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US4664883A
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Method of making electrolytic capacitor anodes
Assignee: Yosemite Investments Inc
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Filing: 1986-06-17
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Granted: 1987-05-12
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Expires: 2006-06-17
Abstract
Abstract A powder of a film-forming metal, such as tantalum, is combined with a binder of polyethylene oxide and ammonium carbonate. The powder-binder combination is pressed to form an anode body and then heated to about 300° C. for about 4 hours to remove the binder. The polyethylene oxide is a superior binding agent producing anodes of high porosity and strength. The ammonium carbonate reacts with liquid polyethylene oxide to release large quantities of gas which sweeps the polyethylene oxide out of the anode pores, resulting in an unusually small amount of binder residue and yielding capacitors with low d.c. leakage.
Inventors
- 👤 Brian Melody
- 👤 Ernest W. Eickelberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:44
CPC Classifications
H; H01; H01G; H01G9/00; H01G9/004; H01G9/04; H01G9/048; H01G9/052; B; B22; B22F; B22F3/00; B22F3/10; B22F3/1017; B22F3/1021; B22F3/1025; B22F3/11; B22F3/1121
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
48 words
A method of making an anode for an electrolytic capacitor, comprising the steps of: providing a powder comprised of a film-forming metal, polyethylene oxide, and ammonium carbonate; pressing the powder to form an anode body; and heating the anode body to remove the polyethylene oxide and ammonium carbonate.
Claim 2
Independent Claim
48 words
A method of making an anode for an electrolytic capacitor, comprising the steps of: providing a powder comprised of a film-forming metal, polyethylene oxide, and ammonium carbonate; pressing the powder to form an anode body; and heating the anode body to remove the polyethylene oxide and ammonium carbonate.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein said step of heating comprises heating to at least the melting range of polyethylene oxide.
Claim 4
Dependent Claim
21 words
The method of claim 2 wherein said step of heating comprises heating to a temperature between 50° C. and 300° C.
Claim 5
Dependent Claim
13 words
The method of claim 1 wherein said powder further includes dried fumed silica.
Claim 6
Dependent Claim
28 words
The method of claim 1 wherein said powder comprises between 94% and 98% film-forming metal, between 1% and 3% polyethylene oxide and between 1% and 3% ammonium carbonate.
Claim 7
Independent Claim
146 words
A method of making a porous anode for an electrolytic capacitor comprising the steps of: providing a powder of film-forming metal particles and a binder comprised of a first substance with desirable binder properties and a second substance which in combination with the first substance is sufficiently stable at pressing temperature to permit the pressing of a strong porous anode body and, at temperatures above pressing temperature but below the temperature at which the film-forming property of the metal degrades, interacts with the first substance to produce a quantity of gas sufficient to sweep the first substance out of the pores of the anode; pressing the powder and binder combination to form an anode body; and heating the anode body to a temperature above the pressing temperature and below the temperature at which the film-forming property of the metal will degrade to remove the binder substances.
Claim 8
Independent Claim
146 words
A method of making a porous anode for an electrolytic capacitor comprising the steps of: providing a powder of film-forming metal particles and a binder comprised of a first substance with desirable binder properties and a second substance which in combination with the first substance is sufficiently stable at pressing temperature to permit the pressing of a strong porous anode body and, at temperatures above pressing temperature but below the temperature at which the film-forming property of the metal degrades, interacts with the first substance to produce a quantity of gas sufficient to sweep the first substance out of the pores of the anode; pressing the powder and binder combination to form an anode body; and heating the anode body to a temperature above the pressing temperature and below the temperature at which the film-forming property of the metal will degrade to remove the binder substances.
Claim 9
Dependent Claim
21 words
The method of claim 6 wherein said step of heating comprises heating to a temperature between 50° C. and 300° C.
Claim 10
Dependent Claim
17 words
The method of claim 6 wherein said second substance has a molecular weight of 96 or less.
Claim 11
Dependent Claim
46 words
The method of claim 6 wherein said second substance is one which reacts with said first substance when said first substance is in a liquid state to produce said quantity of gas, but does not so react when said first substance is in a solid state.
Claim 12
Dependent Claim
20 words
A material for use in forming anodes for electrolytic capacitors, said material comprising tantalum powder, polyethylene oxide and ammonium carbonate.
Claim 13
Dependent Claim
20 words
A material for use in forming anodes for electrolytic capacitors, said material comprising tantalum powder, polyethylene oxide and ammonium carbonate.
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) | 1990-05-11 | 1990-11-10 | 1991-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-11 | 1994-11-10 | 1995-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-11 | 1998-11-10 | 1999-05-12 | $7700.00 | Window Closed / Lapsed |