The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 22, 1994
Filed:
Nov. 10, 1993
Teiji Sato, Tokyo, JP;
Hitoshi Nakata, Tokyo, JP;
Takayuki Ishizuki, Tokyo, JP;
Shoichi Iwaya, Tokyo, JP;
Koji Takahashi, Tokyo, JP;
Yuuiti Sannohe, Tokyo, JP;
Hitoshi Tanaka, Tokyo, JP;
Mizusawa Industrial Chemicals Ltd., Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
A process for producing a columbite-type niobate and a process for producing a niobium-containing lead-type perovskite compound using the columbite-type niobate. A precursor slurry of a columbite compound composed of a fresh niobium hydroxide, a metal acetate and ammonium aqueous solution is spray-dried, and is calcined at 500.degree. C. or higher to obtain a crystalline columbite-type compound having grain sizes of 1 .mu.m or smaller to which was then mixed a lead component. The mixture is calcined, pulverized and is sintered at a temperature of 800.degree. to 1100.degree. C. to synthesize a highly dielectric material of a niobium-containing lead-type composite perovskite. The precursor of columbite is calcined at 500.degree. to 1100.degree. C. to obtain fine columbite-type niobate crystals of grain sizes of 1 .mu.m or smaller. A lead-type perovskite compound using the above crystals can be sintered at a temperature of as low as 950.degree. C. or lower, and the sintered product thereof has a homogeneous and fine texture and excellent dielectric properties that could not be obtained by the conventional solid-phase process.