Murata Manufacturing Co., Ltd.

Hitoshi Nishimura

Tomotaka Hirata

Hiroyuki Wada

Masahiro Naito

Kohei Shimada

Sui Uno

Hiroki Awata

Tomomi Koga

Kenji Takagi

Noriyuki Inoue

Takafumi Okamoto

Shinya Isota

Toshihiro Okamatsu

Taketsugu Ogura

A multilayer ceramic capacitor includes a laminated body including an inner layer portion including ceramic dielectric layers and internal electrodes, and outer layer portions including ceramic dielectric layers. External electrodes connected to the internal electrodes are provided on both ends of the laminated body. The main constituent of the inner layer portion is a perovskite-type compound represented by ABO. The outer layer portions include first outer layers and second outer layers respectively containing oxides that differ from each other in main constituents, and boundary reaction layers are provided between the first outer layers and the second outer layers. First ceramic dielectric layers outside the boundary reaction layers differ in color from second ceramic dielectric layers inside the boundary reaction layers.

Multilayer ceramic capacitor

As a dielectric ceramic constituting dielectric layers of a laminated ceramic capacitor, a dielectric ceramic is used which contains, as its main constituent, a perovskite-type compound containing Ca and Zr and optionally containing Sr, Ba, and Ti, and further contains Si, Mn, and Al, and when the total content of Zr and Ti is regarded as 100 parts by mol, the total content (100&#xd7;m) of Ca, Sr, and Ba meets 1.002&#x2266;m&#x2266;1.100 in terms of parts by mol, the Si content n meets 0.5&#x2266;n&#x2266;10 in terms of parts by mol, the Mn content u meets 0.5&#x2266;u&#x2266;10 in terms of parts by mol, and the Al content w meets 0.02&#x2266;w&#x2266;4 in terms of parts by mol, m and n satisfying &#x2212;0.4&#x2266;100(m&#x2212;1)&#x2212;n&#x2266;3.9.

Laminated ceramic capacitor

A laminated ceramic capacitor having a laminated body composed of a plurality of ceramic layers for inner layers; a plurality of internal electrodes at the interfaces between the plurality of ceramic layers for inner layers; and a plurality of ceramic layers for outer layers, provided on the top and bottom so as to sandwich the plurality of ceramic layers for inner layers. The ceramic layers for inner layers are composed of a material containing a multiple oxide including an alkaline-earth metal. The ceramic layers for outer layers respectively have TiOceramic layers containing TiOas their main constituent for certain layers including the outermost layers, and multiple oxide ceramic layers containing a multiple oxide including an alkaline-earth metal for the other layers.

A laminated body that contains a perovskite-type compound containing Sr, Ba, Zr, and Ti and containing; Si; Mn; Al; and V. When the total content of Zr and Ti is 100 parts by mol, the total content m of Sr and Ba meets 100&#x2266;m&#x2266;105, the Si content a meets 0.1&#x2266;a&#x2266;4.0, the Mn content b meets 0.1&#x2266;b&#x2266;4.0, the Al content c meets 0.01&#x2266;c&#x2266;3.0, the V content d meets 0.01&#x2266;d&#x2266;0.3, the molar ratio w of Sr and Ba to Sr meets 0.60&#x2266;w&#x2266;0.95, the molar ratio z of the total of Zr and Ti to Zr meets 0.92&#x2266;z&#x2266;0.98, w and y meets and the crystal grains are 1.2 &#x3bc;m or less in average grain size.

Laminated ceramic capacitor and manufacturing method therefor

A method of manufacturing a laminated ceramic capacitor having a dielectric ceramic which contains, as its main constituent, a perovskite-type compound containing Ca and Zr and optionally containing Sr, Ba, and Ti, and further contains Si, Mn, and Al, and when the total content of Zr and Ti is regarded as 100 parts by mol, the total content (100&#xd7;m) of Ca, Sr, and Ba meets 1.002&#x2266;m&#x2266;1.100 in terms of parts by mol, the Si content n meets 0.5&#x2266;n&#x2266;10 in terms of parts by mol, the Mn content u meets 0.5&#x2266;u&#x2266;10 in terms of parts by mol, and the Al content w meets 0.02&#x2266;w&#x2266;4 in terms of parts by mol, m and n satisfying &#x2212;0.4&#x2266;100(m&#x2212;1)&#x2212;n&#x2266;3.9.

