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US4897374A
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Dielectric ceramic and process of preparing it
Assignee: Sumitomo Metal Mining Co Ltd
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Filing: 1988-12-15
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Granted: 1990-01-30
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Expires: 2008-12-15
Abstract
Abstract A dielectric ceramic having the composition represented by the general formula (I): Ba.sub.x A.sub.y B.sub.1-x-y F.sub.z O.sub.w wherein A is at least one selected from the group consisting of Mg, Zn, Ni and Co; B is at least one selected from Ta and Nb; x, y, and z are numbers represented by 0.48≦x≦0.52, 0.15≦y≦0.19 and 0.00025≦z≦0.05, respectively; and w is a number such that the total electric charges of cations of A and B and anions of F are neutralized to make the ceramic substantially neutral as a whole, and a process of preparing the dielectric ceramic. This ceramic has a high dielectric constant and unloaded Q and has a small temperature coefficient of resonance frequency.
Inventors
- 👤 Kazutoshi Matsumoto
- 👤 Ko Takada
- 👤 Takehiro Hiuga
- 👤 Tetsuya Mukai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:53
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/495
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
89 words
A dielectric ceramic having the composition represented by the general formula (I): Ba.sub.x A.sub.y B.sub.1-x-y F.sub.z O.sub.w wherein A is at least one selected from the group consisting of Mg, Zn, Ni and Co; B is at least one selected from Ta and Nb; x, y, and z are numbers represented by 0.48≦x≦0.52, 0.15≦y≦0.19 and 0.00025≦z≦0.05, respectively; and w is a number such that the total electric charges of cations of A and B and anions of F are neutralized to make the ceramic substantially neutral as a whole.
Claim 2
Dependent Claim
89 words
A dielectric ceramic having the composition represented by the general formula (I): Ba.sub.x A.sub.y B.sub.1-x-y F.sub.z O.sub.w wherein A is at least one selected from the group consisting of Mg, Zn, Ni and Co; B is at least one selected from Ta and Nb; x, y, and z are numbers represented by 0.48≦x≦0.52, 0.15≦y≦0.19 and 0.00025≦z≦0.05, respectively; and w is a number such that the total electric charges of cations of A and B and anions of F are neutralized to make the ceramic substantially neutral as a whole.
Claim 3
Dependent Claim
63 words
The dielectric ceramic according to claim 1, wherein the A in said general formula (I) consists of at least one selected from the group consisting of Mg and Zn and at least one selected from the group consisting of Ni and Co, each of said Ni and Co being present in a proportion of not more than 40 mol % in the A.
Claim 4
Dependent Claim
26 words
The dielectric ceramic according to claim 2, wherein Ni and Co in total are present in a proportion of not more than 40% in the A.
Claim 5
Dependent Claim
52 words
The dielectric ceramic according to claim 1, wherein the A in said general formula (I) consists of Mg and at least one selected from the group consisting of Ni and Co, said Ni and Co in total being present in a proportion of not more than 40 mol % in the A.
Claim 6
Dependent Claim
52 words
The dielectric ceramic according to claim 1, wherein the A in said general formula (I) consists of Zn and at least one selected from the group consisting of Ni and Co, said Ni and Co in total being present in a proportion of not more than 70 mol % in the A.
Claim 7
Dependent Claim
39 words
The dielectric ceramic according to claim 1, wherein the A in said general formula (I) is one selected from Mg, Zn, Ni, or Co, and the B in said general formula (I) is one selected from Ta or Nb.
Claim 8
Dependent Claim
27 words
The dielectric ceramic according to claim 1, wherein the A in said general formula (I) is Mg, and the B in said general formula (I) is Ta.
Claim 9
Dependent Claim
25 words
The dielectric ceramic according to claim 1, wherein the A in said general formula (I) is Zn, and the B consists of Ta and Nb.
Claim 10
Dependent Claim
28 words
The dielectric ceramic according to claim 1, wherein x, y and z in said general formula (I) are numbers in a range of 0.49≦x≦0.51, 0.15≦y≦0.18 and 0.0005≦z≦0.01, respectively.
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US4585745A
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JPS6118101A
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US4716134A
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EP0252668A2
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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) | 1993-01-29 | 1993-07-31 | 1994-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-29 | 1997-07-31 | 1998-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-29 | 2001-07-31 | 2002-01-30 | $7700.00 | Window Closed / Lapsed |