Anisotropic iron nitride permanent magnets

1. A permanent magnet, comprising:

a plurality of aligned iron nitride nanoparticles wherein the iron nitride nanoparticles include α″-Fe 16 N 2 phase domains;

wherein a ratio of integrated intensities of an α″-Fe 16 N 2 (004) x-ray diffraction peak to an α″-Fe 16 N 2 (202) x-ray diffraction peak is greater than 0.19, where the diffraction vector is parallel to alignment direction, and

wherein the iron nitride nanoparticles exhibit a squareness measured parallel to the alignment direction that is greater than a squareness measured perpendicular to the alignment direction.

2. The permanent magnet of claim 1 , wherein the aligned nanoparticles are configured as a wire, a sheet, or a tape, and wherein the wire, sheet, or tape are bonded to provide the permanent magnet.

3. The permanent magnet of claim 1 , wherein a ratio of integrated intensities of an α″-Fe 16 N 2 (004) x-ray diffraction peak to an α″-Fe 16 N 2 (202) x-ray diffraction peak is greater than at least 50%.

4. The permanent magnet of claim 1 , wherein a ratio of integrated intensities of an α″-Fe 16 N 2 (004) x-ray diffraction peak to an α″-Fe 16 N 2 (202) x-ray diffraction peak is greater than at least 100%.

5. The permanent magnet of claim 1 , wherein the iron nitride nanoparticles exhibit a squareness measured parallel to the alignment direction that is greater than 0.50.

6. The permanent magnet of claim 1 , wherein the iron nitride nanoparticles exhibit a squareness measured parallel to the alignment direction that is greater than 0.75.

7. The permanent magnet of claim 1 , wherein the iron nitride nanoparticles exhibit a squareness measured parallel to the alignment direction that is greater than 0.9.

8. A nanocomposite, comprising:

a population of aligned anisotropic nanoparticles, the nanoparticles comprising an α″-Fe 16 N 2 phase; and

a binder,

wherein the nanocomposite exhibits a squareness measured in a parallel direction that is larger than a squareness observed in a perpendicular direction to the direction of alignment of the anisotropic nanoparticles, and

wherein the nanocomposite exhibits an X-ray diffraction pattern having an intensity of an α″-Fe 16 N 2 (004) peak that is greater than the intensity of an α″-Fe 16 N 2 (202) peak by 0.19 in a diffraction pattern, where the diffraction vector is parallel to the alignment direction.

9. The nanocomposite of claim 8 , wherein the binder comprises a polymeric material.

10. The nanocomposite of claim 9 , wherein the polymeric material comprises an epoxy, an acrylic, an acrylate, a bismaleimide, an ester, a urethane, a styrene, a polyvinyl alcohol, a polyvinyl acetate, a cellulose acetate, an ethyl cellulose, a polycarbonate, a polyester, a syndiotactic polystyrene, or a combination thereof.

11. The nanocomposite of claim 8 , wherein the weight fraction of the nanoparticles relative to the nanocomposite is in the range of from 80% to 95%.

12. The nanocomposite of claim 8 , wherein the weight fraction of the nanoparticles relative to the nanocomposite is in the range of from 85% to 95%.

13. The nanocomposite of claim 8 , wherein the weight fraction of the nanoparticles relative to the nanocomposite is in the range of from 90% to 95%.

14. The nanocomposite of claim 8 , wherein the volume fraction of the nanoparticles relative to the nanocomposite is in the range of from 40% to 75%.

15. The nanocomposite of claim 8 , wherein the volume fraction of the nanoparticles relative to the nanocomposite is in the range of from 50% to 75%.

16. The nanocomposite of claim 8 , wherein the volume fraction of the nanoparticles relative to the nanocomposite is in the range of from 60% to 75%.

17. A plurality of anisotropic iron nitride nanoparticles, the plurality of anisotropic iron nitride nanoparticles being characterized as having a saturation magnetization, MSat, >190 emu/g and coercivity, Hc, greater than 2,500 Oe;

wherein a ratio of integrated intensities of an α″-Fe 16 N 2 (004) x-ray diffraction peak to an α″-Fe 16 N 2 (202) x-ray diffraction peak is greater than 0.19.

18. The plurality of anisotropic iron nitride nanoparticles of claim 17 , wherein the plurality of anisotropic iron nitride nanoparticles are further characterized as having a uniform phase composition throughout, wherein the plurality of anisotropic iron nitride nanoparticles comprises a higher mass fraction of α″-Fe16N2 phase and a lower mass fraction of α-Fe and ε-Fe2-3N phases.

19. The plurality of anisotropic iron nitride nanoparticles of claim 18 , wherein the weight percent of the α″-Fe16N2 phase is at least 70%.

20. The plurality of anisotropic iron nitride nanoparticles of claim 17 , wherein the iron nitride nanoparticles are coated with one or more of carbon, boron, aluminum oxide, copper metal, or aluminum metal.

21. A permanent magnet, comprising a plurality of iron nitride nanoparticles, the permanent magnet being characterized as having a saturation magnetization, MSat, in the range of from about 12.5 kG to about 14 kG, wherein a ratio of integrated intensities of an α″-Fe 16 N 2 (004) x-ray diffraction peak to an α″-Fe 16 N 2 (202) x-ray diffraction peak is greater than 0.19.

22. The permanent magnet of claim 21 , wherein the iron nitride nanoparticles are magnetically aligned and bonded in a matrix.

23. The permanent magnet of claim 21 , wherein the nanoparticles are further characterized as having a uniform phase composition throughout, wherein the nanoparticles comprises a higher mass fraction of α″-Fe16N2 phase and a lower mass fraction of α-Fe and ε-Fe2-3N phases.

24. The permanent magnet of claim 23 , wherein the weight percent of the α″-Fe16N2 phase is at least 70%.

25. The permanent magnet of claim 21 , wherein the iron nitride nanoparticles are coated with one or more of carbon, boron, aluminum oxide, copper metal, or aluminum metal.

26. The permanent magnet of claim 21 , wherein at least a portion of the iron nitride nanoparticles are characterized as being deagglomerated discrete primary particles.