Pentadionate: An Alternate Sol-Gel Method for the Synthesis of Ferroelectric Ba1−xSrxTiO3

1999 ◽  
Vol 606 ◽  
Author(s):  
Pramod K. Sharma ◽  
K. A. Jose ◽  
V. V. Varadan ◽  
V. K. Varadan
Keyword(s):  
Metal Oxides ◽  
Sol Gel ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Barium Strontium ◽  
Transitional Metal ◽  
Heat Treated ◽  
Transitional Metal Oxides ◽  
Sol Gel Synthesis ◽  
Gel Processing

AbstractSol-gel synthesis of transitional metal oxides is one of the important technique to obtain the pure and homogenous materials at low temperature. In this work, Barium strontium titantate (BST) was synthesized by sol-gel processing using 2,4-pentadionate as the precursors of metal oxides. The Ba1−xSrxTiO3 was prepared for four values of x i.e. 0.2, 0.4, 0.5 and 0.6. The obtained powders were heated from 400 °C to 800 °C at the interval of 100 °C to determine the temperature of crystallization. The phase of the final products was investigated by x-ray diffraction (XRD). Two particle sizes (< 100 nm and 200-400 nm) were observed under the scanning electron microscope (SEM) of the heat treated xerogel. The dielectric properties were determined by impedance analyzer at the frequency of 1MHz and explained in detail for the different values of x.

Sol-Gel Synthesis of SnO2-TiO2 System - Morphologic, Photocatalytic and Antibacterial Properties

2018 ◽  
Vol 762 ◽  
pp. 273-277
Author(s):  
Anzelms Zukuls ◽  
Gundars Mežinskis ◽  
Aigars Reinis ◽  
Ingus Skadins ◽  
Juta Kroica ◽  
...  
Keyword(s):  
Sol Gel ◽  
Antibacterial Properties ◽  
Soda Lime ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
Oxide Coatings ◽  
Atomic Force ◽  
Heat Treated ◽  
Soda Lime Silicate Glass ◽  
Sol Gel Synthesis

SnO2-TiO2 sol-gel coatings on soda-lime silicate glass heat treated at 500 °C and xerogel specimens also heat treated at 500 °C were investigated in this study. The morphology of 1, 3, 5 and 7 mol% SnO2 doped titanium oxide coatings were evaluated with a scanning electron microscope (SEM), an atomic force microscope (AFM) and an UV-VIS light spectrophotometer, whilst xerogel structure was analysed with X-ray diffraction spectroscopy (XRD). The physicochemical properties of the TiO2-SnO2 systems depended mainly on the Sn-to-Ti ratio. The surface morphology of the layer was compact and homogeneous with no visible cracks. Anatase and rutile phase was found in the tested 1, 3, 5, 7 and 10 mol% SnO2 doped and heat treated xerogel specimens. Rutile phase content in the heat treated xerogel was reduced, if Sn4+ content was increased. Photocatalytic activity and antibacterial properties were evaluated as well.

Sol-Gel Processing of Glasses and Glass-Ceramics for Microelectronic Packaging

1991 ◽  
Vol 249 ◽  
Author(s):  
M.A. Sriram ◽  
P.N. Kumta
Keyword(s):  
Dielectric Constant ◽  
Thermal Analyses ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Signal Propagation ◽  
Ceramic Materials ◽  
X Ray Diffraction ◽  
Low Dielectric ◽  
Heat Treated ◽  
Gel Processing

In recent years considerable progress has been made in electronic packaging substrate technology. The future need of miniaturization of devices to increase the signal processing speeds calls for an increase in the device density requiring the substrates to be designed for better thermal, mechanical and electrical efficiency.Fast signal propagation with minimum delay requires the substrate to possess very low dielectric constant. Several glasses and glass-ceramic materials have been identified over the years which show good promise as candidate substrate materials. Among these borophosphate and borophosphosilicate glass-ceramics have been recently identified to have the lowest dielectric constant (3.8). Sol-gel processing has been used to synthesize borosilicate, borophosphosilicate and borophosphate glasses and glass-ceramics using inexpensive boron oxide and phosphorus pentoxide precursors. Preliminary results of the processing of these gels and the effect of volatility of boron alkoxide and its modification on the gel structure are described. X-ray diffraction, Differential thermal analyses and FTIR have been used to characterize the as-prepared and heat treated gels.

