@article { ISI:000229811300003, title = {Coprecipitation technique to prepare ZnM2O6 powders}, journal = {Bulletin of Materials Science}, volume = {28}, number = {3}, year = {2005}, month = {JUN}, pages = {205-207}, publisher = {INDIAN ACADEMY SCIENCES}, type = {Article}, address = {C V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIA}, abstract = {

A simple coprecipitation technique was successfully applied for the preparation of pure ultrafine single phase, ZnNb2O6 (ZN). Ammonium hydroxide was used to precipitate Zn2+ and Nb5+ cations as hydroxides simultaneously. This precursor on heating at 750 degrees, produced ZN powders. For comparison, ZN powders were also prepared by the traditional solid state method. The phase contents and lattice parameters were studied by the powder X-ray diffraction (XRD). Particle size and morphology were studied by transmission electron spectroscopy (TEM).

}, keywords = {Ceramics, Electron microscopy, electronic materials, X-ray diffraction}, issn = {0250-4707}, doi = {10.1007/BF02711248}, author = {Deshpande, V. V. and Patil, M. M. and Navale, S. C. and Ravi, V.} } @article { ISI:000230275100032, title = {Synthesis of bismuth oxide nanoparticles at 100 degrees C}, journal = {Materials Letters}, volume = {59}, number = {19-20}, year = {2005}, month = {AUG}, pages = {2523-2525}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple gel to crystal conversion route has been followed for the preparation of ultrafine Bi2O3 particles at 80-100 degrees C under refluxing conditions. Freshly prepared bismuth hydroxide gel is allowed to crystallize under refluxing and stirring conditions for 6-12 h. Formation of nanocrystallites of Bi2O3 is confirmed by X-ray diffraction (XRD) study. The thermal decomposition of bismuth hydroxide yields Bi2O3 only at 400 degrees C. This shows the advantage of the present method. Transmission electron microscope (TEM) investigations revealed that the average particle size is 50 nm for these oven-dried powders. (c) 2005 Elsevier B.V All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.03.037}, author = {Patil, M. M. and Deshpande, V. V. and Dhage, S. R. and Ravi, V.} } @article { ISI:000225588700025, title = {Synthesis of bismuth titanate by the urea method}, journal = {Materials Letters}, volume = {59}, number = {4}, year = {2005}, month = {FEB}, pages = {514-516}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple urea precipitation route was adopted for the preparation of bismuth titanate (Bi4Ti3O12) powders. Stoichiometric quantities of BiCl3 and TiOCl2 were mixed with the required amount of urea (the ratio of total metal cations to urea is five), and the mixture was heated on a water bath. This leads to the formation of precipitate, which was decomposed at 973 K. The formation of bismuth titanate was observed on calcining powders at 973 K by X-ray diffraction studies. The average particle size is found to be 100 nm by microscopy. The room temperature dielectric constant is found to be 150 at 1 kHz. The hysteresis loop parameters were also obtained by home-built Sawer-Tower circuit. (C) 2004 Elsevier B.V. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, dielectric properties, ferroelectricity, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2004.10.038}, author = {Anilkumar, Mettu and Dhage, S. R. and Ravi, V.} } @article { ISI:000226803200008, title = {Synthesis of fine particles of ZnO at 100 degrees C}, journal = {Materials Letters}, volume = {59}, number = {7}, year = {2005}, month = {MAR}, pages = {779-781}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple gel to crystal conversion route has been followed for the preparation of fine ZnO at 80-100 degreesC under refluxing conditions. Freshly prepared zinc hydroxide gel is allowed to crystallize under refluxing and stirring conditions for 4-6 It. Formation of fine crystallites of ZnO is confirmed by X-ray diffraction (XRD) study. Transmission electron microscope (TEM) investigations revealed that the average particle size is 100 nm for these powders. (C) 2004 Elsevier B.V All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2004.11.019}, author = {Dhage, S. R. and Pasricha, R. and Ravi, V.} } @article { ISI:000228510500005, title = {Synthesis of nanocrystalline Mn3O4 at 100 degrees C}, journal = {Materials Research Bulletin}, volume = {40}, number = {4}, year = {2005}, month = {APR}, pages = {605-609}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A simple gel to crystal conversion route has been followed for the preparation of nanocrystalline tetragonal Mn3O4 powders at 80-100 degrees C under refluxing conditions. Freshly prepared manganese hydroxide gel is allowed to crystallize under refluxing and stirring conditions for 4-6 h. Formation of nano crystallites of Mn3O4 is confirmed by X-ray diffraction (XRD) study. Transmission electron microscope (TEM) investigations revealed that the average particle size is 50 nm for these powders. (c) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0025-5408}, doi = {10.1016/j.materresbull.2005.01.009}, author = {Anilkumar, Mettu 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:000238624000017, title = {Synthesis of MgNb2O6 by coprecipitation}, journal = {Materials Research Bulletin}, volume = {41}, number = {7}, year = {2006}, month = {JUL}, pages = {1353-1356}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A simple coprecipitation technique was used successfully to synthesize fine powders of MgNb2O6 (MN) phase. An aqueous mixture of ammonium carbonate and ammonium hydroxide was used to precipitate Mg2+ and Nb5+ cations as carbonate and hydroxide respectively under basic conditions. This precipitate on heating at 750 degrees C produced MN powders. For comparison MN powders were prepared by the traditional solid state method. The phase content and the lattice parameters were studied by powder X-ray diffraction (XRD). Particle size and morphology of the particles were studied by scanning electron microscopy (SEM). (C) 2006 Elsevier Ltd. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, electronic materials, X-ray diffraction}, issn = {0025-5408}, doi = {10.1016/j.materresbull.2005.12.009}, author = {Navale, S. C. and Gaikwad, A. B. and Ravi, V.} } @article { ISI:000244008300030, title = {Co-precipitation technique to prepare BaTa2O6}, journal = {Ceramics International}, volume = {33}, number = {2}, year = {2007}, month = {JAN}, pages = {297-299}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A mixture of ammonium oxalate and ammonium hydroxide was used to co-precipitate barium and tantalum ions as barium oxalate and tantalum hydroxide under basic conditions. On calcination at 750 degrees C, this precursor yielded BaTa2O6 (BT) ceramics. This is much lower temperature as compared to that prepared by traditional solid-state method (1000 degrees C) as reported for the formation of BaTa206. Transmission electron microscope (TEM) investigations revealed that the average particle size is 70 nm for the calcined powders. The room temperature dielectric constant at 1 kHz is found to be 100. (c) 2005 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

