METHOD FOR PRODUCING SOFT MAGNETIC METAL POWDER COATED WITH MG-CONTAINING OXIDE FILM AND METHOD FOR PRODUCING COMPOSITE SOFT MAGNETIC MATERIAL USING SAID POWDER

• US 20120070567A1
• Filed: 09/07/2011
• Published: 03/22/2012
• Est. Priority Date: 09/06/2004
• Status: Active Grant

• Current Assignee: Diamet Corporation (Mitsubishi Materials Corporation)
• Original Assignee: Diamet Corporation (Mitsubishi Materials Corporation)
• Inventors: Watanabe, Muneaki, Nakayama, Ryoji, Uozumi, Gakuji
• Granted Patent: US 8,409,371 B2
• Time in Patent Office: Days
• US Class Current: 427/127
• CPC Class Codes: B22F 1/06 Metallic powder characterised by the shape of the particles nanosized particles B22F1/054
• CPC Class Codes: B22F 1/145 Chemical treatment, e.g. passivation or decarburisation
• CPC Class Codes: B22F 1/16 Metallic particles coated with a non-metal coated with lubricating or binding agents or with organic material B22F1/10
• CPC Class Codes: B22F 2201/02 Nitrogen
• CPC Class Codes: B22F 2201/03 Oxygen
• CPC Class Codes: B22F 2201/11 Argon
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/02 Compacting only
• CPC Class Codes: B22F 3/10 Sintering only
• CPC Class Codes: C22C 33/02 by powder metallurgy working metallic powder B22F
• CPC Class Codes: C22C 38/00 Ferrous alloys, e.g. steel alloys cast-iron alloys C22C37/00
• CPC Class Codes: C22C 38/02 containing silicon
• CPC Class Codes: C22C 38/06 containing aluminium
• CPC Class Codes: C22C 38/08 containing nickel C22C38/105 takes precedence
• CPC Class Codes: C22C 38/10 containing cobalt
• CPC Class Codes: C22C 38/12 containing tungsten, tantalum, molybdenum, vanadium, or niobium
• CPC Class Codes: C22C 38/18 containing chromium
• CPC Class Codes: H01F 1/33 mixtures of metallic and non-metallic particles; metallic particles having oxide skin
• CPC Class Codes: H01F 41/0246 Manufacturing of magnetic circuits by moulding or by pressing powder magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36

Abstract

A method for producing a soft magnetic metal powder coated with a Mg-containing oxide film, comprising the steps of adding and mixing a Mg powder with a soft magnetic metal powder which has been subjected to heating treatment in an oxidizing atmosphere at a temperature of 40 to 500° C. to obtain a mixed powder, and heating the mixed powder at a temperature of 150 to 1,100° C. in an inert gas or vacuum atmosphere under a pressure of 1×10⁻¹² to 1×10⁻¹ MPa, while optionally tumbling; and a method for producing a composite soft magnetic material from the soft magnetic metal powder coated with a Mg-containing oxide film.

Claims

1. A method for producing a soft magnetic powder coated with a Mg-containing oxide film used for producing a composite soft magnetic material having a resistivity of 65 μ

Ω

m or more, comprising the steps of;

subjecting a soft magnetic metal powder to oxidation treatment to provide a raw powder material;

adding and mixing a Mg powder with said raw powder material to obtain a mixed powder; and

heating said mixed powder at a temperature of 150 to 1,100°

C. in an inert gas or vacuum atmosphere under a pressure of 1×

10<sup>−

12</sup> to 1×

10<sup>−

1</sup> MPa, thereby obtaining a soft magnetic metal powder coated with Mg-containing oxide film, wherein said soft magnetic powder is an iron powder, an insulated-iron powder, Fe—

Al iron-based soft magnetic alloy powder, Fe—

Ni iron based soft magnetic alloy powder, Fe—

Cr iron-based soft magnetic alloy powder, Fe—

Si iron-based soft magnetic alloy powder, Fe—

Si—

Al iron based soft magnetic alloy powder, Fe—

Co iron-based soft magnetic alloy powder, Fe—

Co—

V iron-based soft magnetic alloy powder, or Fe—

P iron-based soft magnetic alloy powder, and wherein said soft magnetic metal powder is used for producing a composite soft magnetic material having resistivity of 65 μ

Ω

m or more.

