US4482935A
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Ceramic capacitors and dielectric compositions
Assignee: STC PLC
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Filing: 1984-04-17
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Granted: 1984-11-13
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Expires: 2004-04-17
Abstract
Abstract A dielectric composition which is particularly suitable for the manufacture of ceramic capacitors, comprises lead magnesium niobate with additions of one or more lead titanate, lead stannate, or lead zirconate. The composition can be fired at a temperature between 950° and 1100° C., which is lower than the conventional firing temperatures of 1200° to 1400° C. The lower firing temperature means that, in the case of multilayer ceramic capacitors, the internal electrodes can be made of cheaper materials than previously with resultant materials and process cost savings. Some of the compositions exhibit higher dielectric constants than conventional Z5U ceramics, which means that capacitor device size can also be reduced.
Inventors
- 👤 Jennifer M. Wheeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:58
CPC Classifications
H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/08; H01G4/12; H01G4/1209; H01G4/1254; H01G4/1263; C; C04; C04B; C04B35/00; C04B35/01; C04B35/495; C04B35/497; C04B35/499
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
69 words
A dielectric composition capable of being fired at a temperature between 950° and 1100° C., consisting essentially of: lead magnesium niobate having the formula Pb(Mg 1/2 Nb 1/2 )O 3 constituting between 60% and 99% by weight of the composition; and at least one member selected from the group consisting of lead titanate, lead stannate, and lead zirconate constituting between about 1% and 40% by weight of the composition.
Claim 2
Dependent Claim
69 words
A dielectric composition capable of being fired at a temperature between 950° and 1100° C., consisting essentially of: lead magnesium niobate having the formula Pb(Mg 1/2 Nb 1/2 )O 3 constituting between 60% and 99% by weight of the composition; and at least one member selected from the group consisting of lead titanate, lead stannate, and lead zirconate constituting between about 1% and 40% by weight of the composition.
Claim 3
Dependent Claim
22 words
The dielectric composition as defined in claim 1, wherein lead magnesium niobate constitutes between 83.3 and 94.1% by weight of the composition.
Claim 4
Dependent Claim
19 words
The dielectric composition as defined in claim 1, wherein the dielectric constant after firing is between 7500 and 10000.
Claim 5
Dependent Claim
48 words
The dielectric composition as defined in claim 1, wherein lead magnesium niobate constitutes between 83.3 and 94.1% by weight, lead titanate between 0 and 8.3% by weight, lead stannate between 0 and and 11.1% by weight, and lead zirconate between 0 and 9.1% by weight, of the composition.
Claim 6
Dependent Claim
73 words
A ceramic capacitor comprising a dielectric composition fired at a temperature between 950° and 1100° C. and consisting essentially of lead magnesium niobate having the formula Pb(Mg 1/2 Nb 1/2 )O 3 constituting between about 60% and 99% of the weight of the composition and at least one member selected from the group consisting of lead titanate, lead stannate, and lead zirconate, constituting between about 1% and 40% by weight of the composition.
Claim 7
Dependent Claim
73 words
A ceramic capacitor comprising a dielectric composition fired at a temperature between 950° and 1100° C. and consisting essentially of lead magnesium niobate having the formula Pb(Mg 1/2 Nb 1/2 )O 3 constituting between about 60% and 99% of the weight of the composition and at least one member selected from the group consisting of lead titanate, lead stannate, and lead zirconate, constituting between about 1% and 40% by weight of the composition.
Claim 8
Dependent Claim
25 words
The ceramic capacitor as defined in claim 5, and further comprising internal electrodes of high silver contents which are fired together with the dielectric composition.
Claim 9
Independent Claim
107 words
A method of manufacturing a multilayer ceramic capacitor, comprising the steps of depositing at least one electrode on each of a plurality of sheet-shaped dielectric members made of a dielectric composition consisting essentially of lead magnesium niobate having the formula Pb(Mg 1/2 Nb 1/2 )O 3 constituting between 60% and 99% by weight of the composition and at least one member selected from the group consisting of lead titanate, lead stannate, and lead zirconate, constituting between 1% and 40% by weight of the composition; assembling the plurality of the sheet-shaped dielectric members into a stack; and firing the stack at a temperature between 950° and 1100° C.
Claim 10
Independent Claim
107 words
A method of manufacturing a multilayer ceramic capacitor, comprising the steps of depositing at least one electrode on each of a plurality of sheet-shaped dielectric members made of a dielectric composition consisting essentially of lead magnesium niobate having the formula Pb(Mg 1/2 Nb 1/2 )O 3 constituting between 60% and 99% by weight of the composition and at least one member selected from the group consisting of lead titanate, lead stannate, and lead zirconate, constituting between 1% and 40% by weight of the composition; assembling the plurality of the sheet-shaped dielectric members into a stack; and firing the stack at a temperature between 950° and 1100° C.
Claim 11
Dependent Claim
22 words
The method as defined in claim 7, and further comprising the step of pressing the stack together prior to said firing step.
Claim 12
Dependent Claim
32 words
The method as defined in claim 7, further comprising the step of dividing the stack into individual capacitor components; and wherein said firing step including firing each of the individual capacitor components.
References Cited (Backward Citations)
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JPS5222119A
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US4223369A
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1987-11-13 | 1988-05-14 | 1988-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-13 | 1992-05-14 | 1992-11-13 | $3760.00 | Window Closed / Lapsed |
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