Taiyo Yuden Co., Ltd.

Youichi Mizuno

Koichiro Morita

Kenji Saito

Hirokazu Chazono

Yasunobu Kawamoto

Jun Nishikawa

Yasuyuki Inomata

Jun Ogasawara

Yoshikazu Okino

Tomoya Hagiwara

Noriyuki Kohzu

Toshikazu Toba

Chie Kawamura

Hisamitsu Shizuno

Yuichi Kasuya

Hideya Teraoka

Hirokazu Orimo

A multi-layer ceramic capacitor is made by alternately layering a dielectric layer constituted by a sintered body of a ceramic powder, and an internal electrode layer. The ceramic powder contains, as a main composition, barium titanate powder having a perovskite structure with a median size of 200 nm or smaller as measured by SEM observation, wherein the barium titanate powder is such that the percentage of barium titanate particle having twin defects in the barium titanate powder is less than 10% as measured by TEM observation and that its crystal lattice c/a is 1.0075 or more.

Ceramic powder and multi-layer ceramic capacitor

A multi-layer ceramic capacitor has a laminate of dielectric layers and internal electrode layers laminated alternately with one another, as well as cover layers formed as the outermost layers at the top and bottom of the laminate in the laminating direction, wherein the dielectric layers are constituted by a sintered compact containing a barium titanate and a silicon compound, and a fresnoite phase having an average grain size of 1 &#x3bc;m or less is present in the dielectric layers.

Multi-layer ceramic capacitor

A multi-layer ceramic capacitor is made by alternately layering a dielectric layer constituted by a sintered body of a ceramic powder, and an internal electrode layer. The ceramic powder contains barium titanate powder having a perovskite structure with a median size of 200 nm or smaller as measured by SEM observation, wherein the barium titanate powder is such that the percentage of barium titanate particles having twin defects in the barium titanate powder is 13% or more as measured by TEM observation and that its crystal lattice c/a is 1.0080 or more. The ceramic powder has a wide range of optimum sintering temperatures and thus offers excellent productivity and is particularly useful in the formation of thin dielectric layers of 1 &#x3bc;m or less.

A multi-layer ceramic capacitor is constituted by ceramic dielectric layers alternately laminated with conductive layers, wherein the ceramic dielectric layers are sintered in such a way that core-shell grains having a core-shell structure are mixed with uniform solid-solution grains resulting from uniform progression of the solid solution process. Such multi-layer ceramic capacitor is characterized in that the area ratio of the core-shell grains to all sintered grains constituting the ceramic dielectric layer is 5 to 15% and that the average grain size of all sintered grains including the core-shell grains and uniform solid-solution grains is 0.3 to 0.5 &#x3bc;m.

Multi-layer ceramic capacitor and method of manufacturing the same

A ceramic powder that contains, as a main composition, barium titanate powder having a perovskite structure with an average particle size (median size) of 200 nm or smaller as measured by SEM observation, wherein the barium titanate powder is such that the percentage of barium titanate particle having twin defects in the barium titanate powder is less than 10% as measured by TEM observation and that its crystal lattice c/a is 1.0075 or more. The ceramic powder is particularly useful in the formation of thin dielectric layers of 1 &#x3bc;m or less and can be used to manufacture MLCCs having both desired capacity and longevity traits.

A ceramic powder that contains, as a main composition, barium titanate powder having a perovskite structure with an average particle size (median size) of 200 nm or smaller as measured by SEM observation, wherein the barium titanate powder is such that the percentage of barium titanate particles having twin defects in the barium titanate powder is 13% or more as measured by TEM observation and that its crystal lattice c/a is 1.0080 or more. The ceramic powder has a wide range of optimum sintering temperatures and thus offers excellent productivity and is particularly useful in the formation of thin dielectric layers of 1 &#x3bc;m or less.

A multi-layer ceramic capacitor, which has an internal electrode of good continuity and may be obtained at a relatively low cost, is disclosed. The internal electrode layer comprises metal particles, wherein the arithmetic mean particle diameter of the metal particles, which is determined based on the particle diameter in the direction parallel with the plane direction of the internal electrode layer, is made smaller than the thickness of the internal electrode layer. The multi-layer ceramic capacitor can be obtained by forming the internal electrode layer using a conductive paste containing a conductive power comprising Ni metal particles coated with particles of a base metal selected from Mn, Co, Fe, Cu, Nb, Ba, Ca, Sr, Ti, Zn, V, and rare earth metals, particles of an oxide thereof and applying a heat treatment in a reducing firing atmosphere having an oxygen partial pressure from about 10to 10atm.

