Multilayer iron nitride hard magnetic materials

Patent metadata

Field	Value
Publication number	US-10573439-B2
Application number	US-201515501697-A
Country	US
Kind code	B2
Filing date	Aug 5, 2015
Priority date	Aug 8, 2014
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

The disclosure describes multilayer hard magnetic materials including at least one layer including α″-Fe 16 N 2 and at least one layer including α″-Fe 16 (N x Z 1-x ) 2 or a mixture of α″-Fe 16 N 2 and α″-Fe 16 Z 2 , where Z includes at least one of C, B, or O, and x is a number greater than zero and less than one. The disclosure also describes techniques for forming multilayer hard magnetic materials including at least one layer including α″-Fe 16 N 2 and at least one layer including α″-Fe 16 (N x Z 1-x ) 2 or a mixture of α″-Fe 16 N 2 and α″-Fe 16 Z 2 using chemical vapor deposition or liquid phase epitaxy.

First claim

What is claimed is:

1. An article comprising a hard magnetic material, the hard magnetic material comprising:
a first set of layers, each layer of the first set of layers comprising α″-Fe 16 N 2 ; and
a second set of layers, each layer of the second set of layers comprising at least one of:
a mixture of α″-Fe 16 N 2 and α″-Fe 16 Z 2 , wherein Z comprises at least one of C, B, or O; or
α″-Fe 16 (N x Z 1-x ) 2 , wherein Z comprises at least one of C, B, or O, wherein x is a number greater than 0 and less than one, and wherein one or more respective layers of the first set of layers alternate with one or more respective layers of the second set of layers.

2. The article of claim 1 , wherein at least one layer of the second set of layers comprises the mixture of α″-Fe 16 N 2 and α″-Fe 16 Z 2 , and wherein the ratio of α″-Fe 16 N 2 to α″-Fe 16 Z 2 in the at least one layer of the second set of layers is about 1:1 or is about 4.667:5.333.

3. The article of claim 1 , wherein at least one layer of the second set of layers comprises α″-Fe 16 (N x Z 1-x ) 2 , and wherein x is equal to about 0.5 or is equal to about 0.4667.

4. The article of claim 1 , wherein the one or more respective layers of the second set of layers are magnetically coupled to the one or more respective layers of the first set of layers by exchange spring coupling.

5. The article of claim 1 , further comprising at least one of a ferromagnetic dopant, a nonmagnetic dopant, or a phase stabilizer.

6. The article of claim 1 , wherein at least one layer of the first set of layers further comprises at least one domain comprising a soft magnetic material, and wherein the α″-Fe 16 N 2 in the at least one layer of the first set of layers is magnetically coupled to the at least one domain comprising a soft magnetic material.

7. The article of claim 1 , wherein the article is an electric motor, a generator, a sensor, an actuator, a component of an automotive vehicle or a component of a wind turbine.

8. A method of forming the article of claim 1 comprising:
heating an iron source to form a vapor comprising an iron-containing compound;
depositing iron from the vapor comprising the iron-containing compound and nitrogen from a vapor comprising a nitrogen-containing compound over a substrate to form a first layer comprising iron and nitrogen;
depositing iron from the vapor comprising the iron-containing compound, nitrogen from the vapor comprising nitrogen-containing compound, and at least one of carbon, boron, or oxygen from a vapor comprising the at least one of carbon, boron, or oxygen over the substrate to form a second layer comprising iron, nitrogen, and the at least one of carbon, boron, or oxygen; and
annealing the first layer to form at least some crystals comprising α″-Fe 16 N 2 and the second layer to form at least some crystals comprising α″-Fe 16 (N x Z 1-x ) 2 or a mixture of α″-Fe 16 N 2 crystals and α″-Fe 16 Z 2 crystals, wherein Z comprises the at least one of carbon, boron, or oxygen, and wherein x is a number greater than zero and less than one.

9. The method of claim 8 , wherein the first layer is formed on the substrate and the second layer is formed on the first layer.

10. The method of claim 8 , wherein the second layer is formed on the substrate and the first layer is formed on the second layer.

