US4081857A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low temperature sintering ceramic capacitor and method of making
Assignee: Kemet Electronics Corp
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Filing: 1976-09-13
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Granted: 1978-03-28
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Expires: 1996-09-13
Abstract
Abstract Fired ceramic bodies, including ceramic capacitors, utilizing lead-free constituent materials fired at temperatures not higher than 1120 DEG C.
Inventors
- 👤 R. C. Frederick Hanold, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:59
CPC Classifications
H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/08; H01G4/12; H01G4/1209; Y; Y10; Y10T; Y10T29/00; Y10T29/43; Y10T29/435
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
135 words
A ceramic capacitor comprising in combination a lead-free dielectric ceramic body in the form of a mixture fired and matured at a maturing temperature not higher than about 1120° C. said mixture before firing consisting essentially of a mixture of the following ceramic materials (i) from 60 to 95% by weight of uncalcined lead free base ceramic material sized not larger than about 2500 A and (ii) about 5 to 40% by weight of lead-free cadmium oxide-containing ceramic material, and electrode material formed on said body in capacitive relationship said base ceramic material not being subjected to a temperature as high as said maturing temperature for any substantial period of time prior to firing and said maturing temperature of said mixture being substantially higher than any temperature to which said mixture has been previously subjected.
Claim 2
Dependent Claim
135 words
A ceramic capacitor comprising in combination a lead-free dielectric ceramic body in the form of a mixture fired and matured at a maturing temperature not higher than about 1120° C. said mixture before firing consisting essentially of a mixture of the following ceramic materials (i) from 60 to 95% by weight of uncalcined lead free base ceramic material sized not larger than about 2500 A and (ii) about 5 to 40% by weight of lead-free cadmium oxide-containing ceramic material, and electrode material formed on said body in capacitive relationship said base ceramic material not being subjected to a temperature as high as said maturing temperature for any substantial period of time prior to firing and said maturing temperature of said mixture being substantially higher than any temperature to which said mixture has been previously subjected.
Claim 3
Independent Claim
138 words
A method of forming a monolithic multilayer lead-free ceramic capacitor comprising the steps of forming a green ceramic body from a mixture consisting essentially of the following ceramic materials (i) from about 5 to 40% by weight of lead-free cadmium oxide-containing ceramic material and (ii) about 60-95% by weight of uncalcined lead-free base ceramic material sized not larger than about 2500 A, applying metal electrodes to said green ceramic body, stacking a plurality of said green ceramic bodies and maturing said electrodes at a maturing temperature not higher than about 1120° C, said base ceramic material not being subjected to a temperature as high as said maturing temperature for any substantial period of time prior to firing and said maturing temperature of said mixture being substantially higher than any temperature to which said mixture has been previously subjected.
Claim 4
Independent Claim
138 words
A method of forming a monolithic multilayer lead-free ceramic capacitor comprising the steps of forming a green ceramic body from a mixture consisting essentially of the following ceramic materials (i) from about 5 to 40% by weight of lead-free cadmium oxide-containing ceramic material and (ii) about 60-95% by weight of uncalcined lead-free base ceramic material sized not larger than about 2500 A, applying metal electrodes to said green ceramic body, stacking a plurality of said green ceramic bodies and maturing said electrodes at a maturing temperature not higher than about 1120° C, said base ceramic material not being subjected to a temperature as high as said maturing temperature for any substantial period of time prior to firing and said maturing temperature of said mixture being substantially higher than any temperature to which said mixture has been previously subjected.
Claim 5
Dependent Claim
34 words
A ceramic capacitor in accordance with claim 1 wherein said base ceramic material is selected from the group consisting of titanates, niobates, zirconates, stannates, alumina, rare earth oxides and unfired mixtures of such materials.
Claim 6
Dependent Claim
17 words
A ceramic capacitor in accordance with claim 1 wherein said base ceramic material is predominantly barium titanate.
Claim 7
Dependent Claim
23 words
A method in accordance with claim 2 wherein the particle sizing of said base ceramic material is not more than about 2500 A.
Claim 8
Dependent Claim
33 words
A method in accordance with claim 2 wherein said base ceramic material is selected from the group consisting of titanates, niobates, zirconates, stannates, alumina, rare earth oxides and unfired mixtures of such materials.
Claim 9
Dependent Claim
16 words
A method in accordance with claim 2 wherein said base ceramic material is predominantly barium titanate.
Claim 10
Dependent Claim
35 words
A ceramic capacitor in accordance with claim 1 wherein the lead-free cadmium oxide containing material consists essentially of about 30 to 80% by weight cadmium oxide and about 20 to 70% by weight bismuth oxide.
Claim 11
Dependent Claim
34 words
A method in accordance with claim 2 wherein the lead-free cadmium oxide containing material consists essentially of about 30 to 80% by weight cadmium oxide and about 20 to 70% by weight bismuth oxide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-27 | 1981-09-26 | 1982-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-27 | 1985-09-26 | 1986-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-27 | 1989-09-26 | 1990-03-28 | $7700.00 | Window Closed / Lapsed |