EP1662518A1 - Soft magnetic material and method for producing same - Google Patents

Soft magnetic material and method for producing same Download PDF

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Publication number
EP1662518A1
EP1662518A1 EP04772795A EP04772795A EP1662518A1 EP 1662518 A1 EP1662518 A1 EP 1662518A1 EP 04772795 A EP04772795 A EP 04772795A EP 04772795 A EP04772795 A EP 04772795A EP 1662518 A1 EP1662518 A1 EP 1662518A1
Authority
EP
European Patent Office
Prior art keywords
magnetic material
soft magnetic
magnetic particles
particles
compaction
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP04772795A
Other languages
German (de)
English (en)
French (fr)
Inventor
Haruhisa SUMITOMO ELECTRIC INDUSTRIES LTD TOYODA
Ryoji TOYOTA JIDOSHA KABUSHIKI KAISHA MIZUTANI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Electric Industries Ltd
Toyota Motor Corp
Original Assignee
Sumitomo Electric Industries Ltd
Toyota Motor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Electric Industries Ltd, Toyota Motor Corp filed Critical Sumitomo Electric Industries Ltd
Publication of EP1662518A1 publication Critical patent/EP1662518A1/en
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0206—Manufacturing of magnetic cores by mechanical means
    • H01F41/0246—Manufacturing of magnetic circuits by moulding or by pressing powder
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/16—Metallic particles coated with a non-metal

