US4027209A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ceramic capacitor having a silver doped dielectric of (Pb,La)(Zr,Ti)O3
Assignee: MRA Laboratories Inc
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Filing: 1975-10-02
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Granted: 1977-05-31
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Expires: 1995-10-02
Abstract
Abstract The dielectric material of a ceramic capacitor contains a high temperature silver doped ceramic with a small proportion of a low temperature glass. The ceramic component consists essentially of a lead zirconate in which from 0.07 to 0.16 molar parts of the lead are replaced by lanthanum and in which from 0.10 to 0.40 molar parts of the zirconate are replaced by titanate. The capacitors may be fired in an air atmosphere without substantial loss of lead at temperatures as high as 2000 DEG F. Silver containing electrodes may be employed in a monolithic capacitor of this invention, the co-fired electrode advantageously causing a silver doping of the ceramic that in turn improves the stability of capacitance with temperature and applied voltage. Alternatively, the ceramic may be predoped with silver to achieve this result.
Inventors
- 👤 Galeb H. Maher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:55
CPC Classifications
H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/08; H01G4/12; H01G4/1209; H01G4/1236; H01G4/1245; Y; Y10; Y10T; Y10T29/00; Y10T29/43; Y10T29/435
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
95 words
A ceramic capacitor comprising a glass ceramic dielectric body and two spaced electrodes in contact with said dielectric body, said body consisting essentially of a major proportion of a calcined high temperature ceramic and a minor proportion of a low temperature glass, said high temperature ceramic consisting essentially of a lead zirconate wherein from 0.07 to 0.16 molar parts of said lead are replaced with lanthanum and wherein from 0.10 to 0.40 molar parts of said zirconate are replaced by titanate, said high temperature ceramic being doped with from 0.1 to 1.0 weight percent silver.
Claim 2
Dependent Claim
95 words
A ceramic capacitor comprising a glass ceramic dielectric body and two spaced electrodes in contact with said dielectric body, said body consisting essentially of a major proportion of a calcined high temperature ceramic and a minor proportion of a low temperature glass, said high temperature ceramic consisting essentially of a lead zirconate wherein from 0.07 to 0.16 molar parts of said lead are replaced with lanthanum and wherein from 0.10 to 0.40 molar parts of said zirconate are replaced by titanate, said high temperature ceramic being doped with from 0.1 to 1.0 weight percent silver.
Claim 3
Dependent Claim
21 words
The ceramic capacitor of claim 1 wherein said body contains no less than 4.5 weight percent of said low temperature glass.
Claim 4
Dependent Claim
23 words
The ceramic capacitor of claim 1 wherein said low temperature glass contains lead oxide in an amount not less than 20 weight percent.
Claim 5
Dependent Claim
69 words
The ceramic capacitor of claim 1 wherein said glass consists essentially by weight of from 8 to 30% of the glass formers selected from B 2 O 3 , SiO 2 , and GeO 2 ; from 0 to 3% Al 2 0 3 ; from 0 to 11% ZnO; from 0 to 50% CdO; from 0 to 90% Bi 2 O 3 and from 0 to 85% PbO.
Claim 6
Dependent Claim
18 words
The ceramic capacitor of claim 1 wherein said glass has a melting temperature of less than 1600° F.
Claim 7
Dependent Claim
49 words
The ceramic capacitor of claim 1 wherein at least one final of said spaced electrodes is buried within said dielectric body and is composed of a silver containing alloy and some of said silver from said alloy having diffused into said high temperature ceramic provides said silver dopant therein.
Claim 8
Dependent Claim
23 words
The ceramic capacitor of claim 6 wherein said final electrode silver alloy is of reduced silver content from that of the initial alloy.
Claim 9
Dependent Claim
92 words
A monolithic ceramic capacitor comprising a glass ceramic dielectric body and at least two spaced electrodes at least one of which is buried within said dielectric body, said body consisting essentially of a major proportion of a calcined high temperature ceramic and a minor proportion of a low temperature glass, said high temperature ceramic being formulated substantially according to Pb.sub.1-x La.sub.x (Zr.sub.y Ti.sub.1-y).sub.1-x/4 0.sub.3 wherein x is from 0.07 to 0.16 and y is from 0.60 to 0.90, said high temperature ceramic being doped with from 0.1 to 1.0 weight percent silver.
Claim 10
Dependent Claim
92 words
A monolithic ceramic capacitor comprising a glass ceramic dielectric body and at least two spaced electrodes at least one of which is buried within said dielectric body, said body consisting essentially of a major proportion of a calcined high temperature ceramic and a minor proportion of a low temperature glass, said high temperature ceramic being formulated substantially according to Pb.sub.1-x La.sub.x (Zr.sub.y Ti.sub.1-y).sub.1-x/4 0.sub.3 wherein x is from 0.07 to 0.16 and y is from 0.60 to 0.90, said high temperature ceramic being doped with from 0.1 to 1.0 weight percent silver.
Claim 11
Dependent Claim
14 words
The ceramic capacitor of claim 8 wherein x is 0.14 and y is 0.75.
Claim 12
Dependent Claim
14 words
The ceramic capacitor of claim 8 wherein x is 0.112 and y is 0.75.
Claim 13
Dependent Claim
19 words
The ceramic capacitor of claim 8 wherein said at least one buried electrode is of a silver containing alloy.
Claim 14
Dependent Claim
25 words
The ceramic capacitor of claim 11 wherein said alloy is a silver-palladium alloy, said silver being from 10 to 75 weight percent of said alloy.
Claim 15
Independent Claim
108 words
A method for producing a ceramic capacitor comprising mixing a major proportion of a pulverized prefired lead zirconate ceramic and a minor proportion of a finely ground low temperature glass, in an organic binder medium wherein from 0.07 to 0.16 molar parts of said lead is replaced with lanthanum and wherein from 0.10 to 0.40 molar parts of said zirconate is replaced by titanate, forming a body of said glass ceramic mixture, forming two spaced electrodes in contact with said glass ceramic body, doping said ceramic with from 0.1 to 1.0 weight percent silver, and firing said body to maturity at a temperature no greater than 2000° F.
Claim 16
Independent Claim
108 words
A method for producing a ceramic capacitor comprising mixing a major proportion of a pulverized prefired lead zirconate ceramic and a minor proportion of a finely ground low temperature glass, in an organic binder medium wherein from 0.07 to 0.16 molar parts of said lead is replaced with lanthanum and wherein from 0.10 to 0.40 molar parts of said zirconate is replaced by titanate, forming a body of said glass ceramic mixture, forming two spaced electrodes in contact with said glass ceramic body, doping said ceramic with from 0.1 to 1.0 weight percent silver, and firing said body to maturity at a temperature no greater than 2000° F.
Claim 17
Dependent Claim
12 words
The method of claim 13 wherein said firing is accomplished in air.
Claim 18
Dependent Claim
24 words
The method of claim 13 wherein said minor proportion of said glass is no less than 4.5% by weight of said glass ceramic mixture.
Claim 19
Dependent Claim
24 words
The method of claim 13 wherein said minor proportion of said glass is from 6% to 7.8% by weight of said glass ceramic mixture.
Claim 20
Dependent Claim
19 words
The method of claim 13 wherein said low temperature glass contains no less than 20% lead oxide by weight.
Claim 21
Independent Claim
143 words
A method for producing a silver doped ceramic capacitor comprising: (a) blending ceramic precursor compounds selected from oxides and carbonates of lead, lanthanum, zirconium and titanium in molar proportions substantially corresponding to the formula Pb.sub.1-x La.sub.x (Zr.sub.y Ti.sub.1-y).sub.1-x/4 O.sub.3 wherein x is from 0.07 to 0.16 and y is from 0.60 to 0.90; (b) calcining by prefiring and then crushing and pulverizing said ceramic blend; (c) mixing a major proportion of said pulverized ceramic and a minor proportion of a finely ground low temperature glass in an organic binder medium; (d) forming a body of said glass ceramic mixture; (e) forming at least two spaced silver containing electrodes in contact with said glass ceramic body; and (f) firing said body to maturity at a temperature no greater than 2000° F., whereby said ceramic is doped with from 0.1 to 1.0 weight percent silver.
