Formation of LiNbO3 powders and thin films by hydrolysis of metal alkoxides
TL;DR: In this paper, LiNbO3 was prepared by simultaneous hydrolysis of lithium and niobium alkoxides (in the mole ratio Li : Nb = 1 : 1) followed by heat treatment.
Abstract: Crystalline LiNbO3 was prepared by simultaneous hydrolysis of lithium and niobium alkoxides (in the mole ratio Li : Nb = 1 :1) followed by heat treatment. Crystallization of LiNbO3 occurs in a wide temperature region, 350 to 700° C, directly from an amorphous hydrolysis product containing residual alkoxy and hydroxy groups. Heat treatment at 700° C results in the formation of fully crystalline LiNbO3 powder with completely formed ferroelectric properties. Hydrolysis of metal alkoxide solutions is successfully used to obtain high-quality LiNbO3 crystalline thin films.
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TL;DR: A review of the sol-gel processing of electrical and magnetic ceramics is given in this article, which includes the synthesis routes and fabrication of ceramic components, including conductors, resistors and insulators, and includes, electronic and ionic properties, varistors, thermistors, superconductors, dielectrics, ferroelectrics, magnetics, and microelectronic materials.
92 citations
TL;DR: In this article, pure lithium niobate (LN) powders were prepared by a wet-chemical method, where Niobium oxide was dissolved in a hot aqueous solution of oxalic acid, followed by the precipitation of niobic acid by the addition of ammonia solution until pH=11.
60 citations
TL;DR: In this article, the formation of the I-III group metal alkoxoniobates has been studied using the physicochemical analysis method, namely the investigation of solubility isotherms for the M 2 O 2 four-membered cycles in edge sharing octahedra.
60 citations
TL;DR: In this paper, a biphasic LiNbO3 was calcined at various elevated temperatures and studied with FTIR/XRD/DTA/SEM methods for gel composition, crystallization, and morphological development.
Abstract: Gel material (Li:Nb = 1:1) of LiNbO3 has been prepared from a novel precursor system, niobium(V) ethoxide−lithium nitrate. The resultant biphasic gel is calcined at various elevated temperatures and studied with FTIR/XRD/DTA/SEM methods for gel composition, crystallization, and morphological development. The progressive formation (crystallization) of LiNbO3 is observed over the calcination temperature range 200−400 °C. It is found that grain growth and secondary recrystallization occur sequentially at higher temperatures. Retention behaviors of carbon-containing species and nitrate ions encapsulated in the gel matrix and a possible LiNbO3 formation mechanism are also addressed.
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TL;DR: A comprehensive X-ray study of lithium niobate at room temperature has been made, prompted by the recently discovered excellent nonlinear optical properties and unusual ferroelectric behavior of this crystal as discussed by the authors.
299 citations
TL;DR: Simultaneous hydrolytic decomposition of barium bis isopropoxide and titanium tetrakis tertiary amyloxide was used to produce stoichiometric BaTiO3.
Abstract: Simultaneous hydrolytic decomposition of barium bis isopropoxide and titanium tetrakis tertiary amyloxide was used to produce stoichiometric BaTiO3. The particle size range was 50 to 150 A. The purity was 99.98+%, the major contaminant being silicon from the glass apparatus. The homogeneity and stoichiometry of the powder were demonstrated by electron microscopy and wet chemical analysis. X-ray and infrared analyses indicate that the material, as-prepared and helium-dried at 5O°C, has the titanate crystal structure. The powder sinters at 1300°C to a high density, translucent body with a uniform microstructure. The experiments suggest that the alkoxy-based preparation of oxides may provide a broad base for improving the quality and reproducibility of electrical and structural ceramics.
247 citations
TL;DR: In this article, it has been shown that thin sheet formation is only possible with the starting solutions exhibiting spinnability in the course of hydrolysis and polymerization of the metal alkoxide.
Abstract: Fundamental problems in preparing thin sheets and coating films of oxides have been discussed on the basis of experiments made in the author's laboratory. It has been found that thin sheet formation is only possible with the starting solutions exhibiting spinnability in the course of hydrolysis and polymerization of the metal alkoxide. This requirement is satisfied by the formation of linear polymers in the solution. Coating films have been prepared by the dip-withdrawal technique. It has been found that coating films of 0.05–0.5 μm in thickness can be provided by one dip-coating run and repetition of the application leads to thicker coating films. The preparation of SiO2, BaTiO3 and transition metal oxide-SiO2 coating films has been discussed.
227 citations
TL;DR: The high surface activity associated with these powders make it possible relatively low temperature processing of the powders compact to near theoretical density and uniform fine grain size bodies as mentioned in this paper, and transmission electron microscopy is used to show nucleation, growth crystallite morphology of the synthesized powders, and microstructural features observed.
168 citations
TL;DR: In this paper, powder preparation from metal alkoxides is discussed in comparison with other conventional techniques, and the advantage of powder preparation is that the ultrafine, monodispersive and compositionally homogenous powder is obtained easily by a simple hydrolysis reaction.
Abstract: An utilization of metal alkoxide is one of the high potential methods for preparing electroceramic powders. The advantage of powder preparation from metal alkoxides is that the ultrafine, monodispersive and compositionally homogenous powder is obtained easily by a simple hydrolysis reaction. Powder preparations from metal alkoxides are discussed in comparison with other conventional techniques.
28 citations