Abstract: A dielectric ceramic composition consists essentially of a main component composed of a solid solution of a three component system Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3 -Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3 -PbTiO.sub.3, characterized in that said main component consists essentially of 68.05 to 69.60 wt % of Pb.sub.3 O.sub.4, 2.41 to 4.00 wt % of MgO, 0.08 to 3.15 wt % of ZnO, 24.01 to 26.66 wt % of Nb.sub.2 O.sub.5, and 0.13 to 2.59 wt % of TiO.sub.2, and has a set of compositional proportions of the three components falling within an area defined by a polygon ABCD encompassed by points A, B, C, and D in FIG. 1, and that a subsidiary component consisting essentially of MgO is incorporated into said main component in an amount of not more than 1.0 part by weight (except 0 part by weight) with respect to 100 part by weight of the main component. The composition may further contain, as a part of the subsidiary component, manganese and/or a compound represented by the general formula: A(Cu.sub.1/2 W.sub.1/2)O.sub.

Abstract: A dielectric ceramic composition of a ternary system Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3 --PbTiO.sub.3 --Pb(Zn.sub.1/2 W.sub.1/2)O.sub.3 comprises a solid solution having a composition represented by the general formula:xPb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3 --yPbTiO.sub.3 --zPb(Zn.sub.1/2 W.sub.1/2)O.sub.3wherein x, y and z are mole fractions of respective three components, and x+y+z=1.00, the composition falling in a compositional area defined by a polygon encompassed by the points A, B, C and D in FIG. 1. The sets of mole fractions of the three components at the points are as follows:______________________________________ x y z ______________________________________ A 0.87 0.125 0.005 B 0.40 0.15 0.45 C 0.30 0.35 0.35 D 0.62 0.375 0.

Abstract: A dielectric ceramic composition of a ternary component system, Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3 -PbTiO.sub.3 -Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3. The three components, Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3, PbTiO.sub.3 and Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 have the compositional proportion expressed by the general formula:xPb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3 -yPbTiO.sub.3 -zPb(Fe.sub.2/3 W.sub.1/3)O.sub.3where x, y and z are proportions in mole % of the three components and x+y+z=100, the proportions of x, y and z falling in the area defined by a polygon ABCD encompassed by the points A, B, C and D shown in FIG. 1, the sets of proportions in mole % of the three components at the verticis, A,B,C and D of said polygon being as follows:______________________________________ x y z ______________________________________ A 87.0 12.5 0.50 B 75.0 15.0 10.0 C 42.5 37.5 20.0 D 62.0 37.5 0.

Abstract: A dielectric ceramic composition consists essentially of Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3, PbTiO.sub.3, Pb(Zn.sub.1/2 W.sub.1/2)O.sub.3 and Pb(Cu.sub.1/3 Nb.sub.2/3)O.sub.3, the mole percentages of said four components being as follows:Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3 --50.0 to 75.0 mole %PbTiO.sub.3 --20.0 to 35.0 mole %Pb(Zn.sub.1/2 W.sub.1/2)O.sub.3 --0.5 to 15.0 mole %Pb(Cu.sub.1/3 Nb.sub.2/3)O.sub.3 --1.0 to 10.0 mole %The dielectric ceramic composition may further contain, as an additive, manganese in an amount of not more than 0.5 mole % in terms of MnO.sub.2. The composition possesses a high dielectric constant of not less than 8000 and a low sintering temperature of 900.degree. to 1000.degree. C.

Abstract: A dielectric ceramic composition consists essentially of Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3, PbTiO.sub.3, Pb(Zn.sub.1/2 W.sub.1/2)O.sub.3 and M(Cu.sub.1/3 Nb.sub.2/3)O.sub.3 (wherein M represents at least one element selected from the group consisting of Ba, Sr and Ca), the mole percentages of said four components being as follows:______________________________________ Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3 45 to 75 mole % PbTiO.sub.3 20 to 40 mole % Pb(Zn.sub.1/2 W.sub.1/2)O.sub.3 0.5 to 15 mole % M(Cu.sub.1/3 Nb.sub.2/3)O.sub.3 1.0 to 10 mole % ______________________________________The dielectric ceramic composition may further contain, as an additive, manganese in an amount of not more than 0.5 mole % in terms of MnO.sub.2. The composition possesses a high dielectric constant of not less than 8000 and a low sintering temperature of 900.degree. to 1000.degree. C.