Abstract: The invention relates to a method of increasing the coercivity of a sintered type NdFeB permanent magnet. The method comprises the following steps: a) preparing of an organic film with a predetermined thickness on a surface of the sintered type NdFeB permanent magnet; b) creating holes in the organic film according to a given pattern with the holes extending to the surface of the sintered type NdFeB permanent magnet; c) filling the holes with a metal powder, the metal powder including or consisting of at least one of Dy and Tb; and d) performing a thermally induced grain boundary diffusion process.

Abstract: The disclosure refers to a NdFeB alloy powder for forming high-coercivity sintered NdFeB magnets. The NdFeB alloy powder includes NdFeB alloy core particles with a multi-layered coating, wherein the multi-layered coating comprises: a first metal layer directly disposed on the NdFeB alloy core particles, wherein the first metal layer consists of at least one of Tb and Dy; a second metal layer directly disposed on the first metal layer, wherein the second metal layer consists of at least one of W, Mo, Ti, Zr, and Nb; and a third metal layer directly disposed on the second metal layer, wherein the third metal layer consists of (i) at least one of Pr, Nd, La, and Ce; or (ii) a combination of one of the group consisting of Cu, Al, and Ga and at least one of the group consisting of Pr, Nd, La, and Ce.

Abstract: The disclosure provides a preparation method, which comprises: providing a moulding die for a ring-shaped sintered Nd—Fe—B magnet; placing a Nd—Fe—B magnetic powder into the mould cavity of the moulding die in a loosely packed state, the loosely packed height of the Nd—Fe—B magnetic powder is L; placing a flexible cylindrical core into the loosely packed Nd—Fe—B magnetic powder at a L/2 position, wherein an axial direction of the flexible cylindrical core is horizontal and parallel to the direction of a magnetic field in the mould cavity; applying a vertical pressure to the Nd—Fe—B magnetic powder to obtain a ring-shaped green block assembly with the flexible cylindrical core embedded; after encapsulating and isolating the ring-shaped green block assembly, applying an isostatic pressure to the ring-shaped green block assembly; sintering the ring-shaped green block assembly to obtain a ring-shaped sintered blank; thermally aging, grinding and slicing the ring-shaped sintered blank.

Abstract: The disclosure relates to a method for improving the coercivity of an arc-shaped Nd—Fe—B magnet. A method for increasing the coercivity of an arc-shaped Nd—Fe—B magnet is provided. Said method comprises the steps of: a) providing of a flexible film with a heavy rare earth coating thereon, wherein the heavy rare earth coating comprises at least one of Dy and Tb; b) arranging the arc-shaped Nd—Fe—B magnet and the flexible film such that a first curved surface of the arc-shaped Nd—Fe—B magnet and the heavy rare earth coating on the flexible film are facing each other; such that a curved surface of the first ceramic body lies on the side of the flexible film opposite the arc-shaped Nd—Fe—B magnet, then pressing the first ceramic body and the magnet together; and d) performing a thermally induced grain boundary diffusion process.

Abstract: A method of increasing coercivity of a sintered Nd—Fe—B permanent magnet includes a first step of providing a sintered Nd—Fe—B magnet block having a pair of block surfaces extending perpendicular to a magnetization direction. The method then proceeds with depositing an organic adhesive layer on one of the block surfaces. Next, the method proceeds with depositing a powder containing at least one heavy rare earth element on the organic adhesive layer. After depositing the powder, the sintered Nd—Fe—B magnet block is pressed to adhere the powder to the organic adhesive layer. Then, the method follows with a step of removing excess powder from the sintered Nd—Fe—B magnet block to form a uniform film. Then, the powder is diffused into the sintered Nd—Fe—B magnet is diffused into the sintered Nd—Fe—B magnet block to produce a diffused magnet block. Next, the method proceeds with aging the diffused magnet block.

