Method for the production of magnet cores, magnet core and inductive component with a magnet core

• US 8,287,664 B2
• Filed: 07/11/2007
• Issued: 10/16/2012
• Est. Priority Date: 07/12/2006
• Status: Expired due to Fees

• Current Assignee: Vacuumschmelze GmbH & Company KG (Vectra Corp.)
• Original Assignee: Vacuumschmelze GmbH & Company KG (Vectra Corp.)
• Inventors: Brunner, Markus
• Primary Examiner(s): Sheehan, John
• Application Number:
  US12/308,753
• Publication Number:
  US 20090320961A1
• Time in Patent Office: 1,924 Days
• Field of Search: None
• US Class Current: 148/306
• CPC Class Codes: B22F 2009/046 by cutting
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 3/02 Compacting only
• CPC Class Codes: B22F 9/002 amorphous or microcrystalline
• 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 1/11 Making amorphous alloys
• CPC Class Codes: C22C 33/003 making amorphous alloys
• CPC Class Codes: C22C 38/02 containing silicon
• CPC Class Codes: C22C 38/12 containing tungsten, tantalum, molybdenum, vanadium, or niobium
• CPC Class Codes: C22C 38/16 containing copper
• CPC Class Codes: C22C 45/02 with iron as the major constituent
• CPC Class Codes: C22C 45/04 with nickel or cobalt as the major constituent
• CPC Class Codes: H01F 1/15308 based on Fe/Ni H01F1/15325 takes precedence
• CPC Class Codes: H01F 1/15333 containing nanocrystallites, e.g. obtained by annealing
• CPC Class Codes: H01F 27/255 made from particles H01F27/26 takes precedence
• 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 magnet core is required to be particularly dense, made of alloys produced in a rapid solidification process and have a minimal coercitive field strength. To achieve these aims, a coarse-grain powder fraction is first produced from an amorphous strip of a soft magnetic alloy. In addition, at least one fine-grain powder fraction is produced from a nanocrystalline strip of a soft magnetic alloy. The particle fractions are then mixed to produce a multi-modal powder, wherein the particles of the coarse-grain particle fraction have an amorphous structure and the particles of the fine-grain powder fraction have a nanocrystalline structure. The multi-modal powder is then pressed to produce a magnet core.

Claims

1. A method for the production of a magnet core, comprising:

producing from an amorphous soft magnetic strip at least one coarse-grain powder fraction having particle diameters between 70 and 200 μ

m;

producing from a nanocrystalline soft magnetic strip made of an alloy capable of nanocrystallisation at least one fine-grain powder fraction having particle diameters between 20 and 63 μ

m;

mixing of the coarse- and fine-grain powder fractions to produce a powder mixture with a multi-modal particle size distribution, wherein the particles of the coarse-grain particle fraction have an amorphous structure and the particles of the fine-grain powder fraction have a nanocrystalline structure;

pressing of the multi-modal powder mixture to produce a magnet core.

2. The method according to claim 1,

further comprising pre-embrittling the amorphous strip by heat treating at a pre-embrittling temperature T_embrittle prior to the production of the coarse-grain powder fraction, wherein the pre-embrittling temperature T_embrittle is related to a crystallisation temperature T_crystal of the amorphous strip by the relationship T_embrittle<

T_crystal.

3. The method according to claim 2

wherein 100°

C.≦

T_embrittle≦

400°

C.

4. The method according to claim 3

wherein 200°

C.≦

T_embrittle 400°

C.

5. The method according to claim 1

wherein the producing of the coarse-grain powder fraction comprises comminuting the amorphous strip in an as-cast state without any preceding heat treatment for pre-embrittling.

6. The method according to claim 1

wherein the producing of the coarse-grain powder fraction comprises comminuting the amorphous strip at a grinding temperature T_mill of −

196°

C.≦

T_mill≦

20°

C.

7. The method according to claim 1

wherein the producing of the fine-grain fraction comprises comminuting the nanocrystalline strip in a cutting mill.

8. The method according to claim 1

wherein the amorphous strip comprises an alloy not capable of nanocrystallisation.

9. The method according to claim 8,

wherein the amorphous strip comprises an iron-based.

