US4525768A
Expired / Lapsed
US
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Ceramic capacitors and dielectric compositions
Assignee: STC PLC
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Filing: 1984-02-28
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Granted: 1985-06-25
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Expires: 2004-02-28
Abstract
Abstract A dielectric composition, particular suitable for the manufacture of ceramic capacitors, comprising non-stoichiometric lead magnesium niobate, non-stoichiometric lead iron niobate and one or more oxide additives, which may be chosen from the group comprising silica, managanese dioxide, ceric oxide, lanthanum oxide, zinc oxide, alumina, tungsten oxide, nickel oxide, cobalt oxide and cuprous oxide. The compositions can be fired at temperatures between 980° and 1075° C., so that in the case of multilayer ceramic capacitors high silver content internal electrodes can be used and, in cases where three or more of the oxide additives are employed, higher dielectric constants, for example 10600 to 16800, of the fired ceramics than conventional ceramics can be achieved, thus permitting capacitor device size reduction. Additions of lead titanate may also be made to the dielectric compositions.
Inventors
- 👤 Jennifer M. Wheeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:06
CPC Classifications
H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/08; H01G4/12; H01G4/1209; H01G4/1254; C; C04; C04B; C04B35/00; C04B35/01; C04B35/495; C04B35/497; Y; Y10; Y10T; Y10T29/00; Y10T29/43; Y10T29/435
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
18 words
A dielectric composition comprising non-stoichiometric lead magnesium niobate, non-stoichiometric lead iron niobate and one or more oxide additives.
Claim 2
Dependent Claim
18 words
A dielectric composition comprising non-stoichiometric lead magnesium niobate, non-stoichiometric lead iron niobate and one or more oxide additives.
Claim 3
Dependent Claim
26 words
A composition as claimed in claim 1, wherein the lead magnesium niobate comprises PbMg 0 .35 to 0.5 Nb 0 .4 to 0.6 O 3 .
Claim 4
Dependent Claim
36 words
A composition as claimed in claim 1, wherein the oxide additives are chosen from the group comprising silica, manganese dioxide, ceric oxide, lanthanum oxide, zinc oxide, alumina, tungsten oxide, nickel oxide, cobalt oxide and cuprous oxide.
Claim 5
Dependent Claim
19 words
A composition as claimed in claim 1, which can be fired at a temperature between 980° and 1075° C.
Claim 6
Dependent Claim
26 words
A composition as claimed in claim 1 including three or more of the oxide additives and having a dielectric constant after firing between 10600 and 16800.
Claim 7
Dependent Claim
29 words
A composition as claimed in claim 1, wherein the lead iron niobate comprises 71% by weight lead oxide, 9% by weight iron oxide and 20% by weight niobium pentoxide.
Claim 8
Dependent Claim
58 words
A composition as claimed in claim 1, wherein the lead magnesium niobate and the lead iron niobate together comprise a base material consisting substantially of 80% by weight of the lead magnesium niobate and 20% by weight of the lead iron niobate; and wherein the additives are added to the base material at the 0.1% by weight level.
Claim 9
Dependent Claim
27 words
A composition as claimed in claim 7, comprising 99.7% by weight of the base material and 0.1% by weight of each of three of the oxide additives.
Claim 10
Dependent Claim
26 words
A dielectric composition as claimed by claim 7 and whose additives are as indicated in one of the Examples quoted in Tables 4, 5 or 6.
Claim 11
Dependent Claim
13 words
A dielectric composition as claimed in claim 1 and additionally comprising lead titanate.
Claim 12
Dependent Claim
15 words
A dielectric composition as claimed in claim 10 and including up to 10% lead titanate.
Claim 13
Dependent Claim
20 words
A ceramic capacitor including dielectric comprising non-stoichiometric lead magnesium niobate, non-stoichiometric lead iron niobate and one or more oxide additives.
Claim 14
Dependent Claim
20 words
A ceramic capacitor including dielectric comprising non-stoichiometric lead magnesium niobate, non-stoichiometric lead iron niobate and one or more oxide additives.