}, keywords = {barium tantalate, Ceramics, Electron microscopy, Oxides, X-ray diffraction}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2005.08.012}, author = {Navale, S. C. and Samuel, Violet and Gaikwad, A. B. and Ravi, V.} } @article { ISI:000245760900020, title = {Low temperature route to prepare LaFeO3 and LaCoO3}, journal = {Materials Letters}, volume = {61}, number = {10}, year = {2007}, month = {APR}, pages = {2030-2032}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A combination of digestion and further low temperature calcination to crystallize the product was employed to prepare LaFeO3 (LF) and LaCoO3 (LC) powders. Freshly co-precipitated lanthanum and ferric (or cobalt) hydroxide gels by sodium hydroxide were allowed to react at 100 degrees C under refluxing and stirring conditions for 4-6 h. These oven dried powders were heated at 450 degrees C to from crystalline LF (or LC) powders. The phase contents and lattice parameters were investigated by X-ray diffraction (XRD). Transmission electron microscope (TEM) investigations were carried out to examine the morphology and average particle size of these powders. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Chemical synthesis, LaFeO3, Precipitation, transmission electron microscopy, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2006.08.009}, author = {Jadhav, A. D. and Gaikwad, A. B. and Samuel, V. and Ravi, V.} } @article { ISI:000252474200009, title = {Low voltage varistor ceramics based on SnO2}, journal = {Bulletin of Materials Science}, volume = {30}, number = {6}, year = {2007}, month = {DEC}, pages = {583-586}, publisher = {SPRINGER}, type = {Article}, address = {233 SPRING STREET, NEW YORK, NY 10013 USA}, abstract = {

The nonlinear current (I)-voltage (V) characteristics of tin dioxide doped with either Nb2O5 and CoO or Sb2O3 and CoO show promising values of nonlinear coefficient (alpha) values (similar to 11) with low breakdown voltages (E-B, similar to 40 V mm(-1)). The pentavalent antimony or niobium acts as donor and increases the electronic conductivity. The crucial parameter for obtaining low breakdown voltage is the grain size, which depends upon sintering duration and temperature of these oxide ceramics.

}, keywords = {Chemical synthesis, electronic materials, Microstructure, tin oxide, X-ray diffraction}, issn = {0250-4707}, doi = {10.1007/s12034-007-0092-8}, author = {Dhage, S. R. and Ravi, V. and Yang, O. B.} } @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: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.} } @article { ISI:000252408000041, title = {Co-precipitation technique to prepare BiTaO4 powders}, journal = {Materials Letters}, volume = {62}, number = {3}, year = {2008}, month = {FEB}, pages = {501-503}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple co-precipitation technique has been successfully used for the preparation of pure ultrafine single phase BiTaO4. A standard ammonium hydroxide solution was used to precipitate Bi3+ and Ta5+ cations as hydroxides simultaneously under basic conditions. This precursor, on heating at 600 degrees C, produced product phase. This is the lowest temperature for the formation of BiTaO4 phase so far reported in the literature. For comparison BiTaO4 powders were also prepared by the traditional solid state method. The phase contents and lattice parameters were studied by the powder X-ray diffraction (XRD). (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {BiTaO4, Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2007.05.074}, author = {Muthurajan, H. and Gupta, U. N. and Rituraj, B. and Rao, N. Koteswara and Pradhan, Sivaram and Radha, R. and Ravi, V.} } @article { ISI:000257367100016, title = {Low temperature synthesis and characterization of BiNbO4 powders}, journal = {Materials Characterization}, volume = {59}, number = {8}, year = {2008}, month = {AUG}, pages = {1083-1087}, publisher = {ELSEVIER SCIENCE INC}, address = {360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA}, abstract = {

