US4759996A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Mitsubishi Electric Corp
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Filing: 1986-12-01
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Granted: 1988-07-26
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Expires: 2006-12-01
Abstract
Abstract Disclosed herein is a magnetic recording medium comprising a non-magnetic substrate, a magnetic layer for data recording formed on the substrate, and a protective layer of nickel (Ni)-tungsten (W)-boron (B) ternary alloy formed on the magnetic layer. The magnetic recording medium will find use as a the external storage such as magnetic disk for computers.
Inventors
- 👤 Hikaru Ogawa
- 👤 Yukio Fukutomi
- 👤 Masayuki Okutani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:21
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10S428/9335; Y10S428/936; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12806; Y10T428/12826; Y10T428/1284; Y10T428/12861; Y10T428/12944
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
137 words
A magnetic recording medium comprising a non-magnetic substrate, a magnetic layer provided in a thin film form on a face side of said non-magnetic substrate, said magnetic layer comprising a metallic material containing at least cobalt (Co), and a protective layer provided in a thin film form on said magnetic layer in order to protect said magnetic layer, wherein said protective layer comprises a thin film of a nickel (Ni)-tungsten (W)-boron (B) ternary alloy deposited on the surface of said magnetic layer in a thickness of 0.05 to 0.1 μm by subjecting said substrate provided thereon with said magnetic layer to a plating treatment in a solution containing 20 g/l of nickel sulfate, 40 g/l of sodium tungstate, 10 g/l of boron sodium hydroxide and 2 cc/l of ammonia at a temperature of 60° to 80° C.
Claim 2
Dependent Claim
137 words
A magnetic recording medium comprising a non-magnetic substrate, a magnetic layer provided in a thin film form on a face side of said non-magnetic substrate, said magnetic layer comprising a metallic material containing at least cobalt (Co), and a protective layer provided in a thin film form on said magnetic layer in order to protect said magnetic layer, wherein said protective layer comprises a thin film of a nickel (Ni)-tungsten (W)-boron (B) ternary alloy deposited on the surface of said magnetic layer in a thickness of 0.05 to 0.1 μm by subjecting said substrate provided thereon with said magnetic layer to a plating treatment in a solution containing 20 g/l of nickel sulfate, 40 g/l of sodium tungstate, 10 g/l of boron sodium hydroxide and 2 cc/l of ammonia at a temperature of 60° to 80° C.
Claim 3
Dependent Claim
19 words
A magnetic recording medium according to claim 1, wherein said magnetic layer comprises a cobalt (Co)-nickel (Ni)-phosphorus (P) alloy.
References Cited (Backward Citations)
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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) | 1991-07-26 | 1992-01-25 | 1992-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-26 | 1996-01-25 | 1996-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-26 | 2000-01-25 | 2000-07-26 | $7700.00 | Window Closed / Lapsed |