11. The method of claim 8 , wherein the iron source comprises solid iron, and wherein the solid iron comprises at least one of iron powder or an iron thin film.

12. The method of claim 8 , wherein iron source comprises a solid iron precursor, and wherein the solid iron precursor comprises at least one of Fe 2 O 3 powder or Fe 2 O 4 powder.

13. The method of claim 8 , wherein the iron source comprises a liquid iron precursor, and wherein the liquid iron precursor comprises at least one of FeC 1 3 or Fe(CO) 5 .

14. The method of claim 8 , wherein the vapor comprising the nitrogen-containing compound is formed by at least heating urea to form a vapor including urea.

15. The method of claim 8 , wherein the vapor comprising the nitrogen-containing compound is formed by at least heating at least one of an amide or hydrazine to form the vapor comprising the nitrogen-containing compound.

16. The method of claim 8 , wherein the vapor comprising the nitrogen-containing compound comprises NH 3 vapor.

17. The method of claim 8 , wherein the vapor comprising the nitrogen-containing compound comprises atomic nitrogen formed from diatomic nitrogen using a plasma.

18. The method of claim 8 , wherein providing the vapor comprising the at least one of carbon, boron, or oxygen comprises heating a solid source of carbon comprising at least one of pure carbon or urea to form a vapor comprising carbon.

19. The method of claim 8 , wherein the vapor comprising the at least one of carbon, boron, or oxygen comprises a vapor comprising at least one of carbon monoxide, carbon dioxide, or methane.

20. The method of claim 8 , further comprising heating the vapor comprising the iron-containing compound and the vapor comprising the nitrogen-containing compound to decompose the vapor comprising the iron-containing compound and the vapor comprising the nitrogen-containing compound to form atomic nitrogen and atomic iron, which deposit on the substrate in the first layer.

21. The method of claim 8 , further comprising heating the substrate above a decomposition temperature of at least one of the vapor comprising the iron-containing compound and the vapor comprising the nitrogen-containing compound such that atomic nitrogen and atomic iron deposit on the substrate in the first layer.

22. The method of claim 8 , further comprising heating the vapor comprising the iron-containing compound, the vapor comprising the nitrogen-containing compound, and the vapor comprising the at least one of carbon, boron, or oxygen to decompose the vapor comprising the iron-containing compound, the vapor comprising the nitrogen-containing compound, and the vapor comprising the at least one of carbon, boron, or oxygen to form atomic nitrogen, atomic iron, and atoms of the at least one of carbon, boron, or oxygen, which deposit on the substrate in the second layer.

23. The method of claim 8 , further comprising heating the substrate above a decomposition temperature of at least one of the vapor comprising the iron-containing compound, the vapor comprising the nitrogen-containing compound, and the vapor comprising the at least one of carbon, boron, or oxygen such that atomic nitrogen, atomic iron, and atoms of the at least one of carbon, boron, or oxygen deposit on the substrate in the second layer.

24. The method of claim 8 , wherein annealing the first layer and the second layer comprises heating the layer at a temperature between about 100° C. and about 300° C. for between about 5 hours and 80 hours.

25. A method of forming the article of claim 1 comprising:
submerging a substrate in a first coating solution comprising a nitrogen-containing solvent and an iron source, wherein the first coating solution is saturated with the iron source at a first temperature above a liquidus temperature of an iron-nitrogen mixture to be deposited from the first coating solution;
cooling the first coating solution to a second temperature to form a supersaturated first coating solution, wherein the second temperature is below the liquidus temperature of the iron-nitrogen mixture;
maintaining the substrate in the supe

Assignees

• Univ Minnesota

Inventors

• Wang Jian-Ping
• Jiang Yanfeng

Classifications

• H01F1/059 Primary

  and Va elements, e.g. Sm2Fe17N2 · CPC title

• C30B29/38

  Nitrides · CPC title

• H02K1/02

  characterised by the magnetic material · CPC title

• C30B19/00

  Liquid-phase epitaxial-layer growth · CPC title

• C30B25/00

  Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth · CPC title