US4786553A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: HGST Japan Ltd
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Filing: 1987-03-27
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Granted: 1988-11-22
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Expires: 2007-03-27
Abstract
Abstract A magnetic recording medium comprises a non-magnetic substrate and a thin magnetic film, the thin magnetic film being composed mainly of Co, Ni and at least one of Zr and Hf, and a concentration of Zr, Hf or Zr and Hf as contained in the thin magnetic film being 0.1 to 30% by atom on the basis of the total of Co and Ni, and has a considerably higher corrosion resistance than that of the conventional magnetic recording medium having a thin Co-Ni magnetic film.
Inventors
- 👤 Yoshihiro Shiroishi
- 👤 Sadao Hishiyama
- 👤 Hiroyuki Suzuki
- 👤 Norikazu Tsumita
- 👤 Tsuneo Suganuma
- 👤 Yoshio Gobara
- 👤 Masaaki Hayashi
- 👤 Makoto Sano
- 👤 Takaaki Shirakura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:23
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/658; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/1266; Y10T428/12771; Y10T428/12806; Y10T428/12826; Y10T428/12847; Y10T428/12854; Y10T428/12861; Y10T428/12944; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
59 words
A magnetic recording medium which comprises a non-magnetic substrate and a thin magnetic film formed thereon, the thin magnetic film consisting essentially of Co, Ni and Zr, and a concentration of Zr being 0.1 to 30% by atom on the total of Co and Ni wherein said Zr is concentrated predominantly near the surface of the thin magnetic film.
Claim 2
Dependent Claim
59 words
A magnetic recording medium which comprises a non-magnetic substrate and a thin magnetic film formed thereon, the thin magnetic film consisting essentially of Co, Ni and Zr, and a concentration of Zr being 0.1 to 30% by atom on the total of Co and Ni wherein said Zr is concentrated predominantly near the surface of the thin magnetic film.
Claim 3
Dependent Claim
26 words
A magnetic recording medium according to claim 1, wherein the concentration of Zr is 2 to 20% by atom on the total of Co and Ni.
Claim 4
Dependent Claim
24 words
A magnetic recording medium according to claim 1, wherein a concentration of Ni is 10 to 60% by atom on the basis of Co.
Claim 5
Dependent Claim
45 words
A magnetic recording medium according to claim 1, wherein a concentration of Ni is 20 to 50% by atom on the basis of Co, and the concentration of Zr is 2 to 20% by atom on the basis of the total of Co and Ni.
Claim 6
Dependent Claim
41 words
A magnetic recording medium according to claim 1, wherein the thin magnetic film contains 0.01 to 15% by atom in total of at least one of Ti, Pt, Ru, Ta, Rh, V, Nb, Cr, and Pd besides Co, Ni, and Zr.
Claim 7
Dependent Claim
23 words
A magnetic recording medium according to claim 1, wherein 0.1 to 15% by atom of oxygen is contained in the thin magnetic film.
Claim 8
Dependent Claim
32 words
A magnetic recording medium according to claim 1, wherein a Cr intermediate layer having a thickness of 100 to 5,000 Å is provided between the non-magnetic substrate and the thin magnetic film.
Claim 9
Dependent Claim
53 words
A magnetic recording medium according to claim 1, wherein the thin magnetic film is a perpendicular magnetic recording layer, and at least one of Si intermediate layer, C intermediate layer and Ge intermediate layer having a thickness of 20 to 1,000 Å is provided between the non-magnetic substrate and the thin magnetic film.
Claim 10
Dependent Claim
31 words
A magnetic recording medium according to claim 1, wherein a non-magnetic protective layer having a thickness of 100 to 1,000 Å is formed on the surface of the thin magnetic film.
Claim 11
Dependent Claim
21 words
A magnetic recording medium according to claim 1, wherein the non-magnetic substrate is an Al alloy plated with NiP or NiWP.
Claim 12
Dependent Claim
29 words
A magnetic recording medium according to claim 10, wherein the non-magnetic substrate is a non-magnetic metallic plate whose surface is oxidized to a depth of 10 to 400 Å.
Claim 13
Dependent Claim
62 words
A magnetic recording medium, which comprises a non-magnetic substrate and a thin magnetic film formed thereon, the thin magnetic film consisting essentially of Co, Ni and Hf, and a concentration of Hf being 0.1 to 30% by atom on the basis of the total of Co and Ni wherein said Hf is concentrated predominantly near the surface of the thin magnetic film.
Claim 14
Dependent Claim
62 words
A magnetic recording medium, which comprises a non-magnetic substrate and a thin magnetic film formed thereon, the thin magnetic film consisting essentially of Co, Ni and Hf, and a concentration of Hf being 0.1 to 30% by atom on the basis of the total of Co and Ni wherein said Hf is concentrated predominantly near the surface of the thin magnetic film.
