Nippon Oil Fats Co., Ltd.

Kazuhito Narumi

Michiaki Sakaguchi

Fumio Takeuchi

A composition for a reduction-reoxidation type semiconductive ceramic capcitor is disclosed which consists substantially of 100 mol % of a barium composite oxide consisting of BaTiO.sub.3 and BaZrO.sub.3 and having a BaZrO.sub.3 content in the range of 0 to 20 mol %, 0.3 to 3.0 mol % of Bi.sub.2 O.sub.3, and 0.1 to 8.5 mol % of at least one member selected from the group consisting of TiO.sub.2 and ZrO.sub.2 and further incorporates therein 0.001 to 1.00% by weight of at least one member selected from the group consisting of the oxides of Cr, Fe, Co, Zn, Cu, Al, Si, and Mg. This composition possesses a breakdown voltage of not less than 400 V, an insulation resistance of not less than 10.sup.9 .OMEGA., an electrostatic capacity of not less than 0.65 .mu.F/cm.sup.2 per unit surface area, and a magnitude, tan .delta., of less than 2.5%.

Composition for reduction-reoxidation type semiconductive ceramic

A ceramic composition for a reduction-reoxidation type semiconductive capacitor, comprising (A) barium titanate or barium titanate and strontium titanate, (B) titanium oxide, and (C) at least one oxide selected from the group consisting of the oxides severally of La, Ce, Nb, Nd, Dy, Y, Sb, W, and Ta in a molar ratio of 100:0.01.about.15:0.01.about.10 and further comprising (D) 0.001 to 1% by weight, based on the total amount of the compounds, (A), (B), and (C), of at least one oxide selected from the group consisting of the oxides severally of Cu, Zn, Al, Mg, and Mo and exhibiting a breakdown voltage of not less than 900 V, and insulation resistance of not less than 10.sup.10 .OMEGA., an electrostatic capacity per unit surface area of not less than 0.06 .mu.F/cm.sup.2, and a low dielectric loss, tan .delta., of not more than 2.0%.

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Bibai, Japan

Kazuhito Narumi