A bulk permanent magnetic material may include between about 5 volume percent and about 40 volume percent Fe.sub.16N.sub.2 phase domains, a plurality of nonmagnetic atoms or molecules forming domain wall pinning sites, and a balance soft magnetic material, wherein at least some of the soft magnetic material is magnetically coupled to the Fe.sub.16N.sub.2 phase domains via exchange spring coupling. In some examples, a bulk permanent magnetic material may be formed by implanting N+ ions in an iron workpiece using ion implantation to form an iron nitride workpiece, pre-annealing the iron nitride workpiece to attach the iron nitride workpiece to a substrate, and post-annealing the iron nitride workpiece to form Fe.sub.16N.sub.2 phase domains within the iron nitride workpiece.

This invention provides methods for fabricating a hard or soft magnet with tailorable magnetic and crystallographic orientations. Methods are disclosed to individually tailor three-dimensional voxels for selected crystallographic orientations and, independently, selected magnetic orientations with location specificity throughout a magnet. Some variations provide a method of making a magnet, comprising: providing a feedstock composition containing magnetic or magnetically susceptible materials; exposing the feedstock composition to an energy source for melting, thereby generating a first melt layer; solidifying the first melt layer in the presence of an externally applied magnetic field, thereby generating a magnetic metal layer containing a plurality of individual voxels; optionally repeating to generate a plurality of solid layers; and recovering a magnet comprising the magnetic metal layer(s), wherein the externally applied magnetic field has a magnetic-field orientation that is selected to control a magnetic axis and a crystallographic texture within the magnetic metal layer(s).

The present invention is a method for producing a rare earth magnet, including preparing a magnetic powder and a modifier powder, mixing them to obtain a mixed powder, compression-molding the mixed powder in a magnetic field to obtain a magnetic-field molded body, and pressure-sintering the magnetic-field molded body to obtain a sintered body, wherein the magnetic powder includes a first particle group and a second particle group, the D.sub.50 values of the first particle group and the second particle group are denoted by d.sub.1 μm and d.sub.2 μm, respectively, d.sub.1 and d.sub.2 satisfy the relationship of 0.350≤d.sub.2/d.sub.1≤0.500, and the ratio between the total volume of the first particle group and the total volume of the second particle group is from 9:1 to 4:1; and a rare earth magnet obtained by the production method.

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.

There is provided a manufacturing method for a rare earth magnet, including forming a zinc-containing coating film on a surface of a particle of a samarium-iron-nitrogen-based magnetic powder to obtain a coated powder, subjecting the coated powder to compression molding to obtain a compacted powder body, and subjecting the compacted powder body to pressure sintering, in which a coating rate of the coating film with respect to an entire surface of the particle of the coated powder is 96% or more, and the formation of the coating film and the pressure sintering of the compacted powder body is carried out in a vacuum or an inert gas atmosphere, and the compression molding of the coated powder is carried out in the atmospheric air.

A ferrite sintered body contains from 48.2% by mole to 49.7% by mole Fe in terms of Fe.sub.2O.sub.3, from 2.0% by mole to 8.0% by mole Cu in terms of CuO, from 12.0% by mole to 19.0% by mole Ni in terms of NiO, and from 28.5% by mole to 33.0% by mole Zn in terms of ZnO, in which when Fe, Cu, Ni, and Zn are converted to Fe.sub.2O.sub.3, CuO, NiO, and ZnO, respectively, and when the total amount of the Fe.sub.2O.sub.3, the CuO, the NiO, and the ZnO is 100 parts by weight, the ferrite sintered body contains from 5 ppm to 25 ppm B in terms of elemental B and 6 ppm to 25 ppm Nb in terms of elemental Nb.

Some variations provide a permanent-magnet structure comprising: a region having a plurality of magnetic domains and a region-average magnetic axis, wherein each of the magnetic domains has a domain magnetic axis that is substantially aligned with the region-average magnetic axis, and wherein the plurality of magnetic domains is characterized by an average magnetic domain size. Within the region, there is a plurality of metal-containing grains characterized by an average grain size, and each of the magnetic domains has a domain easy axis that is dictated by a crystallographic texture of the metal-containing grains. The region has a region-average easy axis based on the average value of the domain easy axis within that region. The region-average magnetic axis and the region-average easy axis form a region-average alignment angle that has a standard deviation less than 30° within the plurality of magnetic domains. Many permanent-magnet structures are disclosed herein.

Provided is a method of manufacturing a magnet capable of using only a single pole, whereby a combination force between a permanent (or referred to as a magnet) and a yoke (or referred to as a shielding metal) can be improved without performing a manual bonding work therebetween and then the efficiency of subsequent processes, such as polishing and plating, after combination and completeness of a product can be improved.

A sintered magnet body is held in a grounded jig exhibiting excellent electrical conductivity, a rare-earth-compound powder is charged and sprayed on the sintered magnet body to electrostatically coat the sintered magnet body with the powder, and thus apply the powder to the sintered magnet body. The sintered magnet body having the powder applied thereto is heat treated to produce a rare-earth magnet. As a result, the rare-earth-compound powder can be uniformly applied to the surface of the sintered magnet body, and the application operating can be performed extremely efficiently.

This invention provides for a rare-earth permanent magnet-forming sintered body obtained by integrally sintering magnet material particles containing a rare-earth substance while shaping the magnet material particles, a rare-earth permanent magnet obtained by magnetizing the sintered body, and a rotary machine in which the permanent magnet is embedded.