US3717504A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1970-08-06
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Granted: 1973-02-20
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Expires: 1990-08-06
Abstract
Abstract A magnetic recording medium prepared by applying a magnetizable layer onto one surface of a non-magnetizable substrate by either electrolytic or non-electrode plating, applying a nickel layer onto the exposed surface of said magnetizable layer having a thickness less than 0.2 Mu and applying a rhodium layer onto the exposed surface of said nickel layer having a thickness greater than 0.2 Mu , the magnetic recording medium having a smooth surface and excellent magnetic properties such as improved rectangular ratio, as well as exhibiting extended service life, the magnetizable layer being protected by said nickel and rhodium layers.
Inventors
- 👤 M Aonuma
- 👤 M Fujiyama
- 👤 G Akashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:32
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/726; G11B5/7262; Y; Y10; Y10S; Y10S29/00; Y10S29/028; Y10S428/00; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/926; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12229; Y10T428/12236; Y10T428/12243; Y10T428/12493; Y10T428/12535; Y10T428/12556; Y10T428/12569; Y10T428/12597; Y10T428/12701; Y10T428/12729; Y10T428/12736; Y10T428/1275; Y10T428/12771; Y10T428/12778; Y10T428/12861; Y10T428/12875; Y10T428/12903; Y10T428/1291
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
83 words
A magnetic recording medium comprising a non-magnetizable substrate, a magnetic recording layer having a thickness greater than 0.05 micron plated onto one surface of said substrate, a first protective layer consisting essentially of a nickel film plated on the exposed surface of said magnetic recording layer and having a thickness less than 0.2 micron and a second protective layer consisting essentially of a rhodium film plated on the exposed surface of said first protective layer and having a thickness greater than 0.02 micron.
Claim 2
Dependent Claim
83 words
A magnetic recording medium comprising a non-magnetizable substrate, a magnetic recording layer having a thickness greater than 0.05 micron plated onto one surface of said substrate, a first protective layer consisting essentially of a nickel film plated on the exposed surface of said magnetic recording layer and having a thickness less than 0.2 micron and a second protective layer consisting essentially of a rhodium film plated on the exposed surface of said first protective layer and having a thickness greater than 0.02 micron.
Claim 3
Dependent Claim
33 words
A magnetic recording medium as set forth in claim 1, in which said nickel film is formed of a member selected from the group comprising nickel, phosphorus-modified nickel and nickel - cobalt alloy.
Claim 4
Dependent Claim
30 words
A magnetic recording medium as set forth in claim 1, in which said rhodium film is formed of pure rhodium or of an alloy containing rhodium as a main component.
Claim 5
Dependent Claim
25 words
A magnetic recording medium as set forth in claim 1, in which said nickel film has a thickness range of 0.1 - 0.2 Mu .
Claim 6
Dependent Claim
25 words
A magnetic recording medium as set forth in claim 1, in which said rhodium film has a thickness range of 0.02 - 0.5 Mu .
Claim 7
Dependent Claim
42 words
The magnetic recording medium according to claim 1 wherein the magnetizable material in said magnetic recording layer comprises a cobalt-nickel alloy and at least one member selected from the group consisting of copper, silver, phosphorus, zinc, rhodium, lanthanum, cerium, neodymium, and tin.
Claim 8
Dependent Claim
14 words
The magnetic recording layer according to claim 6 wherein said group member is copper.
Claim 9
Dependent Claim
24 words
The magnetic recording medium according to claim 1 wherein said substrate is aluminum, aluminum alloy, copper alloy, glass, magnesium alloy, polyethylene terephthalate or polypropylene.
Claim 10
Dependent Claim
24 words
The magnetic recording medium according to claim 1 wherein said magnetic recording layer has a thickness in the range of 0.1 - 1.0 microns.
References Cited (Backward Citations)
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US3417389A
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US3328195A
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US3370979A
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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) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |