Monolithic ceramic capacitors and improved ternary ceramic compositions for producing same
AssigneeFerro Corporation
InventorJames M. Wilson
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Abstract
A multi-layer ceramic capacitor is prepared from a novel ceramic composition produced from the oxides of lead (PbO), iron (Fe.sub.2 O.sub.3), niobium (Nb.sub.2 O.sub.5), nickel (NiO), and tungsten (WO.sub.3), or the synthesized compounds Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3, Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3, together with a small quantity of a Mn(NO.sub.3).sub.2 solution to improve certain electric properties of the capacitor. When used in the correct proportions the oxides disclosed herein are capable of producing monolithic ceramic capacitors having Z5U ratings. In particular, the lead, nickel, niobate compound tends to flatten and to lower the curie peak for the ceramic composition.
Claims3
A ceramic composition capable of producing capacitors having a temperature coefficient range of +22% to -56% at an operating temperature range of +10.degree. C. to +85.degree. C., and an insulation resistance of 7.5.times.10.sup.9 .OMEGA. or higher, and consisting essentially of [Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3 ]X, [Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 ]Y and [Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3 ]Z, and from 0.1 to 0.75 wt.% Mn(NO.sub.3).sub.2, where X+Y+Z=1.0, and the proportions of X, Y, and Z fall within the ranges of about:
- 0.55.ltoreq.X.ltoreq.0.70,
- 0.15.ltoreq.Y.ltoreq.0.36, and,
- 0.07.ltoreq.Z.ltoreq.0.32.
Dependencies are inferred from the claim text.