COIL-TYPE ELECTRONIC COMPONENT AND ITS MANUFACTURING METHOD

• US 20120119871A1
• Filed: 01/12/2012
• Published: 05/17/2012
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co)
• Original Assignee: Taiyo Yuden Company Limited (Taiyo Yuden Co)
• Inventors: OGAWA, Hideki, TANADA, Atsushi, MATSUURA, Hitoshi, TANAKA, Kiyoshi, KISHI, Hiroshi, KAWANO, Kenji
• Granted Patent: US 8,704,629 B2
• Time in Patent Office: Days
• US Class Current: 336/221
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: C22C 1/02 by melting C22C1/1036 takes precedence
• 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: H01F 1/12 of soft-magnetic materials
• CPC Class Codes: H01F 1/14766 Fe-Si based alloys
• CPC Class Codes: H01F 1/22 pressed, sintered, or bound together
• CPC Class Codes: H01F 1/24 the particles being insulated
• 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 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
• CPC Class Codes: H01F 41/098 Mandrels; Formers
• CPC Class Codes: H01F 41/10 Connecting leads to windings making electric connections in general H01R43/00
• CPC Class Codes: H01F 41/125 Other insulating structures; Insulating between coil and core, between different winding sections, around the coil
• CPC Class Codes: H01F 5/02 wound on non-magnetic supports, e.g. formers
• CPC Class Codes: H01F 5/06 Insulation of windings
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49069 Data storage inductor or core
• CPC Class Codes: Y10T 29/49071 by winding or coiling
• CPC Class Codes: Y10T 29/49073 : by assembling coil and core
• CPC Class Codes: Y10T 29/49144 : by metal fusion

Abstract

A coil-type electronic component has a coil inside or on the surface of its base material and is characterized in that: the base material is constituted by a group of grains of a soft magnetic alloy containing iron, silicon and other element that oxidizes more easily than iron; the surface of each soft magnetic alloy grain has an oxide layer formed on its surface as a result of oxidization of the grain; this oxide layer contains the other element that oxidizes more easily than iron by a quantity larger than that in the soft magnetic alloy grain; and grains are bonded with one another via this oxide layer.

Claims

1. A coil-type electronic component having a coil provided inside or on a surface of a base material, characterized in that:

the base material is constituted by a group of grains of a soft magnetic alloy containing iron, silicon and chromium that oxidizes more easily than iron;

the surface of each soft magnetic alloy grain has an oxide layer formed on its surface as a result of oxidization of the grain by heat treatment in an atmosphere containing oxygen;

the oxide layer contains more chromium than does the alloy grain; and

the grains are bonded with one another via the oxide layer.

2. A coil-type electronic component according to claim 1, characterized in that the soft magnetic alloy has a composition of 2 to 8 percent by weight of chromium, 1.5 to 7 percent by weight of silicon, and 88 to 96.5 percent by weight of iron.

3. A coil-type electronic component according to claim 1, characterized in that the oxide layer via which the soft magnetic alloy grains are bonded with one another is thicker than an oxide layer, other than the bonding oxide layer, on the surface of the soft magnetic alloy grains.

4. A coil-type electronic component according to claim 1, characterized in that the oxide layer via which the soft magnetic alloy grains are bonded with one another is thinner than an oxide layer, other than the bonding oxide layer, on the surface of the soft magnetic alloy grains.

5. A coil-type electronic component according to claim 1, characterized in that at least some of the soft magnetic grains are grains on which the oxide layer has a thickness of at least 50 nanometers.

6. A coil-type electronic component according to claim 1, characterized in that the oxide layer via which the grains are bonded with one another is of the same phase.

7. A coil-type electronic component according to claim 1, characterized in that the average size of the soft magnetic grains based on arithmetic mean is 30 micrometers or less.

8. A coil-type electronic component according to claim 1, characterized in that the oxide layer includes in this order

a first oxide layer where the content of the iron component decreases while the content of the element that oxidizes easily increases, and

a second oxide layer where the content of the iron component increases and the content of the element that oxidizes easily also decreases, as viewed outwardly from the soft magnetic alloy grain.

9. A coil-type electronic component according to claim 8, characterized in that the first oxide layer, as viewed outwardly from the soft magnetic alloy grain, has an inflection point with respect to the content of chromium.

10. A coil-type electronic component according to claim 1, characterized in that the oxide layer has a peak strength ratio of chromium which is higher than the peak strength ratio of chromium in the grain, based on calculation by the ZAF method through energy diffusion X-ray analysis using a scanning electron microscope.

11. A coil-type electronic component according to claim 1, characterized in that the coil has its end electrically connected to a conductive film formed on a surface of the base material.

12. A coil-type electronic component according to claim 1, characterized in that the coil is a coil conductor formed inside the base material.

13. A coil-type electronic component according to claim 12, characterized in that the coil conductor forms conductive patterns and is a conductor sintered simultaneously with the base material.

14. A method for manufacturing a coil-type electronic component having a coil provided in its base material, wherein the method comprises:

a step of obtaining a molded product by pressing a mixture of binder and soft magnetic alloy grains which contain iron, silicon and chromium that oxidizes more easily than iron;

a step of obtaining a base material by heat-treating the molded product in an atmosphere containing oxygen to form an oxide layer on the surface of the soft magnetic alloy grains and bond the soft magnetic alloy grains with one another via the oxide layer; and

a step of providing a coil and electrodes for pulling out in the base material.

16. A manufacturing method for a coil-type electronic component according to claim 14, characterized in that the oxygen atmosphere is a standard atmosphere.

15. A method for manufacturing a coil-type electronic component having a coil provided in its base material, wherein the method comprises:

a step of obtaining a molded product by forming a mixture of binder and soft magnetic alloy grains which contains iron, silicon and chromium that oxidizes more easily than iron into sheets, forming coil conductive patterns on the sheets, and stacking the sheets;

a step of obtaining a base material having a coil inside by heat-treating the molded product in an atmosphere containing oxygen to form an oxide layer on the surface of the soft magnetic alloy grains and bond the soft magnetic alloy grains with one another via the oxide layer; and

a step of providing electrodes for pulling out in the base material.

17. A manufacturing method for a coil-type electronic component according to claim 15, characterized in that the oxygen atmosphere is a standard atmosphere.