Murata Manufacturing Co., Ltd.

Murata Manufacturingco., Ltd.

Murata Mfg. Co., Ltd.

Nobuyuki Wada

Yukio Hamaji

Takashi Hiramatsu

Yoshiaki Kohno

Jun Ikeda

Harunobu Sano

Takanori Nakamura

Toshikazu Takeda

Tsuyoshi Yamana

Yukio Sakabe

Hiroshi Takagi

Seiji Kanba

Masahiko Kimura

Norihiko Sakamoto

Kosuke Shiratsuyu

Takaharu Miyazaki

Hidehiko Tanaka

Noriyuki Kubodera

Shinobu Mizuno

Shozo Kojima

Masamitsu Shibata

Syunsuke Nakaya

Yukako Takahashi

A dielectric ceramic that forms dielectric ceramic layers of a multilayer ceramic capacitor contains a Ba and Ti containing perovskite compound, Ca, R (R denotes a rare earth element, such as La), M (M denotes Mn or the like), and Si. The Ca content ranges from 0.5 to 2.5 molar parts, the R content ranges from 0.5 to 4 molar parts, the M content ranges from 0.5 to 2 molar parts, and the Si content ranges from 1 to 4 molar parts, based on 100 molar parts of Ti. In perovskite crystal grains, the Ca diffusion depth is 10% or less of the average grain size of the crystal grains, and the Ca concentration in a Ca diffusion region is 0.2 to 5 molar parts higher than the Ca concentration near the center of each of the crystal grains.

Multilayer ceramic capacitor and method for producing the same

A method for manufacturing a piezoelectric element that includes a piezoelectric ceramic body containing an internal electrode. The piezoelectric ceramic body is mainly made of a perovskite complex oxide containing an alkali metal niobate-based compound containing at least one element selected from among K, Li, and Na. The internal electrode is made of a base metal material, such as Ni or Cu. The piezoelectric element is produced by co-sintering the internal electrode and the piezoelectric ceramic body in a reducing atmosphere.

Method of manufacturing a piezoelectric element

A dielectric ceramic composition of the present invention contains, as a main component, a tungsten-bronze-type composite oxide represented by a composition formula (KNa)SrNbO(wherein 0&#x2266;y&#x3c;0.2) and, as an auxiliary component, Mn in an amount in the range of 0.1 to 40 parts by mole relative to 100 parts by mole of the main component.

Dielectric ceramic composition and monolithic ceramic capacitor

The present invention provides a dielectric ceramic composition whose electrostatic capacity has an excellently low temperature dependence; which can be fired in a reducing atmosphere; and which is advantageously used in a laminated ceramic capacitor having an internal electrode formed of a base metal such as nickel or nickel alloy. The dielectric ceramic composition is represented by the following formula: &lcub;Ba Ca O&rcub; TiO &plus;&agr;MgO&plus;&bgr;MnO, wherein 0.001&lE;&agr;&lE;0.05; 0.001&lE;&bgr;&lE;0.025; 1.000<m&lE;1.035; and 0.02&lE;x&lE;0.15.

Laminated ceramic capacitor

A dielectric ceramic which exhibits small variation in dielectric constant, allows use of a base metal, can be fired in a reducing atmosphere and which is suitable for constituting a dielectric ceramic layer for, e.g., a laminated ceramic capacitor is obtained by firing barium titanate powder in which the c-axis/a-axis ratio in the perovskite structure is about 1.000 or more and less than about 1.003 and the amount of OH groups in the crystal lattice is about 2.0 wt. % or less. The barium titanate powder starting material preferably has a maximum particle size of about 0.3 &mgr;m or less and an average particle size of about 0.05-0.15 &mgr;m. Each particle of the barium titanate powder preferably comprises a low-crystallinity portion and a high-crystallinity portion, the diameter of the low-crystallinity portion being about 0.5 times or more 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 starting material), 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.

