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.

A hybrid rotor assembly is provided. The assembly utilizes two different types of magnets within the lamination cavities of the lamination stack: sintered permanent magnets and bonded magnets.

Magnets having various portions of different densities and resistivities are disclosed. In a refinement, the various portions may have the same composition but different physical structures. Unique dies may be used to during processing, such as during sintering to manufacture the magnets. The die may include conductive and non-conductive surfaces that contact the green magnetic powder mixture during sintering such that the electrical current applied to the magnetic powder mixture is managed by the conductive and non-conductive surfaces to provide unique and complex magnets. Methods of manufacturing the magnets with the dies such as field assisted sintering, i.e., spark plasma sintering, are also disclosed.

A permanent magnet of the embodiment includes: a composition represented by a composition formula: R(Fe.sub.pM.sub.qCu.sub.rC.sub.tCo.sub.1-p-q-r-t).sub.z (R is at least one element selected from rare-earth elements, M is at least one element selected from Ti, Zr and Hf, 0.27p0.45, 0.01q0.05, 0.01r0.1, 0.002t0.03, and 6z9); and a metallic structure including a main phase containing a Th.sub.2Zn.sub.17 crystal phase, and a sub phase of the element M having an element M concentration of 30 atomic % or more. The sub phase of the element M precipitates in the metallic structure. A ratio of a circumferential length to a precipitated area of the sub phase of the element M is 1 or more and 10 or less.

A method for manufacturing a raw magnet includes manufacturing a first raw form from a first magnetic base material; manufacturing a second raw form from a second magnetic base material; applying an external magnetic field to at least one raw form selected from a group consisting of the first raw form and the second raw form during and/or after manufacturing of the raw form. Wherein a third raw form is manufactured from the first raw form and the second raw form by joining them together. A separating layer is provided between a first connection surface of the first raw form and a second connection surface of the second raw form. The third raw form is sintered.

A method for producing a raw material powder of a permanent magnet, includes: preparing a material powder of a permanent magnet, measuring magnetic characteristics of the material powder, and judging the quality of the material powder as the raw material powder based on a preliminarily determined relation between magnetic characteristics and the structure of the material powder. A method for producing a permanent magnet includes integrating material powders judged as good in the step of judging the quality as raw material powders by the method for producing a raw material powder of a permanent magnet. A method for inspecting a permanent magnet material powder includes transmitting a magnetic field to a material powder of a permanent magnet, receiving the magnetic field from the material powder, and measuring a magnetic field difference between the transmitted magnetic field and the received magnetic field as magnetic characteristics of the material powder.

A rare earth permanent magnet includes a main phase composed of a main phase particle and a grain boundary present among a plurality of the main phase particles. The grain boundary includes a region whose electric resistance is higher than that of the main phase.

A sinterable magnetic powder composition including: from 50 to 95% of a powder magnet; and from 5 to 50% by weight of at least one thermoplastic polymer; for the total weight of the composition, said powder composition having a D50 comprised within the range of 0.1 to 100 m. And, to the use of the composition in processes used to agglomerate powders, layer by layer, by melting or sintering, for manufacturing three-dimensional magnetic objects.

A sintered magnet, the sintered magnet including a core portion, a shell portion arranged at an outer part of the sintered magnet, and a diffusion portion arranged at least partially between the core portion and the shell portion. The shell portion has a coercivity, which is at least 30 kA/m larger than the coercivity of the core portion. In the diffusion portion, the coercivity is not less than the coercivity of the core portion and not larger than the coercivity of the shell portion and the value of the coercivity gradually increases from the core portion towards the shell portion. The thickness of the core portion is not less than 1 mm and the total thickness of the shell portion and the diffusion portion is at least 5 mm.

To provide a production method capable of enhancing the magnetic properties, particularly, the coercive force, of a SmFeN-based rare earth magnet and a production apparatus used therefor.

A method for producing a rare earth magnet, comprising mixing a magnetic raw material powder containing Sm, Fe and N with a modifier powder containing metallic Zn to obtain a mixed powder, filling the mixed powder into a molding die to obtain a filled product, melting at least a part of the modifier powder in the filled product while applying a pressure of 20 MPa or less to the filled product or without applying a pressure to obtain an intermediate molded product, and subjecting the intermediate molded product to liquid phase sintering at a pressure of 20 MPa or more to obtain a sintered body; and a production apparatus used therefor.