Magnetic material including α″-Fe16(NxZ1-x)2 or a mixture of α″-Fe16Z2 and α″-Fe16N2, where Z includes at least one of C, B, or O

Patent metadata

Field	Value
Publication number	US-12018386-B2
Application number	US-202016949038-A
Country	US
Kind code	B2
Filing date	Oct 9, 2020
Priority date	Oct 11, 2019
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

The disclosure describes a method that includes forming a soft magnetic material by a technique including melt spinning. The soft magnetic material includes at least one of: at least one of an α″-Fe 16 (N x Z 1-x ) 2 phase domain or an α′-Fe 8 (N x Z 1-x ), where Z includes at least one of C, B, or O, and where x is a number greater than zero and less than one; or at least one of an α″-Fe 16 N 2 phase domain or an α′-Fe 8 N phase domain, and at least one of an α″-Fe 16 Z 2 phase domain or an α′-Fe 8 Z phase domain.

First claim

What is claimed is:

1. A method comprising:
forming a soft magnetic material by a technique comprising:
melting a precursor composition comprising iron to form a molten composition comprising iron,
melt spinning the molten composition to form a melt-spun product,
forming nano-pores in the melt-spun product,
at least one of nitridizing the melt-spun product having the nano-pores, introducing N in the precursor composition, or introducing N in the molten composition, and
at least one of introducing Z in the melt-spun product having the nano-pores, introducing Z in the precursor composition, or introducing Z in the molten composition, and

wherein the soft magnetic material comprises at least one of:
at least one of an α″-Fe 16 (N x Z 1-x ) 2 phase domain or an α′-Fe 8 (N x Z 1-x ), wherein x is a number greater than zero and less than one; or
at least one of an α″-Fe 16 N 2 phase domain or an α′-Fe 8 N phase domain, and at least one of an α″-Fe 16 Z 2 phase domain or an α′-Fe 8 Z phase domain,
wherein Z includes at least one of C, B, or O.

2. A method comprising:
forming a bulk soft magnetic material by a technique comprising:
melting a precursor composition comprising iron and carbon to form a molten composition comprising iron and carbon,
melt spinning the molten composition to form a melt-spun product,
forming nano-pores in the melt-spun product,
nitridizing the melt-spun product having the nano-pores,
introducing Z in the melt-spun product having the nano-pores, and
compacting the melt-spun product having the nano-pores and including Z to form the bulk soft magnetic material,

wherein the soft magnetic material comprises at least one of:
at least one of an α″-Fe 16 (N x Z 1-x ) 2 phase domain or an α′-Fe 8 (N x Z 1-x ), wherein x is a number greater than zero and less than one; or
at least one of an α″-Fe 16 N 2 phase domain or an α′-Fe 8 N phase domain, and at least one of an α″-Fe 16 Z 2 phase domain or an α′-Fe 8 Z phase domain,
wherein Z includes at least O.

3. The method of claim 1 , wherein the molten composition comprises carbon, and wherein forming the soft magnetic material by the technique comprising melt spinning comprises:
melt spinning the molten composition comprising iron and carbon to form iron-carbon ribbons; and
nitriding the iron-carbon ribbons to form an iron-carbon-nitrogen material.

4. The method of claim 1 , wherein the molten composition comprises carbon, and wherein forming the soft magnetic material by the technique comprising melt spinning comprises:
melt spinning the molten composition comprising iron and carbon to form iron-carbon ribbons;
ball milling the iron-carbon ribbons to form iron-carbon powder; and
nitriding the iron-carbon powder.

5. The method of claim 3 , wherein the precursor composition comprises cast iron.

6. The method of claim 1 , wherein the soft magnetic material comprises at least one dopant, and wherein the at least one dopant comprises at least one of Cu, Co, Ti, Mn, Al, V, Cr, Zn, Ga, Ge, Zr, Nb, Mo, P, Si, or Mg.

7. The method of claim 1 , further comprising:
assembling a plurality of the soft magnetic materials to form a bulk soft magnetic material.

