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US4587178A
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US
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Magnetic recording medium
Assignee: Victor Company of Japan Ltd
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Filing: 1982-07-26
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Granted: 1986-05-06
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Expires: 2002-07-26
Abstract
Abstract A magnetic recording medium comprising a support, a first layer formed on the support by evaporating cobalt or its alloy by an oblique-incidence vacuum evaporation technique, and a second plated layer made of cobalt or its alloy and formed by a wet plating. The cobalt alloy for the first layer substantially consists of, aside from cobalt, up to 30 wt % of Ni, Fe, Cu, W, Cr, Ru or a mixture thereof. On the other hand, the cobalt alloy for the second layer substantially consists of up to 40 wt % of Ni, up to 8 wt % of P and the balance of Co.
Inventors
- 👤 Shigeo Shimizu
- 👤 Toshio Kato
- 👤 Hitoshi Oda
- 👤 Masanobu Shigeta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:18
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/672; G11B5/84; G11B5/8416; G11B5/851; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535; Y10T428/12556; Y10T428/12569; Y10T428/12771; Y10T428/12861; Y10T428/12931; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
121 words
A magnetic recording medium comprising a support, a first layer having a thickness of 5 to 5000 Å and made of cobalt or a cobalt alloy containing up to 30 wt % of at least one member selected from the group consisting of Ni, Fe, Cu, W, Cr, and Ru and the balance of cobalt, said first layer being formed on one surface of said support by an oblique-incidence vacuum evaportaion, and a second layer having a thickness of 200 to 25,000 Å and made of cobalt or a cobalt alloy containing up to 40 wt % of Ni and up to 8 wt % of P, said second layer being formed on said first layer by eletroplating or electroless plating.
Claim 2
Dependent Claim
121 words
A magnetic recording medium comprising a support, a first layer having a thickness of 5 to 5000 Å and made of cobalt or a cobalt alloy containing up to 30 wt % of at least one member selected from the group consisting of Ni, Fe, Cu, W, Cr, and Ru and the balance of cobalt, said first layer being formed on one surface of said support by an oblique-incidence vacuum evaportaion, and a second layer having a thickness of 200 to 25,000 Å and made of cobalt or a cobalt alloy containing up to 40 wt % of Ni and up to 8 wt % of P, said second layer being formed on said first layer by eletroplating or electroless plating.
Claim 3
Dependent Claim
16 words
A magnetic recording medium according to claim 1, wherein said first layer is made of cobalt.
Claim 4
Dependent Claim
18 words
A magnetic recording medium according to claim 1, wherein said first layer is made of the cobalt alloy.
Claim 5
Dependent Claim
20 words
A magnetic recording medium according to claim 3, wherein said cobalt alloy of said first layer is a Co-Ni alloy.
Claim 6
Dependent Claim
16 words
A magnetic recording medium according to claim 1, wherein said second layer is made of cobalt.
Claim 7
Dependent Claim
18 words
A magnetic recording medium according to claim 1, wherein said second layer is made of the cobalt alloy.
Claim 8
Dependent Claim
48 words
A magnetic recording medium according to claims 1 or 6, wherein the cobalt alloy for said second layer further comprises up to 10 wt % of at least one member selected from the group consisting of Mn, W and Zn whereby resistance to corrosion and abrasion are improved.
Claim 9
Dependent Claim
33 words
A magnetic recording medium according to claim 1, wherein the cobalt or its alloy for said first layer is evaporated at an incident angle, with respect to the support, of over 70°, inclusive.
Claim 10
Dependent Claim
24 words
A magnetic recording medium according to claim 1, wherein the thickness of said first layer is in the range of 50 to 500 Å.
Claim 11
Dependent Claim
24 words
A magnetic recording medium according to claim 1, wherein the thickness of said second layer is in the range of 300 to 5,000 Å.
Claim 12
Dependent Claim
35 words
A magnetic recording medium according to claim 1, wherein said medium has a recording and reproducing direction parallel to an axis of easy magnetization of a magnetic layer composed of the first and second layers.
References Cited (Backward Citations)
US4371590A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |