US4495241A
Expired / Lapsed
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Magnetic tape
Assignee: Nippon Gakki Co Ltd
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Filing: 1983-01-04
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Granted: 1985-01-22
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Expires: 2003-01-04
Abstract
Abstract An extremely thin highly magnetic layer is formed on one surface side only of an age-hardening type magnet alloy film by local age-hardening after solution treatment for the purpose of high density recording without any process difficulties.
Inventors
- 👤 Kenzaburo Iijima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:35
CPC Classifications
H; H01; H01F; H01F41/00; H01F41/14; H01F41/22; C; C21; C21D; C21D9/00; C21D9/52; G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/84; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
52 words
Magnetic tape comprising a base layer formed by solution treatment of an age-hardening type magnet alloy material and a ferromagnetic surface layer which is formed on one surface side of said base layer by age-hardening of said magnet alloy material and has a thickness in a range from 0.1 to 2 micronmeters.
Claim 2
Dependent Claim
52 words
Magnetic tape comprising a base layer formed by solution treatment of an age-hardening type magnet alloy material and a ferromagnetic surface layer which is formed on one surface side of said base layer by age-hardening of said magnet alloy material and has a thickness in a range from 0.1 to 2 micronmeters.
Claim 3
Dependent Claim
29 words
Magnetic tape as claimed in claim 1 in which the volume occupation ratio of ferromagnetic particles in said ferromagnetic surface layer is in a range from 15 to 80%.
Claim 4
Dependent Claim
29 words
Magnetic tape as claimed in claim 1 in which the axial diameter of ferromagnetic particles in said ferromagnetic surface layer is in a range from 0.05 to 1 micronmeters.
Claim 5
Dependent Claim
24 words
Magnetic tape as claimed in claim 1 in which the axial ratio of ferromagnetic particles in said ferromagnetic surface layer is 3.0 or larger.
Claim 6
Dependent Claim
24 words
Magnetic tape as claimed in claim 1 in which the density of ferromagnetic particles in said ferromagnetic surface layer is 200/μm 2 or larger.
Claim 7
Dependent Claim
43 words
Magnetic tape as claimed in claim 1 in which said age-hardening type magnet alloy material is selected from a group consisting of Alnico type magnet alloys, Fe-Cr-Co type magnet alloys, Cu-Ni-Fe type magnet alloys, Pt-Co type magnet alloys and Au-Fe-Co type magnet alloys.
Claim 8
Dependent Claim
78 words
Magnetic tape as claimed in claim 6 in which the volume occupation ratio of ferromagnetic particles in said ferromagnetic surface layer is in a range from 15 to 80%, the axial diameter of said particles in said surface layer is in a range from 0.05 to 1 micrometers, the axial ratio of said particles in said surface layer is at least 3.0 and the density of said particles in said surface layer ist at least 200/μm 2 .
Claim 9
Dependent Claim
37 words
Magnetic tape as claimed in claim 7 in which said age-hardening type magnet alloy material is an Fe-Cr-Co type alloy containing 44% by weight of iron, 31% by weight of chromium and 25% by weight of cobalt.
Claim 10
Dependent Claim
30 words
Magnetic tape comprising a solution treated age-hardening type magnet alloy material having on one surface side an age hardening formed ferromagnetic surface layer of 0.1 to 2 micrometers in thickness.
Claim 11
Dependent Claim
30 words
Magnetic tape comprising a solution treated age-hardening type magnet alloy material having on one surface side an age hardening formed ferromagnetic surface layer of 0.1 to 2 micrometers in thickness.
Claim 12
Dependent Claim
29 words
Magnetic tape as claimed in claim 9 in which the volume occupation ratio of ferromagnetic particles in said ferromagnetic surface layer is in a range from 15 to 80%.
Claim 13
Dependent Claim
29 words
Magnetic tape as claimed in claim 9 in which the axial diameter of ferromagnetic particles in said ferromagnetic surface layer is in a range from 0.05 to 1 micronmeters.
Claim 14
Dependent Claim
24 words
Magnetic tape as claimed in claim 9 in which the axial ratio of ferromagnetic particles in said ferromagnetic surface layer is 3.0 or larger.
Claim 15
Dependent Claim
78 words
Magnetic tape as claimed in claim 9 in which the volume occupation ratio of ferromgnetic particles in said ferromagnetic surface layer is in a range from 15 to 80%, the axial diameter of said particles in said surface layer is in a range from 0.05 to 1 micrometers, the axial ratio of said particles in said surface layer is at least 3.0 and the density of said particles in said surface layer is at least 200/μm 2 .
Claim 16
Dependent Claim
37 words
Magnetic tape as claimed in claim 13 in which said age-hardening type magnet alloy material is an Fe-Cr-Co type alloy containing 44% by weight of iron, 31% by weight of chromium and 25% by weight of cobalt.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-01-22 | 1988-07-23 | 1989-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-22 | 1992-07-23 | 1993-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-22 | 1996-07-23 | 1997-01-22 | $7700.00 | Window Closed / Lapsed |