Patent US3975217A successfully refreshed from Google Patents.
US3975217A
Expired / Lapsed
US
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Finely divided magnetic cobalt powder
Assignee: Viridian Inc Canada
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Filing: 1974-12-06
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Granted: 1976-08-17
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Expires: 1994-12-06
Abstract
Abstract A cobalt powder product is described which is composed of cobalt particles about 0.8 microns or smaller in size and have refractory oxide particles fixed on the surfaces thereof. The powder is particularly suitable for manufacture of sintered carbide products as well as for use in magnetic products such as magnetic inks and tapes.
Inventors
- 👤 Wasyl Kunda
- 👤 Winfried J. Huppmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:10
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70605; G11B5/70615; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/06; H01F1/061; H01F1/44; H01F1/442; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12181
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
72 words
Non-pyrophoric magnetic cobalt particles of a size no larger than about 0.8 micron, said particles having sub-micron sized refractory oxide particles fixed on the surfaces thereof and containing less than 0.2 wt. % carbon and less than 2 wt % oxygen exclusive of the oxygen associated with said refractory oxide, said cobalt particles being further characterized by a coercivity of 200 to 400 oersteds and a remanent induction value of 2000-7000 gauss.
Claim 2
Dependent Claim
72 words
Non-pyrophoric magnetic cobalt particles of a size no larger than about 0.8 micron, said particles having sub-micron sized refractory oxide particles fixed on the surfaces thereof and containing less than 0.2 wt. % carbon and less than 2 wt % oxygen exclusive of the oxygen associated with said refractory oxide, said cobalt particles being further characterized by a coercivity of 200 to 400 oersteds and a remanent induction value of 2000-7000 gauss.
Claim 3
Dependent Claim
40 words
Magnetic cobalt particles according to claim 1 having the refractory oxide particles formed of an oxide of at least one of the metals of the group consisting of Mg, Ca, Ba, Al, Be, Ce, Hf, La, Th, Y and Zr.
Claim 4
Dependent Claim
18 words
Magnetic cobalt particles according to claim 2 containing from about 0.1 to about 6 wt % refractory oxide.
Claim 5
Dependent Claim
18 words
Magnetic cobalt particles according to claim 3 having the refractory oxide particles formed of yttria, magnesia or thoria.
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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) | 1979-08-17 | 1980-02-16 | 1980-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-17 | 1984-02-16 | 1984-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-17 | 1988-02-16 | 1988-08-17 | $7700.00 | Window Closed / Lapsed |