Method for Producing Soft Magnetic Metal Powder Coated With Mg-Containing Oxide Film and Method for Producing Composite Soft Magnetic Material Using Said Powder

1 . A method for producing a soft magnetic metal powder coated with a Mg-containing oxide film, comprising the steps of: subjecting a soft magnetic metal powder to oxidation treatment to provide a raw powder material; adding and mixing a Mg powder with said raw powder material to obtain a mixed powder; and heating said mixed powder at a temperature of 150 to 1,100° C. in an inert gas or vacuum atmosphere under a pressure of 1×10 −12 to 1×10 −1 MPa, thereby obtaining a soft magnetic metal powder coated with a Mg-containing oxide film.

2 . The method according to claim 1 , further comprising the step of heating said soft magnetic metal powder coated with a Mg-containing oxide film in an oxidizing atmosphere at a temperature of 50 to 400° C.

3 . The method according to claim 1 , wherein said step of subjecting a soft magnetic metal powder to oxidation treatment comprises heating a soft magnetic metal powder in an oxidizing atmosphere at a temperature of 50 to 500° C.

4 . A raw powder material for producing a soft magnetic metal powder coated with a Mg-containing oxide film, provided by subjecting a soft magnetic metal powder to oxidation treatment.

5 . A method for producing a soft magnetic metal powder coated with a Mg-containing oxide film, comprising the steps of: adding and mixing a Mg powder with a soft magnetic metal powder to obtain a mixed powder; and heating said mixed powder at a temperature of 150 to 1,100° C. in an inert gas or vacuum atmosphere under a pressure of 1×10 −12 to 1×10 −1 MPa, followed by heating in an oxidizing atmosphere at a temperature of 50 to 400° C. to effect oxidation treatment, thereby obtaining a soft magnetic metal powder coated with a Mg-containing oxide film.

6 . A method for producing a soft magnetic powder coated with a Mg—Si-containing oxide film, comprising the steps of: forming an oxide film on a surface of a soft magnetic powder to provide an oxide-coated soft magnetic powder; adding and mixing a silicon monoxide powder with said oxide-coated soft magnetic powder; performing heating in a vacuum atmosphere at a temperature of 600 to 1,200° C. during or following said mixing of a silicon monoxide powder with said oxide-coated soft magnetic powder; adding and mixing a Mg powder with the resultant; and performing heating in a vacuum atmosphere at a temperature of 400 to 800° C. during or following said mixing of an Mg powder with the resultant.

7 . A method for producing a soft magnetic powder coated with a Mg—Si-containing oxide film, comprising the steps of: forming an oxide film on a surface of a soft magnetic powder to provide an oxide-coated soft magnetic powder; adding and mixing a silicon monoxide powder and a Mg powder with said oxide-coated soft magnetic powder; and performing heating in a vacuum atmosphere at a temperature of 400 to 1,200° C. during or following said mixing of a silicon monoxide powder and a Mg powder with said oxide-coated soft magnetic powder.

8 . A method for producing a soft magnetic powder coated with a Mg—Si-containing oxide film, comprising the steps of: forming an oxide film on a surface of a soft magnetic powder to provide an oxide-coated soft magnetic powder; adding and mixing a Mg powder with said oxide-coated soft magnetic powder; performing heating in a vacuum atmosphere at a temperature of 400 to 800° C. during or following said mixing of a Mg powder with said oxide-coated soft magnetic powder; adding and mixing a silicon monoxide powder with the resultant; and performing heating in a vacuum atmosphere at a temperature of 600 to 1,200° C. during or following said mixing of a silicon monoxide powder with the resultant.

9 . The method according to claim 6 , wherein said step of forming an oxide film on a surface of a soft magnetic powder comprises heating a soft magnetic powder in an oxidizing atmosphere at a temperature of room temperature to 500° C.

10 . The method according to claim 9 , wherein said silicon monoxide is added in an amount of 0.01 to 1% by mass, and said Mg powder is added in an amount of 0.05 to 1% by mass.

11 . The method according to claim 10 , wherein said vacuum atmosphere is an atmosphere under a pressure of 1×10 −12 to 1×10 −1 MPa.

12 . A raw powder material for producing a soft magnetic powder coated with a Mg—Si-containing oxide film, comprising an oxide-coated soft magnetic powder obtained by forming an oxide film on a surface of a soft magnetic powder.

13 . The method according to claim 1 , wherein said heating in a vacuum or inert gas atmosphere is performed while tumbling.

14 . The method according to claim 1 , wherein said soft magnetic metal powder is an iron powder, an insulated-iron powder, Fe—Al iron-based soft magnetic alloy powder, Fe—Ni iron-based soft magnetic alloy powder, Fe—Cr iron-based soft magnetic alloy powder, Fe—Si iron-based soft magnetic alloy powder, Fe—Si—Al iron-based soft magnetic alloy powder, Fe—Co iron-based soft magnetic alloy powder, Fe—Co—V iron-based soft magnetic alloy powder, or Fe—P iron-based soft magnetic alloy powder.

15 . A method for producing a raw powder material defined in claim 1 comprising a soft magnetic powder which has been subjected to oxidation treatment, which comprises the steps of: adding and mixing a Si powder with an Fe—Si iron-based soft magnetic powder or Fe powder, followed by heating in a non-oxidizing atmosphere to obtain an Fe—Si iron-based soft magnetic powder having a high-concentration Si diffusion layer which has a Si concentration higher than the Fe—Si iron-based soft magnetic powder or Fe powder; and subjecting said Fe—Si iron-based soft magnetic powder having a high-concentration Si diff layer to oxidizing treatment, thereby obtaining a surface-oxidized, Fe—Si iron-based soft magnetic raw powder material having an oxide layer formed on the high-concentration Si diffusion layer.

16 . A method for producing a composite soft magnetic material having excellent resistivity and mechanical strength, comprising the steps of: subjecting a soft magnetic metal powder coated with a Mg-containing oxide film produced by the method of claim 1 to press molding; and sintering the resultant at a temperature of 400 to 1,300° C.

17 . A method for producing a composite soft magnetic material having excellent resistivity and mechanical strength, comprising the steps of: mixing an organic insulating material, inorganic insulating material or a mixed material of an organic insulating material and an inorganic insulating material with a soft magnetic metal powder coated with a Mg-containing oxide film produced by the method of claim 1 , followed by powder compaction; and sintering the resultant at a temperature of 500 to 1,000° C.

18 . A composite soft magnetic material exhibiting excellent resistivity and mechanical strength, which is produced by the method of claim 16 .

19 . An electromagnetic circuit component comprising a composite soft magnetic material of claim 18 .

20 . The electromagnetic circuit component according to claim 19 , which is a magnetic core, motor core, generator core, solenoid core, ignition core, reactor core, transcore, choke coil core or magnetic sensor core.

21 . An electric appliance having integrated therein an electromagnetic circuit component of claim 20 .

22 . The method according to claim 7 wherein said step of forming an oxide film on a surface of a soft magnetic powder comprises heating a soft magnetic powder in an oxidizing atmosphere at a temperature of room temperature to 500° C.

23 . The method according to claim 22 , wherein said silicon monoxide is added in an amount of 0.01 to 1% by mass, and said Mg powder is added in an amount of 0.05 to 1% by mass.

24 . The method according to claim 23 , wherein said vacuum atmosphere is an atmosphere under a pressure of 1×10 −12 to 1×10 −1 MPa.

25 . The method according to claim 8 wherein said step of forming an oxide film on a surface of a soft magnetic powder comprises heating a soft magnetic powder in an oxidizing atmosphere at a temperature of room temperature to 500° C.

26 . The method according to claim 25 , wherein said silicon monoxide is added in an amount of 0.01 to 1% by mass, and said Mg powder is added in an amount of 0.05 to 1% by mass.

27 . The method according to claim 26 , wherein said vacuum atmosphere is an atmosphere under a pressure of 1×10 −12 to 1×10 −1 MPa.

28 . The method according to claim 5 , wherein said heating in a vacuum or inert gas atmosphere is performed while tumbling.