Multi-layer ceramic capacitor and manufacturing method thereof

A multilayer ceramic capacitor and a method of manufacturing the same is provided. The capacitor comprises dielectric layers and internal electrode layers alternately stacked. Two of the internal electrode layers that are located outermost and/or at least one of the internal electrode layers that is located inside each outermost internal electrode layer are substantially oxidized and do not function as electrodes. The capacitance of the multilayer ceramic capacitor depends on the unoxidized internal electrode layers other tan the oxidized ones. The method of manufacturing a multilayer ceramic capacitor comprises forming green dielectric layers, forming green internal electrode layers, preparing a green ceramic chip, forming green external electrodes, and firing the green ceramic chip.

Multilayer ceramic capacitor and method for manufacturing the same

In one inventive aspect, a multilayer ceramic capacitor is provided, in which occurrence of cracks can be prevented even when temperature of the capacitor itself is increased. Non-flat portions are formed in both sides in a width direction of each of inner electrode layers. In addition, the non-flat portions comprise regions substantially changed into oxide regions, therefore a thermal expansion coefficient of the non-flat portions can be decreased so that stress due to difference in thermal expansion coefficient to non-flat portions can be reduced, and the stress can be dispersed in accordance with curvature or inclination of the non-flat portions. That is, stress generated when temperature of the capacitor itself is increased is decreased and dispersed, thereby occurrence of cracks due to the stress can be prevented in side margins of the ceramic chip.

Multilayer ceramic capacitor and manufacturing method of the same

A ceramic capacitor has at least one dielectric layer and at least two electrodes having the dielectric layers therebetween. The dielectric layer includes a sintered body of ceramic grains containing a primary component of a perovskite crystal structure in a form of ABOand a ratio A/B of outer portions of the ceramic grains is greater than that of an inner portions thereof.

Ceramic capacitor and method for the manufacture thereof

A ceramic capacitor has at least one dielectric layer and at least two electrodes having the dielectric layers therebetween. The dielectric layer includes a sintered body of ceramic grains containing a primary component of a perovskite crystal structure in a form of ABO and a ratio A/B of outer portions of the ceramic grains is greater than that of an inner portions thereof.

A ceramic capacitor containing at least one dielectric layer formed from a dielectric ceramic composition comprising a sintered body containing ceramic particles having a core/shell structure in an amount of 15% or more based on the total ceramic particles of the sintered body, the core/shell structured particle being composed of a core portion, which is BaTiO crystal, and a shell portion surrounding the core portion, which is made of a solid solution comprising BaTiO as a major component, has excellent temperature characteristics and a long life-time.

Dielectric ceramic composition and ceramic capacitor

The ceramic capacitor in accordance with the present invention is fabricated by employing a dielectric ceramic composition in forming dielectric layers thereof, wherein the dielectric ceramic composition contains an oxide of Ba and Ti, an oxide of Re (Re used herein represents one or more rare-earth elements selected from Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Tb and Y), an oxide of Mg, one or more oxides selected from oxides of Mn, V and Cr, an oxide of Mo and/or W and SiO or a glass component including SiO , wherein the amount of the oxide of Ba and Ti is 100 mol % in terms of BaTiO , the amount of the oxide of Re is 0.25 to 1.5 mol % in terms of Re O , the amount of the oxide of Mg is 0.2 to 1.5 mol % in terms of MgO and the amount of one or more oxides of Mn, V or Cr is 0.03 to 0.6 mol % in terms of Mn O , V O , Cr O , respectively, and the amount of the oxide of Mo and/or W is 0.025 to 0.25 mol % in terms of MoO and WO .

A dielectric ceramic composition includes 100 mol % of an oxide of Ba, Ti and Zr, 0.25 to 1.5 mol % of an oxide of Re, Re representing one or more elements selected from the group consisting of Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Y, 0.1 to 0.4 mol % of an oxide of Mg, 0.03 to 0.6 mol % of oxides of one or more elements selected from the group consisting of Mn, V and Cr and 0.02 to 0.3 mol % of oxides of one or two elements of Mo and W. The ceramic composition further includes a glass component having SiO and x in the oxide of Ba(Ti Zr )O ranges from about 0.05 to about 0.26.

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Tokyo, Japan

Youichi Mizuno