@article { ISI:000230338900015, title = {Synthesis of rutile from ATO and stearic acid}, journal = {Materials Letters}, volume = {59}, number = {21}, year = {2005}, month = {SEP}, pages = {2673-2675}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Nanocrystalline titanium dioxide in the rutile phase has been obtained from the solid state reaction between ammonium titanyl oxalate (ATO) and stearic acid at 400 degrees C in air. The fine powders of ATO and stearic acid are mixed well using acetone in an agate mortar and pestle for 2 h. This mixture (weight ratio of ATO to stearic acid \> 5) on heating at 400 degrees C produces rutile powders. For the ratios of ATO to stearic acid \< 5, a mixture of anatase and rutile phases is obtained. Pure ATO yields anatase phase on decomposition at 400 degrees C. These powders were characterized by X-ray diffraction (XRD), BET surface area measurements and transmission electron microscopy (TEM) studies. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray techniques}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.04.016}, author = {Patil, M. M. and Deshpande, V. V. and Deshpande, S. B. and Samuel, V. and Ravi, V.} } @article { ISI:000238866300004, title = {Coprecipitation technique to prepare Sr0.5Ba0.5Nb2O6}, journal = {Bulletin of Materials Science}, volume = {29}, number = {3}, year = {2006}, month = {JUN}, pages = {221-223}, publisher = {INDIAN ACADEMY SCIENCES}, type = {Article}, address = {C V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIA}, abstract = {

An aqueous mixture of ammonium oxalate and ammonium hydroxide was used to coprecipitate barium and strontium ions as oxalates and niobium ions as hydroxide under basic conditions. This precursor on calcining at 750 degrees C yielded Sr0.5Ba0.5Nb2O6 phase. This is a much lower temperature than that prepared by traditional solid state method (1000 degrees C) as reported for the formation of Sr0.5Ba0.5Nb2O6 (SBN). Transmission electron microscopic (TEM) investigations revealed that the average particle size was 80 nm for the calcined powders. The room temperature dielectric constant at I kHz was found to be 1100. The ferroelectric hysteresis loop parameters of these samples were also studied.

}, keywords = {Ceramics, Electron microscopy, ferroelectricity, Oxides, X-ray diffraction}, issn = {0250-4707}, doi = {10.1007/BF02706488}, author = {Murugan, A. Vadivel and Gaikwad, A. B. and Samuel, V. and Ravi, V.} } @article { ISI:000237158200003, title = {Phase evolution of NiTiO3 prepared by coprecipitation method}, journal = {Materials Letters}, volume = {60}, number = {15}, year = {2006}, month = {JUL}, pages = {1791-1792}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple coprecipitation technique was used for the preparation of NiTiO3 powders. Ammonium carbonate solution was added to a solution mixture containing stoichiometric amounts of Ni(NO3)(2) and TiOCl2 to precipitate nickel as carbonate and titanium as hydroxide under basic conditions. The precipitate was calcined at different temperatures ranging from 100 to 800 degrees C and phase evolution of NiTiO3 was investigated by X-ray diffraction (XRD) studies. It is observed that nickel titanate was formed at 750 degrees C. For comparison, NiTiO3 was also prepared by standard ceramic process. Particle size and morphology was studied by transmission electron microscopy (TEM). (c) 2005 Elsevier B.V. All fights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, NiTiO3, Oxides, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.12.023}, author = {Murugan, A. Vadivel and Samuel, V. and Navale, S. C. and Ravi, V.} } @article { ISI:000246158300058, title = {Coprecipitation technique to prepare NiNb2O6}, journal = {Materials Letter}, volume = {61}, number = {11-12}, year = {2007}, month = {MAY}, pages = {2354-2355}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A mixture of ammonium carbonate and ammonium hydroxide was used to coprecipitate nickel and niobium ions as nickel carbonate and niobium hydroxide under basic conditions. This precursor yielded NiNb2O6 (NN) ceramics on calcining at 700 degrees C (at a temperature lower than 800 degrees C which is necessary for the formation of NiNb2O6 when prepared by the traditional solid state method). The average particle size and morphology of these powders were investigated by transmission electron microscope (TEM). (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Chemical synthesis, Electron microscopy, electronic materials, Oxides, X-ray methods}, issn = {0167-577X}, doi = {10.1016/j.matlet.2006.09.010}, author = {Samuel, V. and Gaikwad, A. B. and Jadhav, A. D. and Natarajan, N. and Ravi, V.} } @article { ISI:000243164000035, title = {Novel technique to prepare LiNbO3 at low temperature}, journal = {Materials Letter}, volume = {61}, number = {3}, year = {2007}, month = {FEB}, pages = {765-766}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Fresh niobium hydroxide was first precipitated from NbF5 solution using an aqueous ammonium hydroxide under basic conditions. Then a simple procedure of mixing lithium and niobium hydroxides together and heating at a low temperature (400 degrees C) produced pure ultrafine single phase LiNbO3 (LN). In the literature, this is the lowest temperature so far reported on the formation of LN. The phase content and lattice parameters are determined by X-ray diffraction (XRD). The average particle size and morphology were studied by transmission electron microscopy (TEM). (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Chemical synthesis, Electron microscopy, electronic materials, LiNbO3, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2006.05.056}, author = {Samuel, V. and Gaikwad, A. B. and Jadhav, A. D. and Mirji, S. A. and Ravi, V.} } @article { ISI:000246260000011, title = {Preparation of nanocrystalline ferroelectric CaBi4Ti4O15 by citrate gel method}, journal = {Ceramics International}, volume = {33}, number = {4}, year = {2007}, month = {JAN}, pages = {569-571}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A gel was formed when an aqueous solution of CaCl2, BiNO3, TiOCl2 and citric acid in stoichiometric ratio is heated on a water bath. This gel on decomposition at 700 degrees C produced nano crystallites of the ternary oxide, CaBi4Ti4O15 (CBT). The phase contents and lattice parameters were studied by the powder X-ray diffraction (XRD). Particle size and morphology was studied by transmission electron spectroscopy (TEM). The room temperature dielectric constant at 1 kHz is 390. The ferroelectric hysteresis loop parameters of these samples were also studied by a home-built Sawyer-tower circuit. (c) 2006 Elsevier Ltd and Techna Group S.H. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray methods}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2005.11.006}, author = {Murugan, A. Vadivel and Gaikwad, A. B. and Samuel, V. and Ravi, V.} } @article { ISI:000257538200034, title = {Co-precipitation technique to prepare BiNbO4 powders}, journal = {Ceramics International}, volume = {34}, number = {6}, year = {2008}, month = {AUG}, pages = {1565-1567}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A simple co-precipitation technique was successfully used for the preparation of pure ultrafine single phase BiNbO4. A standard ammonium hydroxide solution was used to precipitate Bi3+ and Ta5+ cations as hydroxides simultaneously under basic conditions. For comparison, BN powders were also prepared by the traditional solid-state method. It is observed that the co-precipitation technique produces BiNbO4 on heating at 600 degrees C, whereas complete phase formation occurs only at 800 degrees C in the solid-state method. The phase contents and lattice parameters were Studied by powder X-ray diffraction (XRD). (C) 2007 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

}, keywords = {BiNbO4, Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2007.03.022}, author = {Radha, R. and Gupta, U. N. and Samuel, V. and Muthurajan, H. and Kumar, H. H. and Ravi, V.} }