29 . The method according to claim 5 , wherein said soft magnetic metal powder is an iron powder, an insulated-iron powder, Fe—Al iron-based soft magnetic alloy powder, Fe—Ni iron-based soft magnetic alloy powder, Fe—Cr iron-based soft magnetic alloy powder, Fe—Si iron-based soft magnetic alloy powder, Fe—Si—Al iron-based soft magnetic alloy powder, Fe—Co iron-based soft magnetic alloy powder, Fe—Co—V iron-based soft magnetic alloy powder, or Fe—P iron-based soft magnetic alloy powder.

30 . A method for producing a raw powder material defined in claim 5 comprising a soft magnetic powder which has been subjected to oxidation treatment, which comprises the steps of: adding and mixing a Si powder with an Fe—Si iron-based soft magnetic powder or Fe powder, followed by heating in a non-oxidizing atmosphere to obtain an Fe—Si iron-based soft magnetic powder having a high-concentration Si diffusion layer which has a Si concentration higher than the Fe—Si iron-based soft magnetic powder or Fe powder; and subjecting said Fe—Si iron-based soft magnetic powder having a high-concentration Si diff layer to oxidizing treatment, thereby obtaining a surface-oxidized, Fe—Si iron-based soft magnetic raw powder material having an oxide layer formed on the high-concentration Si diffusion layer.

31 . A method for producing a composite soft magnetic material having excellent resistivity and mechanical strength, comprising the steps of: subjecting a soft magnetic metal powder coated with a Mg-containing oxide film produced by the method of claim 5 to press molding; and sintering the resultant at a temperature of 400 to 1,300° C.

32 . A method for producing a composite soft magnetic material having excellent resistivity and mechanical strength, comprising the steps of: mixing an organic insulating material, inorganic insulating material or a mixed material of an organic insulating material and an inorganic insulating material with a soft magnetic metal powder coated with a Mg-containing oxide film produced by the method of claim 5 , followed by powder compaction; and sintering the resultant at a temperature of 500 to 1,000° C.

33 . The method according to claim 6 , wherein said heating in a vacuum or inert gas atmosphere is performed while tumbling.

34 . The method according to claim 6 , wherein said soft magnetic metal powder is an iron powder, an insulated-iron powder, Fe—Al iron-based soft magnetic alloy powder, Fe—Ni iron-based soft magnetic alloy powder, Fe—Cr iron-based soft magnetic alloy powder, Fe—Si iron-based soft magnetic alloy powder, Fe—Si—Al iron-based soft magnetic alloy powder, Fe—Co iron-based soft magnetic alloy powder, Fe—Co—V iron-based soft magnetic alloy powder, or Fe—P iron-based soft magnetic alloy powder.

35 . A method for producing a raw powder material defined in claim 6 comprising a soft magnetic powder which has been subjected to oxidation treatment, which comprises the steps of: adding and mixing a Si powder with an Fe—Si iron-based soft magnetic powder or Fe powder, followed by heating in a non-oxidizing atmosphere to obtain an Fe—Si iron-based soft magnetic powder having a high-concentration Si diffusion layer which has a Si concentration higher than the Fe—Si iron-based soft magnetic powder or Fe powder; and subjecting said Fe—Si iron-based soft magnetic powder having a high-concentration Si diff layer to oxidizing treatment, thereby obtaining a surface-oxidized, Fe—Si iron-based soft magnetic raw powder material having an oxide layer formed on the high-concentration Si diffusion layer.

36 . A method for producing a composite soft magnetic material having excellent resistivity and mechanical strength, comprising the steps of: subjecting a soft magnetic metal powder coated with a Mg-containing oxide film produced by the method of claim 6 to press molding; and sintering the resultant at a temperature of 400 to 1,300° C.

37 . A method for producing a composite soft magnetic material having excellent resistivity and mechanical strength, comprising the steps of: mixing an organic insulating material, inorganic insulating material or a mixed material of an organic insulating material and an inorganic insulating material with a soft magnetic metal powder coated with a Mg-containing oxide film produced by the method of claim 6 , followed by powder compaction; and sintering the resultant at a temperature of 500 to 1,000° C.

38 . The method according to claim 7 , wherein said heating in a vacuum or inert gas atmosphere is performed while tumbling.

