EP0123318A2
Expired / Lapsed
EP
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Acicular particulate material containing iron carbide
Assignee: Daikin Industries Ltd
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Filing: 1984-04-25
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Granted: —
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Expires: 2004-04-25
Abstract
Abstract Acicular particles containing an iron carbide prepared by contacting acicular iron oxyhydroxide or acicular iron oxide with CO or a mixture thereof with H 2 , have a high coercive force and orientation property in magnetic field.
Inventors
- 👤 Yoshiyuki Shibuya
- 👤 Shigeo Daimon
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 19:47
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/10; H01F1/11; C; C01; C01B; C01B32/00; C01B32/90; C01B32/907; C30; C30B; C30B25/00; C30B25/005; C30B29/00; C30B29/10; C30B29/36; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; C01P; C01P2002/00; C01P2002/70; C01P2002/72; C01P2002/74; C01P2004/00; C01P2004/01; C01P2004/03; C01P2004/10; C01P2004/54; C01P2004/60; C01P2004/61; C01P2004/62; C01P2006/00; C01P2006/42; C01P2006/60; C01P2006/80
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
6 words
Acicular particles containing an iron carbide.
Claim 2
Dependent Claim
6 words
Acicular particles containing an iron carbide.
Claim 3
Dependent Claim
18 words
. 2. Acicular particles as definded in claim 1 having an average axial ratio of at least 3.
Claim 4
Dependent Claim
20 words
Acicular particles as defined in claim 1 or 2 having an iron carbide content of at least 20 wt. %.
Claim 5
Dependent Claim
22 words
Acicular particles as defined in any of claims 1-3 comprising an iron oxide and/or elemental carbon in addition to the iron carbide.
Claim 6
Dependent Claim
22 words
Acicular particles as defined in any of claims 1-4 wherein the surface of the iron carbide is coated with a surface-treating agent.
Claim 7
Dependent Claim
17 words
Acicular particles as defined in any of claims 1-5 wherein the iron carbide contains a sintering-preventing agent.
Claim 8
Dependent Claim
33 words
A process for producing acicular particles containing an iron carbide characterized in that an acicular iron oxyhydroxide or acicular iron oxide is contacted with CO or a mixture thereof with H 2 .
Claim 9
Dependent Claim
33 words
A process for producing acicular particles containing an iron carbide characterized in that an acicular iron oxyhydroxide or acicular iron oxide is contacted with CO or a mixture thereof with H 2 .
Claim 10
Dependent Claim
16 words
A process as defined in claim 7 wherein the iron oxyhydroxide is α-FeOOH, b-FeOOH or f-FeOOH.
Claim 11
Dependent Claim
27 words
A process as defined in claim 7 wherein the iron oxide is a-Fe 2 O 3 , α-Fe 2 O 3 or Fe 3 O 4 .
Claim 12
Dependent Claim
21 words
A process as defined in claim 7 or 8 wherein the iron oxyhydroxide has a surface at least 5 in pH.
Claim 13
Dependent Claim
20 words
A process as defined in claim 2, 8 or 10 wherein the iron oxyhydroxide is coated with a sintering-preventing agent.
Claim 14
Dependent Claim
25 words
A process as defined in any of claims 7-11 wherein the contact temperature is about 250 to about 400°C, preferably about 300 to about 400°C.
Claim 15
Dependent Claim
12 words
A magnetic material comprising acicular particles according to any of claims 1-6.
Claim 16
Dependent Claim
13 words
A magnetic coating composition comprising acicular particles according to any of claims 1-6.
Claim 17
Dependent Claim
25 words
A magnetic recording medium which consists a substrate and a magnetic recording layer thereon, the layer comprising acicular particles according to any of claims 1-6.
References Cited (Backward Citations)
US3572993A
Cited
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