US4769282A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Sumitomo Metal Mining Co Ltd
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Filing: 1986-06-20
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Granted: 1988-09-06
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Expires: 2006-06-20
Abstract
Abstract A magnetic recording medium comprising a non-magnetic substrate and a magnetic layer formed on the substrate, in which the magnetic layer comprises 1-8% metal element M consisting of one or more of B, Al, Si, P, Ge, Sn, Sb, Se, Te, Pb, Bi, Cu, Ti, V, Cr, Zr, Nb, Mo, W and Ta, less than 13% by weight of one or more of rare earth elements of Y, La, Ce, Pr, Nd, Sm, Gd, Tb, or Dy, 3-13% by weight of oxygen, balance of Co and inevitable impurities. The magnetic layer may contain less than 22% by weight of Ni. The magnetic recording medium has a favorable corrosion resistance and excellent magnetic properties.
Inventors
- 👤 Junya Tada
- 👤 Tomohisa Watanabe
- 👤 Makoto Akihiro
- 👤 Kouichi Oka
- 👤 Takehiko Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:22
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/658; G11B5/73; G11B5/739; G11B5/73911; G11B5/73917; G11B5/73919; G11B5/73921; G11B5/73923; G11B5/73927; G11B5/73935; G11B5/84; G11B5/85; G11B5/851; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
97 words
A magnetic recording medium comprising a non-magnetic substrate and a crystalline magnetic layer formed on said substrate, said crystalline magnetic layer comprising, on a weight basis, 1-8% of one or more metal elements M selected from the group consisting of B, Al, Si, P, Ge, Sn, Sb, Se, Te, Pb, Bi, Cu, Ti, V, Cr, Zr, Nb, Mo, W and Ta, between 0.4 and 13% of at least one rare earth element selected from the group consisting of La, Ce, Pr, Nd, Sm, Gd, and Dy, 3-13% of oxygen, and a balance of Co and inevitable impurities.
Claim 2
Dependent Claim
97 words
A magnetic recording medium comprising a non-magnetic substrate and a crystalline magnetic layer formed on said substrate, said crystalline magnetic layer comprising, on a weight basis, 1-8% of one or more metal elements M selected from the group consisting of B, Al, Si, P, Ge, Sn, Sb, Se, Te, Pb, Bi, Cu, Ti, V, Cr, Zr, Nb, Mo, W and Ta, between 0.4 and 13% of at least one rare earth element selected from the group consisting of La, Ce, Pr, Nd, Sm, Gd, and Dy, 3-13% of oxygen, and a balance of Co and inevitable impurities.
Claim 3
Dependent Claim
22 words
A magnetic recording medium as defined in claim 1, wherein the magnetic layer further contains between 2.8 and 22% by weight Ni.
Claim 4
Dependent Claim
35 words
A magnetic recording medium as defined in claim 1, wherein the inevitable impurities are less than 1% by weight of one or more elements selected from the group consisting of C, S, Zn and Fe.
Claim 5
Dependent Claim
20 words
A magnetic recording medium as defined in claim 1, wherein the magnetic layer has a thickness of 0.1 μm-1.0 μm.
Claim 6
Dependent Claim
15 words
A magnetic recording medium as defined in claim 1, wherein the non-magnetic substrate is glass.
Claim 7
Dependent Claim
17 words
A magnetic recording medium as defined in claim 1, wherein the non-magnetic substrate is made of Al.
Claim 8
Dependent Claim
28 words
A magnetic recording medium as defined in claim 1, wherein the magnetic layer is formed by a sputtering method, an ion plating method or a vacuum deposition method.
Claim 9
Dependent Claim
29 words
A magnetic recording medium as defined in claim 1, wherein the non-magnetic substrate is subjected to a primary treatment of corona discharging treatment before the magnetic layer deposition thereon.
Claim 10
Dependent Claim
24 words
A magnetic recording medium as defined in claim 1, wherein the non-magnetic substrate is flexible, stretch resistant, and has a thickness of 5-25 μm.
Claim 11
Dependent Claim
29 words
A magnetic recording medium as defined in claim 9, wherein the non-magnetic substrate is composed of a polymer selected from the group consisting of polyester, acetate, polycarbonate and polyimide.
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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) | 1991-09-06 | 1992-03-07 | 1992-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-06 | 1996-03-07 | 1996-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-06 | 2000-03-07 | 2000-09-06 | $7700.00 | Window Closed / Lapsed |