Techniques are disclosed for milling an iron-containing raw material in the presence of a nitrogen source to generate anisotropically shaped particles that include iron nitride and have an aspect ratio of at least 1.4. Techniques for nitridizing an anisotropic particle including iron, and annealing an anisotropic particle including iron nitride to form at least one a″-Fe16N2 phase domain within the anisotropic particle including iron nitride also are disclosed. In addition, techniques for aligning and joining anisotropic particles to form a bulk material including iron nitride, such as a bulk permanent magnet including at least one a″-Fe16N2 phase domain, are described. Milling apparatuses utilizing elongated bars, an electric field, and a magnetic field also are disclosed.

Provided is an anisotropic magnetic powder having a low oxygen concentration, a small average particle size, a narrow particle size distribution, and a high remanence, and a method for producing the anisotropic magnetic powder. The present disclosure relates to a method for producing an anisotropic magnetic powder, including: pretreating an oxide containing Sm and Fe by heat-treating the oxide in a reducing gas atmosphere to obtain a partial oxide; heat-treating the partial oxide in the presence of a reducing agent to obtain alloy particles; nitriding the alloy particles to obtain a nitride; and treating the nitride with an alkali to obtain a magnetic powder.

A production method of a Fe.sub.16N.sub.2 based permanent magnet includes the following steps: 1) obtaining a Fe.sub.16N.sub.2 compound in a form of micro flakes by applying a nitriding process to α′-Fe powders of micro or nano sizes; 2) forming a structure by combining a polymer material with the Fe.sub.16N.sub.2 compound and utilizing a 3D printer; and 3) applying a magnetization process to the structure obtained in step 2 to obtain a magnetized structure and carrying out a heat treatment process to the magnetized structure to obtain the Fe.sub.16N.sub.2 based permanent magnet. The production method is continuous, less difficult, and less costly compared to the production of previous permanent magnets.

Techniques are disclosed for milling an iron-containing raw material in the presence of a nitrogen source to generate anisotropically shaped particles that include iron nitride and have an aspect ratio of at least 1.4. Techniques for nitridizing an anisotropic particle including iron, and annealing an anisotropic particle including iron nitride to form at least one α″-Fe.sub.16N.sub.2 phase domain within the anisotropic particle including iron nitride also are disclosed. In addition, techniques for aligning and joining anisotropic particles to form a bulk material including iron nitride, such as a bulk permanent magnet including at least one α″-Fe.sub.16N.sub.2 phase domain, are described. Milling apparatuses utilizing elongated bars, an electric field, and a magnetic field also are disclosed.

A sintered magnet contains Sm—Fe—N-based crystal grains and has high coercivity; and a magnetic powder is capable of forming a sintered magnet without lowering the coercivity even if heat is generated in association with the sintering. A sintered magnet comprises a crystal phase composed of a plurality of Sm—Fe—N-based crystal grains and a nonmagnetic metal phase present between the Sm—Fe—N crystal grains adjacent to each other, wherein a ratio of Fe peak intensity I.sub.Fe to SmFeN peak intensity I.sub.SmFeN measured by an X-ray diffraction method is 0.2 or less. A magnetic powder comprises Sm—Fe—N-based crystal particles and a nonmagnetic metal layer covering surfaces of the Sm—Fe—N crystal particles.

A method may include wet ball milling a plurality of iron nitride nanoparticles in the presence of a surface active agent to modify a surface of the plurality of iron nitride nanoparticles and form a plurality of surface-modified iron nitride nanoparticles for a variety of biomedical applications and soft magnetic materials related applications.

A novel ferromagnetic phase of manganese-bismuth alloy has an NiAs-type unit cell structure, similar to that of Low Temperature Phase manganese-bismuth, but with manganese atoms populating interstitial sites. The novel phase, termed β-MnBi, possesses maximum magnetic coercivity at unusually high temperature. A method for forming β-MnBi includes annealing MnBi nanoparticles, for example by hot compaction, at temperature lower than 175° C.

The disclosure describes techniques for forming nanoparticles including Fe.sub.16N.sub.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.sub.16N.sub.2, Fe.sub.16(NB).sub.2, Fe.sub.16(NC).sub.2, or Fe.sub.16(NCB).sub.2.

The disclosure describes techniques for forming nanoparticles including Fe.sub.16N.sub.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 nano particle 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.sub.16N.sub.2, Fe.sub.16(NB).sub.2, Fe.sub.16(NC).sub.2, or Fe.sub.16(NCB).sub.2.

Provided are: a novel magnetic material having high magnetic stability, in particular, having an extremely high saturation magnetization; and a method for producing the same, wherein the magnetic material, due to having a higher saturation magnetization than ferrite magnetic materials and a higher electrical resistivity than existing metallic magnetic materials, resolves problems such as eddy current loss. According to the present invention, Co-ferrite nanoparticles obtained by wet synthesis are reduced in hydrogen and subjected to grain growth, and bcc- or fcc-(Fe, Co) phases and Co-enriched phases are nano-dispersed using phase separation via a disproportionation reaction to prepare a magnetic material powder. In addition, the magnetic material powder is sintered into a solid magnetic material.