A rare earth sintered magnet according to the present disclosure includes: a main phase satisfying general formula (Nd, La, Sm)—Fe—B and including crystal grains based on R.sub.2Fe.sub.14B crystal structures; and a crystalline subphase based on an oxide phase represented by (Nd, La, Sm)—O. The subphase has a higher concentration of Sm than the main phase.

The present invention provides a manufacturing method for obtaining a compression-bonded magnet with which it is possible to achieve, at a high level, both a residual magnetic flux density (Br) and the magnitude of a reverse magnetic field (Hk) that reduces Br by 10%. The manufacturing method of the present invention includes a molding step of compressing a bonded magnet raw material composed of a compound or the like of magnetic powder and a binder resin in a heated and oriented magnetic field. The bonded magnet raw material has a mass ratio of the magnet powder of 90 to 95.7 mass% to a total of the magnet powder and the binder resin. The magnet powder includes coarse powder having an average particle diameter of 40 to 200 .Math.m and fine powder having an average particle diameter of 1 to 10 .Math.m. The coarse powder has a mass ratio of 60 to 90 mass% to a total of the coarse powder and the fine powder. The coarse powder includes rare earth anisotropic magnet powder subjected to hydrogen treatment. The binder resin includes a thermosetting resin. The molding step is carried out with a compressing force of 8 to 70 MPa and a heating temperature of 120° C. to 200° C.

Disclosed are a soft bistable magnetic actuator, a fabrication method thereof, a fatigue testing device, and an auto underwater vehicle. The method for fabricating the soft bistable magnetic actuator includes the following operations: casting a soft precursor by injection molding, wherein the soft precursor consists of a soft deformable portion and a soft peripheral portion surrounded, the soft deformable portion is made of magnetic particles and polymer, and the soft peripheral portion is made of a magnetic particle, a mixture of organic liquid, and polymer; and extracting the organic liquid by an organic solvent shrinks the soft peripheral portion, buckles the soft deformable portion towards one side.

To provide a rare earth magnet having excellent coercive force and a production method thereof. A rare earth magnet, wherein the rare earth magnet comprises a magnetic phase containing Sm, Fe, and N, a Zn phase present around the magnetic phase, and an intermediate phase present between the magnetic phase and the Zn phase, wherein the intermediate phase contains Zn and the oxygen content of the intermediate phase is higher than the oxygen content of the Zn phase; and a method for producing a rare earth magnet, including mixing a magnetic raw material powder having an oxygen content of 1.0 mass % or less and an improving agent powder containing metallic Zn and/or a Zn alloy, and heat-treating the mixed powder.

R—Fe—B sintered magnet has a main phase containing R.sub.2(Fe,(Co)).sub.14B intermetallic compound and a grain boundary phase. The inter-particle grain boundary includes an expanded width part that is surrounded by a narrow width part at which the inter-particle width is 10 nm or less and that has a structure distended in the inter-particle width direction as compared with the grain boundary width of the narrow width part; the inter-particle width at the expanded width part is at least 30 nm; Fe/R ratio in the expanded width part is 0.01-2.5; the main phase includes, in the surface part thereof, an HR-rich phase represented by (R′,HR).sub.2(Fe,(Co)).sub.14B (R′ represents rare-earth elements excluding Dy, Tb, and Ho, and that essentially include Nd; and HR represents Dy, Tb, and Ho); the contained amount of HR in the HR-rich phase is higher than that in the central part of the main phase.

A magnet manufacturing device includes a heater, a nozzle, a magnetic field application magnet and a stage. The heater heats a mixture of magnetic particles and a resin material. The nozzle has an internal flow passage that conducts the mixture while the resin material is molten. The nozzle has a discharge port which discharges the mixture and thereby forms each of a plurality of filaments. The magnetic field application magnet applies a magnetic field to the internal flow passage. The stage has a stage surface on which the plurality of filaments are placed. The discharge port is relatively movable with respect to the stage surface such that the plurality of filaments are stacked to form an arbitrary shape.

A method for continuous manufacture of permanent magnets. A material sheet is formed into an open tube, having a lengthwise opening. Magnetic powder may be poured into the lengthwise opening on a continuous basis. The tube opening is then formed closed and sealed. The magnetic powder is magnetically pre-aligned by subjecting it to a first magnetic field. The tube containing the powder may be compressed into a desired shape, forming an elongated permanent magnet. After compression, the elongated magnet is magnetized by a second magnetic field in two-step process, wherein the elongated permanent magnet is subjected to a magnetic field from first magnetizing coil that is pulsed with a first electric current in a first direction, followed by a second magnetizing coil being pulsed with a second magnetizing electric current in a second direction. The elongated magnet may be formed into any arbitrary shape, such as a ring or coil.

A method is provided in which a lower box comprising a base, walls that surround the base and an open side, and an upper box comprising a cover, walls that surround the cover and an open side are provided. One or more objects are arranged on the base of the lower box. The object(s) are covered with the upper box such that the open side of the upper is oriented towards the base of the box, the walls of the upper box are arranged on the base of the lower box and a gap is formed between the walls of the upper box and the walls of the lower box. A powder material is introduced into the gap in order to form an assembly having an interior. The powder material provides a mechanical obstacle to gas exchange between the interior and the environment. This assembly is then heat treated.

A method for producing a powdered starting material, which is provided for production of rare earth magnets, including includes the following steps: pulverizing an alloy, including at least one rare earth metal, wherein a powdered intermediate product is formed from the alloy including the at least one rare earth metal, and carrying out at least one classification aimed at particle size and/or particle density for the powdered intermediate product. A fraction of the powdered intermediate product, which is formed by the at least one classification, is used for fabrication of rare earth magnets. Furthermore, at least one dynamic classifier is provided, implementing at least one classification directed at particle size and/or particle density for the powdered intermediate product and thereby separates the fraction from the powdered intermediate product, which forms the starting material for manufacturing rare earth magnets.

A rare earth magnet includes a main phase and a particle boundary phase and in which an overall composition is represented by a formula, (R.sup.2.sub.(1-x)R.sup.1.sub.x).sub.yFe.sub.(100-y-w-z-v)Co.sub.wB.sub.zM.sup.1.sub.v.(R.sup.3.sub.(1-p)M.sup.2.sub.p).sub.q.(R.sup.4.sub.(1-s)M.sup.3.sub.s).sub.t, where R.sup.1 is a light rare earth element, R.sup.2 and R.sup.3 are a medium rare earth element, R.sup.4 is a heavy rare earth element, M.sup.1, M.sup.2, M.sup.3 are a predetermined metal element. The main phase includes a core portion, a first shell portion, and a second shell portion. The content proportion of medium rare earth element is higher in the first shell portion than in the core portion, the content proportion of medium rare earth element is lower in the second shell portion than in the first shell portion. The second shell portion contains heavy rare earth elements.