Non-reducing dielectric ceramic composition

Claim 1

A non-reducing dielectric ceramic composition consisting essentially of 60 to 99.5 wt % of a basic composition expressed by the general formula: XPb(Mg.sub.166 Nb.sub.2/3)O.sub.3 --yPb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3 --zPbTiO.sub.3 where x, y and z are proportions by weight percentage of the three components, Pb(Mg 1/3 Nb 2/3 )O 3 , Pb(Zn 1/3 Nb 2/3 )O 3 and PbTiO 3 , and 0.05 to 40 wt % of an anti-reducing agent incorporated therein and expressed by the general formula: aLi.sub.2 O--bRO--cB.sub.2 O.sub.3 +(1-a-b-c)SiO where R is at least one element selected from the group consisting of Mg, Ca, Sr and Ba, a, b and c are molar fractions of the respective component and take values within the following respective ranges: 0≦a<0.2, 0.1≦b<0.55 0=c<0.4, said basic composition having a set of proportions, by weight percentage, of the three components, x, y and z, falling within the compositional area encompassed by the polygon ABCD defined by points, A, B, C, and D shown in FIG. 1, the sets of proportions, by weight percentage, of the three components at said points being as follows: ______________________________________ x y z ______________________________________ 89.0 1.0 10.0 80.0 10.0 10.0 59.5 40.0 0.5 98.5 1.0 0.5. ______________________________________