Dielectric ceramic, method for producing the same, laminated ceramic electronic element, and method for producing the same

A monolithic ceramic electronic component includes a laminate including a plurality of ceramic layers obtained by sintering a ceramic raw material powder, and a plurality of internal electrodes located between the ceramic layers and obtained by sintering a metallic powder. The ceramic layers have a thickness of about 3 &mgr;m or less and are composed of ceramic grains having an average particle diameter of more than about 0.5 &mgr;m, the particle diameter of the ceramic grains in the thickness direction of the ceramic layers is smaller than the thickness of the ceramic layers, and the internal electrodes have a thickness of about 0.2 to 0.7 &mgr;m. Preferably, the monolithic ceramic electronic component further includes an external electrode formed on each of the opposing ends of the laminate, the ceramic layers are composed of a ceramic dielectric material, and each of the plurality of internal electrodes is formed with an edge being exposed to either one of the opposing ends of the laminate so as to be electrically connected to either one of the external electrodes to form a monolithic ceramic capacitor.

Monolithic ceramic electronic component

A monolithic ceramic component has inner electrodes which are thin having a thickness of from about 0.2 &mgr;m to 0.7 min, and thereby, delamination is inhibited even though ceramic layers are thin, having a thickness up to about 3 &mgr;m. The mean particle size of the ceramic grains of the ceramic layers is up to 0.5 &mgr;m, so that the concavities and convexities at the interfaces between the inner electrodes and the ceramic layers can be reduced. Preferably, metal powder in a paste used to form the inner electrodes has a mean particle size of from about 10 to 200 nm, and thereby, the metal filling ratio and the smoothness of the inner electrodes can be enhanced, and the coverage can be improved.

Provided is a highly reliable laminated ceramic capacitor in which decrease of dielectric constant under a high electric field is small and which satisfies the B-grade and X7R grade characteristics, using Ni for the inner electrodes, wherein the dielectric material contains about 0.2 to 5.0 parts by weight of Li,O&mdash;(Si, Ti),&mdash;MO oxides (MO is at least one of the compounds of Al,O,and ZrO,) or SiO,&mdash;TiO,&mdash;XO oxides (XO is at least one of the compounds of BaO, CaO, SrO, MgO, ZnO and MnO) relative to 100 parts by weight of a principal component represented by (Ba,Ca,O),TiO,&plus;&agr;Re,O,&plus;&bgr;MgO&plus;&ggr;MnO (Re,O,represents at least one of Y,O,, Gd,O,, Tb,O,, Dy,O,, Ho,O,, Er,O,and Yb,O,).

Dielectric ceramic composition and laminated ceramic capacitor using the same

Dielectric ceramic composition

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,and a high-crystallinity portion,, 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.

The present invention provides a dielectric ceramic composition containing 100 parts by weight of essential component represented by (BaO).sub.m TiO.sub.2 +M.sub.2 O.sub.3 +R.sub.2 O.sub.3 +BaZrO.sub.3 +MgO+MnO (wherein M.sub.2 O.sub.3 represents Sc.sub.2 O.sub.3 and/or at least one of Eu.sub.2 O.sub.3, Gd.sub.2 O.sub.3, Tb.sub.2 O.sub.3 and Dy.sub.2 O.sub.3) and 0.2 to 3.0 parts by weight of a side component represented by Li.sub.2 O--(Si, Ti)O.sub.2 --MO (wherein MO represents Al.sub.2 O.sub.3 and or ZrO.sub.2) or SiO.sub.2 --TiO.sub.2 --XO (wherein XO represents at least one of BaO, CaO, SrO, MgO, ZnO and MnO), and a ceramic capacitor using the same.

Dielectric ceramic composition and monolithic ceramic capacitor using

The present invention provides a nonreducing dielectric ceramic including a sintered compact composed of a plurality of particles expressed by a maximum diameter of about 0.5 .mu.m and an average diameter of about 0.1 to 0.3 .mu.m, each of the plurality of particles having a uniform composition and a uniform crystal system, and individual particles having the same composition and crystal system. A compact monolithic electronic part with high-reliability can be realized by using such ceramic.

Dielectric ceramic and monolithic ceramic electronic part using the same

A nonreducible dielectric ceramic composition of a system, (A.sub.1-x R.sub.x).sub.y BO.sub.3, is produced using using at least one compound selected from the group consisting of water-soluble inorganic compounds and organic solvent-soluble organometallic compounds of rare earth element R together with oxides and/or carbonates of elements A and B.

Production of nonreducible dielectric ceramic composition

A functionally gradient circuit board is constituted by a mixture of a metal and an insulating ceramic composition, the abundance ratio of the metal component to the component of the insulating ceramic composition being changed in the direction of thickness of the board.

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Shiga-ken, Japan

Nobuyuki Wada