BiNbO4 powders, a potential microwave dielectric ceramic were prepared by both coprecipitation and solid state techniques. In the former method, an aqueous ammonium hydroxide was used to precipitate Bi3+ and Ta5+ cations as hydroxides simultaneously under basic conditions. It is observed that the co-precipitation produces BiNbO4 phase on heating at 600 degrees C, whereas complete phase formation occurs only at 800 degrees C in the case of solid state method. The phase contents and lattice parameters were studied by powder X-ray diffraction. The sequence of the reaction and phase evolution of BiNbO4 were also studied by the X-ray diffraction. The samples were characterized by the differential-thermal/thermo-gravimetric analyses and scanning electron microscopy techniques. (C) 2007 Elsevier Inc. All rights reserved.

}, keywords = {BiNbO4, Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {1044-5803}, doi = {10.1016/j.matchar.2007.08.026}, author = {Radha, R. and Muthurajan, H. and Rao, N. Koteswara and Pradhan, Sivaram and Gupta, U. N. and Jha, Ratnesh Kumar and Mirji, S. A. and Ravi, V.} } @article { ISI:000253106100026, title = {Low temperature synthesis of SrNb2O6 and SrTa2O6 using hydroxide precursor}, journal = {Materials Letters}, volume = {62}, number = {6-7}, year = {2008}, month = {MAR}, pages = {892-894}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

SrNb2O6 (SN) or SrTA(2)O(6) (ST) compounds were prepared at low temperatures for the first time from hydroxide precursors. A simple procedure of mixing commercially purchased strontium hydroxide and niobium (or tantalum) hydroxide thoroughly together and heating at a low temperature (\<400 degrees C) produced SrNb2O6 (SN) or SrTa2O6 (ST) powders. This is the lowest temperature so far reported for the formation of these phases. These materials are potential candidates for ferroelectric and electro-optic applications. The reaction sequence and evolution of the phase formation were investigated by X-ray diffraction (XRD) studies. The average particle size and morphology of these powders were studied by scanning electron microscopy (SEM). (C) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Chemical synthesis, Electron microscopy, electronic materials, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2007.07.006}, author = {Muthurajan, H. and Kumar, H. H. and Koteswara Rao, N. and Pradhan, Sivaram and Jha, Ratnesh Kumar and Ravi, V.} } @article { ISI:000257365900027, title = {Novel hydroxide precursors for low temperature synthesis of selected ternary oxides}, journal = {Materials Research Bulletin}, volume = {43}, number = {7}, year = {2008}, month = {JUL}, pages = {1842-1849}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A novel method of using hydroxide precursors to reduce the synthesis temperature for few selected ternary oxides has been presented here. This technique is very useful and advantageous when the ternary oxides contain an alkaline earth element. The selected compositions for this method are BaCeO3 (BC), BaBiO3 (BB), La0.7Sr0.3CoO3 (LSCO) and BaBi2Nb2O9 (BBN). Commercially purchased strontium (or barium) hydroxide and freshly prepared lanthanum, cobalt, bismuth and niobium hydroxides were mixed thoroughly in stoichiometric ratio and heated at different temperatures ranging from 100 to 700 degrees C for 10 h for corresponding compositions. The sequence of the reaction and evolution of the product phase were studied by the X-ray diffraction (XRD) studies. The phase purity and lattice parameters were also determined by XRD investigations. All the product phases in each case were formed at relatively low temperature than when they were prepared by co-precipitation or solid state method. The morphology and average particle size of these powders were investigated by scanning electron microscopy (SEM). (C) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0025-5408}, doi = {10.1016/j.materresbull.2007.07.006}, author = {Muthurajan, H. and Rao, N. Koteswara and Gupta, U. N. and Pradhan, Sivaram and Jha, Ratnesh Kumar and Kumar, H. H. and Mirji, S. A. and Ravi, V.} } @article { ISI:000252408000048, title = {Synthesis of LSMO at low temperature by novel hydroxide precursor technique}, journal = {Materials Letters}, volume = {62}, number = {3}, year = {2008}, month = {FEB}, pages = {527-529}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A novel technique of mixing individual hydroxide is employed to prepare La0.65Sr0.35MnO3 (LSMO) at low temperature. Freshly prepared lanthanum and manganese hydroxides are mixed thoroughly with strontium hydroxide in stoichiometric ratio and heated at different temperatures ranging from 100 to 500 degrees C for 6 h. At 500 degrees C, formation of La0.65Sr0.35MnO3 was confirmed by the X-ray diffraction studies (XRD). This is the lowest temperature so far reported in the literature. The particle size and morphology were investigated by scanning electron microscopy (SEM). (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Ceramics, Electron microscopy, La0.65Sr0.35MnO3, Oxides, Precipitation, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2007.05.077}, author = {Gupta, U. N. and Muthurajan, H. and Kumar, H. H. and Rao, N. Koteswara and Gokhale, Suresh P. and Ravi, V.} }