On the formation of M2+ -Sb3+ -alkoxide precursors and sol-gel processing of M-Sb oxides with M = Cr, Mn, Fe, Co, Ni, Cu and Zn

1992 ◽  
Vol 27 (6) ◽  
pp. 1617-1625 ◽  
Author(s):  
G. Westin ◽  
M. Nygren
Keyword(s):  
Sol Gel ◽  
Gel Processing ◽  
Alkoxide Precursors ◽  
Cu And Zn

Physical-Chemical Properties of TiO2 Membranes Controlled By Sol-Gel Processing

1988 ◽  
Vol 132 ◽  
Author(s):  
Qunyin Xu ◽  
Marc A. Anderson
Keyword(s):  
Primary Particle ◽  
Sol Gel ◽  
Chemical Properties ◽  
Primary Particle Size ◽  
Chemical Processes ◽  
Gel Structure ◽  
Physical Chemical ◽  
Membrane Porosity ◽  
Gel Processing ◽  
Alkoxide Precursors

ABSTRACTParticulate TiO2 membranes have been prepared by sol-gel techniques from alkoxide precursors. The degree of aggregation, which is controlled by physical chemical processes during sol preparation influences the gelling volume and gel structure. While three types of gel structures have been proposed, the porosity of the final membrane seems to be little affected by these hydrogel structures. Firing temperature is a much more critical parameter. It is concluded that the primary particle size determines the final membrane porosity in this TiO2 system.

Sol-gel processing of PbTiO3 and Pb(Zr0.52Ti0.48)O3 fibers

1992 ◽  
Vol 7 (4) ◽  
pp. 992-996 ◽  
Author(s):  
Ulagaraj Selvaraj ◽  
A.V. Prasadarao ◽  
Sridhar Komarneni ◽  
Keith Brooks ◽  
Stewart Kurtz
Keyword(s):  
Heat Treatment ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Heat Treated ◽  
Viscous Solutions ◽  
Gel Processing ◽  
Alkoxide Precursors

Homogeneous and stoichiometric PbTiO3 and PbZr0.52Ti0.48O3 gel fibers were drawn from viscous solutions prepared by sol-gel processing of alkoxide precursors. The fibrous gels on heating at 450 and 600 °C, respectively, formed the well-crystallized phases of PbTiO3 and PbZr0.52Ti0.48O3. Fibers heat treated at 700 °C are a few centimeters long and 50 to 150 μm in diameter. PbZr0.52Ti0.48O3 fibers subjected to heat treatment at 700 °C for 1 h consisted of fully dense submicron grains (0.15 to 0.2 μm). However, PbTiO3 fibers under analogous conditions showed a few micropores with grains of ∼0.1 μm. Dielectric constants of these PbTiO3 and PbZr0.52Ti0.48O3 fibers were approximately 300 and 800, respectively.

Crystallization of barium titanate thin films synthesized via sol-gel processing

1995 ◽  
Vol 53 ◽  
pp. 258-259
Author(s):  
M. C. Gust ◽  
N. D. Evans ◽  
M. L. Mecartney
Keyword(s):  
Thin Films ◽  
Barium Titanate ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Independent Films ◽  
X Ray ◽  
Fine Grained ◽  
Diffraction Patterns ◽  
Gel Processing ◽  
Alkoxide Precursors

Sol-gel processing of oxide thin films offers the potential to generate different microstructures by varying process parameters such as water of hydrolysis, chemical precursor, or substrate. For this work, barium titanate (BaTiO3) thin films were prepared by the sol-gel method in order to try and generate different microstructures for dielectric measurements. However, for BaTiOs prepared using alkoxide precursors, the final microstructures of the films were found to be almost process independent. Films using different precursors, different substrates, and different amounts of water of hydrolysis all showed similar TEM microstructures. All the films after final heat treatment were polycrystalline, nanoporous, and randomly oriented BaTiO3; they were also fine-grained, with an average uniform grain size of 25-50 nm (Fig. 1). This fine-grained microstructure has also been observed in other studies of sol-gel derived BaTiO3 thin films. In addition to BaTiO3, electron diffraction patterns showed the presence of trace amounts of rutile TiO2 that were not observed by x-ray diffraction (XRD).

New insight in the role of modifying ligands in the sol-gel processing of metal alkoxide precursors: A possibility to approach new classes of materials

2006 ◽  
Vol 40 (2-3) ◽  
pp. 163-179 ◽  
Author(s):  
Vadim G. Kessler ◽  
Gerald I. Spijksma ◽  
Gulaim A. Seisenbaeva ◽  
Sebastian Håkansson ◽  
Dave H. A. Blank ◽  
...  
Keyword(s):  
Sol Gel ◽  
Metal Alkoxide ◽  
Gel Processing ◽  
Alkoxide Precursors

New Chemistry for the Sol-Gel Process: Acetone as a New Condensation Reagent

1992 ◽  
Vol 271 ◽  
Author(s):  
Subhash C. Goel ◽  
Michael Y. Chiang ◽  
Patrick C. Gibbons ◽  
William E. Buhro
Keyword(s):  
Aldol Condensation ◽  
Sol Gel ◽  
Metal Alkoxide ◽  
Sol Gel Process ◽  
New Process ◽  
Gel Processing ◽  
Alkoxide Precursors

ABSTRACTA nonhydrolytic sol-gel process that uses acetone as the condensation reagent is described. In the new process, the hydrocarbon soluble Zn(OCEt3)2 is converted to a rigid, transparent gel and then to ZnO by an aldol-condensation-elimination sequence. The chemical pathway for the transformation has been established, and differs completely from the pathway for the conventional hydrolytic sol-gel processing of alkoxide precursors. The new, nonhydrolytic strategy may prove applicable to a variety of metal-alkoxide systems.

Barium Titanium Alkoxides for Barium Titanates: Synthesis, Characterization, and Applications

1994 ◽  
Vol 351 ◽  
Author(s):  
Victor W. Day ◽  
Todd A. Eberspacher ◽  
Walter G. Klemperer ◽  
Shurong Liang
Keyword(s):  
Sol Gel ◽  
Solvent Molecule ◽  
X Ray Diffraction ◽  
Aryl Group ◽  
Barium Titanates ◽  
Acidic Conditions ◽  
Moisture Sensitive ◽  
Gel Processing ◽  
Hydrolysis Of ◽  
Alkoxide Precursors

ABSTRACTSeveral new crystalline bimetallic alkoxide precursors for barium titanates processing have been prepared: {[Ba(Solv)2]2[Ti(OAr)6]2} (1) (Solv = coordinated solvent molecule, Ar = aryl group), [Ba(CH2OHCH2OH)4(H20)][Ti(OCH2CH2O)3] (2), Ba[Ti2(OR)9]2 (3) (R = methyl, ethyl, and n-propyl), and [Ba(BzOH)Ti2O(OBz)8]2 (4) (Bz = benzyl). These precursors have been characterized by elemental analysis, IR, NMR, and single-crystal X-ray diffraction techniques. Compound 1 is well-suited for sol-gel processing of BaTiO3 powders and thin films under a variety of conditions. The facile preparation of 2 using relatively inexpensive starting materials makes it a viable alternative for the synthesis of BaTiO3 fine powders. Both compounds 3 and 4 are fairly moisture-sensitive; hydrolysis of these precursors under acidic conditions affords the formation of gels instead of precipitates. The reactivity of 3 toward hydrolysis can be tailored by varying the alkyl group.

Synthesis and characterization of BaMgAl10O17:Eu phosphors derived by sol–gel processing

2002 ◽  
Vol 126 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Junying Zhang ◽  
Zhongtai Zhang ◽  
Zilong Tang ◽  
Zishan Zheng ◽  
Yuanhua Lin
Keyword(s):  
Sol Gel ◽  
Synthesis And Characterization ◽  
Gel Processing
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