US4127511A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ceramic electrical resistor with nonlinear voltage characteristic
Assignee: BBC Brown Boveri AG Switzerland
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Filing: 1977-06-30
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Granted: 1978-11-28
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Expires: 1997-06-30
Abstract
Abstract A ceramic electrical resistor with nonlinear current-voltage characteristic has a base of zinc oxide and at least one other component. A method is provided for producing such resistors.
Inventors
- 👤 Hans P. Klein
- 👤 Anton Menth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:17
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/105; H01C7/108; H01C7/112
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
125 words
A method of producing a ceramic electrical resistor, having a nonlinear voltage-dependent current-voltage characteristic, and having a composition consisting essentially of 50-99 mol% zinc oxide, 0.05 to 10 mol% of at least one oxide of boron, and from 0.01 to 5 mol % of at least one oxide selected from the group consisting of the oxides of cobalt, manganese, chromium, antimony, silicon, and mixtures thereof, and wherein said composition contains essentially no bismuth oxide; which comprises the steps: mixing the starting materials in powder form and with grain size of from 0.1 to 1μ; drying; sifting; calcining at around 450° C. for from 1 to 3 hours; pressing; and sintering the resulting briquette in air at from 1100° to 1350° C. for about 1 hour.
Claim 2
Independent Claim
125 words
A method of producing a ceramic electrical resistor, having a nonlinear voltage-dependent current-voltage characteristic, and having a composition consisting essentially of 50-99 mol% zinc oxide, 0.05 to 10 mol% of at least one oxide of boron, and from 0.01 to 5 mol % of at least one oxide selected from the group consisting of the oxides of cobalt, manganese, chromium, antimony, silicon, and mixtures thereof, and wherein said composition contains essentially no bismuth oxide; which comprises the steps: mixing the starting materials in powder form and with grain size of from 0.1 to 1μ; drying; sifting; calcining at around 450° C. for from 1 to 3 hours; pressing; and sintering the resulting briquette in air at from 1100° to 1350° C. for about 1 hour.
Claim 3
Dependent Claim
22 words
The method of claim 1, wherein said pressing is carried out at a pressure of from 300 to 500 kg/cm 2 .
Claim 4
Dependent Claim
14 words
The method of claim 1, wherein said temperature is from 1200° to 1250° C.
Claim 5
Dependent Claim
18 words
The method of claim 1, wherein said sintered briquette is provided with metal contacts on its flat faces.
Claim 6
Dependent Claim
18 words
The method of claim 4, wherein said contacts are produced by baking, vapor deposition, sputtering, or metal spraying.
Claim 7
Dependent Claim
34 words
The method of claim 1, which further comprises annealing said sintered briquette for 15 hours at a temperature of from 600° to 1,000° C. under a pressure of 760 torr. in an oxygen atmosphere.
Claim 8
Dependent Claim
14 words
The method of claim 6, wherein said temperature is from 800° to 850° C.
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) | 1981-11-27 | 1982-05-29 | 1982-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-27 | 1986-05-29 | 1986-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-27 | 1990-05-29 | 1990-11-28 | $7700.00 | Window Closed / Lapsed |