Definitions

  • the present invention relates to a soft magnetic material and a method for producing the same, and more specifically, it relates to a soft magnetic material comprising composite magnetic particles having metal magnetic particles and insulating coating films and a method for producing the same.
  • Patent literature 1 discloses such a soft magnetic material.
  • Patent Literature 1 Japanese Patent Laying-Open No. 6-267723
  • an object of the present invention is to provide a soft magnetic material having optimized electric resistivity and a method for producing the same.
  • the soft magnetic material according to the present invention comprises a plurality of composite magnetic particles.
  • Each of the plurality of composite magnetic particles has a metal magnetic particle and an insulating coating film, containing at least one substance selected from a group consisting of aluminum oxide, zirconium oxide and silicon oxide, surrounding the surface of the metal magnetic particle.
  • Electric resistivity p of the soft magnetic material is at least 3000 ⁇ cm and not more than 50000 ⁇ cm.
  • magnetic permeability ⁇ of the soft magnetic material is at least 2000 and not more than 4000.
  • the method for producing a soft magnetic material according to the present invention is a method for producing the aforementioned soft magnetic material and comprises the steps of preparing a compaction by pressing a plurality of composite magnetic particles having metal magnetic particles and insulating coating films, containing at least one substance selected from a group consisting of aluminum oxide, zirconium oxide and silicon oxide, surrounding the surfaces of the metal magnetic particles and performing first heat treatment on the compaction at a temperature of at least 400°C and not more than 900°C.
  • the method for producing a soft magnetic material further comprises the step of pressing the compaction after the first heat treatment and thereafter performing second heat treatment on the compaction under the atmospheric pressure at a temperature of at least 400°C and not more than 900°C.
  • a soft magnetic material having desired magnetic characteristics and a method for producing the same can be provided.
  • a soft magnetic material according to the present invention has a plurality of composite magnetic particles, and each of the composite magnetic particles has a metal magnetic particle and an insulating coating film surrounding the surface of the metal magnetic particle.
  • the metal magnetic particles are generally made of iron (Fe).
  • the metal magnetic particles are not restricted to iron, but may alternatively be formed by other magnetic particles.
  • the metal magnetic particles may be made of an iron (Fe)-silicon (Si) alloy, an iron (Fe)-nitrogen (N) alloy, an iron (Fe)-nickel (Ni) alloy, an iron (Fe)-carbon (C) alloy, an iron (Fe)-boron (B) alloy, an iron (Fe)-cobalt (Co) alloy, an iron (Fe)-phosphorus (P) alloy, an iron (Fe)-nickel (Ni)-cobalt (Co) alloy or an iron (Fe)-aluminum (Al)-silicon (Si) alloy.
  • the metal magnetic particles may be of a simple substance of metal or an alloy.
  • the average particle diameter of the metal magnetic particles is preferably at least 5 ⁇ m and not more than 200 ⁇ m. If the average particle diameter of the metal magnetic particles is less than 5 ⁇ m, the metal is so easily oxidized that the magnetic characteristics of the soft magnetic material may be reduced. If the average particle diameter of the metal magnetic particles exceeds 20 ⁇ m, compressibility of mixed powder is reduced in a subsequent pressure-forming step. Thus, the density of a compaction obtained through the pressure-forming step may be so reduced that it is difficult to handle the compaction.
  • the average particle size described herein refers to a particle size obtained when the sum of masses of particles added in ascending order of particle size in a histogram of particle sizes measured by sieving reaches 50 % of the total mass, that is, 50 % particle size D.
  • the insulating coating films can be made of an oxide insulator containing aluminum and/or zirconium and/or silicon.
  • the electric resistivity p of the soft magnetic material can be increased by covering the surfaces of the metal magnetic particles with the insulating coating films.
  • iron loss of the soft magnetic material resulting from eddy current can be reduced by inhibiting the eddy current from flowing between the metal magnetic particles.
  • the electric resistivity p of the soft magnetic material is at least 3000 ⁇ cm and not more than 50000 ⁇ cm. If the electric resistivity p is less than 3000 ⁇ cm, the electric resistivity is reduced to reduce the effect of suppressing the eddy current.
  • the electric resistivity p exceeds 50000 ⁇ cm contrarily thereto, the electric resistivity is unpreferably excessively increased. More specifically, increase of the electric resistivity p means increase of the quantity of the insulating coating films. If the quantity of the insulating coating films is excessively increased, magnetic characteristics such as magnetic permeability and magnetic flux density are deteriorated.
  • the electric resistivity p of the soft magnetic material is preferably at least 6000 ⁇ cm and not more than 15000 ⁇ cm, more preferably at least 8000 ⁇ cm and not more than 10000 ⁇ cm.
  • the thickness of the insulating coating films is preferably at least 0.005 ⁇ m and not more than 20 ⁇ m. Energy loss resulting from eddy current can be effectively suppressed by setting the thickness of the insulating coating films to at least 0.005 ⁇ m.
  • the thickness of the insulating coating films is set to not more than 20 ⁇ m, the volume ratio of the insulating coating films occupying the soft magnetic material is not excessively increased. Thus, a soft material having prescribed saturation magnetic flux density can be formed.
  • magnetic permeability ⁇ of the soft magnetic material is at least 2000 and not more than 4000. Further preferably, the magnetic permeability ⁇ of the soft magnetic material is at least 2500 and not more than 3500.
  • a method for producing the aforementioned soft magnetic material is now described.
  • a plurality of composite magnetic particles are prepared. These composite magnetic particles are introduced into a powder compaction, and mixed powder is pressure-formed under a condition of pressure of at least 390 MPa and not more than 1500 MPa, for example.
  • the pressure forming is preferably performed under an inert gas atmosphere or a decompressed atmosphere. In this case, the mixed powder can be prevented from oxidation by oxygen in the atmosphere.
  • well-known warm pressing or die wall lubrication is so employed as to densify the compaction, improve the space factor and improve the magnetic characteristics.
  • the powder temperature in the warm pressing is preferably 100°C to 180°C.
  • organic matter may intervene between the composite magnetic particles.
  • the composite magnetic particles and the organic matter must be previously mixed with each other.
  • the mixing method is not restricted but any of mechanical alloying, vibration ball milling, satellite ball milling, mechanofusion, coprecipitation, chemical vapor deposition (CVD), physical vapor deposition (PVD), plating, sputtering, vapor deposition and a sol-gel process can be used.
  • Thermoplastic resin such as thermoplastic polyimide, thermoplastic polyamide, thermoplastic polyamidimide, polyphenylene sulfide, polyamidimide, poly(ethersulfone), polyether imide or poly(etheretherketone) can be employed for the organic matter.
  • This organic matter is so provided that the organic matter functions as a lubricant between the plurality of composite magnetic particles. Thus, breakage of the insulating coating films can be suppressed in the pressure-forming step.
  • the compaction obtained by the pressure forming is heat-treated at a temperature of at least 400°C and not more than 900°C.
  • Large numbers of strains and dislocations are caused in the compaction obtained through the pressure-forming step, and the strains and the dislocations result in reduction of the magnetic permeability and increase of the coercive force.
  • the heat treatment is performed on the compaction, in order to eliminate these strains and dislocations. Such heat treatment is required also when the organic matter intervenes between the composite magnetic particles.
  • the soft magnetic material is compressed again to be improved in density, and thereafter heat-treated under the atmospheric pressure at a temperature of 400°C and not more than 900°C.
  • the inventive soft magnetic material can be produced.
  • hysteresis loss is reduced if the coercive force of the soft magnetic material is small, the coercive force is also increased if the hysteresis loss is large, and the magnetic permeability is increased if the coercive force is small. Improvement of the magnetic permeability leads to reduction of the hysteresis loss.
  • the material is so constituted as to increase the magnetic permeability, leading to reduction of the hysteresis loss.
  • the eddy current loss includes eddy current loss in the respective particles and eddy current loss caused between the particles.
  • the eddy current loss between the particles must be reduced, and it is possible to reduce the eddy current loss according to the present invention since the specific resistance of the soft magnetic material is increased in the range not damaging the magnetic characteristics.
  • compositions of aluminum oxide, zirconium oxide and silicon oxide constituting the insulating coating films in the present invention are not particularly restricted. More specifically, the composition of aluminum oxide is not restricted to Al 2 O 3 , and the atomic ratio between aluminum and oxygen may be properly changed. Also as to the composition ratio of zirconium oxide, the ratio between zirconium and oxygen may be properly changed. Further, the ratio between silicon and oxygen may be properly changed also as to the composition ratio of silicon oxide.
  • Fig. 1 is a schematic diagram showing a section of a soft magnetic material according to an embodiment of the present invention.
  • the soft magnetic material comprises a plurality of composite magnetic particles 30.
  • Each of the plurality of composite magnetic particles 30 has a metal magnetic particle 10 and an insulating coating film 20, containing at least one substance selected from a group consisting of aluminum oxide, zirconium oxide and silicon oxide, surrounding the surface of the metal magnetic particle 10.
  • the electric resistivity p of the soft magnetic material is at least 3000 ⁇ cm and not more than 50000 ⁇ cm.
  • Organic matter 40 intervenes between the composite magnetic particles 30.
  • Example 1 a soft magnetic material according to the present invention was produced.
  • iron particles having an average particle diameter of 70 ⁇ m were prepared as metal magnetic particles. These iron particles were coated with Al 2 O 3 films serving as insulating coating films by a wet method. At this time, the thickness of the insulating coating films was set to about 100 nm. Composite magnetic particles were formed by surrounding the surfaces of the iron particles with the Al 2 O 3 films through this coating.
  • Mixed powder was prepared by mixing the composite magnetic particles and particles of polyphenylene sulfide resin having an average particle diameter of not more than 100 ⁇ m with each other.
  • the mixed powder was introduced into a metal mold and subjected to pressure molding.
  • the pressure molding was performed in a nitrogen gas atmosphere
  • the metal mold was set to the normal temperature, and the pressure was set to 882 MPa.
  • a sample of a compaction was obtained.
  • the compaction was heat-treated.
  • the heat treatment was performed in a nitrogen gas atmosphere at a temperature of 800°C for 3 hours. Electric resistivity, density and magnetic permeability ⁇ of the sample thereafter measured were 5670 ⁇ cm, 7.5 g/cm 3 and 2050 respectively.
  • Somalloy 500 (trade name) was prepared as composite magnetic particles.
  • Somalloy 500 is composite magnetic particles prepared by molding phosphate coating films on the surfaces of iron particles.
  • Mixed powder was prepared by mixing particles of polyphenylene sulfide into the composite magnetic particles. The mixed powder was introduced into a compaction and subjected to pressure forming. At this time, the pressure forming was performed in a nitrogen gas atmosphere, the metal mold was set to the normal temperature, and the pressure was set to 882 MPa. Thus, a compaction was obtained.
  • the compaction was heat-treated.
  • the heat treatment was performed in a nitrogen gas atmosphere at a temperature of 300°C for 0.5 hours. Thereafter electric resistivity and magnetic permeability of the compaction were measured.
  • the electric resistivity was 350 ⁇ cm, and the magnetic permeability ⁇ was 600.
  • the inventive soft magnetic material can satisfy the magnetic characteristics required to the soft magnetic material.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Soft Magnetic Materials (AREA)
  • Powder Metallurgy (AREA)
EP04772795A 2003-09-03 2004-09-03 Soft magnetic material and method for producing same Withdrawn EP1662518A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2003311353A JP2005079511A (ja) 2003-09-03 2003-09-03 軟磁性材料およびその製造方法
PCT/JP2004/012846 WO2005024859A1 (ja) 2003-09-03 2004-09-03 軟磁性材料およびその製造方法