Sol-Gel Synthesis of GdAlO3 Buffer Layers on SrTiO3 (100) Substrates

2007 ◽  
Vol 124-126 ◽  
pp. 647-650
Author(s):  
Jae Cheol Bang ◽  
Jin Hyeok Kim ◽  
Frederick F. Lange
Keyword(s):  
Single Crystal ◽  
Sol Gel ◽  
Precursor Solution ◽  
Buffer Layers ◽  
Binary Solvent ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Synthesis ◽  
Relationship Of ◽  
Gel Processing

To identify the possibility of using GdAlO3 (GAO) as a buffer layer for YBa2Cu3O7-δ (YBCO) coated superconductor wire, we report the result of GAO deposition on SrTiO3 (STO) single crystal substrates by sol-gel processing. Precursor solution was prepared by dissolving stoichiometric quantities of gadolinium hexahydrate and aluminum isoproxide in a mixed binary solvent (2-4 pentanedione:methyl alcohol=1:1). The solutions were spin-coated on STO (100) single crystal substrates and heated at 500~1100 for 2 h in wet Ar-5% H2 atmosphere. A FESEM observation of the surface morphology of the GAO has shown that it has a very smooth surface with a faceted morphology indicating epitaxy. It was shown in x-ray diffraction characterization that epitaxial GAO films with epitaxial orientation relationship of (001)[112]GAO||(100)[110]STO have been grown on STO (100) substrates.

Sol-gel Synthesis, Magnetic and Structural Characterization of BaFe11.6–2xMxTixO19 (M=Co, Zn, Sn) Compounds.

2002 ◽  
Vol 755 ◽  
Author(s):  
G. Mendoza-Suárez ◽  
A.F. Fuentes ◽  
J.I. Escalante-García ◽  
O.E. Ayala-Valenzuela
Keyword(s):  
Magnetocrystalline Anisotropy ◽  
Sol Gel ◽  
Treatment Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Barium Ferrites ◽  
Crystallite Sizes ◽  
Sol Gel Synthesis

ABSTRACTSubstituted barium ferrites powders with Ti4+-M2+ (M = Co, Zn, Sn) cationic mixtures were prepared by a sol-gel route. The materials were heat-treated in the range 925–1000 °C and characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). The results showed that the effect of the substitution, x was to lower the coercivity (Hc), owing to the decrease of the magnetocrystalline anisotropy of the magnetoplumbite structure of the BaM. In this regard Sn-Ti substitutions tended to decrease Hc more rapidly than Zn-Ti and Ti-Co substitutions, in that order. Regarding the saturation magnetization (Ms), Zn-Ti mixtures showed slightly better Ms than Ti-Co substitutions; however, the Sn-Ti showed a more marked decrease as x increased. As revealed by SEM, the effect of the heat-treatment temperature was to increase the volume of multi-domain particles, following a Hc decrease due to grain coarsening. Contrarily, as a result of the improved crystallinity of the samples, as observed from the XRD peaks, Ms enhancement was recorded. Crystallite sizes decreased below 100 nm as x increased, although it was also dependent on the cationic mixture. In this respect Sn-Ti substitutions needed higher treatment temperatures to yield materials with adequate crystallinity and phase constitution.

Sol-gel synthesis of cerium-doped yttrium silicates and their luminescent properties

2010 ◽  
Vol 25 (2) ◽  
pp. 229-234 ◽  
Author(s):  
Jakub Růžička ◽  
Daniel Nižňanský ◽  
Martin Nikl ◽  
Romana Kucerková ◽  
Carla Cannas
Keyword(s):  
Sol Gel ◽  
Luminescent Properties ◽  
Luminescence Spectra ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Heat Treated ◽  
Efficiency Losses ◽  
Pure Phases ◽  
Scintillation Efficiency ◽  
Sol Gel Synthesis

The Ce-doped yttrium ortho- and pyrosilicate powders were prepared in a powder form by the formamide-modified sol-gel method. Crystal structure was checked by x-ray diffraction and sample morphology by transmission electron microscopy measurements. Both ortho- and pyrosilicate pure phases were obtained by the previously mentioned preparation procedure and proper annealing temperature was determined to obtain the maximum scintillation efficiency. Luminescence spectra and decays were measured to better evaluate the source of efficiency losses in the scintillator mechanism of samples heat-treated at lower temperatures. The potential of this preparation method for manufacturing the nanocomposite scintillators was discussed.

scholarly journals Sodium Solid Electrolytes: NaxAlOy Bilayer-System Based on Macroporous Bulk Material and Dense Thin-Film

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 854
Author(s):  
Antonia Hoppe ◽  
Cornelius Dirksen ◽  
Karl Skadell ◽  
Michael Stelter ◽  
Matthias Schulz ◽  
...  
Keyword(s):  
Pore Size ◽  
Bulk Material ◽  
Sol Gel ◽  
Dense Layer ◽  
X Ray Diffraction ◽  
Bilayer System ◽  
Step Procedure ◽  
Short Circuits ◽  
Α Al2o3 ◽  
Sol Gel Synthesis

