Soft magnetic composite materials

• US 8,075,710 B2
• Filed: 06/15/2006
• Issued: 12/13/2011
• Est. Priority Date: 06/15/2005
• Status: Active Grant

• Current Assignee: Hoganas AB (H. Intressenter AB)
• Original Assignee: Hoganas AB (H. Intressenter AB)
• Inventors: Skårman, Björn, Ye, Zhou, Jansson, Patricia
• Primary Examiner(s): Sheehan, John
• Application Number:
  US11/921,514
• Publication Number:
  US 20090042051A1
• Time in Patent Office: 2,007 Days
• Field of Search: None
• US Class Current: 148/306
• CPC Class Codes: B22F 1/00 Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
• CPC Class Codes: B22F 1/102 Metallic powder coated with organic material
• CPC Class Codes: B22F 1/16 Metallic particles coated with a non-metal coated with lubricating or binding agents or with organic material B22F1/10
• CPC Class Codes: B22F 2003/241 Chemical after-treatment on the surface
• CPC Class Codes: B22F 2003/248 Thermal after-treatment
• CPC Class Codes: B22F 2201/00 Treatment under specific atmosphere
• CPC Class Codes: B22F 2201/02 Nitrogen
• CPC Class Codes: B22F 2201/05 Water or water vapour
• CPC Class Codes: B22F 2201/10 Inert gases
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/02 Compacting only
• CPC Class Codes: B22F 3/1021 Removal of binder or filler removal of binder from ceramics C04B35/638
• CPC Class Codes: B22F 3/24 After-treatment of workpieces or articles B22F3/1146 takes precedence
• CPC Class Codes: H01F 1/14 metals or alloys
• CPC Class Codes: H01F 1/24 the particles being insulated
• CPC Class Codes: H01F 1/33 mixtures of metallic and non-metallic particles; metallic particles having oxide skin
• CPC Class Codes: H01F 27/255 made from particles H01F27/26 takes precedence
• CPC Class Codes: H01F 3/08 made from powder powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06
• 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: Y10T 428/12028 : Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]

Abstract

A process for the manufacture of soft magnetic composite components is provided including the steps of: die compacting a powder composition including a mixture of soft magnetic, iron or iron-based powder, core particles of which are surrounded by an electrically insulating, inorganic coating, and an organic lubricant in an amount of 0.05 to 1.5% by weight of the composition, the organic lubricant being free from metal and having a temperature of vaporization less than the decomposition temperature of the coating; ejecting the compacted body from the die; heating the compacted body in an inert atmosphere to a temperature above the vaporization temperature of the lubricant and below the decomposition temperature of the inorganic coating for removing the lubricant from the compacted body, and subjecting the body obtained after heating the compacted body in an inert atmosphere to heat treatment at a temperature between 300 and 600 in water vapor.

Claims

1. A process for the manufacture of soft magnetic composite components comprising the steps of:

die compacting a powder composition comprising a mixture of soft magnetic, iron or iron-based powder, core particles of which are surrounded by an electrically insulating, inorganic coating, and an organic lubricant in an amount of 0.05 to 1.5% by weight of the composition, said organic lubricant being free from metal and having a temperature of vaporisation less than the decomposition temperature of the coating;

ejecting the compacted body from the die;

heating the compacted body in an inert atmosphere to a temperature above the vaporisation temperature of the lubricant and below the decomposition temperature of the inorganic coating for removing the lubricant from the compacted body, and

subjecting the body obtained after heating the compacted body in an inert atmosphere to heat treatment at a temperature between 300°

C. and 600°

C. in water vapour.

2. A process according to claim 1, wherein the compaction is performed at elevated temperature.

3. A process according to claim 2, wherein the compaction is performed at a temperature of at most 60°

C. below the melting temperature of the organic lubricant.

4. A process according to claim 1, wherein the temperature of vaporization of the lubricant is less than 500°

C.

5. A process according to claim 1, wherein the treatment in water vapour (steam treatment) is performed at a temperature less than 550°

C.

6. A process according to claim 1, wherein the core particles consist of essentially pure iron.

7. A process according to claim 1, wherein the inorganic coating insulating the core particles includes phosphorus.

8. A process according to claim 1, wherein the mean particle size of the insulated powder particles is between 106 and 425 μ

m.

9. A process according to claim 1, wherein at least 20% of the insulated powder particles have a particle size above 212 μ

m.

10. A process according to claim 1, wherein the amount of lubricant is 0.05-1.0% by weight of the composition.

13. A process according to claim 1, wherein the lubricant is selected from the group consisting of stearamide, erucyl-stearamide and behenyl alcohol.

14. A process according to claim 1, wherein the lubricant is an amide wax.

15. A soft magnetic composite component prepared according to claim 1 having an oxidized crust and an unoxidized core.

18. A process according to claim 1 wherein the lubricant is ethylene-bisstearamide.

19. A process according to claim 1 wherein the inert atmosphere is nitrogen.

20. A process according to claim 1 wherein the process is adapted to produce a soft magnetic composite component having a transverse rupture strength of at least 120 MPa, a permeability of at least 700 and a core loss at 1 Tesla and 400 Hz of at most 70 W/kg.

11. A process for the manufacture of soft magnetic composite components comprising the steps of:

die compacting a powder composition comprising a mixture of soft magnetic, iron or iron-based powder, core particles of which are surrounded by an electrically insulating, inorganic coating, and an organic lubricant in an amount of 0.05 to 1.5% by weight of the composition, said organic lubricant being free from metal and having a temperature of vaporisation less than the decomposition temperature of the coating;

ejecting the compacted body from the die;

heating the compacted body in a non reducing atmosphere to a temperature above the vaporisation temperature of the lubricant and below the decomposition temperature of the inorganic coating for removing the lubricant from the compacted body, and

subjecting the body obtained after heating the compacted body in a non reducing atmosphere to heat treatment at a temperature between 300°

C. and 600°

C. in water vapour,

wherein the lubricant is selected from the group consisting of primary amides and secondary amides of saturated or unsaturated fatty acids or combinations thereof, wherein the lubricant has a temperature of vaporization in air of between 200 to 350°

C.

12. A process for the manufacture of soft magnetic composite components comprising the steps of:

die compacting a powder composition comprising a mixture of soft magnetic, iron or iron-based powder, core particles of which are surrounded by an electrically insulating, inorganic coating, and an organic lubricant in an amount of 0.05 to 1.5% by weight of the composition, said organic lubricant being free from metal and having a temperature of vaporisation less than the decomposition temperature of the coating;

ejecting the compacted body from the die;

heating the compacted body in a non reducing atmosphere to a temperature above the vaporisation temperature of the lubricant and below the decomposition temperature of the inorganic coating for removing the lubricant from the compacted body, and

subjecting the body obtained after heating the compacted body in a non reducing atmosphere to heat treatment at a temperature between 300°

C. and 600°

C. in water vapour,

wherein the lubricant is selected from the group consisting of saturated or unsaturated fatty alcohols, wherein the lubricant has a temperature of vaporization in air of between 200 to 350°

C.

16. A soft magnetic composite component having a transverse rupture strength of at least 120 MPa, a permeability of at least 700 and a core loss at 1 Tesla and 400 Hz of at most 70 W/kg.

17. A soft magnetic composite component having a transverse rupture strength of at least 120 MPa, a permeability of at least 800 and a core loss at 1 Tesla and 400 Hz of at most 65 W/kg.