Patent US4537641A successfully refreshed from Google Patents.
US4537641A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing valve-metal anodes for electrolytic capacitors
Assignee: H.C. Starck GmbH
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Filing: 1984-03-16
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Granted: 1985-08-27
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Expires: 2004-03-16
Abstract
Abstract To produce valve-metal anodes for electrolytic capacitors, reducing agents are added to the already sintered and/or unsintered anode bodies to improve the electrical properties, whereupon heating is carried out at temperatures above the melting point of the reducing agents and below the temperatures conventionally used for sintering the valve-metal anodes.
Inventors
- 👤 Wolf-Wigand Albrecht
- 👤 Axel Hoppe
- 👤 Uwe Papp
- 👤 Rudiger Wolf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:55
CPC Classifications
H; H01; H01G; H01G9/00; H01G9/004; H01G9/04; H01G9/048; H01G9/052; B; B22; B22F; B22F9/00; B22F9/16; B22F9/18; B22F9/20
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
62 words
A process for producing a valve-metal anode for electrolytic capacitors which comprises heating under a high vacuum or under an inert gas atmosphere a previously heat-treated, shaped and pressed mass of valve-metal powder in the presence of a reducing metal at a temperature above the melting point of the reducing metal and below a temperature conventionally used for sintering a valve-metal anode.
Claim 2
Dependent Claim
62 words
A process for producing a valve-metal anode for electrolytic capacitors which comprises heating under a high vacuum or under an inert gas atmosphere a previously heat-treated, shaped and pressed mass of valve-metal powder in the presence of a reducing metal at a temperature above the melting point of the reducing metal and below a temperature conventionally used for sintering a valve-metal anode.
Claim 3
Dependent Claim
18 words
A process according to claim 1, wherein the heating is carried out at a temperature below 1600° C.
Claim 4
Dependent Claim
23 words
A process according to claim 2, wherein the heating is carried out at a temperature between about 650° C. and about 1150° C.
Claim 5
Dependent Claim
14 words
A process according to claim 3, wherein the reducing metal is an alkali metal.
Claim 6
Dependent Claim
15 words
A process according to claim 3, wherein the reducing metal is an alkaline earth metal.
Claim 7
Dependent Claim
12 words
A process according to claim 3, wherein the reducing metal is aluminum.
Claim 8
Dependent Claim
17 words
A process according to claim 4, wherein the reducing metal is magnesium, calcium or magnesium and calcium.
Claim 9
Dependent Claim
20 words
A process according to claim 1, wherein the previously heat-treated, shaped and pressed mass of valve-metal powder has been agglomerated.
Claim 10
Dependent Claim
20 words
A process according to claim 1, wherein the previously heat-treated, shaped and pressed mass of valve-metal power has been sintered.
Claim 11
Dependent Claim
18 words
A process according to claim 1, wherein the valve metal powder comprises tantalum, tantalum hydride or doped tantalum.
References Cited (Backward Citations)
GB354785A
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GB698753A
Cited
GB735085A
Cited
GB798750A
Cited
US3647415A
Cited
GB1247410A
Cited
US3829310A
Cited
US4231790A
Cited
US4084965A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-08-26 | 1989-02-25 | 1989-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-26 | 1993-02-25 | 1993-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-26 | 1997-02-25 | 1997-08-27 | $7700.00 | Window Closed / Lapsed |