METALLIC MAGNETIC MATERIAL FOR MAGNETIC ELEMENT OF A CHOKE COIL AND SMD CHOKE COIL

• US 20090095380A1
• Filed: 11/30/2007
• Published: 04/16/2009
• Est. Priority Date: 10/15/2007
• Status: Active Grant

• Current Assignee: Sekisin Industry Co., Ltd.
• Original Assignee: Sekisin Industry Co., Ltd.
• Inventors: TOYOSHIMA, Yotaro, SATO, Namio, YAMAMOTO, Katsutoshi
• Granted Patent: US 7,767,035 B2
• Time in Patent Office: Days
• US Class Current: 148/309
• CPC Class Codes: H01F 1/14791 Fe-Si-Al based alloys, e.g. Sendust
• CPC Class Codes: H01F 27/255 made from particles H01F27/26 takes precedence
• CPC Class Codes: H01F 37/00 Fixed inductances not covered by group H01F17/00
• 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 metallic magnetic material for magnetic element for magnetic element of a choke coil and an SMD choke power coil for accommodating low voltage and high current in a personal computer, graphic card, high frequency power supply, etc, is prepared by baking a powder of Fe—Si—Al alloy sendust, obtained by an atomization process and having an average particle diameter of 10 to 70 μm, at 600° C. to 1000° C. in air or in an oxidizing atmosphere and mixing the baked sendust with 3 to 45 wt % of a carbonyl iron powder with an average particle diameter of 1 to 10 μm. The metallic magnetic material for magnetic element according to the present invention is used in a coil-embedded SMD power choke coil having a square or rectangular shape with a height of 1 mm to 7 mm and with a length of one side being 3 mm to 13 mm.

Claims

1. A metallic magnetic material for magnetic element of a choke coil, the metallic magnetic material being prepared by baking an Fe—

Si—

Al alloy sendust powder, obtained by an atomization process and having an average particle diameter of 10 to 70 μ

m, at 600°

C. to 1000°

C. in air or an oxidizing atmosphere and mixing the baked sendust with 3 to 45 wt % of a carbonyl iron powder with an average particle diameter of 1 to 10 μ

m.

2. The metallic magnetic material for magnetic element of a choke coil according to claim 1, prepared by baking the sendust in air or the oxidizing atmosphere so that with respect to an initial magnetic permeability μ

of the carbonyl iron powder in a range of 20 to 35, an initial magnetic permeability p of the sendust becomes no more than the initial permeability of the carbonyl iron powder but 10 or more, and then mixing the baked sendust with the carbonyl iron powder.

3. The metallic magnetic material for magnetic element of a choke coil according to claim 1, wherein 1 to 3 wt % of powder epoxy, 1 to 3 wt % of talc, and 2 to 4 wt % of epoxy-based varnish are added to the metallic magnetic material for magnetic element.

4. The metallic magnetic material for magnetic element of a choke coil according to claim 1, wherein a portion of the 3 to 45 wt % carbonyl iron powder is replaced, in a range of 0 to 50 wt %, by any one or a mixed powder of another electrolytic iron powder, Fe-3.5Si alloy, Fe-50Ni alloy, and Fe-3.5Si-4.5Cr alloy with an average particle diameter of 1 to 10 μ

m.

5. An SMD choke coil comprising the metallic magnetic material for magnetic element of a choke coil according to claim 1 and having a square or rectangular shape with a height of 1 mm to 7 mm and with a length of one side being 3 mm to 13 mm.