10. The method according to claim 8,

wherein the amorphous strip comprises an alloy of the composition M_α

Y_β

Z_γ

,

wherein M is at least one element from the group consisting of Fe, Ni and Co,

wherein Y is at least one element from the group consisting of B, C and P,

wherein Z is at least one element from the group consisting of Si, Al and Ge, and

wherein α

, β and

γ

are specified in atomic percent and meet the following conditions;

70≦

α

≦

85;

5≦

β

≦

20; and

0≦

γ

≦

20,

wherein up to 10 atomic percent of the M component may be replaced by at least one element from the group consisting of Ti, V, Cr, Mn, Cu, Zr, Nb, Mo, Ta and W, and

and wherein up to 10 atomic percent of the (Y+Z) component may be replaced by at least one element from the group including In, Sn, Sb and Pb.

11. The method according to claim 1, wherein

the amorphous strip and the nanocrystalline strip comprise the same alloy, and wherein the alloy is capable of nanocrystallisation.

12. The method according to claim 1, wherein

the amorphous strip and the nanocrystalline strip comprise different alloys, and wherein both alloys are capable of nanocrystallisation.

13. The method according to claim 1, wherein

at least one of the amorphous strip and the nanocrystalline strip comprise an alloy capable of nanocrystallisation and that has the composition (Fe_1-aM_a)_100-x-y-z-α

-β

-γ

Cu_xSi_yB_zM′

_α

M″

_β

X_γ

,

wherein M is Co and/or Ni,

wherein M′

is at least one element from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo,

wherein M″

is at least one element from the group consisting of V, Cr, Mn, Al, elements of the platinum group, Sc, Y, rare earths, Au, Zn, Sn and Re,

wherein X is at least one element from the group consisting of C, Ge, P, Ga, Sb, In, Be and As, and

wherein a, x, y, z, α

, β and

γ

are specified in atomic percent and meet the following conditions;

0≦

a≦

0.5;

0.1≦

x≦

3;

0≦

y≦

30;

0≦

z≦

25;

0≦

y+z≦

35;

0.1≦

α

≦

30;

0≦

β

≦

10; and

0≦

γ

≦

10.

14. The method according to claim 1, wherein

at least one of the amorphous strip and the nanocrystalline strip comprise an alloy capable of nanocrystallisation and that has the composition (Fe_1-a-bCo_aNi_b)_100-x-y-z M_xB_yT_z,

wherein M is at least one element from the group consisting of Nb, Ta, Zr, Hf, Ti, V and Mo,

wherein T is at least one element from the group consisting of Cr, W, Ru, Rh, Pd, Os, Ir, Pt, Al, Si, Ge, C and P, and

wherein a, b, x, y and z are specified in atomic percent and meet the following conditions:

0≦

a≦

0.29;

0≦

b≦

0.43;

4≦

x≦

10;

3≦

y≦

15; and

0≦

z≦

5.

15. The method according to claim 1, wherein

at least one of the amorphous strip and the nanocrystalline strip comprises an alloy capable of nanocrystallisation and that has the composition Fe_73.5Nb₃Cu₁Si_15.5B₇, Fe_73.5Nb₃Cu₁Si_13.5B₉, Fe₈₆Cu₁Zr₇B₆, Fe₉₁Zr₇B₃ or Fe₈₄Nb₇B₉.

16. The method according to claim 1,

wherein

the pressing of the multi-modal powder mixture is conducted at a pressing temperature T_press such that T_press>

T_embrittle to produce a magnet core.

17. The method according to claim 1,

further comprising subjecting the magnet core to heat treatment at a heat treatment temperature T_anneal after pressing.

18. The method according to claim 17,

wherein the heat treatment temperature T_anneal and a crystallisation temperature T_crystal of a soft magnetic alloy of the amorphous strip have the relationship T_anneal≧

T_crystal.

19. The method according to claim 17,

wherein T_anneal>

500°

C.

20. The method according to claim 17,

wherein the heat treatment temperature T_anneal and a crystallisation temperature T_crystal of a soft magnetic alloy of the amorphous strip have the relationship T_anneal≦

T_crystal.

21. The method according to claim 20,

wherein 400°

C.≦

T_anneal≦

450°

C.

22. The method according to claim 1,

further comprising adding one or more processing aids comprising binders, lubricants, or combinations thereof to the multi-modal powder mixture prior to pressing.

23. The method according to claim 2,

wherein the heat treating is conducted in a controlled atmosphere.

