US4642136A
Expired / Lapsed
US
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PTC ceramic composition
Assignee: Toshiba Corp
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Filing: 1985-02-07
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Granted: 1987-02-10
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Expires: 2005-02-07
Abstract
Abstract A PTC ceramic composition comprising a fundamental component represented by the formula: (V.sub.1-x A.sub.x).sub.2 O.sub.3 wherein x is a value within the range of 0≦x≦0.02 and A is at least one of Cr and Al, and tin in an amount of 1 to 25 % by weight based on the total weight of the composition, has a small electric resistance in the low resistance state, good PTC properties, and a high density.
Inventors
- 👤 Noburu Fukushima
- 👤 Hisashi Yoshino
- 👤 Shunji Nomura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:50
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/022
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
63 words
A PTC ceramic composition which comprises (i) a fundamental component represented by the formula: (.sub.1-x A).sub.2 O.sub.3 wherein x denotes an atomic proportion and has a value within the range of 0.001≦x≦0.02, and A is at least one of Cr and Al, and (ii) tin in an amount of 1 to 25 % by weight, based on the total weight of the composition.
Claim 2
Dependent Claim
63 words
A PTC ceramic composition which comprises (i) a fundamental component represented by the formula: (.sub.1-x A).sub.2 O.sub.3 wherein x denotes an atomic proportion and has a value within the range of 0.001≦x≦0.02, and A is at least one of Cr and Al, and (ii) tin in an amount of 1 to 25 % by weight, based on the total weight of the composition.
Claim 3
Dependent Claim
31 words
The PTC ceramic composition according to claim 1, wherein said component tin is included in an amount of 2.0 20.0 % by weight based on the total weight of the composition.
Claim 4
Dependent Claim
28 words
The PTC ceramic composition according to claim 1, wherein said fundamental component is represented by the formula: (V.sub.1-x Cr.sub.x).sub.2 O.sub.3 wherein x is as defined in claim 1.
Claim 5
Dependent Claim
28 words
The PTC ceramic composition according to claim 1, wherein said fundamental component is represented by the formula: (V.sub.1-x Al.sub.x).sub.2 O.sub.3 wherein x is as defined in claim 1.
Claim 6
Dependent Claim
23 words
The PTC ceramic composition according to claim 1 wherein said tin is obtained from oxide starting material used to produce said ceramic composition.
Claim 7
Dependent Claim
32 words
The PTC ceramic composition according to claim 1 wherein said vanadium and at least one of chromium and aluminum are obtained, respectively, from oxide starting material used to produce said ceramic composition.
Claim 8
Dependent Claim
23 words
The PTC ceramic composition according to claim 1 wherein said tin consists essentially of metallic tin interposed among grains of said fundamental component.
References Cited (Backward Citations)
US4483933A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |