US4794042A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
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Filing: 1986-10-09
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Granted: 1988-12-27
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Expires: 2006-10-09
Abstract
Abstract A magnetic recording medium wherein a magnetic layer containing a particulate magnetic material and a binder is formed on a substrate exhibits improved performance as magnetic recording tape, disk, and sheet when the particulate magnetic material comprises particles having iron carbide at least on the surface thereof and optional oxide particles, and the particulate magnetic material contains 5 to 90% by weight of iron carbide in the form of FenC.
Inventors
- 👤 Yuichi Kubota
- 👤 Keiji Koga
- 👤 Kazunori Tamazaki
- 👤 Tsutomu Aoyama
- 👤 Akio Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 01:49
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70652; G11B5/70668; G11B5/70673; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2998; Y10T428/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
77 words
A magnetic recording medium comprising a substrate and a magnetic layer formed thereon and containing a particulate magnetic material and a radiation curable binder, characterized in that the particulate magnetic material comprises (a) magnetic particles having iron carbide of the formula: Fe n C where n is a number of at least 2 at least on the surface thereof and (b) oxide particles, and the particulate magnetic material contains 5 to 90% by weight of iron carbide.
Claim 2
Dependent Claim
77 words
A magnetic recording medium comprising a substrate and a magnetic layer formed thereon and containing a particulate magnetic material and a radiation curable binder, characterized in that the particulate magnetic material comprises (a) magnetic particles having iron carbide of the formula: Fe n C where n is a number of at least 2 at least on the surface thereof and (b) oxide particles, and the particulate magnetic material contains 5 to 90% by weight of iron carbide.
Claim 3
Dependent Claim
78 words
A magnetic recording medium comprising a disk-shaped flexible substrate and a magnetic layer formed thereon and containing a particulate magnetic material formed thereon and containing a particulate magnetic material and a radiation curable binder, characterized in that the particulate magnetic material comprises magnetic particles having iron carbide of the formula: Fe n C where n is a number of at least 2 at least on the surface thereof and contains 5 to 90% by weight of iron carbide.
Claim 4
Dependent Claim
78 words
A magnetic recording medium comprising a disk-shaped flexible substrate and a magnetic layer formed thereon and containing a particulate magnetic material formed thereon and containing a particulate magnetic material and a radiation curable binder, characterized in that the particulate magnetic material comprises magnetic particles having iron carbide of the formula: Fe n C where n is a number of at least 2 at least on the surface thereof and contains 5 to 90% by weight of iron carbide.
Claim 5
Dependent Claim
45 words
A magnetic recording medium according to claim 2 wherein the particulate magnetic material further comprises at least one member selected from the group consisting of magnetic metal particles, gamma-iron oxide particles, cobalt-coated iron oxide particles, barium ferrite particles, and strontium ferrite particles, and mixtures thereof.
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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) | 1991-12-27 | 1992-06-27 | 1992-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-27 | 1996-06-27 | 1996-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-27 | 2000-06-27 | 2000-12-27 | $7700.00 | Window Closed / Lapsed |