US4236927A
Expired / Lapsed
US
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Method for the manufacture of iron-containing sintered electrodes
Assignee: Daimler Benz AG
•
Filing: 1978-08-25
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Granted: 1980-12-02
•
Expires: 1998-08-25
Abstract
Abstract A method for manufacturing an iron-containing sintered electrode for alkaline accumulators as well as the product obtained by such method, in which iron powder and at least one reducible iron compound are intimately mixed with each other; the powder mixture is sintered into a stable body and the reducible iron compound is reduced to highly active iron.
Inventors
- 👤 Horst Buhl
- 👤 Manfred Gutjahr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:46
CPC Classifications
H; H01; H01M; H01M4/00; H01M4/02; H01M4/24; H01M4/26; H01M4/30; Y; Y02; Y02E; Y02E60/00; Y02E60/10; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 57
Claim 1
Independent Claim
59 words
A method for manufacturing iron-containing sintered electrodes for alkaline accumulators, in which iron powder is sintered with the use of a filler, comprising the steps of intimately mixing with each other the iron powder and at least one reducible iron compound, sintering the powder mixture into a stable body, and reducing the reducible iron compound into highly active iron.
Claim 2
Independent Claim
59 words
A method for manufacturing iron-containing sintered electrodes for alkaline accumulators, in which iron powder is sintered with the use of a filler, comprising the steps of intimately mixing with each other the iron powder and at least one reducible iron compound, sintering the powder mixture into a stable body, and reducing the reducible iron compound into highly active iron.
Claim 3
Dependent Claim
34 words
A method according to claim 1, characterized in that FeO, Fe 2 O 3 or Fe 3 O 4 as well as mixtures thereof are used as the at least one reducible iron compound.
Claim 4
Dependent Claim
29 words
A method according to claim 1, characterized in that the iron and the reducible compound are at a ratio with respect to weight between about 8:1 and about 1:4.
Claim 5
Dependent Claim
30 words
A method according to claim 3, characterized in that iron and the reducible iron compound are mixed with each other at a weight ratio between about 4:1 and about 1:2.
Claim 6
Dependent Claim
20 words
A method according to claim 3, comprising the step of bringing the powder mixture into desired shape prior to sintering.
Claim 7
Dependent Claim
18 words
A method according to claim 5, characterized in that the powder mixture is compressed prior to the sintering.
Claim 8
Dependent Claim
31 words
A method according to claim 6, characterized in that a pressure of about 500 to about 2,000 kg/cm 2 is used for the compressing of the powder mixture prior to sintering.
Claim 9
Dependent Claim
18 words
A method according to claim 6, characterized in that a pressure of about 1,000 kg/cm 2 is used.
Claim 10
Dependent Claim
37 words
A method according to claim 7, characterized in that the loosely charged powder mixture is condensed prior to sintering by compressing it to at most about 7 times the original density of the loosely charged powder mixture.
Claim 11
Dependent Claim
35 words
A method according to claim 7, characterized in that the loose powder mixture is condensed prior to sintering by compressing it to about 5 to 6 times the original density of the loose powder mixture.
Claim 12
Dependent Claim
19 words
A method according to claim 9, characterized in that the iron powder is obtained by reduction prior to mixing.
Claim 13
Dependent Claim
20 words
A method according to claim 10, characterized in that the iron powder has a particle size smaller than 30 μm.
Claim 14
Dependent Claim
20 words
A method according to claim 10, characterized in that the iron powder has a particle size smaller than 10 μm.
Claim 15
Dependent Claim
26 words
A method according to claim 12, characterized in that the at least one iron compound is a powder having a particle size smaller than 30 μm.
Claim 16
Dependent Claim
26 words
A method according to claim 14, characterized in that the at least one iron compound is a powder having a particle size smaller than 10 μm.
Claim 17
Dependent Claim
22 words
A method according to claim 14, characterized in that the sintering and the reduction are carried out sequentially in separate method steps.
Claim 18
Dependent Claim
18 words
A method according to claim 16, characterized in that the sintering is carried out in an inert atmosphere.
Claim 19
Dependent Claim
20 words
A method according to claim 17, characterized in that sintering temperatures between about 550° C. and 1,100° C. are used.
Claim 20
Dependent Claim
21 words
A method according to claim 18, characterized in that sintering temperatures between about 600° C. and about 800° C. are used.
Claim 21
Dependent Claim
28 words
A method according to claim 18, characterized in that the sintering operation is carried out during a period of time of about 15 minutes to about 5 hours.
Claim 22
Dependent Claim
24 words
A method according to claim 20, characterized in that the reduction following the sintering is carried out in hydrogen or a hydrogen-containing gas mixture.
Claim 23
Dependent Claim
24 words
A method according to claim 21, characterized in that the reduction is carried out at temperatures between about 500° C. and about 1,000° C.
Claim 24
Dependent Claim
24 words
A method according to claim 22, characterized in that the reduction is carried out at temperatures between about 500° C. and about 700° C.
Claim 25
Dependent Claim
27 words
A method according to claim 22, characterized in that the reduction is carried out during a period of time of about 5 minutes to about 10 hours.
Claim 26
Dependent Claim
25 words
A method according to claim 14, characterized in that the sintering and reduction are carried out simultaneously in hydrogen or in a hydrogen-containing gas mixture.
Claim 27
Dependent Claim
27 words
A method according to claim 25, characterized in that the simultaneous sintering and reduction is carried out at temperatures between about 500° C. and about 1,000° C.
