Preparation of BSCCO Precursors by Water Extraction Variant of Sol-Gel Process

1992 ◽  
Vol 271 ◽  
Author(s):  
A. Deptula ◽  
W. Lada ◽  
T. Olczak ◽  
A. Di Bartolomeo
Keyword(s):  
Thermal Treatment ◽  
Sol Gel ◽  
Water Extraction ◽  
Sol Gel Process ◽  
Emulsion Drops ◽  
Preparation Step

ABSTRACTThe starling acetate sols of molar compositions of Bi:Pb:Sr:Ca:Cu=I-2:O:2:l: 2, 11–2:0:2:2:3 and 111–1.6:0.4:2:2:3 were prepared by NH4OH addition at various rates, followed by evaporation. Sols were gelled by further evaporation to shard or to microspheres (diameter below 100 μm) by water extraction from the sol emulsion drops formed in 2-ethyl-l-hexanol. The gels were converted to BSCCO phases by thermal treatment. The processes were characterized by XRD and IR examinations. The influence of the sol preparation step connected with formation of polynuclear cations on the following stages of the process was examined.

Preparation of Superconducting YBa2Cu3O7−x Compounds By Water Extraction Variant Of Sol-Gel Process

1990 ◽  
Vol 180 ◽  
Author(s):  
A. Deptula ◽  
W. Lada ◽  
T. Olczak ◽  
T. zoltowski ◽  
A. Di Bartolomeo
Keyword(s):  
Thermal Treatment ◽  
Sol Gel ◽  
Ammonium Hydroxide ◽  
Water Extraction ◽  
Spherical Particles ◽  
Acidic Solutions ◽  
Sol Gel Process

ABSTRACTThe starting sols were prepared by addition of ammonium hydroxide to acidic solutions of Y-Ba-Cu acetates or by dissolving solid Ba9CO9 or CuCO9.CuCOH)2H2O in acetates of the remaining components. The sols were then gelled to spherical particles with diameter below 50μm by extracting water with 2-ethyl-l-hexanol or to shard by evaporation of water. After thermal treatment of both powders amorphous and then crystalline YBa2Cu,9O7−x were obtained. Formation of these compounds is strongly improved by aging the gel at 200°C. Green and sintered pellets exhibit excellent superconductivity properties.

Some Comments on the Production of Medium Sized Spherical Particles by Anion and Water Extraction Variant of Sol-Gel Process

1994 ◽  
Vol 372 ◽  
Author(s):  
A. Deptula ◽  
W. Łstoke;ada ◽  
T. Olczak ◽  
A. Chmielewski
Keyword(s):  
Particle Size ◽  
Sol Gel ◽  
Ceramic Materials ◽  
Extraction Process ◽  
Spherical Particles ◽  
Drastic Reduction ◽  
Sol Gel Process ◽  
Emulsion Drops ◽  
Clustering Effect ◽  
Non Destructive

AbstractMedium sized spherical particles (with diameters below 100 μm) of ceramic materials (Al203 and Al203 +8%TiO2) were produced in the following steps: (1) preparation of concentrated hydroxide sols of cations by extraction of anions using Primene JMT, (2) formation of sol emulsion in 2-ethylhexanol-1 containing various amounts of surfactants (EH), (3) gelation of emulsion drops by extraction of water with partially dehydrated EH, (4) non-destructive thermal treatment. Principal properties of the sol depend on the temperature of the extraction process. For preparation of lowanionic sols a two step extraction process, separated by digestion of the aqueous phase at boiling point, was necessary. It was found that the parameters of emulsion formation as well as the properties of the sols significantly influence the particle size distribution. It was concluded that lowering of the sol- EH interracial tension by the surfactant does not influence the process. On the contrary the “anti-clustering” effect of surfactants is essential for preparation of perfect spherical powders. The thermal decomposition of gels to oxides is determinant for densities, specific surface area and carbon content. Medium sized spherical powders are free flowing. The compactibility and sinterability of those powders are poor. However drastic reduction of particle size by milling (connected with their transformation to irregular shape) significantly improves the sinterability.

