Synthesis and Dielectric Properties of SrBi2Nb2O9 Layered Perovskite by Sol-Gel Processing

1998 ◽  
Vol 541 ◽  
Author(s):  
Y. Wu ◽  
F. S. Ohuchi ◽  
G. Z. Cao
Keyword(s):  
Heat Treatment ◽  
Sol Gel ◽  
Dip Coating ◽  
Dielectric Constants ◽  
Layered Perovskite ◽  
Condensation Process ◽  
Complexing Agent ◽  
Low Dielectric ◽  
Gel Processing ◽  
Multiple Step

AbstractFerroelectric layered perovskite strontium bismuth niobium oxide SrBi2Nb2O9(SBN) ceramics and films were made by sol-gel processing. A multiple step hydrolysis-condensation process was applied to the synthesis of the SBN sol by using inorganic salts as precursors with citric acid as a complexing agent. Single phase polycrystalline SBN was obtained after heat-treatment at 650°C. It was found that the dielectric constants of SBN ceramics were dependent on heat-treatment. SEM, XPS, TGA/DTA and XRD analyses indicated that bismuth-deficiency may contribute to the relatively low dielectric constants. While a prolonged firing time at high temperatures may lead to a lattice expansion resulting in a significant decrease of the dielectric constant. C-oriented SBN films were obtained by dip-coating onto SrTiO3 substrates and the films are dense and crack-free with a thickness of 900 nm.

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.

Chemical Solution Deposition of Lanthanum Zirconate Buffer Layers on Biaxially Textured Ni–1.7% Fe–3% W Alloy Substrates for Coated-conductor Fabrication

2002 ◽  
Vol 17 (6) ◽  
pp. 1543-1549 ◽  
Author(s):  
S. Sathyamurthy ◽  
M. Paranthaman ◽  
T. Aytug ◽  
B. W. Kang ◽  
P. M. Martin ◽  
...  
Keyword(s):  
Sol Gel ◽  
Rf Sputtering ◽  
Cube Texture ◽  
Dip Coating ◽  
Buffer Layers ◽  
Lanthanum Zirconate ◽  
Solution Deposition ◽  
Ybco Films ◽  
Current Densities ◽  
Gel Processing

Sol-gel processing of La2Zr2O7 (LZO) buffer layers on biaxially textured Ni–1.7% Fe–3% W alloy substrates using a continuous reel-to-reel dip-coating unit has been studied. The epitaxial LZO films obtained have a strong cube texture and uniform microstructure. The effects of increasing the annealing speed on the texture, microstructure, and carbon content retained in the film were studied. On top of the LZO films, epitaxial layers of yttria-stabilized zirconia and Ceria (CeO2) were deposited using rf sputtering, and YBa2Cu3Ox (YBCO) films were then deposited using pulsed laser deposition. Critical current densities (Jc) of 1.9 MA/cm2 at 77 K and self-field and 0.34 MA/cm2at 77 K and 0.5 T have been obtained on these films. These values are comparable to those obtained on YBCO films deposited on all-vacuum deposited buffer layers and the highest ever obtained using solution seed layers.

Single-layer submicron-thick BaTiO3 coatings from poly(vinylpyrrolidone)-containing sols: Gel-to-ceramic film conversion, densification, and dielectric properties

2001 ◽  
Vol 16 (11) ◽  
pp. 3116-3123 ◽  
Author(s):  
Hiromitsu Kozuka ◽  
Atsushi Higuchi
Keyword(s):  
Heat Treatment ◽  
Condensation Reaction ◽  
Single Layer ◽  
Dip Coating ◽  
Single Step ◽  
Dielectric Constants ◽  
Isothermal Heat Treatment ◽  
Coating Films ◽  
Ceramic Film ◽  
C Decomposition

BaTiO3-coating films were prepared from a solution containing poly(vinylpyrrolidone) (PVP) of molar composition Ba(CH3COO)2:Ti(OC2H5)4:PVP:CH3COOH:H2O: C2H5OH = 1:1:0.5:27:4:5, via nonrepetitive, single-step dip-coating. The gel films were found to be converted into BaTiO3 films via evaporation of the solvent and CH3COOH below 210 °C, decomposition of PVP at 210–360 °C, decomposition of CH3COO− below 440 °C, and crystallization at 500–610 °C. The decomposition of PVP was accompanied by the progress of the condensation reaction, which resulted in significant reduction in film thickness. When the gel films were heated isothermally at 700 °C, crack-free BaTiO3 films as thick as 0.9 μm were obtained. When the gel films were heated isothermally at 360 °C and then at 700 °C, the film became denser. Higher dielectric constants around 290 were found for the film that underwent the isothermal heat treatment at 360 °C. A slower rate of PVP decomposition was thought to be the key for the film densification.

