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Abstract

A dielectric ceramic composition consists essentially of a basic composition of a ternary system, Pb(Mg.sub.1/2 W.sub.1/2)O.sub.3 -PbTiO.sub.3 -PbZrO.sub.3, and 0.05 to 6.5 wt % of an antireducing agent incorporated therein. The basic composition comprises a main component represented by the general formula: xPb(Mg.sub.1/2 ; W.sub.1/2)O.sub.3 -yPbTiO.sub.3 -zPbZrO.sub.3 wherein x, y and z are mole percentages of the respective components, and 0.3 to 2.0 wt % of ZnO contained therein. The main component has a composition falling within the area of a polygen ABCD defined by points A(52.0, 44.0, 4.0), B(47.0, 38.3, 15.0), C(44.0, 40.0, 16.0), D(49.0, 46.0, 5.0) in the attached figure. The antireducing agent has a composition expressed by the general formula: .alpha.Li.sub.2 O+.beta.RO+.gamma.B.sub.2 O.sub.3 +(1-.alpha.-.beta.-.gamma.)SiO.sub.2 wherein RO is at least one oxide selected from the group consisting of BaO, CaO, SrO and MgO, .alpha., .beta. and .gamma. are mole fracions of the respective components and take each value within the following respective ranges, 0<.alpha.<0.2, 0.1.ltoreq..beta.<0.55, 0<.gamma.<0.4. The main component may contain manganese oxide in an amount of not more than 2.0 wt % in terms of MnO.sub.2.

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First Claim