Barium titanate powder and preparation method thereof

Abstract

The method for producing barium titanate powder comprises mixing a barium compound producing barium oxide by pyrolysis and titanium dioxide having 99.8 wt.% or more of purity, 5 m not 2/g or more of specific surface area obtained by BET method and 30% or less, preferably 5% or less, rutile ratio obtained by X-ray diffraction method, and calcining preferably under a circumferential pressure of 1x10 not 3 Pa or less in total pressure, wherein the obtained barium titanate powder is microparticle and contains high tetragonal crystallinity.The barium titanate powder to be sintered is provided to obtain a dielectric in a laminated ceramic capacitor, wherein the powder is down-sized and improved in crystal form to enable to improve the temperature characteristic of capacitance in the laminated ceramic capacitor.

Description

technical field [0001] The invention relates to barium titanate powder and a preparation method thereof, in particular to barium titanate powder with relatively high square crystallinity and a preparation method thereof. Background technique [0002] As a method for producing barium titanate powder for obtaining dielectric ceramics, a solid phase reaction method has been used conventionally. To synthesize barium titanate by this solid phase reaction method, a method of mixing and calcining powders of barium carbonate and titanium dioxide is widely used. In order to obtain fine-grained barium titanate powder by this method, fine-grained barium carbonate powder and fine-grained titanium dioxide powder are mixed as uniformly as possible. [0003] In addition, in the above method, as titanium dioxide, in order not to deteriorate the properties of the resulting dielectric ceramic, typically, a high-purity substance obtained by thermally decomposing titanium tetrachloride is used....

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Problems solved by technology

[0005] However, if fine-grained rutile-type titanium dioxide powder is used to granulate the barium titanate powder, there is a problem that the tetragonal crystallinity of the obtained barium titanate becomes low due to the poor reactivity of the rutile-type titanium dioxide powder.

Moreover, if the tetragonal crystallinity of barium titanate is low, for example, when it is used as a raw material powder of a dielectric in a laminated ceramic capacitor, in the sintering process, the added components added to the raw material powder are likely to be solid-dissolved in barium titanate, Therefore, it is difficult to obtain a sintered body of a core-shell structure after sintering, and thus there is a problem that the temperature characteristic of the electrostatic capacitance of the resulting laminated ceramic capacitor deteriorates.

[0006]