US3841869A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making light-duty electrical contacts composed of silver and ruthenium dioxide
Assignee: Schneider Electric USA Inc
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Filing: 1973-06-25
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Granted: 1974-10-15
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Expires: 1993-06-25
Abstract
Abstract A light-duty electrical contact material which consists of a mixture of silver and ruthenium dioxide, the ruthenium dioxide content being in the range 0.1 to 13.0 atomic percent. For reasons of economy, the preferred ruthenium dioxide content is 1.3 percent. The material is produced by powder metallurgical techniques from fine, irregular silver powder and preferably ultra fine ruthenium metal powder. Fine ruthenium dioxide powder can be utilized in place of the ruthenium metal powder.
Inventors
- 👤 T Davies
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:08
CPC Classifications
H; H01; H01H; H01H1/00; H01H1/02; H01H1/021; H01H1/023; H01H1/0237; C; C22; C22C; C22C5/00; C22C5/06
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
65 words
A METHOD OF PRODUCING A LIGHT-DUTY ELECTRICAL CONTACT INCLUDING THE STEPS OF MIXING FINE, IRREGULAR SILVER POWDER WITH FINE RUTHENIUM DIOXIDE POWDER TO PROVIDE A MIXTURE HAVING A RUTHENIUM DIOXIDE CONENT IN THE RANGE 0.1 TO 13.0 ATOMIC PERCENT; COMPACTING THE MIXTURE INTO A DESIRED SHAPED; AND HEATING THE COMPACTED SHAPE IN AN INERT ATMOSPHERE FOR A PERIOD OF TIME TO EFFECT SINTERING OF SAME.
Claim 2
Independent Claim
65 words
A METHOD OF PRODUCING A LIGHT-DUTY ELECTRICAL CONTACT INCLUDING THE STEPS OF MIXING FINE, IRREGULAR SILVER POWDER WITH FINE RUTHENIUM DIOXIDE POWDER TO PROVIDE A MIXTURE HAVING A RUTHENIUM DIOXIDE CONENT IN THE RANGE 0.1 TO 13.0 ATOMIC PERCENT; COMPACTING THE MIXTURE INTO A DESIRED SHAPED; AND HEATING THE COMPACTED SHAPE IN AN INERT ATMOSPHERE FOR A PERIOD OF TIME TO EFFECT SINTERING OF SAME.
Claim 3
Dependent Claim
51 words
A method as claimed in claim 1 wherein the compacting is effected at a pressure in the range 10 to 20 tons per square inch, and wherein the sintering is effected at a temperature in the range 850* to 940*C for a period of time of not less than 1 hour.
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) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |