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Patent US4550088A successfully refreshed from Google Patents.
US4550088A
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Ceramic composition for dielectric in multilayer capacitors
Assignee: Kemet Electronics Corp
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Filing: 1985-03-19
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Granted: 1985-10-29
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Expires: 2005-03-19
Abstract
Abstract Lead oxide-base material for multilayer ceramic capacitors having high dielectric constant and insulation resistance over wide temperature range, e.g., 10° C. to 85° C.
Inventors
- 👤 Hyun D. Park
- 👤 Arthur E. Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:35
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/495; C04B35/497; H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/08; H01G4/12; H01G4/1209; H01G4/1254
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
195 words
A lead oxide-base dielectric ceramic material having high dielectric constant and high insulation resistance which is capable of being formed from a mixture of oxide powders by sintering at temperatures in the range of 900° to 1050° C., said ceramic material consisting essentially of by weight, 2.49 to 6.67% Fe 2 O 3 24.18 to 28.14% Nb 2 O 5 2.09 to 3.59% MgO 0.025 to 0.10% MnO 2 0.20 to 1.50% in the aggregate of one or more of the following oxides: GeO 2 , SiO 2 , Bi 2 O 3 , CdO, ZnO, Al 2 O 3 , CuO and B 2 O 3 , chemically combined with at least 20% by weight of PbO, to form a sintering aid additive having a melting point of no more than 775° C. and a resistivity at 25° C. of at least 10 13 ohm-cm, said dielectric composition having a total lead oxide content, as PbO, of from 64.32 to 66.20% and having an atomic ratio of Pb to the sum of Nb, Fe and Mg of from 0.893 to 0.913 and the weight ratio of MgO to FeO is from 0.34 to 1.3.
Claim 2
Dependent Claim
195 words
A lead oxide-base dielectric ceramic material having high dielectric constant and high insulation resistance which is capable of being formed from a mixture of oxide powders by sintering at temperatures in the range of 900° to 1050° C., said ceramic material consisting essentially of by weight, 2.49 to 6.67% Fe 2 O 3 24.18 to 28.14% Nb 2 O 5 2.09 to 3.59% MgO 0.025 to 0.10% MnO 2 0.20 to 1.50% in the aggregate of one or more of the following oxides: GeO 2 , SiO 2 , Bi 2 O 3 , CdO, ZnO, Al 2 O 3 , CuO and B 2 O 3 , chemically combined with at least 20% by weight of PbO, to form a sintering aid additive having a melting point of no more than 775° C. and a resistivity at 25° C. of at least 10 13 ohm-cm, said dielectric composition having a total lead oxide content, as PbO, of from 64.32 to 66.20% and having an atomic ratio of Pb to the sum of Nb, Fe and Mg of from 0.893 to 0.913 and the weight ratio of MgO to FeO is from 0.34 to 1.3.
Claim 3
Dependent Claim
36 words
A ceramic material in accordance with claim 1, wherein the dielectric constant is at least 10,000 and the insulation resistance is at least 10 12 ohm-cm at 25° C. and 10 11 ohm-cm at 85° C.
Claim 4
Dependent Claim
39 words
A ceramic material in accordance with claim 1 which is characterized by a microstructure comprising a predominantly lead perovskite solid solution phase as determined by X-ray diffraction surrounding small discrete regions of metal oxide residues of sintering aid additive.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-28 | 1989-04-29 | 1989-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-28 | 1993-04-29 | 1993-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-28 | 1997-04-29 | 1997-10-29 | $7700.00 | Window Closed / Lapsed |