Abstract: A method of increasing coercivity of an Nd—Fe—B sintered permanent magnet includes a step of providing an organic film. A powder, containing at least one heavy rare earth elements, is uniformly deposited on the organic film forming a diffusion source. Then, a sintered Nd—Fe—B magnet block having a pair of block surfaces extending perpendicular to a magnetization direction is provided. Next, the diffusion source is deposited on at least one of the block surfaces with the powder being in abutment relationship with at least one of the block surfaces. After depositing the diffusion source, the sintered Nd—Fe—B magnet block containing the diffusion source is pressed allowing the powder of the diffusion source to be in close contact with the block surface. The diffusion source is then diffused into the sintered Nd—Fe—B magnet block to produce a diffused magnet block. Next, the diffused magnet block is aged.

Abstract: A method of improving coercivity of an Nd—Fe—B magnet includes a first step of providing an Nd—Fe—B 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 Nd—Fe—B magnet to prevent a reduction in corrosion resistance caused by oxygen and fluorine and hydrogen. After forming the first solidified film, the Nd—Fe—B magnet is subjected a diffusion treatment in a vacuum or an inert atmosphere. After the diffusion treatment, the Nd—Fe—B magnet is subjected to an aging treatment in the vacuum or the inert atmosphere.

Abstract: A method of manufacturing a plurality of R—Fe—B sintered magnets using a plasma flame apparatus and a furnace. The method includes a first step of providing a sintered magnet block. Then, the sintered magnet block is machined to form machined magnets. The method continues with a step of cleaning surfaces of the machined magnets to form cleaned magnets. The method then proceeds with depositing a plurality of spherical droplets of a heavy rare earth powder selected from at least one of Dy or Tb on the surfaces of the cleaned magnets, to produce a plurality of magnets including a uniform film of Dy or Tb. Then, the magnets including the uniform film are sintered to diffuse the uniform film into the magnets through grain boundary phases of the magnets to produce the R—Fe—B sintered magnets. A plasma flame apparatus is also disclosed herein.

Abstract: A method of making a rare earth magnet containing zero heavy rare earth elements includes a step of mixing the fine grain powder with the lubricant having a weight content of at least 0.03 wt. % and no greater than 0.2 wt. % for a period of between 1 and 2 hours. The step of pulverizing is further defined as jet milling the alloy powder with the lubricant using a carrier gas of argon or nitrogen. The method further includes a step of controlling oxygen content during the steps of melting, forming, disintegrating, mixing, pulverizing, molding, and sintering whereby the impurities including Carbon (C), Oxygen (O), and Nitrogen (N) satisfies 1.2C+0.6O+N?2800 ppm. A rare earth magnet composition including C, O, and N whereby C, O, and N satisfies 1.2C+0.6O+N?2800 ppm and has zero heavy rare earth elements.

Abstract: A sintered Nd—Fe—B magnet comprising at least one light rare earth element having a weight content between 31 wt. % and 35 wt. %, at least one heavy rare earth element having a weight content of no more than 0.2 wt. %, B having a weight content between 0.95 wt. % and 1.2 wt. %, at least one additive including Ti and having a weight content between 1.31 wt. % and 7.2 wt. %, Fe as a balance, and impurities including C, O, and N. Ti has a weight content between 0.3 wt. % and 1 wt. % and forms a Titanium-Iron-Boron phase with Fe and Boron B and being present in the sintered Nd—Fe—B magnet between 0.86 vol. % and 2.85 vol. %. The C, O, and N satisfy 630 ppm?1.2C+0.6O+N?3680 ppm. The sintered Nd—Fe—B magnet has a squareness factor of at least 0.95.

Abstract: An apparatus for plating Nd—Fe—B magnet includes a cathode and a target source holder defining a predetermined distance of 5 mm to 200 mm therebetween. A pulse bias power supply having a first positive terminal connected to an anode and a first negative terminal connected to the cathode. A DC bias power supply having a second positive terminal connected to the anode and a second negative terminal connected to the target source holder. The anode is connected to the earth ground. A method for plating the Nd—Fe—B magnet includes steps of maintaining the predetermined distance of 5 mm to 200 mm between the cleaned Nd—Fe—B magnet and the target source material, increasing a first electric potential to the cathode and a second electric potential to the target source holder with the second electric potential greater than the first electric potential, and maintaining a potential differential of 0V to 500V therebetween.

