107 results about "Sintered magnets" patented technology

This application provides a large-size NdFeB magnet and its preparation method. The preparation method includes: mixing a main alloy powder and an auxiliary alloy powder in a ratio of 10:(1-3) to obtain a mixed alloy powder; molding the mixed alloy powder and then isostatically pressing it to obtain a green blank; sintering the green blank using a multi-stage heating method to obtain a sintered magnet; wherein the multi-stage heating includes: heating to 1000-1100℃ at at least three gradually decreasing heating rates and holding at that temperature for 1-6 hours; and cooling the sintered magnet to obtain a NdFeB magnet. This application, through a dual alloying process and gradually reducing the heating rate during sintering, can effectively suppress cracking of the magnet during sintering and obtain a large-size magnet with excellent magnetic properties.

The invention discloses a cerium-containing high-abundance rare earth sintered neodymium iron boron permanent magnet which does not contain heavy rare earth and does not need a grain boundary diffusion process and a preparation method thereof. The magnet is formed by crushing and mixing three alloy casting pieces, the three alloy casting pieces are an Nd / Pr-rich phase, a Ce-La-rich phase and a Y-Nd-rich phase respectively, and Ce accounts for more than or equal to 30wt% of the total amount of all rare earth elements; the trace elements (Al, Cu, Ga, Nb, Zr and the like) are uniformly introduced in the smelting stage of each main phase, and grain boundary reconstruction is induced through in-situ hydrotreating to form a thin and continuous rare earth-rich grain boundary phase; and after orientation compression molding, vacuum sintering and multi-stage heat treatment, a sintered magnet with excellent magnetic performance is obtained. According to the product, the intrinsic coercive force Hcj is larger than or equal to 15 kOe, the residual magnetism Br is larger than or equal to 13.7 kG, and the maximum magnetic energy product (BH) max is larger than or equal to 39 MGOe. The problems that a high-Ce magnet is low in coercive force, discontinuous in grain boundary phase and the like are solved, the method does not need to depend on Dy / Tb heavy rare earth and a grain boundary diffusion technology thereof, the cost is reduced by 30% or above, and the method is suitable for the fields of new energy automobiles, wind power generation and the like and has a good industrialization prospect.

The invention relates to the technical field of release agents, and discloses a silicone-oil-free wet-process magnet profiling release agent and a preparation process thereof, and the silicone-oil-free wet-process magnet profiling release agent comprises a core functional copolymer, a water-based non-silicon defoaming agent and deionized water. The core functional copolymer is prepared from a hydrophilic self-repairing film-forming monomer, a molecular-level flexible lubricating monomer, a powerful mold anchoring monomer and a programmed pyrolysis triggering monomer through free radical copolymerization. According to the technical scheme, the functions of self-repairing film forming, molecular-level lubrication, mold anchoring and programmed pyrolysis are integrated through a single macromolecular structure. A demolding film layer formed by the water-based demolding agent is uniform and compact, mold sticking and blank defects in the profiling process are avoided, the water-based demolding agent can be completely decomposed and volatilized in the magnet sintering process, and solid residues are not generated, so that the high magnetic performance of a sintered magnet is guaranteed, and the problems that an existing water-based demolding agent is prone to generating film layer defects, poor in system stability, residues after sintering and the like are solved.

An Sm-Fe-N-based sintered magnet comprising a sintered body of a magnetic material containing an Sm-Fe-N-based magnetic powder and a Zn-Al alloy powder, wherein the Al content of the Zn-Al alloy powder is 6-84 atom%, and the open porosity of the sintered magnet is not more than 15%.

