Abstract: The present disclosure discloses a cerium-added RE-T-B-M series sintered neodymium-iron-boron magnet, which relates to the technical field of neodymium-iron-boron permanent magnets, the structure of the magnet contains a RE2Fe14B main phase, a RE-rich phase, a REFe2 phase, and a sandwich grain boundary phase, wherein the sandwich grain boundary phase includes a RE-rich phase, a Fe-rich phase, and a REFe2 phase, and in the sandwich grain boundary phase, starting from the side near the grains of RE2Fe14B main phase, the first layer is the RE-rich phase, the second layer is the Fe-rich phase, and the third layer is the REFe2 phase, where RE includes cerium element and at least one of other rare earth elements, and the cerium element accounts for 3.0-15.0% by mass of the total elements, T is iron element and cobalt element, B is boron element, and M is Al, Cu, Ga, and Ti elements.

Abstract: The present disclosure refers to a method for preparing sintered NdFeB magnets, including: a) Preparing alloy flakes from a raw material by strip casting, performing a hydrogen decrepitation to produce alloy pieces, pulverization the alloy pieces to an alloy powder, performing molding and orientation, cold isostatic pressing, and getting a green compact; b) Putting the green compact into a vacuum furnace and performing a first sintering step in 830 to 880° C. for 2 to 10 hours and 5×10?1 Pa or less; c) Performing a second sintering step while applying a pressure to the green compact achieved by step b), the pressure is 1 MPa to 5 MPa and the sintering temperature is 720 to 850° C. for 15 to 60 minutes, and the temperature of the first sintering step is at least 10° C. higher than that of the second sintering step; d) Subjecting the sintered magnet of step c) to an annealing treatment.

Abstract: 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.

Abstract: 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.

Abstract: The present disclosure refers to a method for preparing sintered NdFeB magnets, including: a) Preparing alloy flakes from a raw material by strip casting, performing a hydrogen decrepitation to produce alloy pieces, pulverization the alloy pieces to an alloy powder, performing molding and orientation, cold isostatic pressing, and getting a green compact; b) Putting the green compact into a vacuum furnace and performing a first sintering step in 830 to 880° C. for 2 to 10 hours and 5×10?1 Pa or less; c) Performing a second sintering step while applying a pressure to the green compact achieved by step b), the pressure is 1 MPa to 5 MPa and the sintering temperature is 720 to 850° C. for 15 to 60 minutes, and the temperature of the first sintering step is at least 10° C. higher than that of the second sintering step; d) Subjecting the sintered magnet of step c) to an annealing treatment.

Abstract: The present disclosure relates to a method for preparing high-performance sintered NdFeB magnets. The method comprises the steps of: a) attaching a multi-element alloy powder onto a surface of the sintered NdFeB magnet, wherein the multi-element alloy is of formula (1) PraRHbGacCud (1) with RH being at least one element selected from Dy and Tb and a, b, c, and d satisfying the conditions 0.30?(a+b)/(a+b+c+d)?0.65, 0.20?d/(c+d)?0.50, and 0.23?b/(a+b)?0.60; and b) performing a diffusion process.

Abstract: The present disclosure refers to a method of preparing a NdFeB magnet powder. The method includes a hydrogen treatment process including the steps of: a) charging NdFeB alloy flakes into a hydrogen treatment furnace, wherein the NdFeB alloy flakes include a neodymium-rich phase and a main phase; b) performing a hydrogen absorption by heating the hydrogen treatment furnace in a first stage to a temperature at which only the neodymium-rich phase undergoes a hydrogen absorption reaction, then introducing and maintaining hydrogen at a predetermined pressure until the hydrogen absorption of the neodymium-rich phase is finished, then stop heating of the hydrogen treatment furnace in a second stage, where the temperature falls to a temperature at which the main phase undergoes a hydrogen absorption reaction; and c) when the hydrogen absorption of step b) is finished, performing a vacuum dehydrogenation of the obtained coarse magnet powder.

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: The present disclosure refers to a preparation method for improving the coercive force of a sintered Nd—Fe—B magnet and comprises: preparing Nd—Fe—B alloy flakes by a strip casting process, followed by hydrogen decrepitation of the Nd—Fe—B alloy flakes and jet milling to obtain an Nd—Fe—B powder; mixing Nd—Fe—B powder and an amount of 0.1 to 5 wt. % of a nanoparticulate powder in a powder mixing machine to obtain a powder mixture; modification of the powder mixture obtained in step B) under inert conditions in a mechanical mixing equipment such that the particles of the Nd—Fe—B powder are rounded and the nanoparticulate powder adheres to the particle surface of the Nd—Fe—B powder; mixing in a lubricant to the modified Nd—Fe—B powder in a powder mixing machine; and align pressing the modified Nd—Fe—B powder into a green body, sintering the green body, and aging of the obtained sintered Nd—Fe—B magnet.

Abstract: 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.

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: A method of making a finished Nd—Fe—B magnet includes a first step of providing a rare earth magnet powder. Then, a green compact is formed using the rare earth magnet powder. The green compact includes at least one orientation surface, at least one non-orientation surface, and at least one pressing surface. Next, the green compact is cut using a cutting apparatus along the at least one orientation surface, the at least one non-orientation surface, or the at least one pressing surface, under an inert atmosphere to produce a plurality of sliced compacts. Then, the sliced compacts are sintered to produce sintered compacts. The sintered compacts are annealed to produce annealed compacts. The annealed compacts are then machined to obtain finished Nd—Fe—B magnets. The step of cutting is performed before the steps of sintering, annealing, and machining. A cutting apparatus for cutting the green compact is also disclosed herein.

Abstract: A sintered R-T-B based permanent magnet includes a body having an easy-axis of magnetization. The body has a plurality of R2T14B main phases spaced from one another and a plurality of grain boundary phases between the R2T14B main phases. The body including zero heavy rare earth elements and the grain boundary phases includes a first and a second grain boundary phase. The first grain boundary phase is disposed between the R2T14B main phases and extends along and parallel to the easy-axis of magnetization whereby the first grain boundary phase forms a plurality of first grain boundary triple point areas with the first grain boundary triple point areas being a rare earth element rich phase having a high content of Al and Ga and includes 65 at. %?Pr+Nd?88 at. %, 10 at. %?Al+Ga?25 at. %, O?10 at. %, and Fe+Cu+Co?2 at. %. A method of making the sintered R-T-B based permanent magnet is disclosed herein.

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: A method of making a rare earth magnet containing zero heavy rare earth elements includes a step of mixing the fine grain power 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.