Magnetic powder, manufacturing method of magnetic powder, and magnetic recording medium

Patent metadata

Field	Value
Publication number	US-10971182-B2
Application number	US-201815992396-A
Country	US
Kind code	B2
Filing date	May 30, 2018
Priority date	Jun 9, 2017
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

Magnetic powder includes: at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and a compound represented by Formula (1); and a surface treatment layer including a silane compound on at least a part of a surface. The magnetic powder has an average particle diameter of 8 nm to 20 nm. The content ratio of carbon atoms of the silane compound included in the surface treatment layer to iron atoms of the at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and the compound represented by Formula (1) is 0.05% to 0.5% in terms of the number of atoms. A manufacturing method thereof and applications thereof are also provided. In Formula (1), A represents at least one metal element other than Fe and a represents a number that satisfies a relationship of 0<a<2.

ε-A a Fe 2-a O 3   (1)

First claim

What is claimed is:

1. Magnetic powder comprising:
at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and a compound represented by Formula (1); and
a surface treatment layer including a silane compound on at least a part of a surface,
wherein the magnetic powder has an average particle diameter of 8 nm to 20 nm, and
a content ratio of carbon atoms of the silane compound included in the surface treatment layer to iron atoms of the at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and the compound represented by Formula (1) is 0.05% to 0.5% in terms of the number of atoms,
ε-A a Fe 2-a O 3   (1)

wherein, in Formula (1), A represents at least one metal element other than Fe and a represents a number that satisfies a relationship of 0<a<2.

2. The magnetic powder according to claim 1 ,
wherein the compound represented by Formula (1) is a compound represented by Formula (1-2),
ε-A 1 x A 2 y A 3 z Fe (2-x-y-z) O 3   (1-2)

in Formula (1-2), A 1 represents at least one trivalent metal element selected from the group consisting of Ga, Al, In, and Rh, A 2 represents at least one divalent metal element selected from the group consisting of Mn, Co, Ni, and Zn, A 3 represents at least one tetravalent metal element selected from the group consisting of Ti and Sn, x represents a number that satisfies a relationship of 0<x<1, y represents a number that satisfies a relationship of 0<y<1, z represents a number that satisfies a relationship of 0<z<1, and x+y+z<2.

3. The magnetic powder according to claim 1 ,
wherein the silane compound is a silane compound having a partial structure represented by Formula (I),

in Formula (I), R 1 represents a hydrocarbon group having 3 to 20 carbon atoms.

4. Magnetic powder comprising:
at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and a compound represented by Formula (1); and
a surface treatment layer including a silane compound having an aromatic ring in a molecule on at least a part of a surface,
wherein the magnetic powder has an average particle diameter of 8 nm to 20 nm, and
a content ratio of carbon atoms of the silane compound included in the surface treatment layer to iron atoms of the at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and the compound represented by Formula (1) is 0.05% to 0.5% in terms of the number of atoms,
ε-A a Fe 2-a O 3   (1)

wherein, in Formula (1), A represents at least one metal element other than Fe and a represents a number that satisfies a relationship of 0<a<2.

5. The magnetic powder according to claim 1 ,
wherein a total content of at least one iron oxide-based compound selected from α-Fe 2 O 3 and γ-Fe 2 O 3 is equal to or smaller than 20 parts by mass with respect to 100 parts by mass of a total content of at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and the compound represented by Formula (1).

6. A manufacturing method of the magnetic powder according to claim 1 , comprising:
performing surface treatment with respect to a surface of particles of at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and the compound represented by Formula (1) with a silane compound including a hydrolyzable organic group in a molecule, to form a surface treatment layer including the silane compound on at least a part of a surface,
ε-A a Fe 2-a O 3   (1)

wherein, in Formula (1), A represents at least one metal element other than Fe and a represents a number that satisfies a relationship of 0<a<2.

7. A magnetic recording medium comprising:
a non-magnetic support; and
a magnetic layer including the magnetic powder according to claim 1 and provided on the non-magnetic support.

8. The magnetic powder according to claim 4 ,
wherein the compound represented by Formula (1) is a compound represented by Formula (1-2),
ε-A 1 x A 2 y A 3 z Fe (2-x-y-z) O 3   (1-2)

in Formula (1-2), A 1 represents at least one trivalent metal element selected from the group consisting of Ga, Al, In, and Rh, A 2 represents at least one divalent metal element selected from the group consisting of Mn, Co, Ni, and Zn, A 3 represents at least one tetravalent metal element selected from the group consisting of Ti and Sn, x represents a number that satisfies a relationship of 0<x<1, y represents a number that satisfies a relationship of 0<y<1, z represents a number that satisfies a relationship of 0<z<1, and x+y+z<2.

9. The magnetic powder according to claim 4 ,
wherein a total content of at least one iron oxide-based compound selected from α-Fe 2 O 3 and γ-Fe 2 O 3 is equal to or smaller than 20 parts by mass with respect to 100 parts by mass of a total content of at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and the compound represented by Formula (1).

10. A manufacturing method of the magnetic powder according to claim 4 , comprising:
performing surface treatment with respect to a surface of particles of at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and the compound represented by Formula (1) with a silane compound including a hydrolyzable organic group in a molecule, to form a surface treatment layer including the silane compound on at least a part of a surface,
ε-A a Fe 2-a O 3   (1)

wherein, in Formula (1), A represents at least one metal element other than Fe and a represents a number that satisfies a relationship of 0<a<2.

11. A magnetic recording medium comprising:
a non-magnetic support; and
a magnetic layer including the magnetic powder according to claim 4 and provided on the non-magnetic support.

12. Magnetic powder comprising:
at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and a compound represented by Formula (1); and
a surface treatment layer including a silane compound on at least a part of a surface, the silane compound including a hydrocarbon group having 3 to 20 carbon atoms directly bonded to a Si atom,
wherein the magnetic powder has an average particle diameter of 8 nm to 20 nm, and
a content ratio of carbon atoms of the silane compound included in the surface treatment layer to iron atoms of the at least one epsilon-phase iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and the compound represented by Formula (1) is 0.05% to 0.5% in terms of the number of atoms,
ε-A a Fe 2-a O 3   (1)

wherein, in Formula (1), A represents at least one metal element other than Fe and a represents a number that satisfies a relationship of 0<a<2.

13. The magnetic powder according to claim 12 ,
wherein the compound represented by Formula (1) is a compound represented by Formula (1-2),
ε-A 1 x A 2 y A 3 z Fe (2-x-y-z) O 3   (1-2)

in Formula (1-2), A 1 represents at least one trivalent metal element selected from the group consisting of Ga, Al, In, and Rh, A 2 represents at least one divalent metal element selected from the group consisting of Mn, Co, Ni, and Zn, A 3 represents at least one tetravalent metal element selected from the group consisting of Ti and Sn, x represents a number that satisfies a relationship of 0<x<1, y represents a number that satisfies a relationship of 0<y<1, z represents a number tha

Assignees

• Fujifilm Corp

Inventors

• Fujimoto Takashi

Classifications

• C01P2006/42

  Magnetic properties · CPC title

• C01P2004/16

  Nanowires or nanorods, i.e. solid nanofibres with two nearly equal dimensions between 1-100 nanometer · CPC title

• G11B5/712 Primary

  characterised by the surface treatment or coating of magnetic particles · CPC title

• G11B5/70678

  Ferrites · CPC title

• C01P2002/54

  one element only · CPC title