Patent US4128421A successfully refreshed from Google Patents.
US4128421A
Expired / Lapsed
US
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Tantalum powder for producing an embrittlement-resistant wire
Assignee: Nrc Inc
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Filing: 1977-10-17
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Granted: 1978-12-05
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Expires: 1997-10-17
Abstract
Abstract Tantalum and tantalum-rich alloys, particularly in wire form, are stabilized against embrittlement by the addition of 50 to 700 parts per million of silicon and optionally with the further addition of 100 to 500 parts per million of carbon.
Inventors
- 👤 Harold G. Marsh
- 👤 James A. Pierret
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:16
CPC Classifications
C; C22; C22C; C22C1/00; C22C1/04; C22C1/045; C22C27/00; C22C27/02
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
114 words
A powder composition suitable for the preparation of an embrittlement-resistant tantalum wrought product composed of substantially pure tantalum containing less than 300 parts per million of columbium, less than 50 parts per million of tungsten, less than 10 parts per million of molybdenum, less than 30 parts per million of chromium, less than 20 parts per million of calcium, and less than 200 parts per million of iron, chromium and nickel combined, said powder composition containing from about 100 to about 2000 parts per million of silicon on an overall basis and comprising individual particles substantially free of silicon and other individual particles containing from about 1% to about 5% of silicon by weight.
Claim 2
Dependent Claim
114 words
A powder composition suitable for the preparation of an embrittlement-resistant tantalum wrought product composed of substantially pure tantalum containing less than 300 parts per million of columbium, less than 50 parts per million of tungsten, less than 10 parts per million of molybdenum, less than 30 parts per million of chromium, less than 20 parts per million of calcium, and less than 200 parts per million of iron, chromium and nickel combined, said powder composition containing from about 100 to about 2000 parts per million of silicon on an overall basis and comprising individual particles substantially free of silicon and other individual particles containing from about 1% to about 5% of silicon by weight.
Claim 3
Dependent Claim
22 words
The composition of claim 1 wherein said silicon is present in an amount from about 200 to about 900 parts per million.
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) | 1981-12-04 | 1982-06-05 | 1982-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-04 | 1986-06-05 | 1986-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-04 | 1990-06-05 | 1990-12-05 | $7700.00 | Window Closed / Lapsed |