Influence Of Hybridation With A Silicate Network On The Properties Of An Eu 3+ Complex Derived From Dipicolinic Acid

1999 ◽  
Vol 576 ◽  
Author(s):  
A. C. Franville ◽  
D. Zambon ◽  
R. Mahiou ◽  
Y. Troin ◽  
J. C. Cousseins
Keyword(s):  
Organic Molecules ◽  
Dipicolinic Acid ◽  
Sol Gel ◽  
Silicate Network ◽  
Hybrid Gels ◽  
Organic Species ◽  
Covalent Grafting ◽  
Sol Gel Process ◽  
Gel Processing ◽  
The Eu

ABSTRACTIn this paper, the preparation, the characterization and the optical features of organicinorganic materials incorporating a trivalent europium organic chelate into a silicate network are described. The covalent grafting and the sol-gel process allow to obtain monophasic hybrid gels in which the structure and the activity of the organic molecules were retained. The Eu3+ coordination mode is not sensitive to the sol-gel processing conditions whereas the morphology of materials, their thermal resistance and their luminescence properties may be adjusted. Characteristics of hybrid compounds are compared to those of the corresponding organic species.

Sol-Gel Process form Heterometallic Alkoxides to Incorporate Alkaline- and Rare Earths in Alumina for automotive Applications

1996 ◽  
Vol 431 ◽  
Author(s):  
C. K. Narula
Keyword(s):  
Elevated Temperatures ◽  
Sol Gel ◽  
Automotive Applications ◽  
Automotive Catalysts ◽  
Heterometallic Alkoxides ◽  
Sol Gel Process ◽  
Alkaline Earths ◽  
Cost Of Materials ◽  
Gel Processing

AbstractThe high cost of materials prepared by sol-gel processing and the loss of useful surface properties at elevated temperature has prevented the application of sol-gel processed materials in automotive exhaust reduction catalyst formulations. In this report, we briefly describe the important developments needed in the next generation automotive catalysts and the role of sol-gel processed materials. We will also discuss the application of heterometallic alkoxides as sol-gel precursors to achieve the molecular distribution of lanthanides and alkaline earths in alumina matrices needed for the stabilization of alumina based materials at elevated temperatures.

Preparation of inorganic/organic hybrid gels by the sol-gel process

1990 ◽  
Vol 119 (2) ◽  
pp. 132-135 ◽  
Author(s):  
Shinzo Kohjiya ◽  
Kenichiro Ochiai ◽  
Shinzo Yamashita
Keyword(s):  
Sol Gel ◽  
Hybrid Gels ◽  
Organic Hybrid ◽  
Sol Gel Process

Undoped and Doped Perovskite Films: Sol-Gel Processing and Characterization

1991 ◽  
Vol 243 ◽  
Author(s):  
Mareike Klee ◽  
Rainer Waser
Keyword(s):  
Crystal Structure ◽  
Field Strength ◽  
Remanent Polarization ◽  
Sol Gel ◽  
Insulation Resistance ◽  
Sol Gel Process ◽  
Gel Processing

AbstractThin undoped Pb(ZrxTi1−x)O3 (x=0.2-0.75), BaTiO3, SrTiO3 as well as acceptor (Mn, Ni) and donor (La, Ce) doped films with thicknesses of 0.2-1 μm have been deposited by a modified sol-gel process. The crystal structure and the morphology of the films as a function of the processing and composition were analyzed. The films were characterized with respect to their ferroelectric and dielectric properities e.g. permittivity, remanent polarization, coervice field strength, insulation resistance.

