Patent US2717984A successfully refreshed from Google Patents.
US4423004A
Expired / Lapsed
US
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Treatment of tantalum powder
Assignee: Sprague Electric Co
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Filing: 1983-03-24
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Granted: 1983-12-27
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Expires: 2003-03-24
Abstract
Abstract Tantalum powder for electrolytic capacitors is treated with a non-aqueous solution of ammonium thiocyanate in N,N'-dimethylformamide or N-methylpyrrolidinone after the powder has been subjected to a thermal treatment in the absence of oxygen step and before the powder is exposed to an oxygen-containing fluid to prevent oxygen uptake by the powder. The thermal treatment step is carried out at 700 DEG C. and above.
Inventors
- 👤 Sidney D. Ross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:06
CPC Classifications
H; H01; H01G; H01G9/00; H01G9/004; H01G9/04; H01G9/048; H01G9/052; H01G9/0525; B; B22; B22F; B22F1/00; B22F1/14; B22F1/145; C; C23; C23F; C23F11/00; C23F11/08; C23F11/18; C23F11/182
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
59 words
A process for treating tantalum powder for electrolytic capacitors comprising contacting the powder after a thermal treatment in the absence of oxygen step at 700° C. and above and before exposure to an oxygen-containing fluid with a nonaqueous solution of ammonium thiocyanate in an amide solvent to passivate said powder to oxygen pickup on exposure to said oxygen-containing fluid.
Claim 2
Dependent Claim
59 words
A process for treating tantalum powder for electrolytic capacitors comprising contacting the powder after a thermal treatment in the absence of oxygen step at 700° C. and above and before exposure to an oxygen-containing fluid with a nonaqueous solution of ammonium thiocyanate in an amide solvent to passivate said powder to oxygen pickup on exposure to said oxygen-containing fluid.
Claim 3
Dependent Claim
12 words
A process according to claim 1 wherein said oxygen-containing fluid is air.
Claim 4
Dependent Claim
11 words
A process according to claim 1 wherein said amide is N,N'-dimethylformamide.
Claim 5
Dependent Claim
11 words
A process according to claim 1 wherein said amide is N-methylpyrrolidinone.
References Cited (Backward Citations)
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Cited
GB951726A
Cited
US3180329A
Cited
US3152893A
Cited
US3299326A
Cited
GB1307149A
Cited
US3697255A
Cited
GB1525900A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-26 | 1987-06-27 | 1987-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-26 | 1991-06-27 | 1991-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-26 | 1995-06-27 | 1995-12-27 | $7700.00 | Window Closed / Lapsed |