COMPOSITE MAGNETIC BODY AND METHOD FOR PRODUCING THE SAME

• US 20120092106A1
• Filed: 07/30/2010
• Published: 04/19/2012
• Est. Priority Date: 08/04/2009
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Takahashi, Takeshi, Matsutani, Nobuya
• Application Number:
  US13/380,090
• Publication Number:
  US 20120092106A1
• Time in Patent Office: Days
• US Class Current: 335/302
• CPC Class Codes: B22F 1/102 Metallic powder coated with organic material
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 3/10 Sintering only
• CPC Class Codes: B22F 3/1021 Removal of binder or filler removal of binder from ceramics C04B35/638
• CPC Class Codes: B22F 3/26 Impregnating making ferrous alloys by impregnation C22C33/0242
• CPC Class Codes: C22C 2202/02 Magnetic
• CPC Class Codes: C22C 33/0278 with at least one alloying element having a minimum content above 5%
• CPC Class Codes: C22C 38/02 containing silicon
• CPC Class Codes: C22C 38/06 containing aluminium
• CPC Class Codes: H01F 1/14791 Fe-Si-Al based alloys, e.g. Sendust
• 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 composite magnetic body is formed by pressure-molding Fe—Al—Si based magnetic metal powder having a composition not more than 5.7 wt % and not less than 8.5 wt % of Al, not more than 6.0 wt % and not less than 9.5 wt % of Si, and the balance of Fe together with an insulating binder, and heat-treating the molded powder at a temperature ranging from 600° C. to 900° C. The magnetic metal powder has a negative magnetocrystalline anisotropy constant at a room temperature, and has a positive magnetostriction constant at the room temperature. A temperature coefficient of core loss at the room temperature is negative. This composite magnetic body has improved temperature characteristics of the core-loss as well as excellent soft magnetic characteristics, such as lower loss and higher permeability.

Claims

1. A composite magnetic body comprising

a molded body formed by pressure-molding Fe—

Al—

Si based magnetic metal powder having a composition not more than 5.7 wt % and not less than 8.5 wt % of Al, not more than 6.0 wt % and not less than 9.5 wt % of Si, and the balance of Fe together with an insulating binder, and heat-treating the molded powder at a temperature ranging from 600°

C. to 900°

C., wherein

the magnetic metal powder has a negative magnetocrystalline anisotropy constant at a room temperature,

the magnetic metal powder has a positive magnetostriction constant at the room temperature, and

the molded body has a negative temperature coefficient of core loss at the room temperature.

2. The composite magnetic body according to claim 1, wherein a minimum temperature at which the core loss is smallest is not lower than 80°

C.

3. The composite magnetic body according to claim 1, wherein the magnetic metal powder contains not more than 6.5 wt % and not less than 8.0 wt % of Al, not more than 6.0 wt % and not less than 9.5 wt % of Si, and the balance of Fe.

4. The composite magnetic body according to claim 1, wherein the magnetic metal powder contains not more than 6.5 wt % and not less than 8.0 wt % of Al, not more than 7.5 wt % and not less than 9.5 wt % of Si, and the balance of Fe.

5. The composite magnetic body according to claim 1 has a coercivity not greater than 160 A/m.

6. The composite magnetic body according to claim 1, wherein the magnetic metal powder has an average particle diameter ranging from 1 μ

m to 100 μ

m.

7. A method for manufacturing composite magnetic body, the method comprising:

preparing Fe—

Al—

Si based magnetic metal powder containing not more than 5.7 wt % and not less than 8.5 wt % of Al, not more than 7.5 wt % and not less than 9.5 wt % of Si, and the balance of Fe;

producing a molded body by mixing the magnetic metal powder with an insulating binder, and pressure-molding the mixed powder and binder; and

providing a composite magnetic body by heating the molded body at a temperature ranging from 600°

C. to 900°

C., wherein

the magnetic metal powder has a negative magnetocrystalline anisotropy constant at a room temperature, and has a positive magnetostriction constant at the room temperature, and

the composite magnetic body has a negative temperature coefficient of core loss at the room temperature.