Claim 28
Dependent Claim
26 words
A method according to claim 26, characterized in that the simultaneous sintering and reduction is carried out at temperatures between about 550° C. and 850° C.
Claim 29
Dependent Claim
30 words
A method according to claim 26, characterized in that the simultaneous sintering and reduction is carried out during a period of time of about 10 minutes to about 10 hours.
Claim 30
Dependent Claim
37 words
A method according to claim 16, 17 or 18, characterized in that FeO, Fe 2 O 3 or Fe 3 O 4 as well as mixtures thereof are used as the at least one reducible iron compound.
Claim 31
Dependent Claim
37 words
A method according to claim 25, 26 or 28, characterized in that FeO, Fe 2 O 3 or Fe 3 O 4 as well as mixtures thereof are used as the at least one reducible iron compound.
Claim 32
Dependent Claim
20 words
A method according to claim 1 or 3, characterized in that the powder mixture is compressed prior to the sintering.
Claim 33
Dependent Claim
31 words
A method according to claim 31, characterized in that a pressure of about 500 to about 2,000 kg/cm 2 is used for the compressing of the powder mixture prior to sintering.
Claim 34
Dependent Claim
18 words
A method according to claim 31, characterized in that a pressure of about 1,000 kg/cm 2 is used.
Claim 35
Dependent Claim
39 words
A method according to claim 1 or 3, characterized in that the loosely charged powder mixture is condensed prior to sintering by compressing it to at most about 7 times the original density of the loosely charged powder mixture.
Claim 36
Dependent Claim
36 words
A method according to claim 1, characterized in that the loose powder mixture is condensed prior to sintering by compressing it to about 5 to about 6 times the original density of the loose powder mixture.
Claim 37
Dependent Claim
20 words
A method according to claim 1, characterized in that the iron powder has a particle size smaller than 30 μm.
Claim 38
Dependent Claim
23 words
A method according to claim 1, characterized in that the iron powder is a powder having a particle size smaller than 10 μm.
Claim 39
Dependent Claim
22 words
A method according to claim 1, characterized in that an iron compound with a particle size smaller than 30 μm is used.
Claim 40
Dependent Claim
26 words
A method according to claim 1, characterized in that the at least one iron compound is a powder having a particle size smaller than 10 μm.
Claim 41
Dependent Claim
24 words
A method according to claim 1, 2, 3, 36 or 38, characterized in that the iron powder is obtained by reduction prior to mixing.
Claim 42
Dependent Claim
24 words
A method according to claim 1 or 3, characterized in that the sintering and the reduction are carried out sequentially in separate method steps.
Claim 43
Dependent Claim
18 words
A method according to claim 41, characterized in that the sintering is carried out in an inert atmosphere.
Claim 44
Dependent Claim
20 words
A method according to claim 42, characterized in that sintering temperatures between about 550° C. and 1,100° C. are used.
Claim 45
Dependent Claim
21 words
A method according to claim 43, characterized in that sintering temperatures between about 600° C. and about 800° C. are used.
Claim 46
Dependent Claim
28 words
A method according to claim 43, characterized in that the sintering operation is carried out during a period of time of about 15 minutes to about 5 hours.
Claim 47
Dependent Claim
24 words
A method according to claim 42, characterized in that the reduction following the sintering is carried out in hydrogen or a hydrogen-containing gas mixture.
Claim 48
Dependent Claim
24 words
A method according to claim 46, characterized in that the reduction is carried out at temperatures between about 500° C. and about 1,000° C.
Claim 49
Dependent Claim
24 words
A method according to claim 47, characterized in that the reduction is carried out at temperatures between about 500° C. and about 700° C.
Claim 50
Dependent Claim
27 words
A method according to claim 47, characterized in that the reduction is carried out during a period of time of about 5 minutes to about 10 hours.
Claim 51
Dependent Claim
27 words
A method according to claim 1 or 3, characterized in that the sintering and reduction are carried out simultaneously in hydrogen or in a hydrogen-containing gas mixture.
Claim 52
Dependent Claim
27 words
A method according to claim 50, characterized in that the simultaneous sintering and reduction is carried out at temperatures between about 500° C. and about 1,000° C.
Claim 53
Dependent Claim
26 words
A method according to claim 51, characterized in that the simultaneous sintering and reduction is carried out at temperatures between about 550° C. and 850° C.
Claim 54
Dependent Claim
30 words
A method according to claim 51, characterized in that the simultaneous sintering and reduction is carried out during a period of time of about 10 minutes to about 10 hours.
Claim 55
Dependent Claim
18 words
An iron containing sintered electrode made according to the method of claim 1, 3, 15, 25, or 45.
Claim 56
Dependent Claim
42 words
An iron containing sintered electrode comprising a stable body formed by intimately mixing iron powder and at least one powdered reducible iron compound, sintering the resulting powder mixture and reducing the iron compound to a highly active iron within said stable body.
Claim 57
Dependent Claim
42 words
An iron containing sintered electrode comprising a stable body formed by intimately mixing iron powder and at least one powdered reducible iron compound, sintering the resulting powder mixture and reducing the iron compound to a highly active iron within said stable body.
References Cited (Backward Citations)
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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) | 1983-12-02 | 1984-06-02 | 1984-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-02 | 1988-06-02 | 1988-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-02 | 1992-06-02 | 1992-12-02 | $7700.00 | Window Closed / Lapsed |