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.

According to the present invention, a method for manufacturing a rare earth magnet that is capable of manufacturing a high-performance rare earth magnet with stable quality in large amount by the grain boundary diffusion method utilizing a film formed by the physical vapor phase deposition method is provided.

According to the present invention, a method for manufacturing a rare earth magnet that is capable of manufacturing a high-performance rare earth magnet with stable quality in large amount by the grain boundary diffusion method utilizing a film formed by the physical vapor phase deposition method is provided.

Certain aspects of the technology disclosed herein include an apparatus and method for forming nanoparticles. The method includes a mechanical milling process induced by aerodynamic, centrifugal, and centripetal forces and further augmented by ultrasound, magnetic pulse, and high voltage impact. A nanoparticle mill having an atmospheric and luminance controlled environment can form precisely calibrated nanoparticles. A nanoparticle mill can include first aerodynamic vane configured to rotate around a central axis of the nanoparticle mill in a first direction, and a second aerodynamic vane configured to rotate around the central axis in a second direction. An aerodynamic shape of an aerodynamic vane can be configured to cause particles within the nanoparticle mill to flow around the aerodynamic vane. The nanoparticle mill can include a primary product line, a nanoparticle sampling line, a particle programming array, a solidifying chamber, or any combination thereof.

Certain aspects of the technology disclosed herein include an apparatus and method for forming nanoparticles. The method includes a mechanical milling process induced by aerodynamic, centrifugal, and centripetal forces and further augmented by ultrasound, magnetic pulse, and high voltage impact. A nanoparticle mill having an atmospheric and luminance controlled environment can form precisely calibrated nanoparticles. A nanoparticle mill can include first aerodynamic vane configured to rotate around a central axis of the nanoparticle mill in a first direction, and a second aerodynamic vane configured to rotate around the central axis in a second direction. An aerodynamic shape of an aerodynamic vane can be configured to cause particles within the nanoparticle mill to flow around the aerodynamic vane. The nanoparticle mill can include a primary product line, a nanoparticle sampling line, a particle programming array, a solidifying chamber, or any combination thereof.

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.

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.

A method for densifying a material includes arranging the material in a cavity of a mold and applying pressure to the material in the mold. While applying pressure to the material in the mold, a magnetic field is applied to the material in the mold to cause the material to transform between a first allotrope phase and a second allotrope phase. Applying the magnetic field to the material includes magnetic cycling, which includes one or more iterations of adjusting the magnetic field to a first strength, and then adjusting the magnetic field to a second strength. The method includes determining a density of the material during the magnetic cycling and, responsive to determination that the determined density reaches a threshold density, stopping the magnetic cycling.

A method for densifying a material includes arranging the material in a cavity of a mold and applying pressure to the material in the mold. While applying pressure to the material in the mold, a magnetic field is applied to the material in the mold to cause the material to transform between a first allotrope phase and a second allotrope phase. Applying the magnetic field to the material includes magnetic cycling, which includes one or more iterations of adjusting the magnetic field to a first strength, and then adjusting the magnetic field to a second strength. The method includes determining a density of the material during the magnetic cycling and, responsive to determination that the determined density reaches a threshold density, stopping the magnetic cycling.

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.