Ultrasmooth metal halide perovskite thin films via sol–gel processing

2016 ◽  
Vol 4 (21) ◽  
pp. 8308-8315 ◽  
Author(s):  
Ross A. Kerner ◽  
Lianfeng Zhao ◽  
Zhengguo Xiao ◽  
Barry P. Rand
Keyword(s):  
Thin Film ◽  
Film Formation ◽  
Sol Gel ◽  
Metal Halide ◽  
Film Morphology ◽  
Metal Halide Perovskite ◽  
Sol Gel Process ◽  
Thin Film Formation ◽  
Halide Perovskite ◽  
Gel Processing

We show that metal halide perovskite thin film formation is a sol–gel process which allows us to improve film morphology, achieving roughness ∼1 nm via process and additive engineering.

scholarly journals Characterization of LiCo Nanopowders Produced by Sol-Gel Processing

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Sina Soltanmohammad ◽  
Sirous Asgari
Keyword(s):  
Thermal Analyses ◽  
Sol Gel ◽  
Lithium Ion ◽  
Chelating Agent ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Size And Morphology ◽  
Gel Processing

LiCo nanopowders, one of the most important cathode materials for lithium-ion batteries, were synthesized via a modified sol-gel process assisted with triethanolamine (TEA) as a complexing agent. The influence of three different chelating agents including acrylic acid, citric acid, and oxalic acid on the size and morphology of particles was investigated. Structure and morphology of the synthesized powders were characterized by thermogravimetric/differential thermal analyses (TG/DTA), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Results indicate that the powder processed with TEA and calcinated at 800 had an excellent hexagonal ordering of -NaFe-type (space group Rm). Also, the other three complexing agents had a decisive influence on the particle size, shape, morphology, and degree of agglomeration of the resulting oxides. Based on the data presented in this work, it is proposed that the optimized size and distribution of LiCo powders may be achieved through sol-gel processing using TEA as a chelating agent.

Sol-Gel Processing of Advanced Dielectric Ceramics for Microwave Applications

1989 ◽  
Vol 155 ◽  
Author(s):  
M. Schnoeller ◽  
W. Wersing
Keyword(s):  
Sol Gel ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
Powder Morphology ◽  
Drying Procedures ◽  
Microwave Components ◽  
Sol Gel Process ◽  
Dielectric Ceramics ◽  
Gel Processing

ABSTRACTHighly dielectric ceramics make it possible to markedly miniaturize passive microwave components. We have successfully synthesized ceramic powders of the most important microwave ceramic systems (ZrTiSn)O2, Ba(TiNiZnTa)O3 and Ba(MgTa)O3 by using the sol-gel process. Nonaqueous solutions of metal organics together with different inorganic metal salts were used as precursors. The gels derived from these solutions are homogeneous and transparent. Different drying procedures were investigated in order to optimize powder morphology. Thermoanalytic methods and high -temperature x-ray diffraction were used to study the decomposition of xerogels and the formation of crystal phases, respectively. The calcination process was found to be complete at temperatures well below 750 °C.For the production of barium-containing powders, wet milling must be avoided because this washes out barium and thus causes undesired phases to appear. A dry milling step of the xerogel solves this problem. The prepared (ZrTiSn)O2 and Ba(TiNiZnTa)O3 already equal or surpass the quality of conventionally prepared ceramics.

Hafnium Metallo-Organic Films and Gels Produced by Sol-Gel Processing

1989 ◽  
Vol 155 ◽  
Author(s):  
Charles D. Gagliardi ◽  
Kris A. Berglund
Keyword(s):  
Light Scattering ◽  
Sol Gel ◽  
Organic Films ◽  
Spin Casting ◽  
Synthesis Technique ◽  
Refractory Oxides ◽  
Sol Gel Process ◽  
Optically Transparent ◽  
Acid Catalyzed ◽  
Gel Processing

ABSTRACTMetallo-organic materials are often used as precursors for highly refractory oxides and hightemperature composites. The feasibility of producing hafnium metallo-organic films and gels by sol-gel techniques is demonstrated in the present study. Since hafnium alkoxides are not commercially available, their preparation is an obstacle in the development of their sol-gel processing applications. A common synthesis technique was used to produce hafnium isopropoxide, which was subsequently hydrolyzed under acid catalyzed conditions to produce films and gels. The films were prepared by spin casting and remained optically transparent. Initially, the gels were also optically transparent, but became translucent upon drying. Raman, IR, and light scattering spectroscopies were used to characterize this sol-gel process, and it is compared with the analogous processing of titanium and zirconium alkoxides.

