A two-step diffusion method for preparing high-performance dual-main-phase sintered mischmetal-iron-boron magnet belongs to the preparing technical field of rare earth permanent magnet materials. The compositions of the two main phase alloys are RE-Fe—B (RE is Nd or Pr) and (Nd, MM)-Fe—B (MM is mischmetal), respectively. First, PrHoFe strip-casting alloy is used as a diffusion source. Next, a PrHo-rich layer is uniformly coated on the surface of (Nd, MM)-Fe—B hydrogen decrepitation powders. The higher anisotropic fields of Pr.sub.2Fe.sub.14B and Ho.sub.2Fe.sub.14B are used to improve the coercivity. Then, the ZrCu strip-casting alloy is used as a diffusion source. A Zr-rich layer is uniformly coated on the surface of the powders after the first-step diffusion, which prevents the growth of the MM-rich main phase grains during the sintering process and the inter-diffusion between the two main phases, thus obtaining high coercivity.

A method of producing an oppositely magnetized magnetic structure within or on a substrate material includes: generating first and second numbers of cavities within or on a substrate material and filling the first and second numbers of cavities with first and second hard magnetic materials, respectively exhibiting first and second coercive field strengths, wherein the second coercive field strength is smaller than the first coercive field strength. The method further includes magnetizing, in a first direction, the first and second arrangements of magnetic structures, by a magnetic field having a field strength that exceeds the first and second coercive field strengths. The method further magnetizes the second arrangement of hard magnetic structures in a second direction, which differs from the first direction, by a second magnetic field having a field strength below the first coercive field strength but greater than the second coercive field strength.

A bonded magnet is provided which includes first and second components. The first and second components have first and second non-action surfaces, and first and second action surfaces that intersect the first and second non-action surfaces, respectively. First and second flux groups curve inside the first and second components from the first and second non-action surfaces to the first and second action surfaces, respectively. The areas of the first and second non-action surfaces are greater than the first and second action surfaces, respectively. The flux densities on the first and second action surfaces are higher than the first and second non-action surfaces, respectively. The pole on the first non-action surface is opposite to the second non-action surface. The first and second non-action surfaces are coupled to each other. The first flux groups continuously extend from one to another.

In one embodiment, a magnet includes a plurality of layers, each layer having a microstructure of sintered particles. The particles in at least one of the layers are characterized as having preferentially aligned magnetic orientations in a first direction.

Disclosed herein is a method and apparatus for forming pellets in a non-ambient environment such as a strong magnetic field. The apparatus includes a die body, a die bottom, a short push pin, a long push pin, a press tube, and an extended push pin. A powder is loaded into the die body, which is then positioned in the non-ambient environment, and the powder allowed to equilibrate. A pellet is then formed by pressing on the extended push pin while the powder is in the non-ambient environment.

A magnet structure includes columnar grains of rare earth permanent magnet phase aligned in a same direction and arranged to form bulk anisotropic rare earth alloy magnet having a boundary defined by opposite ends of the columnar grains and lacking triple junction regions, and rare earth alloy diffused onto opposite ends of the bulk anisotropic rare earth alloy magnet.

An R—Fe—B base sintered magnet is provided consisting essentially of R (which is at least two rare earth elements and essentially contains Nd and Pr), M.sub.1 which is at least two of Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb, and Bi, M.sub.2 which is at least one of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W, boron, and the balance of Fe, and containing an intermetallic compound R.sub.2(Fe,(Co)).sub.14B as a main phase. The magnet contains an R—Fe(Co)-M.sub.1 phase as a grain boundary phase, the R—Fe(Co)-M.sub.1 phase contains A phase which is crystalline with crystallites of at least 10 nm formed at grain boundary triple junctions, and B phase which is amorphous and/or nanocrystalline with crystallites of less than 10 nm formed at intergranular grain boundaries and optionally grain boundary triple junctions.

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).

A method for preparing a NdFeB permanent magnetic material may include providing a covered NdFeB magnetic powder by depositing heavy rare earth particles or high-melting particles onto a NdFeB magnetic powder by physical vapor deposition; and performing orientation molding and sintering on the covered NdFeB magnetic powder to provide the NdFeB permanent magnetic material.

A method includes depositing a layer of alloy particles including rare earth permanent magnet phase above a substrate, laser scanning the layer while cooling the substrate to melt the particles, selectively initiate crystal nucleation, and promote columnar grain growth in a same direction as an easy axis of the rare earth permanent magnet phase. The method also includes repeating the depositing and scanning to form bulk anisotropic rare earth alloy magnet with aligned columnar grains.