Tdk Corporation

Japan Aerospace Exploration Agency

Hidesada Natsui

Tatsuya Ishii

Takeo Tsukada

Shinichi Yoda

Kentei Yono

Shigekazu Hidaka

Kenichiro Masuda

Taku Masai

Sanshiro Aman

Atsunobu Masuno

A novel ceramic composition having a high relative dielectric constant. A ceramic composition includes a unit cell having at least two crystal structures selected from the group made of a monoclinic crystal, a tetragonal crystal, an orthorhombic crystal, and a rhombohedral crystal, characterized in that when the crystal structures are represented by the symmetry notation according to the Glazer method, namely xyz, n1, n2, and n3 are at least one selected from the group made of + and &#x2212;, or at least two selected from the group made of 0, +, and &#x2212;. By using this ceramic composition, a novel ceramic composition having a high relative dielectric constant can be obtained.

Ceramic composition

A hexagonal type barium titanate powder comprising barium titanate as a main component shown by a generic formula of (BaM)(TiGa)Oand having hexagonal structure wherein;

Hexagonal type barium titanate powder, producing method thereof, dielectric ceramic composition, electronic component, and producing method of the electronic component

To provide a hexagonal type barium titanate powder having a fine and uniform particle size and contributing to a thinner dielectric layer. A hexagonal type barium titanate powder according to the present invention has the following characteristics that a maximum particle diameter is 1.0 &#x3bc;m or less, a ratio of 90% accumulated particle diameter and 50% accumulated particle diameter is 3.0 or less, and a hexagonal ratio is 50% or more.

Hexagonal type barium titanate powder, producing method thereof, dielectric ceramic composition and electronic component

Dielectric ceramic composition includes a hexagonal type barium titanate as a main component shown by a generic formula of (BaM)(TiMn)Oand having hexagonal structure wherein an effective ionic radius of 12-coordinated 'M' is &#x2212;20% or more to +20% or less with respect to an effective ionic radius of 12-coordinated Baand the A, B, &#x3b1; and &#x3b2; satisfy relations of 1.000&#x3c;(A/B)&#x2266;1.040, 0&#x2266;&#x3b1;&#x3c;0.003, 0.03&#x2266;&#x3b2;&#x2266;0.2, and as subcomponents, with respect to the main component, certain contents of alkaline earth oxide such as MgO and the like, MnOand/or CrO, and CuO and AlOand rare earth element oxide and glass component including SiO. According to the present invention, it can be provided the hexagonal type barium titanate powder and the dielectric ceramic composition which are preferable for producing electronic components such as a capacitor and the like showing comparatively high specific permittivity, having advantageous insulation property and having sufficient reliability.

Dielectric ceramic composition includes a hexagonal type barium titanate as a main component shown by a generic formula (BaM)(TiMn)Oand having hexagonal structure wherein an effective ionic radius of 12-coordinated 'M' is &#x2212;20% or more to +20% or less with respect to an effective ionic radius of 12-coordinated Baand the A, B, &#x3b1; and &#x3b2; satisfy relations of 0.900&#x2266;(A/B)&#x2266;1.040, 0.003&#x2266;&#x3b1;&#x2266;0.05, 0.03&#x2266;&#x3b2;&#x2266;0.2, and as subcomponents, with respect to the main component, certain contents of alkaline earth oxide such as MgO and the like, MnOand/or CrO, CuO, AlO, rare earth element oxide and glass component including SiO. According to the present invention, it can be provided the hexagonal type barium titanate powder and dielectric ceramic composition which are preferable for producing electronic components such as a capacitor and the like showing high specific permittivity, having advantageous insulation property and sufficient reliability.

Dielectric ceramic composition comprising a barium titanate including barium titanate having hexagonal structure as a main component, and an element 'M', an effective ionic radius of the 'M' is within &#xb1;20% with respect to an effective ionic radius of 12-coordinated Baor with respect to an effective ionic radius of 6-coordinated Ti, an ionic valence of the &#x201c;M&#x201d; is larger than that of the Ba or Ti.

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Tokyo, Japan

Hidesada Natsui