Sol-gel processing of cordierite: Effect of seeding and optimization of heat treatment

1990 ◽  
Vol 5 (5) ◽  
pp. 1095-1103 ◽  
Author(s):  
Ann M. Kazakos ◽  
Sridhar Komarneni ◽  
Rustum Roy
Keyword(s):  
Heat Treatment ◽  
Single Phase ◽  
Excess Free Energy ◽  
Sol Gel ◽  
Nucleating Agents ◽  
Optimum Conditions ◽  
Nanosized Powders ◽  
Nanocomposite Gels ◽  
Powder Compacts ◽  
Gel Processing

Three series of cordierite powders were prepared by the sol-gel route: a single phase (monophasic) gel prepared from alkoxides, a nominally triphasic nanocomposite gel made with two nanosized powders and one solution phase, and a truly compositionally triphasic nanocomposite gel prepared from three nanosized powders. Crystalline α-cordierite seeds were also incorporated with the gels and their effectiveness as nucleating agents was investigated and found to lower the crystallization temperature of α-cordierite by 125–150°C. The densification behavior of powder compacts was examined and alterations made to the heat treatment until optimum conditions were found. The truly triphasic compact sintered at 1300°C for 2 h resulted in 100% of theoretical density whereas the nominally triphasic and monophasis pellets densified to 96% and 80%, respectively. The enhanced densification achieved with powder compacct prepared for triphasic nanocomposite gels is due to part to the excess free energy of the three components.

ChemInform Abstract: Sol-Gel-Derived Mesoporous Silica Films with Low Dielectric Constants.

ChemInform ◽  
2001 ◽  
Vol 32 (10) ◽  
pp. no-no
Author(s):  
Seana Seraji ◽  
Yun Wu ◽  
Michael Forbess ◽  
Steven J. Limmer ◽  
Tammy Chou ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Silica Films ◽  
Low Dielectric

scholarly journals Effect of Deposition Conditions on Phase Content and Mechanical Properties of Yttria-Stabilized Zirconia Thin Films Deposited by Sol-Gel/Dip-Coating

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Francisco J. Cano ◽  
Orlando Castilleja-Escobedo ◽  
L. J. Espinoza-Pérez ◽  
Cecilia Reynosa-Martínez ◽  
Eddie Lopez-Honorato
Keyword(s):  
Heat Treatment ◽  
Wear Rate ◽  
Adhesion Strength ◽  
Surface Defects ◽  
Sol Gel ◽  
Dip Coating ◽  
Yttria Stabilized Zirconia ◽  
Cubic Phase ◽  
Phase Content ◽  
Stabilized Zirconia

The effect of yttria concentration (0-33.4 mol%), extraction rates (0.17, 0.33, 0.50, and 0.67 mm s-1), and the number of layers (up to four) on the phase content, surface defects, thickness, hardness, adhesion strength, and wear rate of yttria-stabilized zirconia coatings produced by sol-gel/dip-coating were studied for its use on thermolabile substrates. At 700°C, a metastable tetragonal phase ( t ″ ) was obtained even with 33.4 mol% yttria when heat treated for 24 hours; however, a fully cubic structure was attained by extending the heat treatment up to 48 hours as confirmed by Raman spectroscopy. Furthermore, it was necessary to use withdrawal speeds of at least 0.67 mm s-1 to produce defect-free coatings. Although the coatings were produced at low temperature, they showed 41% lower wear rate than steel and an adhesion strength of 30 MPa. Our work stresses the importance of the heat treatment history on the stabilization of the cubic phase in sol-gel YSZ coatings.

A Molecular Route to Dip-coated Transition Metal Nitride Thin Films.

2004 ◽  
Vol 848 ◽  
Author(s):  
Andrew W. Jackson ◽  
Andrew L. Hector
Keyword(s):  
Thin Films ◽  
Transition Metal ◽  
Spin Coating ◽  
Sol Gel ◽  
Particle Growth ◽  
Dip Coating ◽  
Stable Emulsion ◽  
Transition Metal Nitride ◽  
Sol Gel Synthesis ◽  
Gel Processing

ABSTRACTThere is an increasing interest in sol-gel synthesis of nitrides. The ability to deposit films of these materials by dip- or spin-coating will increase the range of applications in which they are viable and is an important step toward general sol-gel processing of nitride materials.With transition metals, the ammono based analogue of the well established alkoxy route to gels is inherently difficult to control. Due to the basicity of the system, the overwhelming tendency is of the starting materials to favour particle growth which results in a precipitate rather than a stable emulsion, unless both environment and synthetic pathway are carefully controlled. Hence reports to date of sol-gel routes to nitrides describe production of powders. We report work on a sol-gel route to titanium nitride with the ammonolysis of titanium amides controlled by temperature and chemical moderators, resulting in stable emulsions useful for dip-coating.

