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Panchanan Pramanik - One of the best experts on this subject based on the ideXlab platform.
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Low‐Temperature Chemical Synthesis of Nanocrystalline MgAl2O4 Spinel Powder
Journal of the American Ceramic Society, 2004Co-Authors: Ranjan K Pati, Panchanan PramanikAbstract:Nanocrystalline MgAl2O4 spinel powder was synthesized by pyrolysis of complex compounds of aluminum and magnesium with triethanolamine (TEA). The soluble metal ion–TEA complexes formed the Precursor Material on complete dehydration of the complexes of aluminum–TEA and magnesium–TEA. Single-phase MgAl2O4 spinel powder resulted after heat treatment of the Precursor Material at 675°C. The Precursor and the heat-treated powders were characterized by X-ray diffractometry (XRD), differential thermal and thermogravimetric analysis, and transmission electron microscopy (TEM). The average crystallite size as measured from the X-ray line broadening was around 14 nm and the average particle size from TEM studies was around 20 nm.
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Chemical synthesis of nanocrystalline lead zirconate-titanate powders using tartarate Precursor
Materials Letters, 1999Co-Authors: Rabindra N. Das, Panchanan PramanikAbstract:Abstract Nanocrystalline (30 nm) lead zirconate-titanate (PZT) ceramics, with Zr/Ti ratio 60:40, was prepared by a chemical method starting from a mixed metal ion–tartarate (Zr 4+ , Ti 4+ )–EDTA (Pb 2+ ) complex solution. After complete evaporation of the mixed complex solution, a fluffy dried mass, known as Precursor Material was obtained. Heat-treatments of the Precursor Material at 400°C/2 h resulting single phase PZT. The Precursor and heat-treated powders were characterized by TG/DTA, XRD and TEM analysis. The result shows that the process provides a technically simple route for the preparation of nanocrystalline PZT powders at low preparation temperatures.
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In situ synthesis of nanosized PZT powders in the Precursor Material and the influence of particle size on the dielectric property
Nanostructured Materials, 1998Co-Authors: R.n. Das, Panchanan PramanikAbstract:Abstract Nanosized PZT powders, with Zr Ti ratio of 60 40 , have been prepared starting from a solution of Diethanolamine (DEA) and hydrated metaloxides of Ti(iv), Zr(iv) and Pb(ii) ions. The metal ions were in solution through complexformation. The soluble metal-DEA complex on complete dehydration, followed by decomposition formed the Precursor Material. The Precursor Material was found to be x-ray single phasic PZT with average particle size 25 nm. The Precursor and heat-treated powders were characterized by DTA, XRD and TEM analysis. For comparative studies PZT powders have also been prepared by heating directly and hydrothermally from the coprecipitate hydrated metal oxides and resulted in single phase PZT at 500 °C/5h, and 220 °C/5h having average particle sizes 190 and 480 nm respectively. The dielectric constant increased exponentially with decreasing size of particles of agglomerated crystallites due to efficient sintering and densification. The dielectric constant of the sintered product from DEA-complex gives superior value i.e., 11518.
Sudhir Chandra - One of the best experts on this subject based on the ideXlab platform.
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morphologies of sol gel derived thin films of zno using different Precursor Materials and their nanostructures
Nanoscale Research Letters, 2007Co-Authors: Harish Bahadur, Avanish Kumar Srivastava, R K Sharma, Sudhir ChandraAbstract:We have shown that the morphological features of the sol–gel derived thin films of ZnO depend strongly on the choice of the Precursor Materials. In particular, we have used zinc nitrate and zinc acetate as the Precursor Materials. While the films using zinc acetate showed a smoother topography, those prepared by using zinc nitrate exhibited dendritic character. Both types of films were found to be crystalline in nature. The crystallite dimensions were confined to the nanoscale. The crystallite size of the nanograins in the zinc nitrate derived films has been found to be smaller than the films grown by using zinc acetate as the Precursor Material. Selected area electron diffraction patterns in the case of both the Precursor Material has shown the presence of different rings corresponding to different planes of hexagonal ZnO crystal structure. The results have been discussed in terms of the fundamental considerations and basic chemistry governing the growth kinetics of these sol–gel derived ZnO films with both the Precursor Materials.
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Morphologies of Sol–Gel Derived Thin Films of ZnO Using Different Precursor Materials and their Nanostructures
Nanoscale Research Letters, 2007Co-Authors: Harish Bahadur, R K Sharma, Ak Srivastava, Sudhir ChandraAbstract:We have shown that the morphological features of the sol–gel derived thin films of ZnO depend strongly on the choice of the Precursor Materials. In particular, we have used zinc nitrate and zinc acetate as the Precursor Materials. While the films using zinc acetate showed a smoother topography, those prepared by using zinc nitrate exhibited dendritic character. Both types of films were found to be crystalline in nature. The crystallite dimensions were confined to the nanoscale. The crystallite size of the nanograins in the zinc nitrate derived films has been found to be smaller than the films grown by using zinc acetate as the Precursor Material. Selected area electron diffraction patterns in the case of both the Precursor Material has shown the presence of different rings corresponding to different planes of hexagonal ZnO crystal structure. The results have been discussed in terms of the fundamental considerations and basic chemistry governing the growth kinetics of these sol–gel derived ZnO films with both the Precursor Materials.
P. Porkodi - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of NASICON—A Molecular Precursor-Based Approach
Chemistry of Materials, 2008Co-Authors: P. Porkodi, V. Kalyanavalli, P Kamaraj, V Yegnaraman, Duraisamy JeyakumarAbstract:Phosphosilicate molecular Precursor for the synthesis of NASICON, natrium super ionic conductor, Na1+xZr2SixP3−xO12 (x = 1 and 2) has been devised and prepared by the hydrolysis of tetraethoxysilane (TEOS) employing sodium phosphate solution. The molecular Precursor was reacted with Zr(OC3H7)4 in ethanol under solvolytic condition to yield nano Precursor Material of NASICON. This Material was annealed at high temperature to yield phase-pure NASICON. The molecular Precursor was characterized using 31P NMR, FTIR spectral data, powder XRD pattern and TG/DTA studies. The structure of the molecular Precursor was deduced from the powder XRD data, which indicates the presence of edge sharing tetrahedral arrangement of −O−Si−O−P−O−Si− chain. The NASICON Precursor Material was characterized using TG/DTA, FTIR, TEM, SEM, MAS 31P NMR and XRD. The conductivity of the synthesized NASICON Material was measured using the pellet annealed at 900 °C and was found to be 5.5 x10−3 S cm−1. The details on the preliminary inves...
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Polyol mediated synthesis of tungsten trioxide and Ti doped tungsten trioxide: Part 1: Synthesis and characterisation of the Precursor Material
Materials Research Bulletin, 2006Co-Authors: P. Porkodi, V Yegnaraman, D. JeyakumarAbstract:Polyol mediated synthesis for the preparation of tungsten trioxide and titanium doped tungsten trioxide has been reported. The reaction was carried out using chlorides of tungsten and titanium in diethylene glycol medium and water as the reagent for hydrolysis at 190 deg. C. Formation of a blue coloured dimensionally stable suspension of the Precursor Materials was observed during the course of the reaction. The particle sizes of the Precursor Materials were observed to be around 100 nm. The Precursor Materials were annealed to give tungsten trioxide and titanium doped tungsten trioxide. The Precursor Materials were characterised using TGA/DTA, FT-IR, optical spectra, SEM, TEM and powder XRD methods. It was observed that the doping of titanium could be effected at least up to 10% of Ti in WO{sub 3}. The TGA/DTA studies indicated that WO{sub 3-x}.H{sub 2}O is the dominant Material that formed during the polyol mediated synthesis. The XRD data of the annealed samples revealed that the crystalline phase could be manipulated by varying the extent of titanium doping in the tungsten trioxide matrix.
D. Jeyakumar - One of the best experts on this subject based on the ideXlab platform.
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Polyol mediated synthesis of tungsten trioxide and Ti doped tungsten trioxide: Part 1: Synthesis and characterisation of the Precursor Material
Materials Research Bulletin, 2006Co-Authors: P. Porkodi, V Yegnaraman, D. JeyakumarAbstract:Polyol mediated synthesis for the preparation of tungsten trioxide and titanium doped tungsten trioxide has been reported. The reaction was carried out using chlorides of tungsten and titanium in diethylene glycol medium and water as the reagent for hydrolysis at 190 deg. C. Formation of a blue coloured dimensionally stable suspension of the Precursor Materials was observed during the course of the reaction. The particle sizes of the Precursor Materials were observed to be around 100 nm. The Precursor Materials were annealed to give tungsten trioxide and titanium doped tungsten trioxide. The Precursor Materials were characterised using TGA/DTA, FT-IR, optical spectra, SEM, TEM and powder XRD methods. It was observed that the doping of titanium could be effected at least up to 10% of Ti in WO{sub 3}. The TGA/DTA studies indicated that WO{sub 3-x}.H{sub 2}O is the dominant Material that formed during the polyol mediated synthesis. The XRD data of the annealed samples revealed that the crystalline phase could be manipulated by varying the extent of titanium doping in the tungsten trioxide matrix.
Harish Bahadur - One of the best experts on this subject based on the ideXlab platform.
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morphologies of sol gel derived thin films of zno using different Precursor Materials and their nanostructures
Nanoscale Research Letters, 2007Co-Authors: Harish Bahadur, Avanish Kumar Srivastava, R K Sharma, Sudhir ChandraAbstract:We have shown that the morphological features of the sol–gel derived thin films of ZnO depend strongly on the choice of the Precursor Materials. In particular, we have used zinc nitrate and zinc acetate as the Precursor Materials. While the films using zinc acetate showed a smoother topography, those prepared by using zinc nitrate exhibited dendritic character. Both types of films were found to be crystalline in nature. The crystallite dimensions were confined to the nanoscale. The crystallite size of the nanograins in the zinc nitrate derived films has been found to be smaller than the films grown by using zinc acetate as the Precursor Material. Selected area electron diffraction patterns in the case of both the Precursor Material has shown the presence of different rings corresponding to different planes of hexagonal ZnO crystal structure. The results have been discussed in terms of the fundamental considerations and basic chemistry governing the growth kinetics of these sol–gel derived ZnO films with both the Precursor Materials.
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Morphologies of Sol–Gel Derived Thin Films of ZnO Using Different Precursor Materials and their Nanostructures
Nanoscale Research Letters, 2007Co-Authors: Harish Bahadur, R K Sharma, Ak Srivastava, Sudhir ChandraAbstract:We have shown that the morphological features of the sol–gel derived thin films of ZnO depend strongly on the choice of the Precursor Materials. In particular, we have used zinc nitrate and zinc acetate as the Precursor Materials. While the films using zinc acetate showed a smoother topography, those prepared by using zinc nitrate exhibited dendritic character. Both types of films were found to be crystalline in nature. The crystallite dimensions were confined to the nanoscale. The crystallite size of the nanograins in the zinc nitrate derived films has been found to be smaller than the films grown by using zinc acetate as the Precursor Material. Selected area electron diffraction patterns in the case of both the Precursor Material has shown the presence of different rings corresponding to different planes of hexagonal ZnO crystal structure. The results have been discussed in terms of the fundamental considerations and basic chemistry governing the growth kinetics of these sol–gel derived ZnO films with both the Precursor Materials.