Claim 22
Independent Claim
143 words
A method for producing a silver doped ceramic capacitor comprising: (a) blending ceramic precursor compounds selected from oxides and carbonates of lead, lanthanum, zirconium and titanium in molar proportions substantially corresponding to the formula Pb.sub.1-x La.sub.x (Zr.sub.y Ti.sub.1-y).sub.1-x/4 O.sub.3 wherein x is from 0.07 to 0.16 and y is from 0.60 to 0.90; (b) calcining by prefiring and then crushing and pulverizing said ceramic blend; (c) mixing a major proportion of said pulverized ceramic and a minor proportion of a finely ground low temperature glass in an organic binder medium; (d) forming a body of said glass ceramic mixture; (e) forming at least two spaced silver containing electrodes in contact with said glass ceramic body; and (f) firing said body to maturity at a temperature no greater than 2000° F., whereby said ceramic is doped with from 0.1 to 1.0 weight percent silver.
Claim 23
Dependent Claim
12 words
The method of claim 18 wherein said firing is accomplished in air.
Claim 24
Dependent Claim
27 words
The method of claim 18 additionally comprising burying at least one of said at least two electrodes within said body to make a monolithic ceramic type capacitor.
Claim 25
Dependent Claim
37 words
The method of claim 18 wherein said silver doping is accomplished during said firing, said blending of said prefired ceramic additionally including the addition of no less than 0.5 weight percent silver oxide in said ceramic blend.
Claim 26
Dependent Claim
47 words
The method of claim 20 wherein said forming and said burying of said electrodes is accomplished prior to said firing and said silver doping is at least partially accomplished at said firing by some of said silver from said electrodes diffusing into and reacting with said ceramic.
Claim 27
Dependent Claim
23 words
The method of claim 22 wherein said buried electrode is a palladium silver alloy, said electrode initially being about 75 weight percent silver.
Claim 28
Dependent Claim
13 words
The method of claim 18 wherein x is 0.14 and y is 0.75.
Claim 29
Dependent Claim
13 words
The method of claim 18 wherein x is 0.112 and y is 0.75.
Claim 30
Independent Claim
149 words
A method for producing a silver doped ceramic capacitor comprising: (a) blending ceramic precursor compounds selected from oxides and carbonates of lead, lanthanum, zirconium and titanium in molar proportions substantially corresponding to the formula Pb.sub.1-x La.sub.x (Zr.sub.y Ti.sub.1-y).sub.1-x/4 0.sub.3 wherein x is from 0.07 to 0.16 and y is from 0.60 to 0.90, and including at least 0.5 weight percent silver oxide in said blend; (b) calcining by prefiring and then crushing and pulverizing said ceramic blend to produce a silver doped ceramic material; (c) mixing a major proportion of said prefired pulverized ceramic material and a minor proportion of a finely ground low temperature glass in an organic binder medium; (d) forming a body of said glass ceramic mixture; (e) forming at least two spaced electrodes in contact with said glass ceramic body; and (f) firing said body to maturity at a temperature no greater than 2000° F.
Claim 31
Independent Claim
149 words
A method for producing a silver doped ceramic capacitor comprising: (a) blending ceramic precursor compounds selected from oxides and carbonates of lead, lanthanum, zirconium and titanium in molar proportions substantially corresponding to the formula Pb.sub.1-x La.sub.x (Zr.sub.y Ti.sub.1-y).sub.1-x/4 0.sub.3 wherein x is from 0.07 to 0.16 and y is from 0.60 to 0.90, and including at least 0.5 weight percent silver oxide in said blend; (b) calcining by prefiring and then crushing and pulverizing said ceramic blend to produce a silver doped ceramic material; (c) mixing a major proportion of said prefired pulverized ceramic material and a minor proportion of a finely ground low temperature glass in an organic binder medium; (d) forming a body of said glass ceramic mixture; (e) forming at least two spaced electrodes in contact with said glass ceramic body; and (f) firing said body to maturity at a temperature no greater than 2000° F.
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) | 1980-05-30 | 1980-11-29 | 1981-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-30 | 1984-11-29 | 1985-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-30 | 1988-11-29 | 1989-05-31 | $7700.00 | Window Closed / Lapsed |