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US5436047A
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Thin film magnetic recording disk comprising a metallic disk blank, a substantially non-magnetic Ni-Cr-O film having a textured surface and a magnetic film
Assignee: HGST Netherlands BV
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Filing: 1993-10-15
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Granted: 1995-07-25
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Expires: 2013-10-15
Abstract
Abstract A magnetic recording disk has an improved surface film formed on the disk blank. A sputter-deposited surface coating containing nickel, chromium and oxygen (Ni--Cr--O) is formed on a AlMg disk blank, after which a cobalt alloy magnetic layer is formed over the Ni--Cr--O coating and a protective overcoat is formed over magnetic layer. The use of the Ni--Cr--O coating on the disk blank eliminates the need for a wet electroless deposition process for creation of a surface coating and results in an inherent texturing of the subsequently deposited magnetic film and protective overcoat which conform to the surface texture of the sputter-deposited Ni--Cr--O. The disks made with the Ni--Cr--O surface film exhibit a very low static friction force between the air-bearing slider and the disk surface when the disks are used in contact start/stop (CSS) disk files.
Inventors
- 👤 James K. Howard
- 👤 Hung-Chang W. Huang
- 👤 Cherngye Hwang
- 👤 Anthony W. Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:26
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/8404; G11B5/62; G11B5/73; G11B5/7368; G11B5/7371; G11B5/7373; G11B5/7377; G11B5/739; G11B5/73911; G11B5/73913; G11B5/73915; G11B5/73917; G11B5/73919; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9335; Y10S428/938; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
80 words
A thin film magnetic recording disk comprising: a metallic disk blank; a substantially non-magnetic Ni--Cr--O film consisting essentially of chromium oxides and nickel-chromium sputter deposited directly on the disk blank from a target or set of targets containing nickel, chromium and oxygen, said Ni--Cr--O film having an essentially amorphous and columnar structure for forming a textured surface on said Ni--Cr--O film; and a magnetic film formed over the Ni--Cr--O film which substantially replicates the textured surface of said Ni--Cr--O film.
Claim 2
Dependent Claim
80 words
A thin film magnetic recording disk comprising: a metallic disk blank; a substantially non-magnetic Ni--Cr--O film consisting essentially of chromium oxides and nickel-chromium sputter deposited directly on the disk blank from a target or set of targets containing nickel, chromium and oxygen, said Ni--Cr--O film having an essentially amorphous and columnar structure for forming a textured surface on said Ni--Cr--O film; and a magnetic film formed over the Ni--Cr--O film which substantially replicates the textured surface of said Ni--Cr--O film.
Claim 3
Dependent Claim
16 words
The disk according to claim 1 wherein the disk blank is an aluminum alloy disk blank.
Claim 4
Dependent Claim
18 words
The disk according to claim 1 wherein oxygen comprises 40 to 50 atomic percent of said Ni--Cr--O film.
Claim 5
Dependent Claim
67 words
A substrate for use in a thin film magnetic recording disk comprising: a metallic disk blank; and a substantially non-magnetic Ni--Cr--O film consisting essentially of chromium oxides and nickel-chromium sputter deposited directly on the disk blank from a target or set of targets containing nickel, chromium and oxygen, said Ni--Cr--O film having an essentially amorphous and columnar structure for forming a textured surface on said Ni--Cr--O film.
Claim 6
Dependent Claim
67 words
A substrate for use in a thin film magnetic recording disk comprising: a metallic disk blank; and a substantially non-magnetic Ni--Cr--O film consisting essentially of chromium oxides and nickel-chromium sputter deposited directly on the disk blank from a target or set of targets containing nickel, chromium and oxygen, said Ni--Cr--O film having an essentially amorphous and columnar structure for forming a textured surface on said Ni--Cr--O film.
Claim 7
Dependent Claim
16 words
The substrate according to claim 4 wherein the disk blank is an aluminum alloy disk blank.
Claim 8
Dependent Claim
18 words
The substrate according to claim 4 wherein oxygen comprises 40 to 50 atomic percent of said Ni--Cr--O film.
Claim 9
Dependent Claim
87 words
A thin film magnetic recording disk comprising: a disk blank; a substantially non-magnetic Ni--Cr--O film consisting essentially of chromium oxides and nickel-chromium and having a thickness greater than 5 microns sputter deposited directly on the disk blank from a target or set of targets containing nickel, chromium and oxygen, said Ni--Cr--O film having an essentially amorphous and columnar structure for forming a textured surface on said Ni--Cr--O film; and a magnetic film formed over the Ni--Cr--O film which substantially replicates the textured surface of said Ni--Cr--O film.
Claim 10
Dependent Claim
87 words
A thin film magnetic recording disk comprising: a disk blank; a substantially non-magnetic Ni--Cr--O film consisting essentially of chromium oxides and nickel-chromium and having a thickness greater than 5 microns sputter deposited directly on the disk blank from a target or set of targets containing nickel, chromium and oxygen, said Ni--Cr--O film having an essentially amorphous and columnar structure for forming a textured surface on said Ni--Cr--O film; and a magnetic film formed over the Ni--Cr--O film which substantially replicates the textured surface of said Ni--Cr--O film.
Claim 11
Dependent Claim
75 words
A substrate for use in a thin film magnetic recording disk comprising: a silicon disk blank; and a substantially non-magnetic Ni--Cr--O film consisting essentially of chromium oxides and nickel-chromium and having a thickness greater than 5 microns sputter deposited directly on the disk blank from a target or set of targets containing nickel, chromium and oxygen, said Ni--Cr--O film having an essentially amorphous and columnar structure for forming a textured surface on said Ni--Cr--O film.
Claim 12
Dependent Claim
75 words
A substrate for use in a thin film magnetic recording disk comprising: a silicon disk blank; and a substantially non-magnetic Ni--Cr--O film consisting essentially of chromium oxides and nickel-chromium and having a thickness greater than 5 microns sputter deposited directly on the disk blank from a target or set of targets containing nickel, chromium and oxygen, said Ni--Cr--O film having an essentially amorphous and columnar structure for forming a textured surface on said Ni--Cr--O film.
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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) | 1998-07-24 | 1999-01-23 | 1999-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-07-24 | 2003-01-23 | 2003-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-07-24 | 2007-01-23 | 2007-07-25 | $7700.00 | Window Closed / Lapsed |