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US4756967A
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Magnetic recording medium
Assignee: Canon Inc
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Filing: 1986-05-23
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Granted: 1988-07-12
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Expires: 2006-05-23
Abstract
Abstract A magnetic recording medium, comprising a non-magnetic substrate, a magnetic recording layer of a ferromagnetic film on the substrate, and a protective layer on the magnetic recording layer. The protective layer is formed of oxide of an alloy of Co and a metal selected from the group consisting of Ti, Zr, Hf, Nb, Ta, Mo, Rh, Pd, and Si. The protective layer is preferably formed by deposition from vapor phase of the metal components constituting the alloy in an oxygen atmosphere under a reduced pressure. The protective layer provides for a durability and corrosion resistance to the magnetic recording medium.
Inventors
- 👤 Morimi Hashimoto
- 👤 Hiroshi Takagi
- 👤 Kenji Suzuki
- 👤 Nobuyuki Saito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:13
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/84; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
127 words
A magnetic recording medium, comprising a non-magnetic substrate, a magnetic recording layer of a ferromagnetic film on said substrate, and a protective layer at least 50 Å in thickness formed on said magnetic recording layer by vapor depositing or sputtering under constant oxygen pressure, said protective layer being formed of an oxide of an alloy of Co and (i) at least one metal selected from the group consisting of Ti, Zr, Hf, Nb, Ta or Mo in an atomic ratio to Co from 1:9 to 9:1 or (ii) at least one element selected from the group consisting of Rh, Pd or Si in an amount of 3 to 30 atomic percent based on the total of Co and said at least one of Rh, Pd or Si.
Claim 2
Dependent Claim
127 words
A magnetic recording medium, comprising a non-magnetic substrate, a magnetic recording layer of a ferromagnetic film on said substrate, and a protective layer at least 50 Å in thickness formed on said magnetic recording layer by vapor depositing or sputtering under constant oxygen pressure, said protective layer being formed of an oxide of an alloy of Co and (i) at least one metal selected from the group consisting of Ti, Zr, Hf, Nb, Ta or Mo in an atomic ratio to Co from 1:9 to 9:1 or (ii) at least one element selected from the group consisting of Rh, Pd or Si in an amount of 3 to 30 atomic percent based on the total of Co and said at least one of Rh, Pd or Si.
Claim 3
Dependent Claim
20 words
A magnetic recording medium according to claim 1, wherein the thickness of said protective layer is 50 to 500 Å.
Claim 4
Dependent Claim
26 words
A magnetic recording medium according to claim 1, wherein said magnetic recording layer comprises a metal selected from the group consisting of Fe, Co, and Ni.
Claim 5
Dependent Claim
14 words
A magnetic recording medium according to claim 3, wherein said magnetic layer comprises Co.
Claim 6
Dependent Claim
34 words
A magnetic recording medium according to claim 1, wherein said protective layer is formed of oxide of an alloy of Co and a metal selected from the group consisting of Ti, Zr and Hf.
Claim 7
Dependent Claim
20 words
A magnetic recording medium according to claim 5, wherein said atomic ratio is in the range of 2:8 to 8:2.
Claim 8
Dependent Claim
33 words
A magnetic recording medium according to claim 1, wherein said protective layer is formed of oxides of an alloy of Co and a metal selected from the group consisting of Nb and Ta.
Claim 9
Dependent Claim
24 words
A magnetic recording medium according to claim 1, wherein said protective layer is formed of oxide of an alloy of V, Nb, and Co.
Claim 10
Dependent Claim
20 words
A magnetic recording medium according to claim 7, wherein said atomic ratio is in a range of 2:8 to 8:2.
Claim 11
Dependent Claim
24 words
A magnetic recording medium according to claim 1, wherein said protective layer is formed of the oxide of an alloy of Mo and Co.
Claim 12
Dependent Claim
25 words
A magnetic recording medium according to claim 1, wherein said protective layer is formed of the oxide of an alloy of Mo, W and Co.
Claim 13
Dependent Claim
20 words
A magnetic recording medium according to claim 12, wherein said atomic ratio is in the range of 2:8 to 8:2.
Claim 14
Dependent Claim
33 words
A magnetic recording medium according to claim 1, wherein said protective layer is formed of oxide of an alloy of Co and a metal selected from the group consisting of Rh and Pd.
Claim 15
Dependent Claim
36 words
A magnetic recording medium according to claim 13, wherein the metal selected from the group consisting of Rh and Pd is contained 5 to 20 atom. % based on the total of Co and said metal.
Claim 16
Dependent Claim
23 words
A magnetic recording medium according to claim 1, wherein said protective layer is formed of oxide of an alloy of Si and Co.
Claim 17
Dependent Claim
30 words
A magnetic recording medium according to claim 15, wherein the Si is contained in a proportion of 5 to 20 atom. % based on the total of Co and Si.
Claim 18
Dependent Claim
73 words
A magnetic recording medium, comprising a non-magnetic substrate, a magnetic recording layer of a ferromagnetic film on said substrate, and a protective layer at least 50 angstroms in thickness formed on said magnetic recording layer by vapor depositing or sputtering under constant oxygen pressure, said protective layer being formed of an oxide of an alloy of Nb, V and Co, wherein the atomic ratio of Co to Nb is from 1:9 to 9:1.
Claim 19
Dependent Claim
73 words
A magnetic recording medium, comprising a non-magnetic substrate, a magnetic recording layer of a ferromagnetic film on said substrate, and a protective layer at least 50 angstroms in thickness formed on said magnetic recording layer by vapor depositing or sputtering under constant oxygen pressure, said protective layer being formed of an oxide of an alloy of Nb, V and Co, wherein the atomic ratio of Co to Nb is from 1:9 to 9:1.
Claim 20
Dependent Claim
72 words
A magnetic recording medium, comprising a non-magnetic substrate, a magnetic recording layer of a ferromagnetic film on said substrate and a protective layer at least 50 angstroms in thickness formed on said magnetic layer by vapor depositing or sputtering under constant oxygen pressure, said protective layer being formed of an oxide of an alloy of Mo, W and Co, wherein the atomic ratio of Co to Mo is from 1:9 to 9:1.
Claim 21
Dependent Claim
72 words
A magnetic recording medium, comprising a non-magnetic substrate, a magnetic recording layer of a ferromagnetic film on said substrate and a protective layer at least 50 angstroms in thickness formed on said magnetic layer by vapor depositing or sputtering under constant oxygen pressure, said protective layer being formed of an oxide of an alloy of Mo, W and Co, wherein the atomic ratio of Co to Mo is from 1:9 to 9:1.
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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) | 1991-07-12 | 1992-01-11 | 1992-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-12 | 1996-01-11 | 1996-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-12 | 2000-01-11 | 2000-07-12 | $7700.00 | Window Closed / Lapsed |