US4184984A
Expired / Lapsed
US
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High breakdown voltage varistor
Assignee: General Electric Co
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Filing: 1977-10-17
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Granted: 1980-01-22
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Expires: 1997-10-17
Abstract
Abstract A metal oxide varistor with high breakdown electric field values, in excess of 1200 v.mm -1 , is processed by sintering a mixture which comprises zinc oxide with significant amounts of bismuth oxide, from approximately 10 mol percent to approximately 25 mol percent silicon dioxide and other beneficial metal oxide additives at temperatures between 800° C. and 1100° C.
Inventors
- 👤 Lionel M. Levinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:55
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/105; H01C7/108; H01C7/112; C; C04; C04B; C04B35/00; C04B35/01; C04B35/453
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
73 words
A metal oxide varistor exhibiting a breakdown voltage in excess of 1,200 v·mm -1 at a current density of 10 -3 amp·cm -2 comprising the reaction product formed by sintering a mixture including a major portion of zinc oxide (ZnO) with bismuth trioxide (Bi 2 O 3 ), and between approximately 10 mol percent and approximately 25 mol percent silicon dioxide (SiO 2 ) at temperatures between approximately 1100° C. and 800° C.
Claim 2
Dependent Claim
73 words
A metal oxide varistor exhibiting a breakdown voltage in excess of 1,200 v·mm -1 at a current density of 10 -3 amp·cm -2 comprising the reaction product formed by sintering a mixture including a major portion of zinc oxide (ZnO) with bismuth trioxide (Bi 2 O 3 ), and between approximately 10 mol percent and approximately 25 mol percent silicon dioxide (SiO 2 ) at temperatures between approximately 1100° C. and 800° C.
Claim 3
Dependent Claim
23 words
The varistor of claim 1 exhibiting an α exponent in excess of 10 at a current density of 10 -3 amp·cm -2 .
Claim 4
Dependent Claim
36 words
The varistor of claim 2 wherein said mixture further includes materials selected from the group consisting of the oxides and fluorides of cobalt, manganese, antimony, chromium, nickel, magnesium, boron, barium, zirconium, molybdenum, strontium, lead, and tin.
Claim 5
Dependent Claim
20 words
The varistor of claim 2 wherein said mixture is sintered for periods between approximately one-quarter hour and approximately two hours.
Claim 6
Dependent Claim
14 words
The varistor of claim 3 wherein said mixture comprises 15 mol percent silicon dioxide.
Claim 7
Dependent Claim
13 words
The varistor of claim 5 wherein said mixture is sintered at 940° C.
Claim 8
Dependent Claim
14 words
The varistor of claim 3 wherein said mixture comprises 171/2 mol percent silicon dioxide.
Claim 9
Dependent Claim
14 words
The varistor of claim 3 wherein said mixture comprises 20 mol percent silicon dioxide.
Claim 10
Dependent Claim
32 words
The varistor of claim 3 wherein said mixture comprises between 10 mol percent SiO 2 and 20 mol percent SiO 2 and is sintered at temperatures between 1050° C. and 900° C.
Claim 11
Dependent Claim
30 words
The varistor of claim 3 comprising 0.425 mol percent each of bismuth trioxide, cobalt trioxide, manganese dioxide, and chromium trioxide; and 0.85 mol percent each antimony trioxide and nickel oxide.
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) | 1983-01-21 | 1983-07-23 | 1984-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-21 | 1987-07-23 | 1988-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-21 | 1991-07-23 | 1992-01-22 | $7700.00 | Window Closed / Lapsed |