The present disclosure relates generally to a method for improving the performance of sintered NdFeB magnet. A method of preparing a sintered NdFeB magnet therefore comprises the steps of: a) preparing alloy flakes from a raw material of the NdFeB magnet by a strip casting process; and b) preparing a coarse alloy powder from the alloy flakes by a hydrogen decrepitation process, the hydrogen decrepitation process including treatment of the alloy flakes under a hydrogen pressure of 0.10 MPa to 0.25 MPa for a duration of 1 to 3.5 hours, then degassing the hydrogen at a predetermined temperature between 300° C. to 400° C. for a duration time of 0.5 to 5 hours, and then mixing the resulting coarse alloy powder with a lubricant.

Disclosed are a method for pulverizing a waste magnet and a waste magnet powder produced by the method. More particularly, disclosed is a method for efficiently producing a waste magnet powder having a small average particle size by pulverizing a raw material containing a hydrogen-occluded rare earth metal before dehydrogenation of the raw 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.

An RIB-based permanent magnet material, a preparation method thereof, and an application thereof. The RIB-based permanent magnet material comprises the following components: R′: 29.5 to 33.5 wt. %, wherein R′ comprises Pr, and the content of Pr is ≥8.85 wt. %; C:0.106 to 0.26 wt. %; O: ≤0.07 wt. %; X: 0 to 5.0 wt. %, wherein X is one or more of Cu, Al, Ga, Co, Zr, Ti, Nb and Mn; B:0.90 to 1.2 wt. %; and Fe:61.4 to 69.5 wt. %. The RIB-based permanent magnet material can improve the performance of a permanent magnet material without employing heavy rare earths. There is no need to control the content of carbon introduced in the process, and the magnet exhibits excellent performance even with a high carbon content.

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.

Disclosed in the present invention is an R—Fe—B sintered magnet and grain boundary diffusion treatment method. The R—Fe—B sintered magnet is obtained by performing HR grain boundary diffusion treatment on an R—Fe—B sintered green body, wherein the green body at least comprises 28 wt %-33 wt % of R, which is at least one rare earth element including Nd; 0.83 wt %-0.96 wt % of B; and 0.3 wt %-1.2 wt % of M. A grain boundary diffusion direction is perpendicular to a magnetization direction, and in the diffusion direction, the ratio of HR contents of any two points spaced from the diffusion plane by a distance of no more than 500 μm is 0.1-1.0. Grain boundary diffusion of a diffusion source is performed in a direction perpendicular to c axis, so that local demagnetization is efficiently controlled, a diffusion effect is enhanced, a manufacturing procedure is simplified, and deformation factors are eliminated.

A process for producing R-T-B-based rare earth magnet powder having excellent coercive force and high remanent flux density. A process for producing R-T-B-based rare earth magnet powder by HDDR treatment, in which a raw material alloy for the R-T-B-based rare earth magnet powder includes R (wherein R represents at least one rare earth element including Y), T (wherein T represents Fe, or Fe and Co) and B (wherein B represents boron), and has a composition including R in an amount of between 12.0 atom % and 17.0 atom %, and B in an amount of between 4.5 atom % and 7.5 atom %; the HDDR treatment includes a DR step including a preliminary evacuation step and a complete evacuation step; and a rate of pressure reduction caused by evacuation in the preliminary evacuation step is not less than 1 kPa/min and not more than 30 kPa/min.

Disclosed are a rare-earth permanent magnet having improved magnetic properties and a method of manufacturing the same. A method of manufacturing a rare-earth permanent magnet may include: preparing a mixed powder including i) a first alloy represented by R1.sub.aR2.sub.bB.sub.cM.sub.dFe.sub.bal and ii) a second alloy represented by R2.sub.bB.sub.cM.sub.dFe.sub.bal where R1 is one or two or more of La, Ce, and Y; R2 is a rare-earth element except for La, Ce, and Y; and M is a metal element; press-forming and sintering the prepared mixed powder in a magnetic field to prepare a sintered body; and performing a heat treatment based on diffusion temperature conditions of an R1 component and an R2 component contained in the prepared sintered body.

A method for producing a NdFeB system sintered magnet. The method includes: a hydrogen pulverization process, in which coarse powder of a NdFeB system alloy is prepared by coarsely pulverizing a lump of NdFeB system alloy by making this lump occlude hydrogen; a fine pulverization process, in which fine powder is prepared by performing fine pulverization for further pulverizing the coarse powder; a filling process, in which the fine powder is put into a filling container; an orienting process, in which the fine powder in the filling container is oriented; and a sintering process, in which the fine powder after the orienting process is sintered as held in the filling container. The processes from hydrogen pulverization through orienting are performed with neither dehydrogenation heating nor evacuation each for desorbing hydrogen occluded in the hydrogen pulverization process. The processes from hydrogen pulverization through sintering are performed in an oxygen-free atmosphere.

A two-step diffusion method for preparing high-performance dual-main-phase sintered mischmetal-iron-boron magnet belongs to the preparing technical field of rare earth permanent magnet materials. The compositions of the two main phase alloys are RE-Fe—B (RE is Nd or Pr) and (Nd, MM)-Fe—B (MM is mischmetal), respectively. First, PrHoFe strip-casting alloy is used as a diffusion source. Next, a PrHo-rich layer is uniformly coated on the surface of (Nd, MM)-Fe—B hydrogen decrepitation powders. The higher anisotropic fields of Pr.sub.2Fe.sub.14B and Ho.sub.2Fe.sub.14B are used to improve the coercivity. Then, the ZrCu strip-casting alloy is used as a diffusion source. A Zr-rich layer is uniformly coated on the surface of the powders after the first-step diffusion, which prevents the growth of the MM-rich main phase grains during the sintering process and the inter-diffusion between the two main phases, thus obtains high coercivity.