Patent US4015030A successfully refreshed from Google Patents.
US4015030A
Expired / Lapsed
US
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Process for stabilization of ferromagnetic material and magnetic recording member
Assignee: Fujifilm Holdings Corp
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Filing: 1975-06-30
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Granted: 1977-03-29
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Expires: 1995-06-30
Abstract
Abstract A process for stabilizing a ferromagnetic material comprising heat-treating a needle-like ferromagnetic material represented by the formula MO x wherein M is a ferromagnetic metal ion or a ferromagnetic non-metal ion and another metal ion, and x is the degree of oxidation which ranges from 1.36 to 1.47, and containing at least 0.5 atom % Co, at a temperature of at least about 40° C, and a process for stabilizing a magnetic recording member comprising heat-treating a magnetic recording member produced by providing a ferromagnetic recording layer comprising (a) a ferromagnetic material represented by the formula MO x wherein M and x are the same as defined above, and containing at least 0.5 atom % Co, and (b) a binder, on a support, at a temperature of at least about 40° C.
Inventors
- 👤 Koji Sasazawa
- 👤 Yasuyuki Yamada
- 👤 Tatsuji Kitamoto
- 👤 Goro Akashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:55
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70678; G11B5/70684; G11B5/70694; A; A63; A63H; A63H1/00; A63H1/32
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
68 words
A process for stabilizing the magnetic properties of a ferromagnetic material which comprises heat-treating a needle-like ferromagnetic material having the formula FeO x and containing at least 0.5 atom % of cobalt wherein x is the degree of oxidation and ranges from 1.36 to 1.47 at a temperature of at least about 40° to 80° C for a time sufficient to achieve the stabilization of said magnetic properties.
Claim 2
Dependent Claim
68 words
A process for stabilizing the magnetic properties of a ferromagnetic material which comprises heat-treating a needle-like ferromagnetic material having the formula FeO x and containing at least 0.5 atom % of cobalt wherein x is the degree of oxidation and ranges from 1.36 to 1.47 at a temperature of at least about 40° to 80° C for a time sufficient to achieve the stabilization of said magnetic properties.
Claim 3
Dependent Claim
19 words
The process according to claim 1, wherein the heat-treating is at a temperature of from 50° to 60° C.
Claim 4
Dependent Claim
17 words
The process according to claim 1, wherein the cobalt content is about 1 to 10 atom %.
Claim 5
Dependent Claim
15 words
The process according to claim 1, wherein the heat-treating is in an inert gas atmosphere.
Claim 6
Dependent Claim
12 words
The process according to claim 4, wherein the inert gas is nitrogen.
Claim 7
Dependent Claim
87 words
A process for stabilizing the magnetic properties of a magnetic recording member which comprises providing a ferromagnetic recording layer comprising (1) a ferromagnetic powder represented by the formula FeOx and containing at least 0.5 atom % of cobalt wherein x is the degree of oxidation and ranges from 1.36 to 1.47 and (2) a binder, on a support, and heat-treating said ferromagnetic recording layer at a temperature of at least about 40° to 80° C for a time sufficient to achieve the stabilization of said magnetic properties.
Claim 8
Dependent Claim
87 words
A process for stabilizing the magnetic properties of a magnetic recording member which comprises providing a ferromagnetic recording layer comprising (1) a ferromagnetic powder represented by the formula FeOx and containing at least 0.5 atom % of cobalt wherein x is the degree of oxidation and ranges from 1.36 to 1.47 and (2) a binder, on a support, and heat-treating said ferromagnetic recording layer at a temperature of at least about 40° to 80° C for a time sufficient to achieve the stabilization of said magnetic properties.
Claim 9
Dependent Claim
23 words
The process according to claim 6, wherein the binder is selected from the group consisting of a thermoplastic resin and a thermosetting resin.
Claim 10
Dependent Claim
22 words
The process according to claim 6, wherein the weight ratio of the ferromagnetic powder to the binder is about 100:10 to 100:200.
Claim 11
Dependent Claim
29 words
The process according to claim 6, wherein the magnetic recording layer additionally contains at least one of a dispersing agent, a lubricant, an abrasive agent, and an antistatic agent.
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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) | 1980-03-28 | 1980-09-27 | 1981-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-28 | 1984-09-27 | 1985-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-28 | 1988-09-27 | 1989-03-29 | $7700.00 | Window Closed / Lapsed |