Powder Metallurgy And New Materials | Chaira D.,National Institute of Technology Rourkela
International Journal of Refractory Metals and Hard Materials | Year: 2016

SiC-B4C-Al cermets containing 5, 10 and 20 wt.% of Al were fabricated by high-energy planetary milling followed by conventional sintering and spark plasma sintering (SPS) techniques separately. The average particle size reduced to ∼3 μm from an initial size of 45 μm after 10 h of milling. The as-milled powders were conventionally sintered at 1950 °C for 30 min under argon atmosphere and SPS was carried out at 1300 °C for 5 min under 50 MPa applied pressure. The formation of Al8B4C7 and AlB12 phases during conventional sintering and SPS were confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. The formation of Al8B4C7 at 700 °C and AlB12 at 1000 °C was well supported by XRD and differential scanning calorimetry (DSC). The maximum relative density, microhardness and indentation fracture resistance of SiC-B4C-10Al consolidated by SPS are 97%, 23.80 GPa and 3.28 MPa·m1/2, respectively. © 2016 Elsevier Ltd. All rights reserved.


Sahani P.,National Institute of Technology Rourkela | Karak S.K.,National Institute of Technology Rourkela | Mishra B.,Dalmia Institute of Scientific and Industrial Research | Chakravarty D.,International Advanced Research Center for Powder Metallurgy And New Materials | Chaira D.,National Institute of Technology Rourkela
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2016

Silicon carbide (SiC)–boron carbide (B4C) based cermets were doped with 5, 10, and 20 wt pct Silicon (Si) and their sinterability and properties were investigated for conventional sintering at 2223 K (1950 °C) and spark plasma sintering (SPS) at 1623 K (1350 °C). An average particle size of ~3 µm was obtained after 10 hours of milling. There is an enhancement of Vickers microhardness in the 10 wt pct Si sample from 18.10 in conventional sintering to 27.80 GPa for SPS. The relative density, microhardness, and indentation fracture toughness of the composition SiC60(B4C)30Si10 fabricated by SPS are 98 pct, 27.80 GPa, and 3.8 MPa m1/2, respectively. The novelty of the present study is to tailor the wettability and ductility of the cermet by addition of Si into the SiC-B4C matrix. Better densification with improved properties is achieved for cermets consolidated by SPS at lower temperatures than conventional sintering. © 2016 The Minerals, Metals & Materials Society and ASM International

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