2. The method according to claim 1, further comprising the step of heating said soft magnetic metal powder coated with a Mg-containing oxide film in an oxidizing atmosphere at a temperature of 50 to 400°

C.

3. The method according to claim 1, wherein said step of subjecting a soft magnetic metal powder to oxidation treatment comprises heating a soft magnetic metal powder in an oxidizing atmosphere at a temperature of 50 to 500°

C.

13. The method according to claim 1, wherein said heating in a vacuum or inert gas atmosphere is performed while tumbling.

15. A method for producing a raw powder material defined in claim 1 comprising a soft magnetic powder which has been subjected to oxidation treatment, which comprises the steps of:

adding and mixing a Si powder with an Fe—

Si iron-based soft magnetic powder or Fe powder, followed by heating in a non-oxidizing atmosphere to obtain an Fe—

Si iron-based soft magnetic powder having a high-concentration Si diffusion layer which has a Si concentration higher than the Fe—

Si iron-based soft magnetic powder or Fe powder;

and subjecting said Fe—

Si iron-based soft magnetic powder having a high-concentration Si diffusion layer to oxidizing treatment, thereby obtaining a surface-oxidized, Fe—

Si iron-based soft magnetic raw powder material having an oxide layer formed on the high-concentration Si diffusion layer.

4. (canceled)

5. A method for producing a soft magnetic metal powder coated with a Mg-containing oxide film used for producing a composite soft magnetic material having resistivity of 65 μ

Ω

m or more, comprising the steps of;

adding and mixing a Mg powder with a soft magnetic metal powder to obtain a mixed powder; and

heating said mixed powder at a temperature of 150 to 1,100°

C. in an inert gas or vacuum atmosphere under a pressure of 1×

10<sup>−

12</sup> to 1×

10<sup>−

1</sup> MPa,

followed by heating said heating mixed powder in an oxidizing atmosphere at a temperature of 50 to 400°

C. to effect oxidation treatment, thereby obtaining a soft magnetic metal powder coated with a Mg-containing oxide film,

wherein said soft magnetic powder is an iron powder, an insulated powder, Fe—

Al iron-based soft magnetic alloy powder, Fe—

Ni iron-based soft magnetic alloy powder, Fe—

Cr iron-based soft magnetic alloy powder, Fe—

Si iron-based soft magnetic alloy powder, Fe—

Si—

Al iron-based soft magnetic alloy powder, Fe—

Co iron-based soft magnetic alloy powder, Fe—

Co—

V iron-based soft magnetic alloy powder, or Fe—

P iron-based soft magnetic alloy powder, and

wherein said soft magnetic metal powder is used for producing a composite soft magnetic material having resistivity of 65 μ

Ω

m or more.

28. The method according to claim 5, wherein said heating in a vacuum or inert gas atmosphere is performed while tumbling.

29. The method according to claim 5, wherein said soft magnetic metal powder is an iron powder, an insulated-iron powder, Fe—

Al iron-based soft magnetic alloy powder, Fe—

Ni iron-based soft magnetic alloy powder, Fe—

Cr iron-based soft magnetic alloy powder, Fe—

Si iron-based soft magnetic alloy powder, Fe—

Si—

Al iron-based soft magnetic alloy powder, Fe—

Co iron-based soft magnetic alloy powder, Fe—

Co—

V iron-based soft magnetic alloy powder, or Fe—

P iron-based soft magnetic alloy powder.

30. A method for producing a raw powder material defined in claim 5 comprising a soft magnetic powder which has been subjected to oxidation treatment, which comprises the steps of:

adding and mixing a Si powder with an Fe—

Si iron-based soft magnetic powder or Fe powder, followed by heating in a non-oxidizing atmosphere to obtain an Fe—

Si iron-based soft magnetic powder having a high-concentration Si diffusion layer which has a Si concentration higher than the Fe—

Si iron-based soft magnetic powder or Fe powder;

and subjecting said Fe—

Si iron-based soft magnetic powder having a high-concentration Si diffusion layer to oxidizing treatment, thereby obtaining a surface-oxidized, Fe—

Si iron-based soft magnetic raw powder material having an oxide layer formed on the high-concentration Si diffusion layer.

6-12. -12. (canceled)

14. (canceled)

16-21. -21. (canceled)