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Patent US3837839A successfully refreshed from Google Patents.
US3837839A
Expired / Lapsed
US
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Method of preparing iron powder suitable for magnetic recording
Assignee: US Philips Corp
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Filing: 1973-02-26
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Granted: 1974-09-24
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Expires: 1993-02-26
Abstract
Abstract A method of preparing a metal powder which consists mainly of iron by reduction of finely divided acicular iron oxide hydrate. The iron oxide hydrate particles are doped with a metal which is catalytic for hydrogen reactions (for example Co, Ni, Ru). The reduction to metal then occurs more rapidly.
Inventors
- 👤 H Laurensberg
- 👤 J Wegener
- 👤 P Greene
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:13
CPC Classifications
C; C21; C21B; C21B13/00; C21B13/008; B; B22; B22F; B22F9/00; B22F9/16; B22F9/18; B22F9/20; B22F9/22; Y; Y02; Y02P; Y02P10/00; Y02P10/10; Y02P10/134
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
17 words
A method as claimed in claim 1, wherein the iron oxide hydrate particles are doped with Ni.
Claim 2
Dependent Claim
17 words
A method as claimed in claim 1 wherein the iron oxide hydrate particles are doped with Co.
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) | 1977-09-23 | 1978-03-25 | 1978-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-23 | 1982-03-25 | 1982-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-23 | 1986-03-25 | 1986-09-24 | $7700.00 | Window Closed / Lapsed |