Claim 15
Dependent Claim
24 words
A magnetic recording medium according to claim 12, wherein a concentration of Ni is 10 to 60% by atom on the basis of Co.
Claim 16
Dependent Claim
32 words
A magnetic recording medium according to claim 12, wherein a Cr intermediate layer having a thickness of 100 to 5,000 Å is provided between the non-magnetic substrate and the thin magnetic film.
Claim 17
Dependent Claim
29 words
A magnetic recording medium according to claim 12, wherein the non-magnetic substrate is a non-magnetic metallic substrate whose surface is oxidized to a depth of 10 to 400 Å.
Claim 18
Dependent Claim
42 words
A magnetic recording medium according to claim 12, wherein at least one of Si intermediate layer, C intermediate layer and Ge intermediate layer having a thickness of 5 to 100 Å is provided between the non-magnetic substrate and the thin magnetic film.
Claim 19
Dependent Claim
31 words
A magnetic recording medium according to claim 12, wherein a non-magnetic protective layer having a thickness of 100 to 1,000 Å is formed on the surface of the thin magnetic film.
Claim 20
Dependent Claim
69 words
A magnetic recording medium, which comprises a non-magnetic substrate and a thin magnetic film formed thereon, the thin magnetic film being consisting essentially of Co, Ni, Hf and Zr, and a concentration of Hf and Zr being 0.1 to 30% by atom on the basis of the total of Co and Ni wherein said Zr and said Hf are concentrated predominantly near the surface of the tine magnatic film.
Claim 21
Dependent Claim
69 words
A magnetic recording medium, which comprises a non-magnetic substrate and a thin magnetic film formed thereon, the thin magnetic film being consisting essentially of Co, Ni, Hf and Zr, and a concentration of Hf and Zr being 0.1 to 30% by atom on the basis of the total of Co and Ni wherein said Zr and said Hf are concentrated predominantly near the surface of the tine magnatic film.
Claim 22
Dependent Claim
24 words
A magnetic recording medium according to claim 18, wherein a concentration of Ni is 10 to 60% by atom on the basis of Co.
Claim 23
Dependent Claim
47 words
A magnetic recording medium according to claim 19, wherein a concentration of Ni is 20 to 50% by atom on the basis of Co, and the concentration of Hf and Zr is 0.1 to 15% by atom on the basis of the total of Co and Ni.
Claim 24
Dependent Claim
32 words
A magnetic recording medium according to claim 18, wherein a Cr intermediate layer having a thickness of 100 to 5,000 Å is provided between the non-magnetic substrate and the thin magnetic film.
Claim 25
Dependent Claim
29 words
A magnetic recording medium according to claim 18, wherein the non-magnetic substrate is a non-magnetic metallic substrate whose surface is oxidized to a depth of 10 to 400 Å.
Claim 26
Dependent Claim
42 words
A magnetic recording medium according to claim 19, wherein at least one of Si intermediate layer, C intermediate layer and Ge intermediate layer having a thickness of 5 to 100 Å is provided between the non-magnetic substrate and the thin magnetic film.
Claim 27
Dependent Claim
31 words
A magnetic recording medium according to claim 18, wherein a non-magnetic protective layer having a thickness of 100 to 1,000 Å is formed on the surface of the thin magnetic film.
Claim 28
Dependent Claim
86 words
A magnetic recording medium which comprises a non-magnetic substrate and a thin magnetic film formed thereon, the thin magnetic film consisting essentially of Co, Ni and either Zr, Hf, or mixtures thereof, a concentration of Ni being 10 to 60% by atom on the basis of Co and a concentration of Zr, Hf, or mixtures thereof being 0.1 to 30% by atom on the total of Co and Ni; the Zr, Hf or mixtures thereof being concentrated predominantly near the surface of the thin magnetic film.
Claim 29
Dependent Claim
86 words
A magnetic recording medium which comprises a non-magnetic substrate and a thin magnetic film formed thereon, the thin magnetic film consisting essentially of Co, Ni and either Zr, Hf, or mixtures thereof, a concentration of Ni being 10 to 60% by atom on the basis of Co and a concentration of Zr, Hf, or mixtures thereof being 0.1 to 30% by atom on the total of Co and Ni; the Zr, Hf or mixtures thereof being concentrated predominantly near the surface of the thin magnetic film.
Claim 30
Dependent Claim
24 words
A magnetic recording medium according to claim 25, wherein the thin magnetic film consists of Co, Ni and either Zr, Hf, or mixtures thereof.
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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) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |