30results about How to "Improve coercive force" patented technology

This invention belongs to the field of permanent magnet materials technology, specifically relating to a high-lanthanum-cerium NdFeB sintered permanent magnet and its preparation method. The raw materials for preparing this high-lanthanum-cerium NdFeB sintered permanent magnet include alloy one and alloy two. The chemical formula of alloy one is [(PrNd)]. 1‑x (RL) x ] a (TM) b (HM) c B d Fe 100‑a‑b‑c‑d Given the following conditions: 0.3 ≤ x < 1, 29.5 ≤ a ≤ 32.5, 0 < b ≤ 5, 0 < c ≤ 0.8, 0.85 ≤ d ≤ 1.1, the chemical formula of the alloy component II is (PrNd). a1 Ga b1 Fe 100‑a1‑b1 70≤a1≤90, 0<b1≤20. By combining alloy one and alloy two, and combining them with appropriate sintering and aging processes, high lanthanum-cerium NdFeB sintered permanent magnets are obtained, achieving surface magnetic hardening of high lanthanum-cerium main phase grains.

This invention discloses a high-coercivity hard magnetic oxide semiconductor thin film with perpendicular magnetic anisotropy and its preparation method. The invention employs a multi-target alternating gradient film preparation process, using NiFeO4 and NiCo2O4 targets for alternating sputtering to prepare NiCo2-xFexO4-NiCo2O4 gradient thin films. Experimental results show that the obtained films exhibit a coercivity as high as 1T and good conductivity, with an anomalous Hall resistivity reaching 52.5 μΩ·cm. This preparation method has the advantages of simplicity and low cost, providing new possibilities for the development of magnetic storage devices. This method has significant application potential for realizing high-density, high-speed, and low-power magnetic storage devices, contributing to the development and application of magnetic storage technology.

The application provides a preparation method of high-performance neodymium-iron-boron magnetic powder, comprising the following steps: A) uniformly heat treating neodymium-iron-boron rapid solidification alloy cast pieces; B) hydrogen breaking and airflow grinding the neodymium-iron-boron rapid solidification alloy cast pieces obtained in step A) to obtain neodymium-iron-boron magnetic powder; C) performing HDDR treatment on the neodymium-iron-boron magnetic powder to obtain HDDR magnetic powder; D) mixing the HDDR magnetic powder with high-melting-point alloy powder to obtain mixed magnetic powder; and E) performing at least one heat treatment on the mixed magnetic powder to obtain high-performance neodymium-iron-boron magnetic powder. The preparation method provided by the application can prepare neodymium-iron-boron magnetic powder with ideal coating structure that the rare earth-rich phase uniformly wraps the main phase crystal grains, and effectively improves the magnetic performance of the magnetic powder and the subsequently prepared magnet.

The application discloses a kind of high thermal conductivity R-T-B rare earth permanent magnet and preparation method thereof, to R-T-B main alloy is added rich R auxiliary alloy, and high thermal conductivity additive powder is added simultaneously, obtain the magnet material with larger thermal conductivity;The mass ratio of main alloy, auxiliary alloy is 7.5~49:1;High thermal conductivity additive powder mass dosage is 0.1wt.%~5.0wt.% of the total mass of main alloy, auxiliary alloy.The application increases the thermal conductivity of magnet by adding the additive with higher thermal conductivity than R-T-B, accelerates the dissipation of magnet heat, reduces the temperature when magnet is used.Compared with the traditional method of adding insulation phase to improve the resistivity and resistance temperature coefficient of magnet, the application can effectively inhibit the loss of magnetic performance of motor magnet in alternating magnetic field.

The present invention belongs to the technical field of rare earth permanent magnet materials, and specifically relates to a high-abundance rare earth rapid quenching alloy and a preparation method thereof. In order to synergistically improve the solubility of La, the Ce 3+ proportion and magnetic properties in the high-abundance rare earth rapid quenching alloy, the high-abundance rare earth rapid quenching alloy of the present invention is expressed in atomic percentage as (La 1.53 Ce 3.57 RE 11.9 )-M x Fe 78‑x -B6, where 0 < x < 1; RE is an optionally added rare earth element selected from one or more of Nd, Pr, Dy, and Tb; M is a doping element selected from at least one of Ag, Sn, Au, and Cu, and the mixing formation enthalpy of the binary system formed by M and Fe is greater than the mixing formation enthalpy of the binary system formed by La and Fe, and it is prepared by a two-step method of vacuum induction melting and melt rapid quenching. The present invention can significantly improve the solubility of La in the matrix phase, and while maintaining a high proportion of Ce 3+ , it greatly optimizes the coercivity and the maximum magnetic energy product.

The invention relates to the technical field of permanent magnet preparation, and particularly discloses a high-temperature-resistant neodymium-iron-boron magnet and a preparation method thereof. The high-temperature-resistant neodymium-iron-boron magnet comprises the following elements in percentage by mass: 17.4%-19.5% of Nd, 0.66%-0.72% of B, 38.37%-41.19% of Fe, 0.36%-4.8% of Dy, 0.18%-0.3% of Nb, 0.18%-0.3% of Al, 0.03%-0.09% of Cu, 29.1%-34.8% of an alloy rapid hardening sheet and the balance of unremovable impurities, wherein the alloy rapid hardening sheet contains Pr, Tb, Bi and Sn; the preparation method comprises the following steps: grinding the surface of an alloy rapid hardening sheet to be bright, mixing the alloy rapid hardening sheet with a pretreated magnet block, adding zirconium oxide balls, putting into a reaction kettle of a rotary diffusion furnace, vacuumizing the reaction kettle, introducing argon, rotating at the rotating speed of 4-6r / min, keeping the temperature at 700-704 DEG C for 3-7h, and carrying out rotary diffusion, so as to obtain the zirconium oxide-based composite material. And then carrying out heat preservation at 850-950 DEG C for 2-4 hours for high-temperature diffusion and heat preservation at 450-550 DEG C for 2-4 hours for tempering heat treatment by using a vacuum tube furnace in a vacuum environment. The high-temperature-resistant neodymium-iron-boron magnet has the advantage that the defect that heat resistance of a conventional neodymium-iron-boron magnet is still insufficient is overcome.

The present application relates to a method for improving the three-point bending strength of neodymium-iron-boron by grain boundary diffusion. The method is as follows: polishing and cutting the surface of a neodymium-iron-boron magnet blank, then ultrasonic cleaning in a degreasing agent solution, followed by acid pickling, water washing and drying to obtain a dry neodymium-iron-boron base material; placing the neodymium-iron-boron base material in a copper plating solution and applying current to carry out copper plating to obtain a copper-coated neodymium-iron-boron base material; physically vapor depositing a heavy rare earth terbium film on the surface of the copper-coated neodymium-iron-boron base material in a direction parallel to the easy magnetization axis to obtain a terbium-copper-coated neodymium-iron-boron base material; and then sequentially carrying out heat treatment and tempering treatment under vacuum conditions. The present application coats a copper film on the neodymium-iron-boron base material by electroplating, then physically vapor deposits a heavy rare earth element terbium on the copper-coated neodymium-iron-boron base material in a direction parallel to the easy magnetization axis, carries out grain boundary diffusion heat treatment, and obtains excellent comprehensive magnetic properties while improving the three-point bending strength of neodymium-iron-boron.

The application discloses a preparation method of a high-performance diffusion Sm-Co composite permanent magnet, and comprises the following steps: mixing alloy components according to (Sm, Re)2(Co, A) 17 After the alloy components are mixed, a proper amount of BiI3 is added, magnetic field orientation forming is carried out, and a Sm-Co magnet green body is obtained; the Sm-Co magnet green body is vacuum pre-fired under certain temperature conditions, and a magnet with a network channel structure in the interior is formed; a soft magnetic phase nano-level Fe or Co powder is mixed with an organic solvent to form a diffusion source mixed solution, the pre-fired Sm-Co magnet is immersed into the mixed solution, and after being taken out, the Sm-Co magnet is placed into a vacuum oven and dried. The BiI3 sublimation technology is used to make the soft magnetic phase and the doped elements effectively enter the grain boundary of the Sm-Co magnet, improve the coupling effect and pinning effect of the soft and hard magnetic phases, and improve the coercive force and maximum magnetic energy product. The preparation method is simple in process, low in cost, less in introduced impurities, and capable of maintaining the magnetic performance of the hard magnetic phase to the maximum extent.

This invention provides a method for preparing low-melting-point rare-earth alloys to improve the coercivity and mechanical properties of cerium-containing sintered NdFeB permanent magnets. The method includes: rotary crushing of low-melting-point rare-earth alloy strips to obtain coarse low-melting-point rare-earth alloy particles; rotary crushing of a matrix alloy casting to obtain coarse matrix alloy particles; mixing the coarse low-melting-point rare-earth alloy particles and the coarse matrix alloy particles, followed by hydrogen crushing and then air jet milling to obtain low-melting-point magnetic powder; orienting and shaping the low-melting-point magnetic powder and then performing isostatic pressing to obtain a billet; sintering and heat-treating the billet to obtain a cerium-containing sintered NdFeB permanent magnet. This invention utilizes melt rapid quenching to prepare low-melting-point rare-earth alloy strips, employs rotary crushing to produce fine coarse particles, and adds these particles during hydrogen crushing to ensure better and more uniform mixing with the matrix alloy, thus meeting the needs of large-scale industrial production.

Provided is an R-T-B-based permanent magnet having improved residual flux density and coercive force. The R-T-B-based permanent magnet contains a rare earth element R, a transition metal element T, and B, wherein the R-T-B-based permanent magnet contains at least Nd as R, the R-T-B-based permanent magnet contains at least Fe among Fe and Co as T, and the R-T-B-based permanent magnet has a plurality of main phase particles containing a crystal of R2T 14 B, and a two-particle grain boundary between two main phase particles adjacent in the easy magnetization axis direction, the thickness of the two-particle grain boundary being 3 nm or less, the two-particle grain boundary having crystallinity and being non-oriented.

The application belongs to the field of rare earth permanent magnet materials, and particularly relates to a high-abundance rare earth permanent magnet material and a preparation method thereof. x Fe 100‑x‑y‑z M y B z The raw materials are weighed according to the mass ratio, the mass ratio of Re:(Fe, M):B is 29:70:1, and the content of the rare earth element Ce accounts for 25-30% of the total rare earth content; (2) the raw materials are sequentially subjected to induction melting, rapid quenching, mechanical crushing and screening of particle size, so that the magnetic powder with a grain size of 20-100 nm is obtained; (3) hot-press forming: the magnetic powder is placed in a mold, a temperature is kept at 600-700 DEG C in a vacuum environment, a pressure of 150-250 MPa is applied, and the pressure is kept for 1-3 minutes, so that a dense hot-pressing blank is obtained; (4) hot deformation forming: the dense hot-pressing blank is deformed at 800-900 DEG C and 50-150 MPa, the deformation amount is not less than 70%, and after being kept for 30-60 seconds, a hot-deformed magnet is obtained. The preparation method has high Ce content, low cost and excellent magnetic properties of the obtained permanent magnet.

The application discloses a strontium ferrite / polyether ether ketone composite magnet and a preparation method and application thereof, and belongs to the technical field of permanent magnet materials.The strontium ferrite / polyether ether ketone composite magnet comprises, in mass fraction, near Curie point magnetic field heat-treated strontium ferrite magnetic powder 84-95 parts, polyether ether ketone 5-15 parts, silane coupling agent 0.5-1.5 parts and lubricant 0.3-0.7 parts.The application adopts the above strontium ferrite / polyether ether ketone composite magnet and the preparation method and application thereof, realizes the synergistic improvement of magnetic performance, mechanical strength and heat resistance through intrinsic magnetic domain structure optimization, interface bonding strengthening and high densification structure design, and can meet the application requirements under the working conditions of high temperature, high reliability and high strength.

This invention relates to a high-performance samarium-cobalt magnet and its preparation method, belonging to the field of magnet technology. This invention discloses a high-performance samarium-cobalt magnet, wherein the samarium-cobalt magnet is composed of a surface coated with N... y H z Sm layer (1‑x) M x (Co a Fe b Cu c Zr d ) e The magnet is made of magnetic powder material, wherein 0 ≤ x < 1, 0 ≤ a ≤ 1, 0 < b < 1, 0 < c < 1, 0 < d < 1, and 4.5 ≤ e ≤ 9. This invention also discloses a method for preparing a high-magnetic-performance samarium-cobalt magnet, the method comprising: mixing raw materials according to elemental ratios, and performing alloy melting using vacuum induction melting technology to obtain Sm... (1‑x) M x (Co a Fe b Cu c Zr d ) e Casting ingots; obtaining magnetic powder from the ingots through coarse crushing; then uniformly coating the surface of the magnetic powder with N. y H z Then, the mixed powder is post-processed to obtain a samarium cobalt magnet with high magnetic properties.

The application discloses a kind of foamed metal foil for grain boundary diffusion, neodymium iron boron diffusion magnet and preparation method.The preparation method of the foamed metal foil for grain boundary diffusion of the application comprises the following steps:1) depositing a rare earth alloy film on the surface of a foamed metal foil sheet to obtain a coated foamed metal foil sheet;2) fold the coated foamed metal foil sheet obtained in step 1) in half, with the coated side facing in, and compress after folding to obtain a foamed metal foil for grain boundary diffusion.The foamed metal foil for grain boundary diffusion of the application enhances the adhesion of the rare earth alloy film, and when used for grain boundary diffusion, it increases the coercivity of the neodymium iron boron magnet while reducing the drop in remanence.

This invention discloses a method for improving the coercivity of NdFeB magnetic materials using phosphor waste, belonging to the field of phosphor waste recycling technology. The invention uses recycled phosphor waste from tri-color fluorescent lamps as raw material. The raw material is first calcined at 300-500℃ to remove colloids, then calcium powder is added and subjected to a second reduction calcination at 500-700℃ in an inert gas atmosphere. After crushing, grinding, acid washing, water washing, drying, and sieving, recycled phosphor material is prepared. Finally, the recycled phosphor material is mixed into NdFeB alloy powder, and following conventional magnetic material production processes, NdFeB blanks are produced through hydrogen crushing, powdering, molding, and sintering, significantly improving the coercivity of NdFeB magnetic materials. This invention features a short process flow, simple equipment requirements, easily achievable experimental conditions, and a short production cycle. It not only improves the coercivity of NdFeB magnetic materials but also recycles phosphor waste from tri-color fluorescent lamps, reducing environmental pollution, and can be used for large-scale industrial production.

This invention discloses a magnetic composite material, its preparation method, and magnetic devices prepared using the same, belonging to the technical field of bonded magnetic composite materials. The invention provides a magnetic powder comprising 0.5-4.5 wt.% lanthanum, 5.0-9.0 wt.% cerium, 2.5-4.0 wt.% praseodymium, 9.0-16.0 wt.% neodymium, 1.0-4.0 wt.% zirconium, 0.1-1.0 wt.% aluminum, 0.5-1.5 wt.% boron, with the remainder being iron (Fe). It also provides a magnetic composite material comprising 83-93 parts of the magnetic powder, 0.2-2 parts of a coupling agent, 7-17 parts of a resin polymer, 0.5-3 parts of a polymeric elastomer, and 0.1-0.5 parts of a lubricant. The magnetic composite material disclosed in this invention, when applied to magnetic devices, possesses characteristics such as low cost, low thermal demagnetization, high magnetic properties, and excellent mechanical and processability, meeting the requirements for magnetic devices in thermal management systems.

The invention discloses a doping preparation method of a high-temperature stable rare earth magnet assembly, and relates to a magnetic material and a preparation technology thereof. Heavy rare earth elements such as terbium and dysprosium are compositely doped into a neodymium iron boron matrix, and technological parameters such as ball milling, compression molding, sintering and magnetic field oriented annealing are optimized, so that the coercive force and magnetic energy product stability of the magnet under a high-temperature working condition are remarkably improved. The method gives consideration to magnetic performance and cost control, is suitable for high-temperature application scenes such as a welding tool magnetic attraction device, effectively solves the problem that the magnetic performance attenuation of a conventional NdFeB magnet at high temperature is fast, improves the high-temperature reliability of the magnet, and prolongs the service life of the magnet.

The invention belongs to the technical field of rare earth permanent magnet materials, and particularly relates to a preparation method for improving the performance of a samarium-cobalt magnet. In order to simply and efficiently improve the magnetic performance of the samarium-cobalt magnet, the samarium-cobalt magnet subjected to sintering solution treatment is subjected to vacuum plastic packaging, then pre-stress treatment is performed, and finally aging treatment is performed to obtain the final-state samarium-cobalt magnet.

The application discloses a neodymium-iron-boron magnet based on grain boundary diffusion for improving magnetic properties and a preparation method thereof. The preparation method comprises the following steps: mixing neodymium-iron-boron magnetic powder, a lubricant and nanotubes or micropipes to obtain mixed magnetic powder; performing orientation compression molding, isostatic pressing and vacuum sintering on the mixed magnetic powder to obtain a diffusion base material; cutting the diffusion base material according to size requirements, grinding off a surface oxide layer, and cleaning to obtain a cleaned base material; uniformly spraying an alloy diffusion source on the surface of the cleaned base material to perform grain boundary diffusion to obtain a magnet; and performing secondary tempering treatment on the magnet to obtain a grain boundary diffusion magnet. In the method, nanotubes or micropipes are added into the neodymium-iron-boron magnetic powder, diffusion channels penetrating through the grain boundaries are formed in the sintering process, and then the magnet is subjected to grain boundary diffusion by using a rare earth alloy diffusion source, so that the grain boundary diffusion depth of heavy rare earth elements is significantly improved, and the magnetic properties of the magnet are improved. The neodymium-iron-boron magnet prepared by the method has excellent performance.

Provided is an Sm-Fe-N-based magnet comprising: first crystal grains containing samarium, iron, and nitrogen and containing 9 at% or more and less than 13 at% of samarium, and second crystal grains containing 13 at% or more of samarium; in the distribution of the average distance between adjacent particles of the second crystal grains, the average distance between adjacent particles having a cumulative frequency of 50% is 7 [mu] m or less, and the average distance between adjacent particles having a cumulative frequency of 90% is 12 [mu] m or less.

This invention discloses a method for forming NdFeB magnets based on ultrasonic electromagnetic coupling resonant internal rheology, relating to the field of rare earth permanent magnet material manufacturing technology. The method includes the following steps: S1. Immersing a NdFeB magnet blank in a fluid medium located within a flexible pressurized chamber, providing the fluid medium with a hydrostatic pressure of 10-50 MPa, heating it to 250-350°C, and emitting high-frequency ultrasonic waves at the interface between the fluid medium and the NdFeB magnet blank. The excitation frequency of the high-frequency ultrasonic waves is 1-5 MHz. A pulsed strong magnetic field is applied to the NdFeB magnet blank 1-2 seconds before the high-frequency ultrasonic waves end. S2. Simultaneously removing the pulsed strong magnetic field and the high-frequency ultrasonic waves, and immediately after removing them, subjecting the blank to cryogenic convection quenching outside the flexible pressurized chamber. When the fluid medium temperature drops below 60°C, the hydrostatic pressure is slowly released, resulting in a NdFeB magnet. This method lowers the thermorheological solidification temperature and improves the intrinsic coercivity and remanence of the NdFeB magnet.

The invention discloses a core-shell type high-loss ferrite electromagnetic material and a preparation method thereof, the core-shell type high-loss ferrite electromagnetic material comprises a shell layer and a core layer, the shell layer is a carbon sphere, the core layer is an M-Ba ferrite material, and the mass ratio of the shell layer to the core layer is 1: (5-15); the molecular formula of the M-Ba ferrite material is BaFe < 12-x > Al < x > O < 19 >, wherein x is equal to 0.0 to 1.0. The characteristics of high-frequency application, high-temperature resistance, process stability and the like of BaFe < 12-x > Al < x > O < 19 > ferrite are utilized, the carbon spheres prepared from potato starch are combined for core-shell compounding, and the composite material has high loss constant and high temperature stability in a high-frequency band and can meet the application requirements of electromagnetic shielding and electromagnetic loss under high frequency.

The application discloses a rare earth slurry for grain boundary diffusion, a diffusion magnet and a preparation method. The rare earth slurry comprises rare earth alloy particles and a composition; the rare earth alloy particles comprise rare earth elements and non-rare earth metal elements; the non-rare earth metal elements are selected from at least one of Cu, Al, Mg, Ga, Sn, Si, Ag, Co, Fe, Zr, Nb, V, Ti, Mo, Ta and Hf; the rare earth elements are selected from at least one of light rare earth elements and heavy rare earth elements, and must contain heavy rare earth elements; and the composition is formed by an ester coupling agent, inorganic fluoride, fluorine-containing borate, a polymer binder, fluorocarbon surfactant and an organic solvent with a weight ratio of 1.8-2.5:12.5-68:12-28:3:0.45-0.5:23-28. The rare earth slurry is suitable for being used as a slurry for grain boundary diffusion of sintered Nd-Fe-B magnets, and the coercive force improvement rate of the magnet can reach more than 100%.

The invention relates to a high-coercivity and high-mechanical property sintered samarium-cobalt magnet and a preparation method thereof, and belongs to the technical field of preparation of samarium-cobalt magnets. The preparation method of the samarium-cobalt magnet comprises the steps that Sm, Co, Fe, Cu and Zr are smelted according to the proportion, an alloy cast ingot is obtained, then the alloy cast ingot is subjected to crushing and jet milling, and samarium-cobalt alloy powder is obtained; the samarium cobalt alloy powder and FeCoNiCuTiAl high-entropy alloy powder are mixed, and mixed powder is obtained; pressing the mixed powder under a magnetic field to obtain a pressed blank, and performing cold isostatic pressing on the pressed blank to obtain a static pressed blank; sintering the static pressure blank to obtain a sintered blank; and carrying out heat treatment on the sintered blank to prepare the samarium-cobalt magnet. The bending strength of the obtained samarium-cobalt magnet is 130 MPa or above, and the coercive force of the obtained samarium-cobalt magnet is 37.0 kOe or above.

The application discloses a grain boundary diffusion material, a neodymium-iron-boron magnet material and a preparation method and application thereof. The grain boundary diffusion material comprises a sintered body and a diffusion source. The sintered body comprises the following components: R: 29-32 wt.%, R being a rare earth element; M: 0.1-2 wt.%, M comprising one or more of Cu, Ga and Co; B: 0.9-1.0 wt.%; Fe: 65-70 wt.%, wt.% being the percentage of the mass of each component to the total mass of the sintered body. The diffusion source comprises the following components: Tb: 60-85 wt.%; Ga: 10-30 wt.%; Cu: 5-20 wt.%, wt.% being the percentage of the mass of each component to the total mass of the diffusion source. The grain boundary diffusion material can significantly improve the coercivity of the neodymium-iron-boron magnet material, while maintaining high remanence and high-temperature stability of the magnetic performance.

The application discloses a neodymium-iron-boron magnet composite modification method, which comprises the following steps: S1, preparing a modified neodymium-iron-boron base body, wherein the neodymium-iron-boron base body comprises 0.13-0.18 wt% of Ga and 0.08-1.02 wt% of Cu; S2, magnetron sputtering deposition of a double-alloy diffusion source, wherein the target material is a Dy-Ho double-alloy target material, and the atomic ratio of Dy to Ho is 1:1; S3, short-time high-temperature vacuum diffusion, heating to 920-980 DEG C, holding for 30 min, secondary aging treatment at 480-520 DEG C for 3 h, and then air quenching to obtain a neodymium-iron-boron magnet; and S4, adopting a chemical plating or electroplating process to deposit a high-phosphorus nickel plating layer on the surface of the neodymium-iron-boron magnet, so as to shorten the heavy rare earth diffusion time and reduce energy consumption under the premise of ensuring diffusion depth, reduce the use amount of expensive Dy while ensuring high coercivity, and form a passivation film in the neodymium-iron-boron magnet to improve corrosion resistance.

The invention discloses a diffused neodymium-iron-boron magnet, an alloy, diffusion slurry and application. The alloy consists of the following components in atomic percent: 30-50% of heavy rare earth element HRE, 20-40% of light rare earth element LRE, 5-15% of transition metal element T 'and the balance of low-melting-point metal element M, wherein HRE is selected from one or more of Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y; lRE is selected from one or more of La, Ce, Pr, Nd, Sm and Eu; t'comprises Co; m is selected from one or more of Cu, Al and Ga. The application of the alloy to the diffused neodymium-iron-boron magnet comprises the following steps that the alloy is smashed into alloy powder; mixing the alloy powder with a binder and a solvent to prepare diffusion slurry; a neodymium iron boron magnet is coated with the diffusion slurry; and carrying out diffusion heat treatment on the coated neodymium-iron-boron magnet.

The application discloses a recycling method of waste neodymium-iron-boron magnets. The method comprises the following steps: 1) taking n waste neodymium-iron-boron magnets to be treated; wherein n is greater than or equal to 2; 2) forming a brazing rare earth alloy layer between the waste neodymium-iron-boron magnets to be treated, stacking the waste neodymium-iron-boron magnets to be treated containing the brazing rare earth alloy layer to obtain a pretreated waste neodymium-iron-boron magnet group; and 3) performing three times of heat treatment on the pretreated waste neodymium-iron-boron magnet group under vacuum conditions to obtain waste neodymium-iron-boron magnets after brazing. The waste neodymium-iron-boron magnets are subjected to diffusion brazing repair, and the coercive force of the waste neodymium-iron-boron magnets is significantly improved.

The application discloses a rare earth slurry for grain boundary diffusion, a Nd-Fe-B diffusion magnet and a method. The rare earth slurry for grain boundary diffusion is prepared from raw materials including a rare earth powder, a heat-conducting powder, a binder and an organic solvent; wherein the rare earth elements in the rare earth powder include light rare earth and / or heavy rare earth; the heat-conducting powder is selected from one of aluminum nitride, silicon carbide and silicon nitride; the weight of the heat-conducting powder is 3-10% of the weight of the rare earth powder; and the particle size of the heat-conducting powder is 15-40 times of the particle size of the rare earth powder. The rare earth slurry for grain boundary diffusion can improve the diffusion effect of a subsequent magnet and the utilization rate of rare earth.

The application relates to the field of magnet materials, and particularly discloses a neodymium-iron-boron material and a preparation method and application thereof. The preparation method of the neodymium-iron-boron material comprises the following steps: S1, respectively melting and pouring main phase material and auxiliary phase material to obtain main phase rapid solidification tablets and auxiliary phase rapid solidification tablets; S2, respectively performing hydrogen breaking treatment on the main phase rapid solidification tablets and the auxiliary phase rapid solidification tablets to obtain main phase coarse powder and auxiliary phase coarse powder, and respectively performing airflow grinding to obtain main phase fine powder and auxiliary phase fine powder; S3, performing pressing on a mixture containing the main phase fine powder and the auxiliary phase fine powder to obtain a blank, and performing sintering to obtain a neodymium-iron-boron material matrix; and S4, performing diffusion treatment on the neodymium-iron-boron material matrix by using a diffusion source; the obtained neodymium-iron-boron material has excellent remanence and coercive force, and good stability of magnetic performance.