Invention Grant
- Patent Title: Dielectric ceramic, method for producing the same, laminated ceramic electronic element, and method for producing the same
- Patent Title (中): 介电陶瓷,其制造方法,层叠陶瓷电子元件及其制造方法
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Application No.: US09233335Application Date: 1999-01-20
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Publication No.: US06205015B1Publication Date: 2001-03-20
- Inventor: Nobuyuki Wada , Jun Ikeda , Takashi Hiramatsu , Yukio Hamaji
- Applicant: Nobuyuki Wada , Jun Ikeda , Takashi Hiramatsu , Yukio Hamaji
- Priority: JP10-008418 19980120; JP10-236736 19980824
- Main IPC: H01G406
- IPC: H01G406

Abstract:
A dielectric ceramic which exhibits an excellent electrostatic capacity-temperature characteristic; which allows use of a base metal such as nickel; which can be fired in a reducing atmosphere; and which is suitable for constituting a dielectric ceramic layer of a laminated ceramic electronic element such as a laminated ceramic capacitor; is obtained by firing barium titanate powder in which the c-axis/a-axis ratio in the perovskite structure is in the range of about 1.003 to 1.010 and the amount of OH groups in the crystal lattice is about 1 wt. % or less. The barium titanate powder a starting material preferably has a maximum particle size of about 0.5 &mgr;m or less and an average particle size of about 0.1-0.3 &mgr;m, and individual particles of the barium titanate powder comprise a low-crystallinity portion 21 and a high-crystallinity portion 23, with the diameter of the low-crystallinity portion being less than about 0.65 times the particle size of the powder. When sintered, the powder satisfies the ratio of (average grain size of the fired dielectric ceramic)/(average particle size of barium titanate powder serving as a starting material), which is referred to as R, of about 0.90-1.2, to thereby suppress considerable grain growth. A laminated ceramic electronic element including a laminate of a plurality of layers of the above-mentioned dielectric ceramic, as well as a method for producing the same, is described.
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