US5069967A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
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Filing: 1989-08-01
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Granted: 1991-12-03
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Expires: 2009-08-01
Abstract
Abstract In a magnetic recording medium wherein a metal thin film magnetic layer and an overcoat are formed on a nonmagnetic substrate, durability is improved when the overcoat comprises a plasma-polymerized film and a topcoat of an organic fluorine compound; a plasma-polymerized film, a protective carbon film, and a topcoat of an organic fluorine compound; a plasma-polymerized film containing C, F and H; or a plasma-polymerized organometallic film and a fluorine or silicon-containing topcoat. Oxidation of the upper surface of the magnetic layer with a plasma is also effective.
Inventors
- 👤 Kenji Yokoyama
- 👤 Masatoshi Nakayama
- 👤 Toru Shimozawa
- 👤 Kunihiro Ueda
- 👤 Fumio Maruta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:38
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/722; G11B5/726; G11B5/7262; G11B5/7264; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/30
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
176 words
A magnetic recording medium comprising: a nonmagnetic substrate having opposed major surfaces, a metal thin film magnetic layer on one major surface of the substrate, a plasma-polymerized film on the magnetic layer, and a topcoat layer having a thickness of from 3 to 300 Å comprising an organic fluorine compound in an amount of at least 50% by weight on the plasma-polymerized film, the plasma-polymerized film comprising carbon, hydrogen, and at least one of nitrogen and oxygen, and having a thickness of 3 to 300 Å, an atomic ratio of C/H of from 1:1 to 1:6, and a combined content of nitrogen and/or oxygen of 2 to 40 atoms %, wherein the plasma-polymerized film is prepared by activating a gaseous reactant into a plasma to generate active species thereof while feeding the reactant into a plasma zone with W/F.M set to 10 7 to 10 15 joule/kg wherein W is an input power applied for plasma generation, F is the flow rate of the gas reactant and M is the molecular weight of the gas reactant.
Claim 2
Dependent Claim
176 words
A magnetic recording medium comprising: a nonmagnetic substrate having opposed major surfaces, a metal thin film magnetic layer on one major surface of the substrate, a plasma-polymerized film on the magnetic layer, and a topcoat layer having a thickness of from 3 to 300 Å comprising an organic fluorine compound in an amount of at least 50% by weight on the plasma-polymerized film, the plasma-polymerized film comprising carbon, hydrogen, and at least one of nitrogen and oxygen, and having a thickness of 3 to 300 Å, an atomic ratio of C/H of from 1:1 to 1:6, and a combined content of nitrogen and/or oxygen of 2 to 40 atoms %, wherein the plasma-polymerized film is prepared by activating a gaseous reactant into a plasma to generate active species thereof while feeding the reactant into a plasma zone with W/F.M set to 10 7 to 10 15 joule/kg wherein W is an input power applied for plasma generation, F is the flow rate of the gas reactant and M is the molecular weight of the gas reactant.
Claim 3
Dependent Claim
31 words
The magnetic recording medium of claim 1 wherein the topcoat comprises at least one member selected from carboxyperfluoropolyethers and salts and esters thereof, perfluoropolyethers, and tetrafluoroethylene polymers, and a mixture thereof.
Claim 4
Dependent Claim
17 words
The magnetic recording medium of claim 1 wherein the surface of the magnetic layer is plasma treated.
Claim 5
Dependent Claim
33 words
The magnetic recording medium of claim 1 wherein the metal thin film magnetic layer predominantly comprises cobalt and at least one optional member selected from the group consisting of Ni, Cr, and P.
Claim 6
Dependent Claim
17 words
The magnetic recording medium of claim 4 wherein the metal thin film magnetic layer further comprises oxygen.
Claim 7
Dependent Claim
23 words
The magnetic recording medium of claim 1 which further comprises an undercoat layer between the substrate and the metal thin film magnetic layer.
Claim 8
Dependent Claim
37 words
The magnetic recording medium of claim 1 or 12 which further comprises an intermediate layer of a nonmagnetic metal disposed contiguous to the surface of the metal thin film magnetic layer on the side of the substrate.
Claim 9
Dependent Claim
28 words
The magnetic recording medium of claim 1 which further comprises a protective layer of a nonmagnetic metal between the metal thin film magnetic layer and the plasma-polymerized film.
Claim 10
Dependent Claim
19 words
The magnetic recording medium of claim 8 wherein the surface of the protective nonmagnetic metal layer is plasma treated.
Claim 11
Dependent Claim
15 words
The magnetic recording medium of claim 6 wherein the undercoat layer has an irregular surface.
Claim 12
Dependent Claim
15 words
The magnetic recording medium of claim 1 wherein the substrate is a rigid nonmagnetic substrate.
Claim 13
Dependent Claim
22 words
The magnetic recording medium of claim 1 which further comprises a protective carbon film between the plasma-polymerized film and the topcoat layer.
Claim 14
Dependent Claim
25 words
The magnetic recording medium of claim 1 which further comprises a protective carbon film between the metal thin film magnetic layer and the plasma-polymerized film.
Claim 15
Dependent Claim
41 words
The magnetic recording medium of claim 1 wherein a first plasma-polymerized film is on the metal thin film magnetic layer, a protective carbon film is on the first plasma-polymerized film, and a second plasma-polymerized film is on the protective carbon film.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-12-02 | 1995-06-03 | 1995-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-02 | 1999-06-03 | 1999-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-02 | 2003-06-03 | 2003-12-03 | $7700.00 | Window Closed / Lapsed |