Method for manufacturing laminated ceramic capacitor

A multilayer ceramic capacitor includes a ceramic main body including an inner layer portion including third ceramic layers and a plurality of inner electrodes arranged at interfaces between the third ceramic layers, and first and second outer layer portions respectively including first and second ceramic layers, the first and second ceramic layers being arranged vertically so as to sandwich the inner layer portion. The third ceramic layers and the first and second outer layer portions contain a perovskite-type compound represented by ABOwhere A contains one or more of Ba, Sr, and Ca, B contains one or more of Ti, Zr, and Hf, and O represents oxygen) as a main component. Where a rare-earth element concentration (C) in the third ceramic layers is compared to a rare-earth element concentration (C) in outermost layer portions including at least outermost surfaces of the first and second outer layer portions, C&#x3e;C(inclusive of C=0).

laminated ceramic capacitor which has favorable moisture resistance includes an inner layer section that has dielectric ceramic layers and internal electrodes stacked alternately, and outer layer sections formed outside the inner layer section. The dielectric ceramic layers have a perovskite-type compound including a main constituent containing Ca and Zr, and an additive containing Si and Mn. The average grain size in the dielectric ceramic layers constituting the outer layer sections is smaller than the average grain size in the dielectric ceramic layers constituting the inner layer section. The Si/Mn molar ratio in the dielectric ceramic near the interfaces between the internal electrodes and the dielectric ceramic layers is &#x2266;15.

A dielectric ceramic composition contains a barium titanate based composite oxide as its main constituent, and contains a first accessory constituent including at least Al and a second accessory constituent including one or more elements selected from among Fe, Co, Ni, Cu, and Zn, wherein the content of the Al is 0.02 to 6 parts by mol with respect to 100 parts by mol of the main constituent, and the content ratio of the second accessory constituent to the Al is 0.01 to 0.4 in terms of mols. Dielectric layers are formed from a sintered body of the dielectric ceramic composition. The addition of various types of accessory elements such as rare-earth elements is possible, if necessary. This invention achieves a dielectric ceramic composition which is capable of ensuring favorable DC bias characteristics while ensuring high reliability, and a laminated ceramic capacitor using the dielectric ceramic composition.

Dielectric ceramic composition and laminated ceramic capacitor

A dielectric ceramic composition enabling one to obtain a laminated capacitor which hardly causes degradation of insulation resistance with time under high-humidity even in using a base metal such as Ni as an internal electrode, contains as a main constituent, a constituent represented by (CaSr)(TiZr)Oin which x and y are 0&#x2266;x&#x2266;1 and 0&#x2266;y&#x2266;0.50, and, as accessory constituents, at least 0.5 parts by mol and at most 15 parts by mol of SiO, at least 0.1 parts by mol and at most 10 parts by mol of MnO, and at least 0.01 parts by mol and at most 0.079 parts by mol of AlO, with respect to 100 parts by mol of the main constituent.

Dielectric ceramic composition and temperature compensation laminated capacitor

Provided is a dielectric ceramic which exhibits desired high temperature load resistance characteristics even under a high electric field strength on the order of 15 kV/mm. The dielectric ceramic contains, as its main constituent, a perovskite compound represented by the general formula (BaCaSrGd)(TiZrHfMgZnMn)O, 0&#x2266;h&#x2266;0.03, 0&#x2266;i&#x2266;0.03; 0.042&#x2266;m&#x2266;0.074; 0.94&#x2266;k&#x2266;1.075; 0&#x2266;(y+j)&#x2266;0.05; 0.015&#x2266;n&#x2266;0.07; 0&#x2266;o&#x2266;0.04; 0&#x2266;p&#x2266;0.05; and 1.0&#x3c;m/(n+o)&#x3c;4.3. The dielectric ceramic can be used advantageously as a material for a dielectric ceramic layer provided in a laminated ceramic capacitor.

Dielectric ceramic and laminated ceramic capacitor

A laminated ceramic capacitor is provided which is excellent in reliability even when its dielectric ceramic layers thinned. For a dielectric ceramic in a laminated ceramic capacitor, a ceramic is used which includes a main component containing a barium titanate based composite oxide represented by the general formula: (BaCaSrRe)(TiZrM)O, where Re is La or the like, M is Mg or the like, and the respective relationships of 0.05&#x2266;x&#x2266;0.50, 0.02&#x2266;y&#x2266;0.3, 0.85&#x2266;k&#x2266;1.05, 0&#x2266;h&#x2266;0.25, 0&#x2266;m&#x2266;0.50, and 0&#x2266;n&#x2266;0.40 are satisfied; and an accessory component as a sintering aid, wherein the average grain diameter of crystal grains in a sintered body is 0.6 &#x3bc;m or less.

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Nagaokakyo, Japan

Hitoshi Nishimura