The present invention provides an apparatus and a method for coating small NdFeB magnets. The apparatus includes a furnace having a roller including at least one stirring piece disposed in the compartment. The stirring pieces have an isosceles triangle or trapezoidal shaped cross-section. The side wall of the furnace defines an inlet aperture and an outlet aperture disposed diametrically opposed to one another. A plurality of target source holders include two first target source holders and two second target source holders disposed on the side wall and spaced from one another and between the inlet aperture and the outlet aperture. The method includes a step of disposing a plurality of conductors with the small NdFeB magnets in the compartment of the roller. The small NdFeB magnets are mixed with the plurality of conductors in the roller with the roller being rotated of between 5 rpm and 20 rpm.

The present invention provides a NdFeB magnet including a first film of aluminum having a first predetermined hardness and an anti-corrosive coating of oxidized aluminum having a second predetermined hardness on the first film. The second predetermined hardness is at least eight times the first predetermined hardness. The present invention also provides a method for preparing a hard aluminum film on the NdFeB magnet. The method includes depositing the first film on the NdFeB magnet under vacuum, disposing the NdFeB magnet having the first film on the anode, and subjecting the NdFeB magnet having the first film to the anodic oxidation process under a solution containing an electrolyte present between 15 wt. % to 20 wt. % to form the anti-corrosive coating on the first film to prevent the NdFeB magnet from corroding. The electrolyte is selected from at least one of sulfuric acid, chromic acid, boric acid, and oxalic acid.

A method of improving coercivity of an NdFeB magnet includes a first step of providing an NdFeB magnet having a first surface and a second surface. Next, a first solidified film of at least one pure heavy rare earth element is formed and attached to the first surface of the NdFeB magnet to prevent a reduction in corrosion resistance caused by oxygen and fluorine and hydrogen. After forming the first solidified film, the NdFeB magnet is subjected a diffusion treatment in a vacuum or an inert atmosphere. After the diffusion treatment, the NdFeB magnet is subjected to an aging treatment in the vacuum or the inert atmosphere.

A magnetically levitated rotor includes a magnetically effective core and a sheathing made of a thermoplastically processible fluoropolymer. The sheathing completely encloses the magnetically effective core. The magnetically effective core comprises at least one permanent magnet and each permanent magnet has a metallic coating for protection against acidic or chemically aggressive substances. A plastic coating is disposed between the metallic coating and the sheathing, and includes a polymer belonging to the family of parylenes.

Provided is a rare earth magnet, on the surface of which a coating film of an ultraviolet cured resin is formed by covering the surface of the rare earth magnet with an ultraviolet curable resin composition and subsequently curing the ultraviolet curable resin composition by irradiating the ultraviolet curable resin composition with ultraviolet light. With respect to this rare earth magnet, the coating film is formed by a method which comprises: a step for having droplets of the ultraviolet curable resin composition adhere to the rare earth magnet surface by ejecting the droplets of the ultraviolet curable resin composition from a tip of a head by an inkjet method wherein droplets are ejected from a head; and a step for curing the ultraviolet curable resin composition by irradiating the ultraviolet curable resin composition adhering to the rare earth magnet surface with ultraviolet light.

An expandable sintered neodymium-iron-boron magnet, a preparation method, and an application are provided. The magnet has a sintered neodymium-iron-boron magnet and an expandable coating coated on the surface of the sintered neodymium-iron-boron magnet. The sintered neodymium-iron-boron magnet coated with the expandable coating is used to replace a conventional assembly method of an epoxy resin adhesive coating magnet and potting resin glue, so that the magnet coated with the expandable coating may be inserted into a magnetic steel groove. The irreversible expansion of the coating itself is used to fix the magnet in the magnetic steel groove. Meanwhile, the use of the expandable coating shortens the assembly time of motors and improves the assembly accuracy of the motors.

An object of the present invention is to provide a novel method for forming an electrolytic copper plating film having excellent adhesion on the surface of a rare earth metal-based permanent magnet. The method of the present invention as a means for achieving the object is characterized in that after a magnet is immersed in a plating solution, a cathode current density of 0.05 A/dm.sup.2 to 4.0 A/dm.sup.2 for performing an electrolytic copper plating treatment is applied thereto over 10 seconds to 180 seconds to start the treatment.

A method of manufacturing a magnetic material, includes a surface oxides decreasing step of decreasing surface oxides of an iron powder; a powder-molded body forming step of mixing the iron powder whose surface oxides are already decreased obtained by the surface oxides decreasing step, and a compound powder A constituted by a La element and a Si element, and compressing and molding the obtained mixture powder; and a sintered body forming step of preparing a sintered body from the powder-molded body obtained by the powder-molded body forming step, by a solid phase reaction under vacuum atmosphere.

An article exhibiting magnetic properties, a method for providing corrosion resistance to an article, and an electric machine element are disclosed. The article comprises a substrate comprising a first portion of a magnetic material, the magnetic material exhibiting magnetic properties. The article further comprises a transition layer comprising a second portion of the magnetic material and a first portion of a coating material. The transition layer is disposed on at least a portion of the substrate. The article further comprises an outer layer comprising a second portion of the coating material. The outer layer is disposed on at least a portion of the transition layer.

An RFeB sintered magnet, and a preparation method therefor and use thereof are provided. The surface of the RFeB sintered magnet has an oxide adhesive layer, and is obtained by means of the heat preservation and heat treatment of an RFeB magnet having a composite diffusion layer on the surface thereof. The heat treatment comprises alternately carrying out a low-temperature heat treatment at 750? C.-830? C. and a high-temperature heat treatment at 830? C.-970? C., and a neodymium iron boron green body having the oxide adhesive layer on the surface thereof is obtained. The grain boundary diffusion of the RFeB magnet is optimized, and the coercive force distribution of the magnet is improved. The RFeB sintered magnet can be used in the field of automobiles, wind power generation, household electric motors, medical apparatuses or mobile communication appliances.