Abstract: The present invention provides an apparatus and a method for coating small Nd—Fe—B 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 Nd—Fe—B magnets in the compartment of the roller. The small Nd—Fe—B magnets are mixed with the plurality of conductors in the roller with the roller being rotated of between 5 rpm and 20 rpm.

Abstract: The present invention provides a Nd—Fe—B 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 Nd—Fe—B magnet. The method includes depositing the first film on the Nd—Fe—B magnet under vacuum, disposing the Nd—Fe—B magnet having the first film on the anode, and subjecting the Nd—Fe—B 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 Nd—Fe—B magnet from corroding. The electrolyte is selected from at least one of sulfuric acid, chromic acid, boric acid, and oxalic acid.

Abstract: A method for bonding a plurality of Nd—Fe—B permanent magnets includes a step of curing the layer of insulating adhesive at an initial temperature of between 20° C. and 250° C. and between 0.1 hr and 24 hr prior to the step of sandwiching. A predetermined clamping pressure of between 0.1 MPa and 10 MPa is then applied to the Nd—Fe—B permanent magnets. The stacked Nd—Fe—B permanent magnet is cured at a predetermined temperature of between 150° C. and 350° C. and between 0.1 hr and 12 hr. A clamping tool apparatus includes at least one of three intermediate guides disposed on the lower plate, in the chamber, spaced from the magnet positioning members, and extends to a proximal end defining a second predetermined distance with the second predetermined distance being less than the first predetermined distance of the magnet positioning members. The upper plate defines a plurality of apertures for receiving the magnet positioning members and the intermediate guides.

Abstract: The present invention provides a method for depositing aluminum on a permanent Nd—Fe—B magnet including a step of cooling the chamber and the arc source by feeding a fluid of water at a cooling temperature of between 0° C. and 5° C. through the chamber and the arc source. The method also includes a step of adjusting a target source and a control magnet of the arc source in the chamber of the multi-arc ion plating apparatus to define a predetermined distance of between 1 cm and 10 cm. The step of depositing the film of aluminum further including steps of applying a current of between 50 A and 70 A and an electrical potential of between 100V and 200V to the target source of aluminum and directing the ions of aluminum using the arc source to the purified permanent Nd—Fe—B magnet for a time period of between 0.5 hours and 5 hours.

Abstract: The present invention provides a method for producing an R-T-B-M sintered magnet having an oxygen content of less than 0.07 wt. % from R-T-B-M raw materials. The composition of R-T-B-M includes R being at least one element selected from a rare earth metal including Sc and Y. The composition also includes T being at least one element selected from Fe and Co. B in the composition is defined as Boron. The composition further includes M being at least one element selected from Ti, Ni, Nb, Al, V, Mn, Sn, Ca, Mg, Pb, Sb, Zn, Si, Zr, Cr, Cu, Ga, Mo, W, and Ta. The present invention provides for a step of creating an inert gas environment in the steps of casting, milling, mixing, molding, heating, and aging to prevent the powder from reacting with the oxygen in anyone of the above mentioned steps.

Abstract: The present invention discloses an R-T-B-M-C sintered magnet and a method for manufacturing the R-T-B-M-C sintered magnet from an R-T-B-M-C alloy powder including the lubricant. The present invention also discloses an apparatus for manufacturing the R-T-B-M-C sintered magnet from the R-T-B-M-C alloy powder including the lubricant. The apparatus includes an alloy powder feeding mechanism for distributing the R-T-B-M-C alloy powder including the lubricant, a filling mechanism including a mold for receiving the R-T-B-M-C alloy powder including the lubricant, a press mechanism for compressing the R-T-B-M-C alloy powder including the lubricant and a stacking mechanism for storing the mold including the R-T-B-M-C alloy powder including the lubricant.