Claim 15
Dependent Claim
27 words
A ceramic capacitor as claimed in claim 12, wherein the lead magnesium niobate comprises PbMg 0 .35 to 0.5 Nb 0 .4 to 0.6 O 3 .
Claim 16
Dependent Claim
51 words
A ceramic capacitor as claimed in claim 12, wherein the oxide additives are chosen from the group comprising silica, managanese dioxide, ceric oxide, lanthanum oxide, zinc oxide, alumina, tungsten oxide, nickel oxide, cobalt oxide and cuprous oxide, and wherein the dielectric is fired at a temperature between 980° and 1075° C.
Claim 17
Dependent Claim
15 words
A ceramic capacitor as claimed in claim 12, wherein the dielectric additionally comprises lead titanate.
Claim 18
Dependent Claim
18 words
A ceramic capacitor as claimed in claim 12, including higher silver content internal electrodes fired with the dielectric.
Claim 19
Dependent Claim
45 words
A multilayer ceramic capacitor including a plurality of layers of dielectric and a plurality of high silver content internal electrodes arranged between the dielectric layers, which dielectric layers are formed of non-stoichiometric lead magnesium niobate, non-stoichiometric lead iron niobate and one or more oxide additives.
Claim 20
Dependent Claim
45 words
A multilayer ceramic capacitor including a plurality of layers of dielectric and a plurality of high silver content internal electrodes arranged between the dielectric layers, which dielectric layers are formed of non-stoichiometric lead magnesium niobate, non-stoichiometric lead iron niobate and one or more oxide additives.
Claim 21
Dependent Claim
28 words
A multilayer ceramic capacitor as claimed in claim 17, wherein the lead magnesium niobate comprises PbMg 0 .35 to 0.5 Nb 0 .4 to 0.6 O 3 .
Claim 22
Dependent Claim
52 words
A multilayer ceramic capacitor as claimed in claim 17, wherein the oxide additives are chosen from the group comprising silica, managanese dioxide, ceric oxide, lanthanum oxide, zinc oxide, alumina, tungsten oxide, nickel oxide, cobalt oxide and cuprous oxide, and wherein the dielectric is fired at a temperature between 980° and 1075° C.
Claim 23
Dependent Claim
16 words
A multilayer ceramic capacitor as claimed in claim 17, wherein the dielectric additional comprises lead titanate.
Claim 24
Independent Claim
72 words
A method of manufacturing a multilayer ceramic capacitor including the steps of screen-printing a plurality of electrodes onto each of a plurality of dielectric members, assembling a stack of the resultant screen-printed members, pressing the stack together, dividing the pressed stack into individual capacitor, and firing the components between 980° and 1075° C., and wherein the dielectric comprises non-stoichiometric lead magnesium niobate, non-stoichiometric lead iron niobate and one or more oxide additives.
Claim 25
Independent Claim
72 words
A method of manufacturing a multilayer ceramic capacitor including the steps of screen-printing a plurality of electrodes onto each of a plurality of dielectric members, assembling a stack of the resultant screen-printed members, pressing the stack together, dividing the pressed stack into individual capacitor, and firing the components between 980° and 1075° C., and wherein the dielectric comprises non-stoichiometric lead magnesium niobate, non-stoichiometric lead iron niobate and one or more oxide additives.
Claim 26
Dependent Claim
26 words
A method as claimed in claim 21 wherein the lead magnesium niobate comprises PbMg 0 .35 to 0.5 Nb 0 .4 to 0.6 O 3 .
Claim 27
Dependent Claim
35 words
A method as claimed in claim 21, wherein the oxides are chosen from the group comprising silica, managanese dioxide, ceric oxide, lanthanum oxide, zinc oxide, alumina, tungsten oxide, nickel oxide, cobalt oxide and cuprous oxide.
Claim 28
Dependent Claim
14 words
A method as claimed in claim 21, wherein the dielectric additionally comprises lead titanate.
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) | 1988-06-24 | 1988-12-24 | 1989-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-24 | 1992-12-24 | 1993-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-24 | 1996-12-24 | 1997-06-25 | $7700.00 | Window Closed / Lapsed |