Improvement in Mechanical Property of SiO2 Films Prepared by Sol-Gel

2013 ◽  
Vol 744 ◽  
pp. 269-272 ◽  
Author(s):  
Pei Tao Guo
Keyword(s):  
Mechanical Property ◽  
Thermal Treatment ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Sol Gel ◽  
Dimethyl Formamide ◽  
Good Mechanical Property ◽  
Chemical Additives ◽  
Sol Gel Process ◽  
Silica Sols

Silica films prepared by the base catalyzed sol–gel process show poor mechanical property. In this study, silica anti-reflective films with good mechanical property have been prepared by the catalyzed sol–gel process with dimethyl formamide added as drying control chemical additives. The silica sol was first dip deposited onto substrate to form films on both sides of the substrate and then subjected to thermal treatment. After thermal treatment, the film was achieved due to the formation of porous structure in the resultant film as a result of decomposing tetraethylorthosilicate and dimethyl formamide. Nano-indenter measurement shows that the Young’s modulus and hardness of base catalyzed films are 10-20GPa and 0.25-0.55GPa, respectively. But the films added with dimethyl formamide are much better than those films derived from base-catalyzed silica sols, the Young’s modulus and hardness are 32-39GPa and 1.22-1.47GPa, respectively. The good mechanical properties make such films potential in both military and civil applications.

Effects of thermal treatment on the structure and luminescent properties of Eu 3+ doped SiO 2 –PMMA hybrid nanocomposites prepared by a sol–gel process

2016 ◽  
Vol 170 ◽  
pp. 588-593 ◽  
Author(s):  
Filipe Augusto de Jesus ◽  
Simei Tarse Sobrinho Santos ◽  
José Maurício Almeida Caiut ◽  
Victor Hugo Vitorino Sarmento
Keyword(s):  
Thermal Treatment ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Hybrid Nanocomposites ◽  
Sol Gel Process

Preparation of Titanium Hexacyanoferrate Microspheres (Diameter <70 μm) by Water Extraction Variant of Sol-Gel Process and its Application to Sorption of 137Cs from Nuclear Reactor Cooling Water

1995 ◽  
Vol 412 ◽  
Author(s):  
A. Deptula ◽  
A. G. Chmielewski ◽  
W. Lada ◽  
T. Olczak
Keyword(s):  
Aqueous Solution ◽  
Nuclear Reactor ◽  
Sol Gel ◽  
Cooling Water ◽  
Special Procedure ◽  
Sol Gel Process ◽  
High Sorption ◽  
Emulsion Drops ◽  
Titania Sol ◽  
Dta Studies

AbstractTitanium hexacyanoferrate microspheres (diameter <70km) were obtained in the following steps: (1) extraction of chlorides from an aqueous solution of TiCl4 with long chain amine -Primene JMT- in paraffin diluent (the resulting sol has the concentration 320 g TiO2/dm3 and the mole ratio Cl-: Ti4+ = 1.83); (2) blending of titania sol with an aqueous solution of K4 Fe(CN)6. 3H2O (280 g/dm3) in order to obtain final sols with Fe(CN)64-: Ti4+ mole ratio of 0.05 - 0.1; (3) formation of multicomponent sol emulsion in 2-ethylhexanol-1 containing I vol. % of Ethomen S/15 (EH), (4) gelation of emulsion drops by extraction of water with partially dehydrated EH; (5) filtration and washing with acetone; (6) drying at 140°C using a special procedure elaborated on the basis of TG and DTA studies.The final product is insoluble in water and exhibits high sorption efficiency of 137 Cs.

Sintering of ZrO2 ‐ CeO2 Spherical Powders Prepared by a Water Extraction Variant of the Sol‐Gel Process

1993 ◽  
Vol 140 (8) ◽  
pp. 2294-2297 ◽  
Author(s):  
A. Deptula ◽  
M. Carewska ◽  
T. Olczak ◽  
W. Lada ◽  
F. Croce
Keyword(s):  
Sol Gel ◽  
Water Extraction ◽  
Sol Gel Process

Hollow Mullite Ceramic Microspheres by Water Extraction of Emulsified Aqueous Droplets

1994 ◽  
Vol 346 ◽  
Author(s):  
Guoxu Liu ◽  
David L. Wilcox
Keyword(s):  
Sol Gel ◽  
Model Material ◽  
Water Extraction ◽  
Microelectronic Packaging ◽  
Droplet Dispersion ◽  
Mullite Ceramic ◽  
Sol Gel Process ◽  
Potential Applications ◽  
Important Processing ◽  
Aqueous Droplet

ABSTRACTThis paper describes a novel colloidal route for the preparation of hollow mullite ceramic microspheres with sizes in the range of 10 μm. An emulsion technique was combined with a water extraction sol-gel process, to form an aqueous droplet dispersion and gel the resulting droplets by extracting water with a dehydrating liquid. The liquid-filled gelled microcapsules were then dried and fired to form hollow ceramic microspheres. Important processing variables controlling the microspherc morphology were determined and a formation mechanism was proposed. Due to its potential applications in microelectronic packaging, mullite was selected as the model material for the present work, but the synthesis technique may be used for making other single or multiphase ceramic compositions

scholarly journals Europium-Doped Sol-Gel SiO2-Based Glasses: Effect of the Europium Source and Content, Magnesium Addition and Thermal Treatment on Their Photoluminescence Properties

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1768 ◽  
Author(s):  
Hussein Fneich ◽  
Nathalie Gaumer ◽  
Stéphane Chaussedent ◽  
Wilfried Blanc ◽  
Ahmad Mehdi
Keyword(s):  
Thermal Treatment ◽  
Glass Structure ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Aqueous Environment ◽  
Silica Glasses ◽  
Sol Gel Process ◽  
Before And After ◽  
Mg Addition

Rare-earth doped silica-based glasses lead the optical materials due to their tailorable spectroscopic and optical properties. In this context, we took advantage of the sol-gel process to prepare various Eu-doped silica glasses to study their luminescent properties before and after annealing at 900 °C. The effect of magnesium on these properties was studied in comparison with Mg-free-glass. Using TEM, nitrogen sorption, XRD and FT-IR, we confirmed that the magnesium modifies the glass structure and the thermal treatment eliminates the aqueous environment, modifying the structure ordering. The emission spectra and the decay time curves show the advantages of the Mg addition and the annealing on the photoluminescent properties.

Production of Spherical Powders of Inorganic Compounds by Water Extraction Variant of Sol-Gel Process

1992 ◽  
Vol 271 ◽  
Author(s):  
A. DeptuLa ◽  
J. Rebandel ◽  
W. Drozda ◽  
W. Lada ◽  
T. Olczak
Keyword(s):  
Acetic Acid ◽  
Pilot Plant ◽  
Inorganic Compounds ◽  
Sol Gel ◽  
Water Extraction ◽  
Salt Solutions ◽  
Sol Gel Process ◽  
Span 80 ◽  
Starting Solutions

ABSTRACTA method of preparation of spherical powders (with particle diameters <100µm) of metal oxidcs, their homegeneous mixtures or compounds, composites and metals has been elaborated. Depending on the nature of cations, the starting solutions were prepared by extraction of anions with Primene JMT from salt solutions, by addition of dopants to the sols or by complexing with acetic acid or/and ammonia. The sols or broths were then emulsified in 2-ethyl-l-hexanol containing SPAN 80. Drops of the emulsion were solidified by extraction of water with the solvent. The process was carried out continuously in a laboratory and/or in a pilot plant.

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