Provided are an anisotropic rare earth sintered magnet having a ThMn.sub.12-type crystal compound as a main phase and exhibits good magnetic characteristics, and a method for producing it. The anisotropic rare earth sintered magnet has a composition of a formula (R.sub.1-aZr.sub.a).sub.v(Fe.sub.1-bCo.sub.b).sub.100-v-w-x-y(M.sup.1.sub.1-cM.sup.2.sub.c).sub.wO.sub.xC.sub.y (where R is one or more kinds selected from rare earth elements and indispensably includes Sm, M.sup.1 is one or more kinds of elements selected from the group consisting of V, Cr, Mn, Ni, Cu, Zn, Ga, Al, and Si, M.sup.2 is one or more kinds of elements selected from the group consisting of Ti, Nb, Mo, Hf, Ta, and W, and v, w, x, y, a, b, and c each satisfy 7≤v≤15 at %, 4≤w≤20 at %, 0.2≤x≤4 at %, 0.2≤y≤2 at %, 0≤a≤0.2, 0≤b≤0.5, and 0≤c≤0.9), which contains a main phase of a ThMn.sub.12-type crystal compound in an amount of 80% by volume or more with the average crystal particle diameter of the main phase being 1 μm or more, which contains an R oxycarbide in the grain boundary area, and which has a density of 7.3 g/cm.sup.3 or more. The production method for the anisotropic rare earth sintered magnet includes grinding an alloy that contains a ThMn.sub.12-type crystal compound phase but does not contain an oxycarbide, then molding it in a mode of pressure powder molding with magnetic field application thereto to give a molded article, and thereafter sintering it at a temperature of 800° C. or higher and 1400° C. or lower to form an oxycarbide in the grain boundary area.

A dual-rotor machine comprising a dual rotor support structure rotatably connected to a frame. A stationary stator is disposed between the rotors and is fixed to the frame. An inner rotor and outer rotor, each comprising a permanent magnet Halbach array, are coaxially disposed with the stator and are rotable about the stator. In this configuration, the inner rotor channels its magnetic flux to its outside, while the outer rotor channels its magnetic flux to its inside. The magnetic flux density at the stator for the dual-rotor machine can be as high as 2 Tesla or higher for high-grade neodymium-iron-boron permanent magnet material, and the stored magnetic energy for conversion to mechanical or electrical energy available to the stator may be at least 0.5 kJ/m. The rotor Halbach arrays may comprise monolithic permanent magnets with continuously variable magnetic field direction.

The disclosure refers to a method for preparing NdFeB magnets including at least one of Ce and La. The method includes:

S1) Separately preparing flakes of alloy R1 and flakes of alloy R2 each by a strip casting process, wherein the alloy R1 includes at least one of La and Ce, but the alloy R2 does not include La and Ce;
S2) separately subjecting the flakes of alloy R1 and R2 to a hydrogen embrittlement process followed by pulverizing the process product to alloy powders by jet milling, wherein a ratio of the average particle sizes D50 of the powder of alloy R1 and R2 satisfied formula:

0.32≤R2/R1≤0.66;

S3) mixing the powder of alloy R1 and R2; and
S4) subjecting the mixed powders to molding and magnetic field orientation, cold isostatic pressing, sintering, and an annealing process.

A compression-molding method for a permanent includes: providing a drive coil to generate an electromagnetic force when a transient current is passed into the drive coil, so as to apply a molding compression force to magnetic powder under compression, and providing an orientation coil to generate an orientation magnetic field when a transient current is passed into the orientation coil, thereby providing the magnetic powder under compression with an anisotropic property; and synchronously passing the transient currents to the drive coil and the orientation coil to synchronously generate the electromagnetic force and the orientation magnetic field, thereby completing compression-molding of the permanent magnet, wherein a magnitude of the electromagnetic force and an intensity of the orientation magnetic field are respectively changed by changing peak values of the transient currents.

The present invention discloses a method for preparing high-performance anisotropic rare-earth-free permanent magnets, comprising the steps of: forming alloy ingots by melting according to a nominal composition of Mn.sub.xBi.sub.100-x, (45≤×≤55); then coarsely crushing the alloy ingots and passing the crushed material through a 100-mesh sieve to obtain coarse powder; putting an appropriate amount of Mn.sub.xBi.sub.100-x alloy coarse powder obtained into a ball-milling tank together with non-magnetic steel balls, with a ratio of ball to powder of 10:1; adding an appropriate amount of ethanol as solvent, and then adding a non-ionic surfactant polyvinylpyrrolidone (PVP) accounting for 5-15% of the power mass to assist in low-energy ball milling; washing the slurry obtained in anhydrous ethyl alcohol, and orientating and curing the washed magnetic powder in a magnetic field after adding binder to obtain high-performance anisotropic Mn—Bi alloy magnets finally.

Provided is a rare earth magnet alloy having a tetragonal R.sub.2Fe.sub.14B crystal structure, including: a main phase containing, as main constituent elements, at least one kind selected from the group consisting of: Nd; La; and Sm, Fe, and B; and a sub-phase containing, as main constituent elements, at least one kind selected from the group consisting of: Nd; La; and Sm, and O, wherein La substitutes for at least one of a Nd(f) site or a Nd(g) site, wherein Sm substitutes for at least one of a Nd(f) site or a Nd(g) site, wherein La segregates in the sub-phase, and wherein Sm is dispersed in the main phase and the sub-phase without segregation.

Methods described herein can include drawing materials to form a drawn filled tubing (DFT) wire. The materials can include a core material, a first layer of a biocompatible material disposed exterior to the filler material, a magnetic material disposed external to the first layer of biocompatible material, and a second layer of biocompatible material disposed exterior to the magnetic material. In some embodiments, the method further comprises melting the core material to form a magnet with a through hole lumen. In some embodiments, the method can further include applying an external magnetic field to the materials during the drawing to align grains of the magnetic material. In some embodiments, the core material can have a melting point lower than a melting point of the magnetic material and the biocompatible material.

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.

A high-Cu and high-Al neodymium iron boron magnet and a preparation method therefor. The high-Cu and high-Al neodymium iron boron magnet comprises: 29.5-33.5% R, over 0.985% B, over 0.50% Al, over 0.35% Cu, over 1% RH, and 0.1-0.4% high-melting-point elements N and Fe, wherein the percentages are the mass percentages of the elements in the total amount of elements, and the mass percentages of the element contents must satisfy the following relationships: (1) 1<RH<0.11R<3.54B; and (2) 0.12RH<Al. By means of combining Al, RH and high-melting-point metal elements that are added at a certain ratio, the problem in which the strength of a high-Cu magnet is insufficient is effectively solved, while the magnetic performance is the magnet material is ensured.

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.