Epitaxial Growth of (110) KnbO3 Films on (100) MgO Substrates via Sol-Gel Processing

1994 ◽  
Vol 341 ◽  
Author(s):  
Garo J. Derderian ◽  
James D. Barrie ◽  
Kenneth A. Aitchison ◽  
Martha L. Mecartney
Keyword(s):  
Surface Layer ◽  
Epitaxial Growth ◽  
Interfacial Layer ◽  
Single Phase ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Sol Gel Process ◽  
Defective Surface ◽  
Gel Processing

AbstractEpitaxial, single phase (110) KnbO3 films were grown on (100) MgO substrates using a sol-gel process employing ethoxide precursors in methanol. The degree of epitaxy was dependent on both the annealing temperature and the amount of potassium in the film. Excess potassium in the sol-gel solution (K/Nb = 1.2) was necessary to produce single phase films. An amorphous or polycrystalline MgO interfacial layer was observed in some films, postulated to have developed after nucleation of KnbO3 and due to a highly defective surface layer.

Properties and microstructure of thin LiNbO3 films prepared by a sol-gel process

1987 ◽  
Vol 2 (5) ◽  
pp. 595-605 ◽  
Author(s):  
D. P. Partlow ◽  
J. Greggi
Keyword(s):  
Sol Gel ◽  
Epitaxial Films ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Film Properties ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Oriented Polycrystalline ◽  
Diffraction Patterns ◽  
Gel Processing

Thin LiNbO3 films were prepared from polymerized sol-gel precursor solutions having various concentrations and water:alkoxide ratios in an effort to investigate the effects of these and other processing variables on the resultant film properties and microstructure. Films deposted on silicon substrates were mostly amorphous when pyrolyzed at 435°C for 30 min. Randomly oriented polycrystalline films having distinctive microstnietures were produced using longer heating times or higher temperatures. All of the films exhibited low refractive indices due to porosity, which was attributed to the low level of hydrolysis water required to produce stable polymeric precursor solutions. When single-crystal LiNbO4 was used as the substrate, epitaxial growth of the film resulted. This ideal case establishes the feasibility of producing epitaxial films via sol-gel processing. All films were characterized by transmission electron microscopy (TEM) and thin-film x-ray diffraction patterns.

scholarly journals Magnetic Resonance as a Structural Probe of a Uranium (Vi) Sol-Gel Process

1990 ◽  
Vol 180 ◽  
Author(s):  
Charles M. King ◽  
R. Bruce King ◽  
A. Ronald Garber ◽  
Major C. Thompson ◽  
Bruce R. Buchanan
Keyword(s):  
Magnetic Resonance ◽  
National Laboratory ◽  
Sol Gel ◽  
Structural Formula ◽  
Chemical Mechanism ◽  
Nmr Studies ◽  
Technical Literature ◽  
Oak Ridge ◽  
Sol Gel Process ◽  
Gel Processing

ABSTRACTNuclear Magnetic Resonance (NMR) investigations on the Oak Ridge National Laboratory process for sol-gel synthesis of microspherical nuclear fuel (UO2), has been extremely useful in sorting out the chemical mechanism in the sol-gel steps. 13C, 15N, and 1H NMR studies on the HMTA gelation agent (hexamethylenetetramine, C6H12N4) has revealed near quantitative stability of this adamantane-like compound in the sol-gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. 17O NMR of uranyl (UO2++) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, [(UO2)3 (μ3-O)(μ2-OH)3]+, induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results will be presented to illustrate that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH+ is occluded as an ‘intercalation’ cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ ion exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH4)2 [(UO2)8 O4 (OH)10]- 8H2)O. This compound is the precursor to sintered UO2 ceramic fuel.

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