Kyocera Corporation

Nobuo Yokoe

Takashi Okawa

Nobuyoshi Fujikawa

Hitoshi Ohkoda

Kazuyoshi Yamashita

Hiroshi Kikuyama

Syuichi Kawaminami

When the ratio of a dielectric ceramic composition is expressed as xPb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3 --yPb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3 --zPb(Sm.sub.1/2 Nb.sub.1/2) O.sub.3, the values x, y and z are set to lie inside the coordinates A, B, C, D, E (but excluding the segment AE) in a triangular diagram of FIG. 1, and wherein BaTiO.sub.3 is added thereto at a ratio of smaller 10 than 10 mol % and MnO.sub.2 is further added thereto at a ratio of from 0.01 to 0.6% by weight. There is obtained a dielectric ceramic which has a high dielectric constant, a low dissipation factor, a temperature more stable of dielectric constant, a good ceramic density and ceramic strength and that can be baked at a low temperature, and that are usable to MLCCS using Ag-Pd electrodes.

Dielectric ceramic composition

Disclosed is a dielectric ceramic material having a chemical composition represented by the formula Sr(Ni.sub.1/3 Nb.sub.2/3)O.sub.3 or (1-x)Sr(Ni.sub.1/3 Nb.sub.2/3)O.sub.3.xBaTiO.sub.3 in which x is a positive number of up to 0.3 and also having a perovskite structure. This dielectric material has a small dielectric loss and a large dielectric constant, and the temperature coefficient of the resonance frequency can be controlled to a small value within a certain range. The dielectric ceramic material is valuably used for microwave dielectric ceramics.

In a multilayer ceramic capacitor comprising internal electrodes of an Ag-Pd alloy, by incorporating 0.05 to 0.7%, by weight of Ag into a ceramic dielectric layer, the equivalent series resistance can be reduced and the capacitance can be increased. Incorporation of Ag in the dielectric layer can be accomplished by adding Ag.sub.2 O into a green sheet of the dielectric material in advance or by firing a green sheet of the dielectric material in a powder containing Ag.sub.2 O.

Multilayer ceramic capacitor and process for preparation thereof

Disclosed is a multilayer ceramic capacitor comprising internal electrodes composed of nickel and terminations composed of a composition comprising at least one member selected from nickel, cobalt and copper and a zinc borosilicate glass. A zinc borosilicate glass comprising 40 to 65 mole % of ZnO, 20 to 40 mole % of B.sub.2 O.sub.3 and 10 to 35 mole % of SiO.sub.2 is especially suitable as the glass component. The terminations are excellent in adhesion to the internal electrodes and adhesion to a dielectric body.

Multilayer ceramic capacitor

Disclosed is a dielectric ceramic material comprising lanthanum magnesiumtitanate having a perovskite structure. The lanthanum magnesiumtitanate is preferably used in the form of a composition of the lanthanum magnesiumtitanate and calcium titanate as the dielectric ceramic material. The dielectric ceramic material has a small dielectric loss and a large dielectric constant, and the temperature coefficient of the resonance frequency can be controlled to a small value within a certain range. This dielectric material is valuable as a microwave resonator.

Dielectric ceramic material

A dielectric ceramic composition prepared by adding 0.1 to 1.3% of B.sub.2 O.sub.3, 1.0 to 3.0% of SiO.sub.2 and 0.5 to 3.0% of ZnO to a composition comprising 18.0 to 27.0% of BaTiO.sub.2, 31.6 to 36.3% of Nd.sub.2 O.sub.3, 27.6 to 35.5% of TiO.sub.2, 2.5 to 8.1% of Bi.sub.2 O.sub.3 and 5.6 to 9.0% of Pb.sub.3 O.sub.4, all percentages being by weight. This dielectric composition has a high dielectric constant and a temperature coefficient controlled within a narrow range and can be fired at relatively low temperatures. Because of these properties, it is used as a multilayer ceramic capacitor in combination with an electrode composed of an Ag-Pd alloy containing a major amount of Ag.

Dielectric composition and laminated capacitor

Disclosed is a dielectric material composition having the following composition formula:

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Kokubu, Japan

Nobuo Yokoe