IRON NITRIDE MAGNETIC MATERIAL INCLUDING COATED NANOPARTICLES
The disclosure describes techniques for forming nanoparticles including Fe 16 N 2 phase. In some examples, the nanoparticles may be formed by first forming nanoparticles including iron, nitrogen, and at least one of carbon or boron. The carbon or boron may be incorporated into the nanoparticles such that the iron, nitrogen, and at least one of carbon or boron are mixed. Alternatively, the at least one of carbon or boron may be coated on a surface of a nanoparticle including iron and nitrogen. The nanoparticle including iron, nitrogen, and at least one of carbon or boron then may be annealed to form at least one phase domain including at least one of Fe 16 N 2 , Fe 16 (NB) 2 , Fe 16 (NC) 2 , or Fe 16 (NCB) 2 .
1 . An iron nitride permanent magnet comprising:
a plurality of consolidated nanoparticles, wherein at least one of the plurality of consolidated nanoparticles comprises:
a core comprising at least one Fe 16 N 2 phase domain; and
a dopant comprising Cr.
2 . The permanent magnet of claim 1 , further comprising a coating of Cr.
3 . The permanent magnet of claim 1 , further comprising an Mn dopant.
4 . The permanent magnet of claim 2 , further comprising a coating of Mn.
5 . The permanent magnet of claim 1 , wherein the iron nitride permanent magnet material has a minimum dimension of at least 0.1 mm.
6 . The permanent magnetic material of claim 2 , wherein the coating defines a thickness between about 0.5 nanometers and about 50 nanometers, and wherein the nanoparticles comprises diameters between about 0.5 nm and about 200 nm.
7 . An iron nitride permanent magnet formed from a precursor comprising an iron nanoparticle and a Cr dopant.
8 . The iron nitride permanent magnet of claim 7 , further comprising an Mn dopant.