Murata Manufacturing Co., Ltd.

Murata Manufacturingco., Ltd.

Murata Mfg. Co., Ltd.

Myrata Mfg. Co., Ltd.

Yukio Hamaji

Harunobu Sano

Nobuyuki Wada

Yukio Sakabe

Hiroyuki Wada

Takashi Hiramatsu

Jun Ikeda

Toshiki Nishiyama

Kunisaburo Tomono

Tatsuo Kunishi

Shinsei Okabe

Norihiko Sakamoto

Masamitsu Shibata

Hiroshi Komatsu

Yoshio Abe

Shoichi Higuchi

Sakiko Iwamoto

Mitsutoshi Kawamoto

Takanori Nakamura

Tsuyoshi Yamana

Nagato Omori

Hidehiko Tanaka

Yoshiaki Mori

Masami Yabuuchi

Shozo Kojima

Yoshiharu Kato

Junichi Saitoh

Shunsuke Nakaya

A process for manufacturing an electronic part having a ceramic body and an outer electrode form on the surface of the body, the outer electrode including a plurality of layers and having a Sn plating layer as the outermost layer. The Sn plating layer having an average crystal grain size of about 1 &mgr;m or less is formed on a Ni or Ni alloy by electroplating in a plating bath having a pH of about 3 to 10.

Process for manufacturing electronic part

An Sn&mdash;Bi alloy plating bath has a pH about 2.0 to 9.0 and comprises Bi ions, Sn ions, complexing agent (I) and complexing agent (II). Complexing agent (I) can be (a) aliphatic dicarboxylic acids having alkyl groups of 1-3 carbon atoms, (b) aliphatic hydroxymonocarboxylic acids having alkyl groups of 1-3 carbon atoms, (c) aliphatic hydroxypolycarboxylic acids having alkyl groups of 1-4 carbon atoms, (d) monosaccharides, polyhydroxycarboxylic acids produced by partially oxidizing the monosaccharides, and their cyclic ester compounds, and (e) condensed phosphoric acids. Complexing Agent (II) can be (s) ethylenediamineteraacetic acid (EDTA), (t) nitrilotriacetic acid (NTA), and (u) trans-1,2-cyclohexanediaminetetraacetic acid (CyDTA).

Sn-Bi alloy plating bath and method of plating using the same

A dielectric ceramic material containing BaTiO as a primary component and a rare earth element as an additional component, wherein the material satisfies the relation 0.7&lE;M/N so as to make the density of the rare earth metal uniform between crystal grains, and the material satisfies the relation 0.8&lE;L/M so as to make the density of the rare earth metal uniform in a crystal grain. In these relations, M represents the number of crystal grains satisfying the relation 0.5&lE;D /D; N represents the number of crystal grains constituting the ceramic material; and L represents the number of crystal grains satisfying the relations 0.5&lE;D /D and S /D &lE;0.3, wherein D represents the mean density of the rare earth element in an arbitrary crystal grain i, D represents the mean density of the rare earth element in the entirety of the ceramic material, and S represents the standard deviation of the density of the rare earth element in the crystal grain i.

Dielectric ceramic material and monolithic ceramic electronic element

Disclosed is a monolithic ceramic capacitor composed of plural dielectric ceramic layers made of a ceramic material comprising strontium titanate and bismuth oxide or the like, plural inner electrodes made of a base metal material comprising nickel or a nickel alloy, which are laminated via the dielectric ceramic layer to produce the electrostatic capacity of the capacitor, and outer electrodes as electrically connected with the inner electrodes. Each dielectric ceramic layer in the capacitor contains a reduction inhibitor, for example aMO&plus;bMnO &plus;cB O &plus;(100&minus;a&minus;b&minus;c)SiO (where M is at least one of Mg, Sr, Ca and Ba; and a, b and c each are, in % by mol, 10&lE;a&lE;60, 5&lE;b&lE;20 and 20&lE;c&lE;35). In producing the capacitor, the laminate of dielectric ceramic layers may be fired in a neutral or reducing atmosphere without being reduced.

Monolithic ceramic capacitor and method of producing the same

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

An electronic part includes a body and an outer electrode formed on the surface of the body, the outer electrode comprising a plurality of layers and having a Sn plating layer as the outermost layer. The Sn plating layer has an average crystal grain size of about 1 &mgr;m or less.

Electronic parts

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

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.

A multilayer ceramic capacitor and a process for producing the same, which comprises dielectric ceramic layers, internal electrodes disposed between the dielectric ceramic layers, and an external electrode connected to the internal electrodes, the dielectric ceramic layers comprising barium titanate, a bismuth compound, and an anti-reducing agent, the internal electrodes comprising nickel or a nickel alloy.

Multilayer ceramic capacitor and process for producing the same

Disclosed is a monolithic ceramic capacitor composed of plural dielectric ceramic layers made of a ceramic material comprising strontium titanate and bismuth oxide or the like, plural inner electrodes made of a base metal material comprising nickel or a nickel alloy, which are laminated via the dielectric ceramic layer to produce the electrostatic capacity of the capacitor, and outer electrodes as electrically connected with the inner electrodes. Each dielectric ceramic layer in the capacitor contains a reduction inhibitor, for example aMO+bMnO.sub.2 +cB.sub.2 O.sub.3 +(100--a--b--c)SiO.sub.2 (where M is at least one of Mg, Sr, Ca and Ba; and a, b and c each are, in % by mol, 10.ltoreq.a.ltoreq.60, 5.ltoreq.b.ltoreq.20 and 20.ltoreq.c.ltoreq.35). In producing the capacitor, the laminate of dielectric ceramic layers may be fired in a neutral or reducing atmosphere without being reduced.

Growing community of inventors

Otsu, Japan

Yukio Hamaji