Murata Manufacturing Co., Ltd.

Murata Mfg. Co., Ltd.

Harunobu Sano

Tomoyuki Nakamura

Yukio Hamaji

Hiroyuki Wada

Norihiko Sakamoto

Yukio Sakabe

Toshihiro Okamatsu

Yoshiaki Kohno

Kotaro Hata

Shinobu Mizuno

Kazuo Muto

Kazuhiro Harada

Hiroyasu Konaka

Tomoo Motoki

Kunisaburo Tomono

Masahiro Naito

Nobuyuki Wada

Goro Nishioka

Hiroaki Matoba

Kenji Hori

Akira Kato

Takehisa Sasabayashi

Takashi Hiramatsu

Nagato Omori

Takaharu Miyazaki

Sakiko Iwamoto

Hiroshi Takagi

Seiji Kanba

Norio Nakajima

Hiroshi Tamura

Shinichi Kobayashi

Tadashi Morimoto

Shinsei Okabe

Osamu Yamaoka

Masayuki Ishihara

Hidehiko Tanaka

Shozo Kobayashi

Hisashi Miki

Hiroaki Ichikawa

Motohiro Shimizu

Yoshitaka Kageyama

Toshiya Esumi

Shunsuke Nakaya

Kentaro Sakai

Toshiyuki Ito

Toshihiro Ikamatsu

Akira Kata

Hiroyasu Konakaka

A dielectric ceramic is provided having a high relative dielectric constant, and in the case in which it is used for a multilayer ceramic capacitor, high insulating properties and superior reliability can be obtained even when the thickness of a dielectric ceramic layer is decreased. The dielectric ceramic used for forming the dielectric ceramic layer of a multilayer ceramic capacitor has a composition represented by 100 (BaCaSrGd)(TiZrHfMg)O+pMnO+qSiO+rCuO, in which 0.995&#x2266;k&#x2266;1.010, 0&#x2266;w&#x3c;0.04, 0&#x2266;x&#x2266;0.04, 0&#x2266;y&#x2266;0.10, 0&#x2266;z&#x2266;0.05, 0.015&#x2266;m&#x2266;0.035, 0.015&#x2266;n&#x2266;0.035, 0.01&#x2266;p&#x2266;1.0, 0.5&#x2266;q&#x2266;2.5, and 0.01&#x2266;r&#x2266;5.0. In addition, a is a value selected with respect to the deviation from 3 so that the primary component is electrically neutral.

Dielectric ceramic and multilayer ceramic capacitor

Dielectric ceramic having a high dielectric constant of 5,500 or more and exhibiting good dielectric constant temperature characteristic, and a small, high-capacitance monolithic ceramic capacitor having an electrostatic capacitance temperature characteristic satisfying the X5R characteristic are provided. The dielectric ceramic includes a BaTiObased or (Ba,Ca)TiObased primary component, a rare-earth element and Cu, and has a structure composed of crystal grains and grain boundaries between the crystal grains. The ratio of the average concentration of the rare-earth element in the grain boundaries to the average concentration of the rare-earth element in the inside of the crystal grains is less than 2, and in a cross section of the dielectric ceramic, the rare-earth element is present in 90% or more of the region of first crystal grains, the number of which is 55% to 85% of the crystal grains, and the rare-earth element is present in less than 10% of the region of second crystal grains, the number of which is 15% to 45% of the crystal grains.

Dielectric ceramic, method for manufacturing dielectric ceramic, and monolithic ceramic capacitor

A nonreducing dielectric ceramic comprising a (Sr, Ca)(Ti, Zr)O-based perovskite principal crystal phase containing 55 mole percent or more of SrTiOand whose powder CuK&#x3b1; X-ray diffraction pattern exhibits a ratio of less than 5% of the maximum peak intensity of the accessory crystal phases being the other crystal phases to the intensity of the maximum peak of the perovskite crystal phase, which is present at 2&#x3b8;=25&#xb0; to 35&#xb0;. This strontium titanate-based nonreducing dielectric ceramic has a high relative dielectric constant of 150 or more, a low third-order harmonic distortion ratio, and an excellent reliability in a high temperature-loading test. Accordingly, it is advantageously used for forming dielectric ceramic layers of a monolithic ceramic capacitor.

Nonreducing dielectric ceramic, and manufacturing method and monolithic ceramic capacitor of the same

A dielectric ceramic includes a compound represented by the general formula: (BaCa)(TiZrCu)O(where 0.96&#x2266;m&#x2266;1.02, 0.001&#x2266;x&#x2266;0.03, 0&#x2266;t&#x2266;0.1, and 0&#x2266;u&#x2266;0.06) as a primary component, a rare earth element Re such as Dy, a metal element M such as Mn, Mg, and Si. In the dielectric ceramic, the Cu is uniformly and dispersedly present in the primary phase grain forming the primary component, and the contents of the accessory components with respect to 100 molar parts of the primary component are 0.1 to 1.5 molar parts of Re, 0.1 to 0.6 molar parts of M, 0.1 to 1.5 molar parts of Mg and 0.1 to 2.0 molar parts of Si. Accordingly, a multilayer ceramic capacitor can be realized which has a high dielectric constant, superior temperature properties, and a high reliability, and also has a small change in electrostatic capacitance with time.

