Dielectric ceramic and producing method thereof, and multilayer ceramic capacitor

A technology of dielectric ceramics and multi-layer ceramics, applied in the field of dielectric ceramics and their preparation, can solve problems such as unstable reaction, reduction of capacitance-temperature characteristics and reliability of dielectric ceramics, reduction of thickness of dielectric ceramics layer, etc.

A technology of dielectric ceramics and multi-layer ceramics, applied in the field of dielectric ceramics and their preparation, can solve problems such as unstable reaction, reduction of capacitance-temperature characteristics and reliability of dielectric ceramics, reduction of thickness of dielectric ceramics layer, etc.

CN1527331AActive Publication Date: 2004-09-08MURATA MFG CO LTD
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  • Dielectric ceramic and producing method thereof, and multilayer ceramic capacitor
  • Dielectric ceramic and producing method thereof, and multilayer ceramic capacitor
  • Dielectric ceramic and producing method thereof, and multilayer ceramic capacitor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0075] In embodiment 1, as shown in table 1, use ABO 3 As main components, it includes Ba, Ca and Ti and has (Ba 0.93 Ca 0.07 )TiO 3 composition, and with BaCO 3 、TiO 2 and SiO 2mixture or Ba-Ti-Si-O crystal oxide as its additive component. By using these components, Examples 1-1 and 1-2 according to the present invention and Comparative Examples 1-1 and 1-2 other than the present invention were evaluated.

[0076] 1. Formation of powdered raw materials for dielectric ceramics.

Embodiment 1-1

[0078] First, for the raw materials of the main components, in order to form (Ba 0.93 Ca 0.07 )TiO 3 Composition, weigh BaCO by volume 3 , CaCO 3 and TiO 2 , which are then mixed together using a ball mill, followed by heat treatment at 1,050°C, thereby forming (Ba 0.93 Ca 0.07 )TiO 3 . The average diameter of the crystal grains was 0.3 μm.

[0079] In order to obtain the described additive components, weigh the BaCO 3 , CaCO 3 and TiO 2 , so that the molar ratio was 9:1:10, and then they were mixed together using a ball mill, followed by heat treatment at 1,000° C., thereby forming Ba—Ti—Si—O crystal oxide. The crystallinity of these oxides was confirmed using XRD. In addition, the average diameter of crystal grains was 0.15 μm.

[0080] Then, weigh by volume (Ba 0.93 Ca 0.07 )TiO 3 and Ba-Ti-Si-O crystal oxide so that the weight ratio is 98:2 as shown in Table 1, and then use a ball mill to mix them together, thereby forming the dielectric compound according ...

Embodiment 1-2

[0082] According to the same method described in the above embodiment 1-1, after obtaining (Ba 0.93 Ca 0.07 )TiO 3 and Ba-Ti-Si-O crystal oxide, weigh by weight (Ba 0.93 Ca 0.07 )TiO 3 and Ba-Ti-Si-O crystal oxide, so that the weight ratio is 95:5 as shown in Table 1, and then use a ball mill to mix them together, thus forming the dielectric material according to Example 1-2 Powdered raw materials for ceramics.

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Abstract

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 ABO3 (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 nm<2 >or less.

Description

technical field [0001] The present invention relates to dielectric ceramics and their preparation methods, and multilayer ceramic capacitors formed using said dielectric ceramics, and more particularly, the present invention relates to an improved method by which the formation of multilayer ceramics can be advantageously reduced The thickness of the capacitor's dielectric ceramic layer. Background technique [0002] In general, multilayer ceramic capacitors are formed by the following steps: [0003] First, ceramic green sheets containing powdery raw materials for dielectric ceramics are prepared, each ceramic green sheet having on its surface a conductive material to be formed in a desired pattern for internal electrodes. For dielectric ceramics, one can use e.g. BaTiO containing 3 material as its main component. [0004] Next, a plurality of ceramic green sheets including ceramic green sheets provided with the above-described conductive material are laminated on each ot...

Claims

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Application Information

Patent Timeline
08 Sep 2004
Publication
CN1527331A
IPC
C04B35/46; C04B35/00; H01B3/00; H01B3/12; H01G4/06; H01G4/12; H01G4/30; H02H3/00
CPC
H01G4/1227; Y10T29/43; H01G4/30; H01G4/12
Inventors
中村友幸; 加藤成