scholarly journals Electrochemical and Oxidation Behavior of Yttria Stabilized Zirconia Coating on Zircaloy-4 Synthesized via Sol-Gel Process

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
S. Rezaee ◽  
Gh. R. Rashed ◽  
M. A. Golozar
Keyword(s):  
Heat Treatment ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Dip Coating ◽  
Open Circuit ◽  
Treatment Temperature ◽  
Yttria Stabilized Zirconia ◽  
Coated Sample ◽  
Stabilized Zirconia ◽  
Temperature Oxidation

Sol-gel 8 wt.% Yttria Stabilized Zirconia (YSZ) thin films were prepared on zirconium (zircaloy-4 alloy) by dip-coating technique followed by heat treating at various temperatures (200°C, 400°C, and 700°C) in order to improve both electrochemical corrosion and high temperature oxidation properties of the substrate. Differential thermal analysis and thermogravimetric analysis (DTA-TG) revealed the coating formation process. X-ray diffraction (XRD) was used to determine the crystalline phase structure transformation. The morphological characterization of the coatings was carried out using scanning electron microscopy (SEM). The electrochemical behavior of the coated and uncoated samples was investigated by means of open circuit potential, Tafel, and electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution. The homogeneity and surface appearance of coatings produced was affected by the heat treatment temperature. According to the corrosion parameters, the YSZ coatings showed a considerable increase in the corrosion resistance, especially at higher heat treatment temperatures. The coating with the best quality, from the surface and corrosion point of view, was subjected to oxidation test in air at 800°C. The coated sample presented a 25% reduction in oxidation rate in comparison with bare substrate.

New Carbon-bridged Hybrid Polymers for Low-k Materials

2005 ◽  
Vol 863 ◽  
Author(s):  
Bum-Gyu Choi ◽  
Byung Ro Kim ◽  
Myung-Sun Moon ◽  
Jung-Won Kang ◽  
Min-Jin Ko
Keyword(s):  
Mechanical Properties ◽  
Hybrid Materials ◽  
Chemical Mechanical Planarization ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Metal Line ◽  
Inorganic Hybrid ◽  
Low Dielectric ◽  
Continuous Stiffness Measurement ◽  
Low K

AbstractReducing interline capacitance and line resistance is required to minimize RC delays, reduce power consumption and crosstalk below 100nm node technology. For this purpose, various inorganic- and organic polymers have been tested to reduce dielectric constants in parallel with the use of copper as metal line. Lowering the dielectric constants, in particular, causes the detrimental effect on mechanical properties, and then leads to film damage and/or delamination during chemical-mechanical planarization CMP) or repeated thermal cure cycles. To overcome this issue, new carbon-bridged hybrid materials synthesized by organometallic silane precursors and sol-gel reaction are proposed.In this work, we have developed new organic-inorganic hybrid low-k dielectrics with linear or cyclic carbon bridged structures. The differently bridged carbon structures were formed by a controlled reaction. 1H NMR, 29Si NMR analysis and GC/MSD analysis were conducted for the structural characterization of new hybrid low-k dielectric. The mechanical and dielectric properties of these hybrid materials were characterized by using nanoindentation with continuous stiffness measurement and Al dot MIS techniques. The results indicated that these organic-inorganic hybrid materials were very promising polymers for low-k dielectrics that had low dielectric constants with high thermal and mechanical properties. It has been also demonstrated that electrical and mechanical properties of the hybrid films could be tailored by copolymerization with PMSSQ and through the introduction of porogen.

Dielectric Properties of Sol - Gel Silica Glasses

1986 ◽  
Vol 72 ◽  
Author(s):  
G. V. Chandrashekhar ◽  
M. W. Shafer
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Elemental Carbon ◽  
Sol Gel ◽  
Fused Silica ◽  
Dielectric Constants ◽  
Low Dielectric Constant ◽  
Silica Glasses ◽  
Low Dielectric ◽  
Gel Technique

AbstractDielectric properties have been measured for a series of porous and fully densified silica glasses, prepared by the sol-gel technique starting from Si-methoxide or Si-fume. The results for the partially densified glasses do not show any preferred orientation for porosity. When fully densified (˜2.25 gms/cc) without any prior treatment of the gels, they have dielectric constants of ≥ 6.5 and loss factors of 0.002 at 1 MHz, compared to values of 3.8 and <0.001 for commercial fused silica. There is no corresponding anomaly in the d.c. resistivity. Elemental carbon present to the extent of 400–500 ppm is likely to be the main cause for this enhanced dielectric constant. Extensive cleaning of the gels prior to densification to remove this carbon were not completely successful pointing to the difficulty in preparing high purity, low dielectric constant glasses via the organic sol-gel route at least in the bulk form.

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