US4069367A
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Magnetic powder material comprising iron oxide particles with a copper-cobalt alloy coating
Assignee: TDK Corp
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Filing: 1973-01-12
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Granted: 1978-01-17
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Expires: 1993-01-12
Abstract
Abstract A powder magnetic material for use as a magnetic recording medium and a method of its manufacture are disclosed. More particularly, the disclosed powder magnetic material is adapted to provide a magnetic recording medium of low electric resistance. In particular, an alloy of cobalt and at least one element selected from the group consisting of vanadium, molybdenum, copper, manganese, nickel, zinc and iron is deposited onto the surface of particles of magnetic iron oxides such as Fe 3 O 4 or γFe 2 O 3 to provide a powdered magnetic material of high coercivity, high magnetic flux density and low electric resistance.
Inventors
- 👤 Shinji Umeki
- 👤 Kazuhide Aue
- 👤 Yasumichi Tokuoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:11
CPC Classifications
B; B22; B22F; B22F9/00; B22F9/16; B22F9/18; B22F9/24; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
91 words
A magnetic powder material comprising magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co and Cu, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being about 3 wt% with respect to the weight of said iron oxide particles and said amount of Cu in said alloy being about 0.4 wt% with respect to the weight of said iron oxide particles.
Claim 2
Dependent Claim
91 words
A magnetic powder material comprising magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co and Cu, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being about 3 wt% with respect to the weight of said iron oxide particles and said amount of Cu in said alloy being about 0.4 wt% with respect to the weight of said iron oxide particles.
Claim 3
Dependent Claim
91 words
A magnetic powder material comprising magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co and Mn, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being about 1.5 wt% with respect to the weight of said iron oxide particles and said amount of Mn in said alloy being about 0.3 wt% with respect to the weight of said iron oxide particles.
Claim 4
Dependent Claim
91 words
A magnetic powder material comprising magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co and Mn, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being about 1.5 wt% with respect to the weight of said iron oxide particles and said amount of Mn in said alloy being about 0.3 wt% with respect to the weight of said iron oxide particles.
Claim 5
Dependent Claim
91 words
A magnetic powder material comprising magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co and Zn, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being about 4 wt% with respect to the weight of said iron oxide particles and said amount of Zn in said alloy being about 3 wt% with respect to the weight of said iron oxide particles.
Claim 6
Dependent Claim
91 words
A magnetic powder material comprising magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co and Zn, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being about 4 wt% with respect to the weight of said iron oxide particles and said amount of Zn in said alloy being about 3 wt% with respect to the weight of said iron oxide particles.
Claim 7
Dependent Claim
115 words
A magnetic powder material comprising magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co, V and Mo, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being in the range of about 0.65-2.15 wt% with respect to the weight of said iron oxide particles, said amount of V in said alloy being in the range of about 0.10-0.44 wt% and said amount of Mo in said alloy being in the range of about 0.05-0.2 wt% with respect to the weight of said iron oxide particles.
Claim 8
Dependent Claim
115 words
A magnetic powder material comprising magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co, V and Mo, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being in the range of about 0.65-2.15 wt% with respect to the weight of said iron oxide particles, said amount of V in said alloy being in the range of about 0.10-0.44 wt% and said amount of Mo in said alloy being in the range of about 0.05-0.2 wt% with respect to the weight of said iron oxide particles.
Claim 9
Dependent Claim
91 words
A magnetic powder material comprising magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co and V, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being about 1.5 wt% with respect to the weight of said iron oxide particles and said amount of V in said alloy being about 1.20 wt% with respect to the weight of said iron oxide particles.
Claim 10
Dependent Claim
91 words
A magnetic powder material comprising magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co and V, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being about 1.5 wt% with respect to the weight of said iron oxide particles and said amount of V in said alloy being about 1.20 wt% with respect to the weight of said iron oxide particles.
Claim 11
Dependent Claim
96 words
A magnetic powder material consisting essentially of magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co and Fe, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being in the range of about 1.33-2.71% with respect to the weight of said iron oxide particles and said amount of Fe in said alloy being about 0.4-1.1 wt% with respect to the weight of said iron oxide particles.
Claim 12
Dependent Claim
96 words
A magnetic powder material consisting essentially of magnetic iron oxide particles having a substantially uniform coating of an alloy consisting essentially of Co and Fe, said alloy being deposited on said iron oxide particles in an amount sufficient to provide high coercivity, high magnetic flux density and low electrical resistance, the amount of Co in said alloy being in the range of about 1.33-2.71% with respect to the weight of said iron oxide particles and said amount of Fe in said alloy being about 0.4-1.1 wt% with respect to the weight of said iron oxide particles.
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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) | 1981-01-16 | 1981-07-18 | 1982-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-16 | 1985-07-18 | 1986-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-16 | 1989-07-18 | 1990-01-17 | $7700.00 | Window Closed / Lapsed |