US4839244A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium with protective layer using graphite fluoride and method of producing same
Assignee: NEC Corp
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Filing: 1988-04-13
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Granted: 1989-06-13
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Expires: 2008-04-13
Abstract
Abstract In a magnetic recording medium such as a magnetic disk, a protective coating excellent in both mechanical durability and corrosion resistance is provided on a layer of a magnetic recording material, which may be a metal film, by jointly using graphite fluoride and an inorganic nonmetallic hard compound which can be selected from oxides such as SiO 2 and Al 2 O 3 , nitrides such as SiN and AlN and carbides such as SiC and WC. The protective coating may be either a single layer of a mixture of graphite fluoride and a hard compound formed by co-sputter deposition or a two-layer coating made up of an inner layer of a hard compound and an outer layer of sputter deposited graphite fluoride.
Inventors
- 👤 Yuji Tsukamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:15
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/722; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
59 words
A magnetic recording medium, comprising: a substrate; a magnetic recording layer which is a thin ferromagnetic metal film formed on the substrate; and a protective layer which overlies the magnetic recording layer and is formed of a mixture of graphite fluoride and at least one inorganic nonmetallic hard compound, said graphite fluoride occupying 10-50 volume percent of said mixture.
Claim 2
Dependent Claim
59 words
A magnetic recording medium, comprising: a substrate; a magnetic recording layer which is a thin ferromagnetic metal film formed on the substrate; and a protective layer which overlies the magnetic recording layer and is formed of a mixture of graphite fluoride and at least one inorganic nonmetallic hard compound, said graphite fluoride occupying 10-50 volume percent of said mixture.
Claim 3
Dependent Claim
20 words
A magnetic recording medium according to claim 1, wherein said at least one inorganic nonmetallic hard compound comprises an oxide.
Claim 4
Dependent Claim
26 words
A magnetic recording medium according to claim 2, wherein said oxide is selected from the group consisting of SiO 2 and Al 2 O 3 .
Claim 5
Dependent Claim
20 words
A magnetic recording medium according to claim 1, wherein said at least one inorganic nonmetallic hard compound comprises a nitride.
Claim 6
Dependent Claim
21 words
A magnetic recording medium according to claim 4, wherein said nitride is selected from the group consisting of SiN and AlN.
Claim 7
Dependent Claim
20 words
A magnetic recording medium according to claim 1, wherein said at least one inorganic nonmetallic hard compound comprises a carbide.
Claim 8
Dependent Claim
21 words
A magnetic recording medium according to claim 6, wherein said carbide is selected from the group consisting of SiC and WC.
Claim 9
Dependent Claim
19 words
A magnetic recording medium according to claim 1, wherein said graphite fluoride occupies 20-40 volume % of said mixture.
Claim 10
Dependent Claim
66 words
A magnetic recording medium, comprising: a substrate; a magnetic recording layer which is a thin ferromagnetic metal film formed on the substrate; an inner protective layer which overlies the magnetic recording layer and is formed of at least one nitride selected from the group consisting of SiN and AlN; and an outer protective layer which overlies the inner protective layer and is formed of graphite fluoride.
Claim 11
Dependent Claim
66 words
A magnetic recording medium, comprising: a substrate; a magnetic recording layer which is a thin ferromagnetic metal film formed on the substrate; an inner protective layer which overlies the magnetic recording layer and is formed of at least one nitride selected from the group consisting of SiN and AlN; and an outer protective layer which overlies the inner protective layer and is formed of graphite fluoride.
Claim 12
Independent Claim
73 words
A method of producing a magnetic recording medium, comprising the steps of: forming a thin ferromagnetic metal film to be used as a magnetic recording layer on a substrate; and co-sputter depositing graphite fluoride and at least one inorganic nonmetallic hard compound on the ferromagnetic metal film so as to form a protective layer of a mixture 10-50 volume % of graphite fluoride and the balance of said at least one hard compound.
Claim 13
Independent Claim
73 words
A method of producing a magnetic recording medium, comprising the steps of: forming a thin ferromagnetic metal film to be used as a magnetic recording layer on a substrate; and co-sputter depositing graphite fluoride and at least one inorganic nonmetallic hard compound on the ferromagnetic metal film so as to form a protective layer of a mixture 10-50 volume % of graphite fluoride and the balance of said at least one hard compound.
Claim 14
Dependent Claim
17 words
A method according to claim 10, wherein said at least one inorganic hard compound comprises an oxide.
Claim 15
Dependent Claim
17 words
A method according to claim 10, wherein said at least one inorganic hard compound comprises a nitride.
Claim 16
Dependent Claim
18 words
A method according to claim 10, wherein said at least one inorganic nonmetallic hard compound comprises a carbide.
Claim 17
Dependent Claim
16 words
A method according to claim 10, wherein said mixture contains 20-40 volume % of graphite fluoride.
Claim 18
Dependent Claim
19 words
A method according to claim 12, wherein said nitride is selected from the group consisting of SiN and AlN.
Claim 19
Independent Claim
74 words
A method of producing a magnetic recording medium, comprising the steps of: forming a thin ferromagnetic metal film to be used as a magnetic recording layer on a substrate; overlaying the ferromagnetic metal film with an inner protective layer formed of at least one nitride selected from the group consisting of SiN and AlN; and sputter depositing graphite fluoride on the inner protective layer to form an outer protective layer formed of graphite fluoride.
Claim 20
Independent Claim
74 words
A method of producing a magnetic recording medium, comprising the steps of: forming a thin ferromagnetic metal film to be used as a magnetic recording layer on a substrate; overlaying the ferromagnetic metal film with an inner protective layer formed of at least one nitride selected from the group consisting of SiN and AlN; and sputter depositing graphite fluoride on the inner protective layer to form an outer protective layer formed of graphite fluoride.
Claim 21
Dependent Claim
17 words
A method according to claim 16, wherein said at least one inorganic hard compound comprises an oxide.
Claim 22
Dependent Claim
17 words
A method according to claim 16, wherein said at least one inorganic hard compound comprises a nitride.
Claim 23
Dependent Claim
18 words
A method according to claim 16, wherein said at least one inorganic nonmetallic hard compound comprises a carbide.
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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) | 1992-06-12 | 1992-12-12 | 1993-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-12 | 1996-12-12 | 1997-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-12 | 2000-12-12 | 2001-06-13 | $7700.00 | Window Closed / Lapsed |