A dielectric ceramic composition of the present invention is represented by the general formula, MgSiO+aSrTiO, wherein x, y and a satisfy the relations of 1.70&#x2266;x&#x2266;1.99, 0.98&#x2266;y&#x2266;1.02, and 0.05&#x2266;a&#x2266;0.40, respectively.

Dielectric ceramic composition and multilayer electronic component

The dielectric ceramic has a composition represented by general formula 100(BaSrCa)(TiZr)O+aBaO+bRO+cMgO+dMnO+eCuO+fVO+gXO(where R is a rare-earth element such as La, Ce or Pr; and XOis an oxide group including at least Si); and 0&#x2266;x&#x2266;0.05, 0&#x2266;y&#x2266;0.08 (preferably 0.02&#x2266;y&#x2266;0.08), 0&#x2266;z&#x2266;0.05, 0.990&#x2266;m, 100.2&#x2266;(100 m+a)&#x2266;102, 0.05&#x2266;b&#x2266;0.5, 0.05&#x2266;c&#x2266;2, 0.05&#x2266;d&#x2266;1.3, 0.1&#x2266;e&#x2266;1.0, 0.02&#x2266;f&#x2266;0.15, and 0.2&#x2266;g&#x2266;2. With this composition, a monolithic ceramic capacitor retaining good dielectric characteristics and temperature characteristics even if a high field strength voltage is applied by further thinning the dielectric layers thereof and having excellent reliability achieving good isolating property, dielectric strength, and high-temperature load life is obtained.

Dielectric ceramic and monolithic ceramic capacitor

A dielectric ceramic is obtained by the steps of obtaining a reaction product composed of a barium titanate base composite oxide represented by the general formula (BaCaSrGd)k(TiZrHfMg)O, in which 0.995&#x2266;k&#x2266;1.015, 0&#x2266;h&#x2266;0.03, 0&#x2266;i&#x2266;0.03, 0.015&#x2266;m&#x2266;0.035, 0&#x2266;y&#x3c;0.05, 0&#x2266;j&#x3c;0.05, 0&#x2266;(y+j)&#x3c;0.05, and 0.015&#x2266;n&#x2266;0.035 hold; mixing less than 1.5 moles of Ma (Ba or the like), less than 1.0 mole of Mb (Mn or the like), and 0.5 to 2.0 moles of Mc (Si or the like) with respect to 100 moles of the reaction product; and firing the mixture thus obtained. This dielectric ceramic has superior humidity resistance, satisfies the F characteristic of the JIS standard and the Y5V characteristic of the EIA standard, has a relative dielectric constant of 9,000 or more, and has superior high-temperature reliability.

Dielectric ceramic, manufacturing method therefor, and multilayer ceramic capacitor

A dielectric ceramic has a ceramic structure of crystal grains and grain boundaries between the crystal grains. The crystal grains are of a main component represented by the formula ABOand an additive containing a rare earth element wherein A is at least one of barium, calcium, and strontium, barium being an essential element, and B is at least one of titanium, zirconium, and hafnium, titanium being an essential element. The average rare earth element concentration in the interior of the crystal grains is about 50% or less the average rare earth element concentration at the grain boundaries. Furthermore, about 20% to 70% of the crystal grains have a rare earth element concentration in the center of the crystal grain of at least about 1/50 the maximum rare earth element concentration in a region extending inward from the surface by a distance corresponding to about 5% of the diameter of the crystal grain.

Dielectric ceramic, methods for making and evaluating the same, and monolithic ceramic electronic component

A dielectric ceramic formed by firing in a reducing atmosphere is provided. A multilayer ceramic capacitor formed by using the aforementioned dielectric ceramic has superior reliability even when the thicknesses of dielectric ceramic layers formed therefrom are reduced. The dielectric ceramic has crystal grains; and crystal boundaries and triple points, which are located between the crystal grains. The crystal grains contain perovskite compound grains composed of a perovskite compound represented by ABO(where A is Ba and Ca, or Ba, Ca and Sr; B is Ti, or Ti and a part thereof which is replaced with at least one of Zr and Hf) and crystal oxide grains composed of a crystal oxide containing at least Ba, Ti and Si, and about 80% or more of the number of the triple points each have a cross-sectional area of about 8 nmor less.

Dielectric ceramic, manufacturing method thereof, and multilayer ceramic capacitor

A dielectric ceramic includes, in composition, a perovskite-type compound having the general formula ABOcontaining Ba, Ca and Ti, and an additive component containing Si, R(La or the like), and M (Mn or the like), the additive component not being solid-dissolved and, moreover, the major component existing in at least 90% of the cross-section of each of the crystal grains of which the number is equal to at least 85% of that of all of the crystal grains contained in the dielectric ceramic, at least the Ba, the Ca, the Ti, the Si, the R, and the M being contained at at least 85% of the analytical points in the crystal grain boundaries of the dielectric ceramic.

Dielectric ceramic, method of producing the same, and monolithic ceramic capacitor

A dielectric ceramic includes a principal component which contains Ba, Ca and Ti and which has a perovskite structure represented by the general formula ABO ; additive components containing, for example, La and Mn; and a sintering aid, wherein crystal grains of the dielectric ceramic contain Ca, and the intergranular variation in the average Ca concentration within each grain is about 5% or more, in terms of CV value, or the ratio of the number of crystal grains in which the intragranular variation in the Ca concentration is about 5% or more, in terms of CV value, to the total number of crystal grains containing Ca is about 10% or more. A monolithic ceramic capacitor fabricated using the dielectric ceramic is also disclosed.

Dielectric ceramic and monolithic ceramic capacitor including same

A dielectric ceramic is composed of ABO as the main component and a rare earth element, wherein A represents barium which may be partly replaced with at least one of calcium and strontium, and B represents titanium which may be partly replaced with at least one selected from zirconium and hafnium. At least 70% of crystal grains of the dielectric ceramic have a cross-section in which a first region containing dissolved rare earth element occupies 5 to 70% of the area of the cross section and a second region free of the dissolved rare earth element occupies 10 to 80% of the periphery of the cross-section. A monolithic ceramic capacitor having thin dielectric ceramic layers composed of this dielectric ceramic exhibits superior capacitance-temperature characteristics and high reliability.

Dielectric ceramic, method for making the same, and monolithic ceramic capacitor

A non-reducing dielectric ceramic contains Ca, Zr and Ti as metallic elements and does not contain Pb. In a CuK&agr; X-ray diffraction pattern, the ratio of the maximum peak intensity of secondary crystal phases to the maximum peak intensity at 2&thgr;&equals;25&deg; to 35&deg; of a perovskite primary crystal phase is about 12% or less, the secondary crystal phases including all the crystal phases other than the perovskite primary crystal phase. The non-reducing dielectric ceramic exhibits superior insulating resistance and dielectric loss after firing in a neutral or reducing atmosphere and high reliability in a high-temperature loading lifetime test and is useful for producing compact high-capacitance monolithic ceramic capacitors.

Non-reducing dielectric ceramic, monolithic ceramic capacitor using the same, and method for making non-reducing dielectric ceramic

Provided is a dielectric ceramic composition suitably used for forming dielectric ceramic layers which constitute a laminated ceramic capacitor obtained by firing in a reducing atmosphere. Even when the dielectric ceramic composition is formed into thin dielectric ceramic layers, a highly reliable laminated ceramic capacitor having a small temperature coefficient of capacitance, a long lifetime under high temperature and high pressure conditions, and a small change in electrostatic capacitance with time under a DC voltage application can be realized. The dielectric ceramic composition contains a primary component, an additive component, and an auxiliary sintering agent, wherein the primary component and the additive component are represented by the formula 100BaTiO &plus;a&lcub;(1&minus;b)R&plus;bV&rcub;&plus;cM, and 1.25&lE;a&lE;8.0, 0<b&lE;0.2, 1.0<c&lE;6.0, and a/c>1.1 are satisfied. R is a compound containing at least one element selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu; V is a compound containing vanadium; and M is a compound containing at least one element selected from the group consisting of Mn, Ni, Mg, Fe and Zn.

Dielectric ceramic composition and laminated ceramic capacitor

A dielectric ceramic includes ABO as a major component and R and M as accessory components, where A is at least one of Ba, Sr and Ca; B is at least one of Ti, Zr and Hf; R is at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y; and M is at least one of Ni, Co, Fe, Cr and Mn. The dielectric ceramic contains the components R and M at about 70% or more of analysis points in grain boundaries. This dielectric ceramic is suitable for use in dielectric ceramic layers of a multilayer ceramic capacitor obtained by firing in a reducing atmosphere, has a long life at high temperatures and high voltages, exhibits less time-dependent change in electrostatic capacity under application of a direct-current voltage and has satisfactory reliability even when its thickness is reduced.

Dielectric ceramic, process for producing the same and multilayer ceramic capacitor

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Kyoto, Japan

Harunobu Sano