COMPOSITE MAGNETIC MATERIAL, BURIED-COIL MAGNETIC ELEMENT USING SAME, AND METHOD FOR PRODUCING SAME

• US 20140286814A1
• Filed: 11/14/2012
• Published: 09/25/2014
• Est. Priority Date: 11/18/2011
• Status: Abandoned Application

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kotani, Junichi, Matsutani, Nobuya
• Application Number:
  US14/349,300
• Publication Number:
  US 20140286814A1
• Time in Patent Office: Days
• US Class Current: 419/30
• CPC Class Codes: B22F 1/052 characterised by a mixture of particles of different sizes or by the particle size distribution
• CPC Class Codes: B22F 1/09 Mixtures of metallic powders
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 1/107 containing organic material comprising solvents, e.g. for slip casting
• CPC Class Codes: B22F 1/142 Thermal or thermo-mechanical treatment
• 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 2003/248 Thermal after-treatment
• CPC Class Codes: B22F 2201/50 air
• 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 9/04 starting from solid material, e.g. by crushing, grinding or milling C22C1/1084 takes precedence; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C
• CPC Class Codes: C22C 19/03 based on nickel
• CPC Class Codes: C22C 33/0207 Using a mixture of prealloyed powders or a master alloy mixtures of metal powder in general B22F1/09
• 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 38/08 containing nickel C22C38/105 takes precedence
• CPC Class Codes: C22C 38/18 containing chromium
• CPC Class Codes: C22C 38/34 with more than 1.5% by weight of silicon
• CPC Class Codes: H01F 1/22 pressed, sintered, or bound together
• CPC Class Codes: H01F 1/26 : by macromolecular organic substances
• CPC Class Codes: H01F 1/33 : mixtures of metallic and non-metallic particles; metallic particles having oxide skin
• CPC Class Codes: H01F 17/04 : with magnetic core
• CPC Class Codes: H01F 2017/048 : with encapsulating core, e.g. made of resin and magnetic powder
• CPC Class Codes: H01F 27/292 : Surface mounted devices
• CPC Class Codes: H01F 41/02 : for manufacturing cores, coils, or magnets H01F41/14 takes precedence; for dynamo-electric machines H02K15/00
• 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 material includes metal magnetic powder and thermosetting resin. The metal magnetic powder includes first metal magnetic powder and second metal magnetic powder. The first metal magnetic powder includes iron and a first element with oxygen affinity higher than that of iron. The second metal magnetic powder includes at least iron. The second metal magnetic powder also includes the first element for an amount smaller than the first element contained in the first metal magnetic powder, or not include the first element. A mean particle diameter of the first metal magnetic powder is greater than a mean particle diameter of the second metal magnetic powder. The second metal magnetic powder is 10 weight % to 30 weight % of the total amount of the metal magnetic powder. This composite magnetic material can secure high magnetic permeability and also improve withstand voltage.

Claims

1. A composite magnetic material comprising:

metal magnetic powder including first metal magnetic powder and second magnetic powder,

the first metal magnetic powder including iron and a first element having oxygen affinity higher than that of iron, and

the second metal magnetic powder including at least iron, and including either one of the first element in an amount smaller than an amount of the first element contained in the first metal magnetic powder or none of the first element; and

thermosetting resin,

wherein

a mean particle diameter of the first metal magnetic powder is greater than a mean particle diameter of the second metal magnetic powder, and

the second metal magnetic powder is not less than 10 weight % and not greater than 30 weight % of a total amount of the metal magnetic powder.

2. The composite magnetic material of claim 1, wherein a surface of the first metal magnetic powder is covered with an oxide film.

3. The composite magnetic material of claim 1, wherein the metal magnetic powder further includes third metal magnetic powder.

4. The composite magnetic material of claim 2, wherein a thickness of the oxide film on the first metal magnetic powder is not less than 10 nm and not greater than 50 nm.

5. The composite magnetic material of claim 1, wherein a surface of the second metal magnetic powder is covered with an anti-oxidizing film.

6. The composite magnetic material of claim 1,

wherein

Vickers hardness of the first metal magnetic powder is not less than 300 Hv, and

Vickers hardness of the second metal magnetic powder is not greater than 180 Hv.

7. The composite magnetic material of claim 1, wherein the first metal magnetic powder is one of Fe—

Si—

Al based, Fe—

Si based, and Fe—

Si—

Cr based metal magnetic powder.

8. The composite magnetic material of claim 1,

wherein

the mean particle diameter of the first metal magnetic powder is not less than 5 μ

m and not greater than 30 μ

m, and

the mean particle diameter of the second metal magnetic powder is not less than 1 μ

m and not greater than 15 μ

m.

9. A buried-coil magnetic element using a composite magnetic material, the composite magnetic material comprising:

metal magnetic powder including first metal magnetic powder and second magnetic powder,

the first metal magnetic powder including iron and a first element having oxygen affinity higher than that of iron, and

the second metal magnetic powder including at least iron, and including either one of the first element in an amount smaller than an amount of the first element contained in the first metal magnetic powder or none of the first element; and

thermosetting resin,

wherein

a mean particle diameter of the first metal magnetic powder is greater than a mean particle diameter of the second metal magnetic powder, and

the second metal magnetic powder is not less than 10 weight % and not greater than 30 weight % of a total amount of the metal magnetic powder.

10. A method for producing a buried-coil magnetic element, comprising:

a first step of preparing a composite magnetic material by mixing metal magnetic powder mainly including iron and uncured thermosetting resin;

a second step of making a molded body by compression-molding the composite magnetic material such that a coil and at least a part of a pair of terminals electrically connected to the coil are embedded; and

a third step of curing the thermosetting resin by heating the composite magnetic material,

wherein

the composite magnetic material includes the metal magnetic powder and the thermosetting resin,

the metal magnetic powder includes first metal magnetic powder and second magnetic powder,

the first metal magnetic powder includes iron and a first element having oxygen affinity higher than that of iron,

the second metal magnetic powder includes at least iron, and includes either one of the first element in an amount smaller than an amount of the first element contained in the first metal magnetic powder or none of the first element,

a mean particle diameter of the first metal magnetic powder is greater than a mean particle diameter of the second metal magnetic powder, and

the second metal magnetic powder is not less than 10 weight % and not greater than 30 weight % of a total amount of the metal magnetic powder.

11. The method for producing the buried-coil magnetic element of claim 10, further comprising a fourth step of heating the composite magnetic material at not less than 65°

C. and not greater than 150°

C. between the first step and the second step.

12. The method for producing the buried-coil magnetic element of claim 10, further comprising a step of granulating the composite magnetic material between the first step and the second step.

13. The method for producing the buried-coil magnetic element of claim 11, further comprising a step of granulating the composite magnetic material between the first step and the fourth step.