This invention discloses an R-T-B sintered magnet with reduced eddy current losses, its preparation method, and its application. The magnet has partition grooves on one or two orientation surfaces, where each orientation surface is perpendicular to the orientation direction of the magnet. The partition grooves extend through the magnet in a first extension direction but not in a second extension direction. The first extension direction of the partition grooves is perpendicular to the orientation direction of the magnet, and the second extension direction is parallel to the orientation direction of the magnet. By creating crisscrossing partition grooves on the magnet and filling them with an insulating layer, this invention increases the resistivity of a thin layer on the magnet's surface by a certain thickness, significantly reducing motor power loss due to eddy current effects. The insulating layer filling the grooves increases the resistivity of both the magnet surface and the grooves, effectively preventing conduction due to poor processing or current breakdown when the groove width is narrow. It also compensates for the reduction in mechanical strength caused by the grooving, ultimately resulting in a low-eddy-current, high-strength sintered magnet.

To provide an R-Fe-B sintered magnet that exhibits high coercivity while keeping material costs down. [Solution] The R-Fe-B sintered magnet contains a rare earth element R including Tb, an element T consisting of Fe or a combination of Fe and Co, B, and each of Al, Cu, and Ga, with an element M consisting of a combination of Al, Cu, and Ga, and includes an RTM phase in the grain boundary phase, where the number of atoms of element M in the RTM phase is in the order of Cu > Al > Ga. Furthermore, in the RTM phase, the atomic ratio of the rare earth element R to element M is preferably 6.0 for the rare earth element R and 1.3 or more for element M.

According to the high-squareness heavy-rare-earth-free R-T-B sintered magnet and the preparation method thereof, the jet milling process is optimized, high-rare-earth alloy B coarse powder is supplemented at the later stage of jet milling, jet milling is carried out at the same time, rare earth is timely and accurately supplemented for rear-section powder with large rare earth loss, the difficulty of later-stage material mixing is reduced, and the high-squareness heavy-rare-earth-free R-T-B sintered magnet is obtained. And the rare earth content of the powder in the post-jet milling stage is increased, so that the rare earth content of the powder in the post-jet milling stage is approximately consistent with the rare earth content of the powder in the previous stage. The particle size distribution of the powder in the later stage is further optimized, the microscopic grain size distribution of the magnet is eventually homogenized, so that the high-squareness heavy-rare-earth-free R-T-B sintered magnet is obtained, the squareness SQ of the magnet is larger than or equal to 0.95, and the intrinsic coercive force Hcj is larger than or equal to 16.5 kOe.

An anti-corrosion treatment method for preparing sintered NdFeB magnet includes preparing a sintered NdFeB matrix, and applying a heat treatment to the sintered NdFeB matrix in an oxidizing atmosphere containing at least one of alcohol or organic acid. A ratio of oxygen partial pressure to water vapor partial pressure in the oxidizing atmosphere is in a range from 1:1 to 300:1. A temperature for the heat treatment is equal to or lower than 300° C. A time for the heat treatment is in a range from 10 minutes to 200 minutes.

A rare earth sintered magnet according to the present disclosure includes: a main phase satisfying general formula (Nd, La, Sm)—Fe—B and including crystal grains based on R2Fe14B crystal structures; and a crystalline subphase based on an oxide phase represented by (Nd, La, Sm)—O. The subphase has a higher concentration of Sm than the main phase.

The application discloses a surface-strengthened R-T-B rare earth permanent magnet based on high-melting-point element grain boundary diffusion and a preparation method thereof. The application adopts heavy rare earth elements (at least one of Dy, Tb and Ho), high-melting-point elements (Zr and Ti) and low-melting-point metals (at least one of Al, Ga and Cu) to prepare a diffusion source, and performs grain boundary diffusion treatment on a sintered magnet, thereby obtaining the surface-strengthened R-T-B rare earth permanent magnet. The grain boundary diffusion high-melting-point element precipitates can inhibit the excessive growth of the main phase grains in the grain boundary diffusion process, realize the refinement of the main phase grains and improve the uniformity of the main phase grain size of the whole magnet. The grain boundary diffusion magnet has higher coercivity and squareness, reduces the reduction amount of the remanence of the magnet after the grain boundary diffusion; and can improve the crack propagation resistance of the Nd-rich phase at the grain boundary, thereby improving the fracture toughness of the magnet while improving the strength of the surface layer of the magnet, so that the qualified rate of the product during surface processing is improved.