Publications (1)

Publication Number Publication Date
EP1662518A1 true EP1662518A1 (en) 2006-05-31

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Family Applications (1)

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EP04772795A Withdrawn EP1662518A1 (en) 2003-09-03 2004-09-03 Soft magnetic material and method for producing same

Country Status (5)

Country Link
EP (1) EP1662518A1 (zh)
JP (1) JP2005079511A (zh)
CN (1) CN1846282A (zh)
BR (1) BRPI0414095A (zh)
WO (1) WO2005024859A1 (zh)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4865527B2 (ja) * 2006-12-18 2012-02-01 富士電機株式会社 軟磁性成形体およびその製造方法
JP5227756B2 (ja) 2008-01-31 2013-07-03 本田技研工業株式会社 軟磁性材料の製造方法
DE102008023059B4 (de) * 2008-05-09 2010-06-10 Eto Magnetic Gmbh Verfahren zum Herstellen eines magnetisierbaren metallischen Formkörpers
JP2009290024A (ja) * 2008-05-29 2009-12-10 Denso Corp 圧粉磁心の製造方法
JP5435398B2 (ja) * 2009-08-27 2014-03-05 Ｔｄｋ株式会社 軟磁性圧粉磁芯、及び、その製造方法
JP5539159B2 (ja) * 2010-11-04 2014-07-02 アイダエンジニアリング株式会社 混合粉末の高密度成形方法および高密度成形装置。
CN107578872B (zh) * 2017-08-10 2019-10-22 深圳市铂科新材料股份有限公司 一种耐高温热处理的金属软磁粉芯的制备方法
KR102004805B1 (ko) * 2017-10-18 2019-07-29 삼성전기주식회사 코일 전자 부품
JP2021021097A (ja) * 2019-07-25 2021-02-18 Tdk株式会社 複合磁性粉及びこれを用いた圧粉磁心、並びに、複合磁性粉の製造方法

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Publication number Priority date Publication date Assignee Title
JP3435223B2 (ja) * 1994-08-26 2003-08-11 住友特殊金属株式会社 センダスト系焼結合金の製造方法
JP2003037018A (ja) * 2001-07-23 2003-02-07 Daido Steel Co Ltd 圧粉磁心の製造方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2005024859A1 *

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Publication number Publication date
WO2005024859A1 (ja) 2005-03-17
JP2005079511A (ja) 2005-03-24
BRPI0414095A (pt) 2006-10-31
CN1846282A (zh) 2006-10-11

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