Abstract A ceramic composition useful in forming capacitors and having the following composition expressed in mole percent of the metal oxides present: NEODYMIUM OXIDE - ABOUT 12 TO ABOUT 20 MOLE PERCENT; BARIUM OXIDE - ABOUT 12 TO ABOUT 20 MOLE PERCENT; TITANIUM OXIDE - ABOUT 60 TO ABOUT 70 MOLE PERCENT; BISMUTH OXIDE - ABOUT 1.5 TO ABOUT 5 MOLE PERCENT; ZIRCONIUM OXIDE - 0 TO ABOUT 5 MOLE PERCENT; STANNIC OXIDE - 0 TO ABOUT 5 MOLE PERCENT; CALCIUM OXIDE AND/OR STRONTIUM OXIDE - 0 TO ABOUT 10 MOLE PERCENT RARE EARTH OXIDES OTHER THAN NEODYMIUM OXIDE - RANGING UP TO ABOUT ONE MOLE PERCENT BUT PREFERABLY LESS THAN ABOUT 0.6 MOLE PERCENT; TITANIUM OXIDE + STANNIC OXIDE + ZIRCONIUM OXIDE - ABOUT 60 TO 70 MOLE PERCENT, AND BARIUM OXIDE + CALCIUM OXIDE + STRONTIUM OXIDE - ABOUT 12 TO ABOUT 25 MOLE PERCENT. A dense, substantially non-porous, ceramic dielectric material fired at a suitable temperature within the range of about 1220*C to about 1300*C., having a K value of about 55 to about 90, a temperature coefficient of dielectric constant (TC) of about -100 to about +100 X 10 6/*C, a % D.F. less than 0.1, and an insulation resistance corresponding to values of at least about 200 ohm-farads ranging up to about 40,000 or more ohm-farads at 125*C.
The composition of claim 1 wherein the barium oxide, calcium oxide and strontium oxide are present as titanates, zirconates and stannates.
Claim 2
Dependent Claim
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The composition of claim 2 wherein the bismuth oxide is present as a titanate, zirconate or stannate.
Claim 3
Dependent Claim
35 words
The composition of claim 1 wherein said neodymium oxide is present in a pre-reacted combined form with titanium oxide at a weight ratio of neodymium oxide to titanium oxide of about 68:32 to about 52:48.
Claim 4
Dependent Claim
35 words
The composition of claim 3 wherein said neodymium oxide is present in a pre-reacted combined form with titanium oxide at a weight ratio of neodymium oxide to titanium oxide of about 68:32 to about 52:48.
Claim 5
Dependent Claim
195 words
A dense, substantially non-porous ceramic dielectric material having a K value of about 55 to about 90, a temperature coefficient of dielectric constant of about -100 to +100 X 10 6/*C, a %D.F. less than 0.1, an insulation resistance such as to correspond to values of at least about 200 ohm-farads at 125*C, said dielectric material having a composition consisting essentially of about 12 to about 20 mole percent neodymium oxide, about 12 to about 20 mole percent barium oxide, about 60 to about 70 mole percent of titanium oxide, about 1.5 to about 5 mole percent of bismuth oxide, from 0 to about 5 mole percent of zirconium oxide, from 0 to about 5 mole percent of stannic oxide, from 0 to about 10 mole percent of calcium oxide, strontium oxide or mixtures thereof, and having a con-tent of rare earth oxides other than neodymium oxide ranging to about one mole percent, the total content of said titanium oxide, stannic oxide and zirconium oxide ranging from about 60 to about 70 mole percent and the total content of barium oxide, calcium oxide and strontium oxide ranging from about 12 to about 25 mole percent.
Claim 6
Dependent Claim
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The ceramic dielectric of claim 6 having a %D.F. of 0.03 or less.
Claim 7
Dependent Claim
19 words
The ceramic dielectric of claim 6 having an insulation resistance corresponding to values of at least about 1000 ohm-farads.