39 . The method according to claim 7 , wherein said soft magnetic metal powder is an iron powder, an insulated-iron powder, Fe—Al iron-based soft magnetic alloy powder, Fe—Ni iron-based soft magnetic alloy powder, Fe—Cr iron-based soft magnetic alloy powder, Fe—Si iron-based soft magnetic alloy powder, Fe—Si—Al iron-based soft magnetic alloy powder, Fe—Co iron-based soft magnetic alloy powder, Fe—Co—V iron-based soft magnetic alloy powder, or Fe—P iron-based soft magnetic alloy powder.

40 . A method for producing a raw powder material defined in claim 7 comprising a soft magnetic powder which has been subjected to oxidation treatment, which comprises the steps of: adding and mixing a Si powder with an Fe—Si iron-based soft magnetic powder or Fe powder, followed by heating in a non-oxidizing atmosphere to obtain an Fe—Si iron-based soft magnetic powder having a high-concentration Si diffusion layer which has a Si concentration higher than the Fe—Si iron-based soft magnetic powder or Fe powder; and subjecting said Fe—Si iron-based soft magnetic powder having a high-concentration Si diff layer to oxidizing treatment, thereby obtaining a surface-oxidized, Fe—Si iron-based soft magnetic raw powder material having an oxide layer formed on the high-concentration Si diffusion layer.

41 . A method for producing a composite soft magnetic material having excellent resistivity and mechanical strength, comprising the steps of: subjecting a soft magnetic metal powder coated with a Mg-containing oxide film produced by the method of claim 7 to press molding; and sintering the resultant at a temperature of 400 to 1,300° C.

42 . A method for producing a composite soft magnetic material having excellent resistivity and mechanical strength, comprising the steps of: mixing an organic insulating material, inorganic insulating material or a mixed material of an organic insulating material and an inorganic insulating material with a soft magnetic metal powder coated with a Mg-containing oxide film produced by the method of claim 7 , followed by powder compaction; and sintering the resultant at a temperature of 500 to 1,000° C.

43 . The method according to claim 8 , wherein said heating in a vacuum or inert gas atmosphere is performed while tumbling.

44 . The method according to claim 8 , wherein said soft magnetic metal powder is an iron powder, an insulated-iron powder, Fe—Al iron-based soft magnetic alloy powder, Fe—Ni iron-based soft magnetic alloy powder, Fe—Cr iron-based soft magnetic alloy powder, Fe—Si iron-based soft magnetic alloy powder, Fe—Si—Al iron-based soft magnetic alloy powder, Fe—Co iron-based soft magnetic alloy powder, Fe—Co—V iron-based soft magnetic alloy powder, or Fe—P iron-based soft magnetic alloy powder.

45 . A method for producing a raw powder material defined in claim 8 comprising a soft magnetic powder which has been subjected to oxidation treatment, which comprises the steps of: adding and mixing a Si powder with an Fe—Si iron-based soft magnetic powder or Fe powder, followed by heating in a non-oxidizing atmosphere to obtain an Fe—Si iron-based soft magnetic powder having a high-concentration Si diffusion layer which has a Si concentration higher than the Fe—Si iron-based soft magnetic powder or Fe powder; and subjecting said Fe—Si iron-based soft magnetic powder having a high-concentration Si diff layer to oxidizing treatment, thereby obtaining a surface-oxidized, Fe—Si iron-based soft magnetic raw powder material having an oxide layer formed on the high-concentration Si diffusion layer.

46 . A method for producing a composite soft magnetic material having excellent resistivity and mechanical strength, comprising the steps of: subjecting a soft magnetic metal powder coated with a Mg-containing oxide film produced by the method of claim 8 to press molding; and sintering the resultant at a temperature of 400 to 1,300° C.

47 . A method for producing a composite soft magnetic material having excellent resistivity and mechanical strength, comprising the steps of: mixing an organic insulating material, inorganic insulating material or a mixed material of an organic insulating material and an inorganic insulating material with a soft magnetic metal powder coated with a Mg-containing oxide film produced by the method of claim 8 , followed by powder compaction; and sintering the resultant at a temperature of 500 to 1,000° C.