Abstract: The present invention relates to a dielectric ceramic composition, comprising from 97.5 to 99.95% by weight of{100-(a+b+c+d)}BaTiO.sub.3 +aZnO+b(2Bi.sub.2 O.sub.3.3AO.sub.2)+cTa.sub.2 O.sub.5 +dRe.sub.2 O.sub.3as main component and from 0.05 to 2.5% by weight of glass mainly comprising SiO.sub.2, and possibly also containing from 0.01 to 0.5% by weight of at least one oxides of Cr, Mn, Fe, Co, and/or Ni. A represents Zr or Sn; Re represents at least one of La, Pr, Nd, Sm, Dy and Er; and {100-(a+b+c+d)}, a, b, c, and d represent molar percent which satisfy the following relationships:______________________________________ 0.5 .ltoreq. a .ltoreq. 4.5 0.5 .ltoreq. b .ltoreq. 4.5 0.5 .ltoreq. c .ltoreq. 4.5 0.5 .ltoreq. d .ltoreq. 5.5.

Abstract: Powder of dielectric ceramic materials is produced by preparing a main component Ba(Ti.sub.1-x-y Zr.sub.x Hf.sub.y)O.sub.3 allowing barium hydroxide, at least one titanium compound, at least one zirconium compound and at least one hafnium compound to react with one another by condensation by catalytic actions of a base selected from the group consisting of alkali and amines; preparing a complex hydroxide of at least one rare earth element and manganese by allowing at least one rare earth element compound and a manganese compound to react with a base selected from the group consisting of alkali and amines in an aqueous solution; preparing at least one carbonate of calcium and magnesium by allowing at least one compound of calcium compounds and magnesium compounds to react with carbonate ions in an aqueous solution; mixing all the precipitates, and drying and thermally treating the resultant mixture.

Abstract: A dielectric ceramic composition consists essentially of a main component of a four component system, Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3 --PbTiO.sub.3 --Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3 --Pb(Zn.sub.1/2 W.sub.1/2)O.sub.3, of which a part of Pb is replaced with at least one substituent selected from the group consisting of Ba, Ca and Sr; and a secondary component selected from the group consisting of w, Zn and Mg. The secondary component is incorporated in the main component in an amount of 0.05 to 10.0 parts by weight per 100 parts by weight of the main component in terms of each oxide, WO.sub.3, ZnO or MgO. The main component consists essentially of 4.0 to 93.0 mol % of Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3, 1.5 to 35.0 mol % of PbTiO.sub.3, 1.5 to 51.0 mol % of Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3, and 1.0 to 34.0 mol % of Pb(Zn.sub.1/2 W.sub.1/2)O.sub.3, the amount of at least one substituent for Pb being 0.1 to 10 mol %.