Patent EP0092394A1 successfully refreshed from Google Patents.
EP0092394A1
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EP
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Ferro magnetic recording materials
Assignee: Memorex Corp
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Filing: 1983-04-15
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Granted: —
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Expires: 2003-04-15
Abstract
Abstract Low performance ferromagnetic oxides are taught to be convertible into high performance ferromagnetic oxides with vastly improved coercivity by suspending ferromagnetic oxide particles in aqueous media, forming a layer of the first metal on the surfaces of the particles, forming a layer of second metal on the surfaces of the first metal and lastly, forming a layer of third metal on the surfaces of the second metal. The first and third metals can be the same in preferrably transition metals such as cobalt. The second metal must be different than the first and third metals such as, for example, iron.
Inventors
- 👤 Mohammed Siddig
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 19:29
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70647; G11B5/712; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/10; H01F1/11; H01F1/112; A; A63; A63B; A63B2225/00; A63B2225/50; A63B43/00; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
74 words
A method of converting low performance ferromagnetic oxides into high performance ferromagnetic oxides comprising: a. Suspending low performance ferromagnetic oxide particles in an aqueous media; b. Forming a layer of a first metal compound on the surfaces of the particles; c. Forming a layer of a second metal compound on the surfaces of the first metal; and d. Forming a layer of a third metal compound on the surfaces of the second metal compound.
Claim 2
Independent Claim
74 words
A method of converting low performance ferromagnetic oxides into high performance ferromagnetic oxides comprising: a. Suspending low performance ferromagnetic oxide particles in an aqueous media; b. Forming a layer of a first metal compound on the surfaces of the particles; c. Forming a layer of a second metal compound on the surfaces of the first metal; and d. Forming a layer of a third metal compound on the surfaces of the second metal compound.
Claim 3
Dependent Claim
21 words
The method of Claim 1 wherein the metal ions of said first metal compound and third metal compound are the same.
Claim 4
Dependent Claim
29 words
The method of Claim 2 wherein said first metal ion and third metal ion are selected from the group consisting of cobalt, iron, manganese, nickel, zinc, and mixtures thereof.
Claim 5
Dependent Claim
23 words
The method of Claim 3 wherein said first metal ion and third metal ion are cobalt and said second metal ion is iron.
Claim 6
Dependent Claim
23 words
The method of Claim 3 wherein said first metal ion and third metal ion are iron and said second metal ion is cobalt.
Claim 7
Dependent Claim
22 words
The method of Claim 1 wherein additional alternating layers of metal compounds are formed on the surfaces of said third metal compound.
Claim 8
Dependent Claim
32 words
The method of claim 6 wherein the metal ions of said additional alternating layers of metal compounds are selected from the group consisting of cobalt, iron, manganese, nickel, zinc and mixtures thereof.
Claim 9
Dependent Claim
55 words
The method of Claim 1 wherein said first, second and third metal compound layers are formed by providing individual solutions of metal salts of each metal compound separately and adding a sufficient quantity of a base to cause metal ion adsorption reactions to take place on each surface to which the metal compounds are applied.
Claim 10
Dependent Claim
27 words
The method of Claim 8 wherein each metal ion solution is added in each instance in an amount to saturate the surfaces to which they are applied.
Claim 11
Dependent Claim
32 words
The method of Claim 1 wherein said low performance ferromagnetic oxides are selected from the group consisting of γ-Fe 2 O 3 , Fe 3 O 4 , and intermediate oxides thereof.
Claim 12
Dependent Claim
29 words
The method of Claim 8 wherein the first and third metal compound layers comprise cobalt ions derived from CoS0 4 ' 7H 2 0 and other divalent cobalt salts.
Claim 13
Dependent Claim
26 words
The method of Claim 11 wherein the second metal compound layer comprises iron ions derived from FeSO 4 ·7H 2 O and other divalent ion salts.
Claim 14
Dependent Claim
10 words
The method of Claim 8 wherein the base comprises NaOH.
Claim 15
Dependent Claim
34 words
A high performance ferromagnetic oxide particle comprising a ferromagnetic oxide core, and coatings of three metal compounds thereon wherein the second metal compound coating is dissimilar to the first and third metal compound coatings.
Claim 16
Dependent Claim
34 words
A high performance ferromagnetic oxide particle comprising a ferromagnetic oxide core, and coatings of three metal compounds thereon wherein the second metal compound coating is dissimilar to the first and third metal compound coatings.
Claim 17
Dependent Claim
20 words
The high performance ferromagnetic oxide particle of Claim 14 wherein said first and third metal compound coatings are the same.
Claim 18
Dependent Claim
32 words
The high performance ferromagnetic oxide particle of Claim 15 wherein said first metal and third metal ions are selected from the group consisting of cobalt, iron, manganese, nickel, zinc and mixtures thereof.
Claim 19
Dependent Claim
27 words
The high performance ferromagnetic oxide particle of Claim 16 wherein said first metal ion and third metal ion comprise cobalt and said second metal ion comprises iron.
Claim 20
Dependent Claim
27 words
The high performance ferromagnetic oxide particle of Claim 16 wherein said first metal ion and third metal ion comprise iron and said second metal ion comprise cobalt.
Claim 21
Dependent Claim
26 words
The high performance ferromagnetic oxide particle of Claim 14 further comprising additional alternating layers of metal compounds formed on the surface of said third metal compound.
Claim 22
Dependent Claim
35 words
The high performance ferromagnetic oxide particle of Claim 19 wherein the metal ions of said alternating layers of metal compounds are selected from the group consisting of cobalt, iron, manganese, nickel, zinc and mixtures thereof.
Claim 23
Dependent Claim
32 words
A high performance ferromagnetic oxide particle comprising a ferromagnetic oxide core, and coatings of two metal compounds thereon, wherein the second metal compound coating is dissimilar to the first metal compound coating.
Claim 24
Dependent Claim
32 words
A high performance ferromagnetic oxide particle comprising a ferromagnetic oxide core, and coatings of two metal compounds thereon, wherein the second metal compound coating is dissimilar to the first metal compound coating.
Claim 25
Dependent Claim
31 words
The high performance ferromagnetic oxide particle of claim 21 wherein said first and second metal ions are selected from the group consisting of cobalt, iron, magnanese, nickel, zinc and mixtures thereof.
Claim 26
Dependent Claim
38 words
The high performance ferromagnetic oxide particle of claim 22 wherein the coercivity of the particle is further increased by subjecting the particle to heat treatment after the metal compound coatings have been applied to the ferromagnetic oxide core.
Claim 27
Dependent Claim
19 words
In a magnetic recording member the improvement comprising the high performance ferromagnetic oxide particles of claims 14 or 21.
References Cited (Backward Citations)
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