US4950555A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Denka Co Ltd
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Filing: 1989-01-09
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Granted: 1990-08-21
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Expires: 2009-01-09
Abstract
Abstract A magnetic recording medium is disclosed, which comprises a substrate having provided thereon a magnetic substance which is composed of an alloy comprising cobalt, phosphorus and at least one member selected from the group consisting of thallium and elements of group Vb of the periodic table, and optionally at least one member selected from the group consisting of nickel and zinc. The magnetic recording medium exhibits a high coercive force, squareness ratio and a high output with a small noise.
Inventors
- 👤 Tooru Michimori
- 👤 Hideaki Nagasaka
- 👤 Toshikazu Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:10
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/656; G11B5/657; G11B5/66; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
64 words
A magnetic recording medium, having a coercive force squareness ratio of not less than 0.90, comprising a substrate having provided thereon by electroless plating a magnetic substance which is composed of an alloy comprising cobalt, phosphorus and at least one element selected from the group consisting of thallium, bismuth, arsenic and antimony in an amount of at least 0.05 to about 5 atomic percent.
Claim 2
Dependent Claim
64 words
A magnetic recording medium, having a coercive force squareness ratio of not less than 0.90, comprising a substrate having provided thereon by electroless plating a magnetic substance which is composed of an alloy comprising cobalt, phosphorus and at least one element selected from the group consisting of thallium, bismuth, arsenic and antimony in an amount of at least 0.05 to about 5 atomic percent.
Claim 3
Dependent Claim
27 words
The magnetic recording medium as claimed in claim 1, wherein said alloy further comprises at least one member selected from the group consisting of nickel and zinc.
Claim 4
Dependent Claim
19 words
The magnetic recording medium as claimed in claim 1, wherein said alloy is composed of cobalt, phosphorus and thallium.
Claim 5
Dependent Claim
20 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of cobalt, phosphorus, nickel and thallium.
Claim 6
Dependent Claim
20 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of cobalt, phosphorus, thallium and zinc.
Claim 7
Dependent Claim
21 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of cobalt, phosphorus, nickel, thallium and zinc.
Claim 8
Dependent Claim
37 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of 70 to 95 atomic% cobalt, 5 to 20 atomic% phosphorus, 0 to 20 atomic % nickel and 0.5 to 5 atomic% thallium.
Claim 9
Dependent Claim
63 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of 70 to 95 atomic% cobalt, 5 to 20 atomic% phosphorus, up to 20 atomic% nickel, 0.5 to 5 atomic% thallium, and zinc, wherein the content of said zinc results from the use of about 2×10 -6 to 2×10 -2 mol/l of zinc ion in an electroless plating bath.
Claim 10
Dependent Claim
34 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of cobalt, phosphorus, nickel, and at least one element selected from the group consisting of thallium, bismuth, arsenic and antimony.
Claim 11
Dependent Claim
17 words
The magnetic recording medium as claimed in claim 1, wherein said at least one element is arsenic.
Claim 12
Dependent Claim
17 words
The magnetic recording medium as claimed in claim 9, wherein said at least one element is arsenic.
Claim 13
Dependent Claim
17 words
The magnetic recording medium as claimed in claim 1, wherein said at least one element is bismuth.
Claim 14
Dependent Claim
17 words
The magnetic recording medium as claimed in claim 9, wherein said at least one element is bismuth.
Claim 15
Dependent Claim
34 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of cobalt, phosphorus, zinc and at least one element selected from the group consisting of thallium, bismuth, arsenic, and antimony.
Claim 16
Dependent Claim
35 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of cobalt, phosphorus, nickel, zinc and at least one element selected from the group consisting of thallium, bismuth, arsenic, and antimony.
Claim 17
Dependent Claim
36 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of 70 to 95 atomic% cobalt, 5 to 20 atomic% phosphorus, up to 20 atomic% nickel and 0.5 to 5 atomic% arsenic.
Claim 18
Dependent Claim
36 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of 70 to 95 atomic% cobalt, 5 to 20 atomic% phosphorus, up to 20 atomic% nickel and 0.5 to 5 atomic% bismuth.
Claim 19
Dependent Claim
61 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of 70 to 95 atomic% cobalt, 5 to 20 atomic% phosphorus, up to nickel, 0.5 to 5 atomic% arsenic and zinc, wherein the content of said zinc results from the use of about 2×10 -6 to 2×10 -2 mol/l of zinc ion in an electroless plating bath.
Claim 20
Dependent Claim
64 words
The magnetic recording medium as claimed in claim 2, wherein said alloy is composed of 70 to 95 atomic% cobalt, 5 to 20 atomic% phosphorus, up to 20 atomic% of nickel, 0.5 to 5 atomic% bismuth and zinc, wherein the content of said zinc results from the use of about 2×10 -6 to 2×10 -2 mol/l of zinc ion in an electroless plating bath.
Claim 21
Dependent Claim
39 words
The magnetic recording medium as claimed in claim 1, wherein said magnetic substance on said substrate is composed of an alloy comprising cobalt, phosphorus and at least one element selected from the group consisting of thallium, bismuth and arsenic.
Claim 22
Dependent Claim
25 words
The magnetic recording medium as claimed in claim 1, wherein said coercive force squareness ratio is in the range of about 0.90 to 0.93 .
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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) | 1993-08-20 | 1994-02-19 | 1994-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-20 | 1998-02-19 | 1998-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-20 | 2002-02-19 | 2002-08-21 | $7700.00 | Window Closed / Lapsed |