A new preparation concept of a partially porous solid-state bilayer electrolyte (BE) for high-temperature sodium-ion batteries has been developed. The porous layer provides mechanical strength and is infiltrated with liquid and highly conductive NaAlCl4 salt, while the dense layer prevents short circuits. Both layers consist, at least partially, of Na-β-alumina. The BEs are synthesized by a three-step procedure, including a sol-gel synthesis, the preparation of porous, calcined bulk material, and spin coating to deposit a dense layer. A detailed study is carried out to investigate the effect of polyethylene oxide (PEO) concentration on pore size and crystallization of the bulk material. The microstructure and crystallographic composition are verified for all steps via mercury intrusion, X-ray diffraction, and scanning electron microscopy. The porous bulk material exhibits an unprecedented open porosity for a NaxAlOy bilayer-system of ≤57% with a pore size of ≈200–300 nm and pore volume of ≤0.3 cm3∙g−1. It contains high shares of crystalline α-Al2O3 and Na-β-alumina. The BEs are characterized by impedance spectroscopy, which proved an increase of ionic conductivity with increasing porosity and increasing Na-β-alumina phase content in the bulk material. Ion conductivity of up to 0.10 S∙cm−1 at 300 °C is achieved.

scholarly journals V2O3/C composite fabricated by carboxylic acid-assisted sol–gel synthesis as anode material for lithium-ion batteries

2021 ◽  
Author(s):  
G. S. Zakharova ◽  
E. Thauer ◽  
A. N. Enyashin ◽  
L. F. Deeg ◽  
Q. Zhu ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Sol Gel ◽  
Carbon Sources ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Battery Electrode ◽  
Sol Gel Synthesis

AbstractThe potential battery electrode material V2O3/C has been prepared using a sol–gel thermolysis technique, employing vanadyl hydroxide as precursor and different organic acids as both chelating agents and carbon sources. Composition and morphology of resultant materials were characterized by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies, physical sorption, and elemental analysis. Stability and electronic properties of model composites with chemically and physically integrated carbon were studied by means of quantum-chemical calculations. All fabricated composites are hierarchically structured and consist of carbon-covered microparticles assembled of polyhedral V2O3 nanograins with intrusions of amorphous carbon at the grain boundaries. Such V2O3/C phase separation is thermodynamically favored while formation of vanadium (oxy)carbides or heavily doped V2O3 is highly unlikely. When used as anode for lithium-ion batteries, the nanocomposite V2O3/C fabricated with citric acid exhibits superior electrochemical performance with an excellent cycle stability and a specific charge capacity of 335 mAh g−1 in cycle 95 at 100 mA g−1. We also find that the used carbon source has only minor effects on the materials’ electrochemical performance.

Fabrication and Characterization of Sol-Gel Derived PZT/WO3 Ceramics

2008 ◽  
Vol 55-57 ◽  
pp. 369-372 ◽  
Author(s):  
T. Sreesattabud ◽  
Anucha Watcharapasorn ◽  
Sukanda Jiansirisomboon
Keyword(s):  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Rhombohedral Phase ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
Calcination Process ◽  
Materials Used ◽  
Phase Characterization ◽  
Gel Processing

Lead zirconate titanate/tungsten oxide (PZT/WO3) ceramics were prepared from the powders synthesized by a modified triol sol-gel processing method. In this study, the starting materials used for synthesis of PZT-sol were zirconium (IV) propoxide, titanium (IV) isopropxide, lead (II) acetate trihydrate and 1,1,1,- tris (hydroxymethyl) ethane. To prepare PZT/xWO3 powders (where x = 0, 0.5, 1 and 3 wt%), nano-sized WO3 was ultrasonically dispersed and mixed with the PZT sol, dried and calcined at 600°C for 4 h. X-ray diffraction results indicated that fully crystallized powders were obtained. Phase characterization suggested that at high WO3 concentration, the reaction between PZT and WO3 occurred during the calcination process. To prepare PZT/xWO3 ceramics, the powders were pressed and sintered at 1100°C for 6 h. Phase characterization by XRD indicated that the content of WO3 significantly affected tetragonal-to-rhombohedral phase transition. Microstructure of thermally etched samples showed that increasing the content of WO3 decreased grain size of the ceramics.

scholarly journals Preparation and morphology of porous SiO2 ceramics derived from fir flour templates

2010 ◽  
Vol 75 (3) ◽  
pp. 385-394 ◽  
Author(s):  
Li Zhong ◽  
Tiejun Shi ◽  
Liying Guo
Keyword(s):  
Amorphous Material ◽  
Sol Gel ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Ordered Structures ◽  
Porous Sio2 ◽  
Pore Size Distributions ◽  
Naoh Solution ◽  
Gel Processing ◽  
Highly Porous

The preparation of SiO2 ceramics with controllable porous structure from fir flour templates via sol-gel processing was investigated. The specific size the fir flour, which was treated with 20 % NaOH solution, was infiltrated with a low viscous silica sol and subsequently calcined in air, which resulted in the formation of highly porous SiO2 ceramics. X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM) were employed to investigate the microstructure and phase formation during processing as well as of the SiO2 ceramics. N2 adsorption measurements were used to analyze the pore size distributions (PSD) of the final ceramics. The results indicated that the surface topography was changed and the proportion of the amorphous material was increased in NaOH-treated fir flour. The final oxide products retained ordered structures of the pores and showed unique pore sizes and distributions with hierarchy on the nanoscale derived from the fir flour.

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