8. The method of claim 1 , wherein forming the soft magnetic material by the technique comprising melt spinning comprises:
melt spinning the molten composition comprising iron to form iron ribbons; and
carburizing and nitriding the iron ribbons to form an iron-carbon-nitrogen material.

9. The method of claim 1 , wherein the molten composition comprises nitrogen, and wherein forming the soft magnetic material by the technique comprising melt spinning comprises:
melt spinning the molten composition comprising iron and nitrogen to form iron-nitrogen ribbons; and
carburizing the iron-nitrogen ribbons to form an iron-carbon-nitrogen material.

10. The method of claim 3 , wherein nitriding the iron-carbon ribbons comprises exposing the iron-carbon ribbons to a nitrogen source at a temperature of between 650° C. and 900° C.

11. The method of claim 3 , further comprising cryo-treating the iron-carbon-nitrogen material in liquid nitrogen.

12. The method of claim 3 , further comprising annealing the iron-carbon-nitrogen material in a nitrogen-containing atmosphere at a temperature between 100° C. and 210° C. for between 5 hours and 100 hours.

13. The method of claim 3 , further comprising, prior to nitriding the iron-carbon ribbons, exposing the iron-carbon ribbons to a reducing atmosphere to reduce a concentration of oxides in the iron-carbon ribbon.

14. The method of claim 3 , further comprising, prior to nitriding the iron-carbon ribbons, leaching some carbon from at least a surface of the iron-carbon ribbons to create porosity in the iron-carbon ribbons.

15. The method of claim 4 , wherein nitriding the iron-carbon powder comprises exposing the iron-carbon powder to a nitrogen source at a temperature between 100° C. and 210° C. for between 5 hours and 100 hours.

16. The method of claim 4 , further comprising, prior to nitriding the iron-carbon powder, exposing the iron-carbon powder to a reducing atmosphere to reduce a concentration of oxides in the iron-carbon powder.

17. The method of claim 4 , further comprising, prior to nitriding the iron-carbon powder, leaching some carbon from at least a surface of the iron-carbon powder to create porosity in the iron-carbon powder.

18. The method of claim 4 , wherein the precursor composition comprises cast iron.

19. The method of claim 5 , wherein the cast iron is encapsulated in elemental iron.

20. The method of claim 10 , wherein the nitrogen source comprises at least one of ammonia, ammonium nitrate, urea, an amide, or hydrazine.

21. The method of claim 13 , further comprising, prior to exposing the iron-carbon ribbons to the reducing atmosphere, exposing the iron-carbon ribbons to an oxidizing atmosphere to form oxides in the iron-carbon ribbons, wherein exposing the iron-carbon ribbons to the reducing atmosphere removes at least some of the formed oxides and forms the nano-pores in the iron-carbon ribbons.

22. The method of claim 15 , wherein the nitrogen source comprises at least one of ammonia, ammonium nitrate, urea, an amide, or hydrazine.

23. The method of claim 16 , further comprising, prior to exposing the iron-carbon powder to the reducing atmosphere, exposing the iron-carbon powder to an oxidizing atmosphere to form oxides in the iron-carbon powder, wherein exposing the iron-carbon powder to the reducing atmosphere removes at least some of the oxides and forms the nano-pores in the iron-carbon powder.

Assignees

• Univ Minnesota

Inventors

• Wang Jian-Ping
• Ma Bin
• Guo Guannan

Classifications

• C23C8/80

  After-treatment · CPC title

• C22C38/001

  containing N · CPC title

• H01F1/147

  Alloys characterised by their composition {(treatment thereof for enhancing their electromagnetic properties C21D8/12)} · CPC title

• B22D23/00 Primary

  Casting processes not provided for in groups B22D1/00 - B22D21/00 (making metallic powder by casting B22F9/08; alumino-thermic welding B23K23/00; remelting metals C22B9/16) · CPC title

• H01F1/065

  obtained by a reduction · CPC title