24. The method according to claim 1,

wherein the coarse-grain powder fraction, the fine-grain powder fraction, or a combination thereof, comprises particles that have been pickled in an aqueous or alcohol solution and dried prior to pressing, and wherein the particles thereby have an electrically insulating coating thereon.

25. A magnet core comprising:

soft magnetic particles with a multi-modal particle size distribution and comprising at least one coarse-grain powder fraction of particles with an amorphous structure and having particle diameters between 70 and 200 μ

m and at least one fine-grain powder fraction of particles with a nanocrystalline structure and having particle diameters between 20 and 63 μ

m; and

one or more processing aids.

26. The magnet core according to claim 25,

wherein the particles with an amorphous structure and the particles with a nanocrystalline structure have the same alloy composition, and wherein the alloy composition is capable of nanocrystallisation.

27. The magnet core according to claim 25,

wherein the particles with an amorphous structure and the particles with a nanocrystalline structure have different alloy compositions, and wherein these alloy compositions are capable of nanocrystallisation.

28. The magnet core according to claim 25,

wherein the particles with an amorphous structure contains particles of an amorphous iron-based alloy.

29. The magnet core according to claim 25,

wherein the particles with an amorphous structure have the alloy composition M_α

Y_β

Z_γ

,

wherein M is at least one element from the group including Fe, Ni and Co,

wherein Y is at least one element from the group including B, C and P,

wherein Z is at least one element from the group including Si, Al and Ge, and

wherein α

, β and

γ

are specified in atomic percent and meet the following conditions;

70≦

α

≦

85;

5≦

β

≦

20;

0≦

γ

≦

20, and

wherein up to 10 atomic percent of the M component may be replaced by at least one element from the group including Ti, V, Cr, Mn, Cu, Zr, Nb, Mo, Ta and W, and

wherein up to 10 atomic percent of the (Y+Z) component may be replaced by at least one element from the group including In, Sn, Sb and Pb.

30. The magnet core according to claim 25,

wherein the particles with a nanocrystalline structure have the alloy composition (Fe_1-aM_a)_100-x-y-z-α

-β

-γ

Cu_xSi_yB_zM′

_α

M″

_β

X_γ

,

wherein M is Co and/or Ni,

wherein M′

is at least one element from the group including Nb, W, Ta, Zr, Hf, Ti and Mo,

wherein M′

is at least one element from the group including V, Cr, Mn, Al, elements of the platinum group, Sc, Y, rare earths, Au, Zn, Sn and Re,

wherein X is at least one element from the group including C, Ge, P, Ga, Sb, In, Be and As, and

wherein a, x, y, z, α

, β and

γ

are specified in atomic percent and meet the following conditions;

0≦

a≦

0.5;

0.1≦

x≦

3;

0≦

y≦

30;

0≦

z≦

25;

0≦

y+z≦

35;

0.1≦

α

≦

30;

0≦

β

≦

10; and

0≦

γ

≦

10.

31. The magnet core according to claim 25,

wherein the particles with a nanocrystalline structure have the alloy composition (Fe_1-a-bCo_aNi_b)_100-x-y-z M_xB_yT_z,

wherein M is at least one element from the group including Nb, Ta, Zr, Hf, Ti, V and Mo,

wherein T is at least one element from the group including Cr, W, Ru, Rh, Pd, Os, Ir, Pt, Al, Si, Ge, C and P, and

wherein a, b, x, y and z are specified in atomic percent and meet the following conditions:

0≦

a≦

0.29;

0≦

b≦

0.43;

4≦

x≦

10;

3≦

y≦

15; and

0≦

z≦

5.

32. The magnet core according to claim 25, wherein

the particles with a nanocrystalline structure have at least one of the alloy compositions Fe_73.5Nb₃Cu₁Si_15.5B₇, Fe_73.5Nb₃Cu₁Si_13.5B₉, Fe₈₆Cu₁Zr₇B₆, Fe₉₁Zr₇B₃ or Fe₈₄Nb₇B₉.

33. The magnet core according to claim 25,

wherein the one or more processing aids include one or more binders or lubricants or both.

34. An inductive component comprising a magnet core according to claim 25.

35. The inductive component according to claim 34,

wherein the inductive component is a choke for power factor correction.

36. The inductive component according to claim 34,

wherein the inductive component is a storage choke.

37. The inductive component according to claim 34,

wherein the inductive component is a filter choke.

38. The inductive component according to claim 34,

wherein the inductive component is a smoothing choke.