A magnet preparation method includes coating powder slurry on at least one of a first surface or a second surface of an NdFeB matrix and carrying out a curing reaction, to obtain a coated magnet, and subjecting the coated magnet to a vacuum heat treatment, a grain boundary diffusion treatment, and an aging treatment. The first surface and the second surface are opposite to each other. The powder slurry includes powder containing heavy rare earth element and UV monomer. The UV monomer includes radical-cured UV monomer. A temperature of the vacuum heat treatment is in a range from 250° C. to 600° C.

A rare-earth sintered magnet is provided, characterized in that it comprises R (R is one or more elements selected from rare earth elements, with Nd being essential), T (T is one or more elements selected from iron group elements, with Fe being essential), X (X is one or two elements selected from B and C, with B being essential), and M. 1 (M 1 The rare earth sintered magnet is selected from one or more of Al, Si, Cr, Mn, Cu, Zn, Ga, Ge, Mo, Sn, W, Pb, and Bi, with less than 0.1% O, less than 0.05% N, and less than 0.07% C, and has an average crystal grain size of less than 4.0 μm. Furthermore, when the orientation degree is set to Or [%] and the average crystal grain size is set to D [μm], it satisfies the relationship (1): 0.26×D+97≦Or≦0.26×D+99. Based on this rare earth sintered magnet, it is possible to obtain magnets with both high Br and high H content. cJ It has excellent magnetic properties.

The invention discloses a neodymium-iron-boron magnet and a preparation method thereof. The neodymium-iron-boron magnet is a sintered magnet obtained by modifying an alloy fine powder raw material through a chemical reagent and then carrying out compression, vacuum treatment and sintering; the alloy fine powder comprises 75 wt%-99 wt% of magnetic powder and 1 wt%-25 wt% of metal fine powder, and the metal fine powder is one or more of lanthanum, cerium, praseodymium, neodymium, iron, aluminum, cobalt, copper and titanium. The preparation method comprises the steps of magnetic powder and metal powder mixing, chemical reagent modification treatment, heat treatment, compression molding, sintering and heat treatment, and the neodymium-iron-boron magnet is obtained. A chemical reagent is used for modifying the magnet, so that the microstructure of the magnet is improved, the interaction effect of a main phase and a grain boundary phase of a magnet base material is improved, grain boundary phase distribution is further optimized through grain boundary diffusion, the comprehensive magnetic performance of the magnet is improved, the use amount of heavy rare earth is reduced, and the bottleneck of high-performance magnet preparation is broken through.

Provided is a method for producing an R-T-B sintered magnet, which does not require the preparation of an inert gas atmosphere. This method for producing an R-T-B sintered magnet comprises: a pulverization step for preparing an alloy powder for an R-T-B sintered magnet; a molding step for preparing a powder molded body using the powder; a cutting step for obtaining a molded body sheet by cutting the powder molded body; and a sintering step for preparing a sintered body by sintering the molded body sheet, in the cutting step, the powder molded body immersed in the liquid is cut by the movement of a metal wire, and the metal wire is a metal stranded wire.

The invention describes a sintered rare earth magnet with a concentration of c of 8001,400 ppm, a maximum concentration of o of 1,000 ppm, and a maximum concentration of N of 800 ppm, a maximum average crystal grain size D50 of 4.5 ppm, and an orientation Or (%) determined by the formula: Or ” (Br / 47tfs)*100, in which D50 and Or satisfy the relationship: Or > 0f7*D5O+95. The sintered magnet shows both high values ​​of Br and HCJ.

The present invention relates to a ferrite sintered magnet, a ferrite particle, a bonded magnet, and a rotary electric machine. The magnet is a ferrite sintered magnet containing a ferrite phase having a crystal structure of a magnetoplumbite type, wherein at least Ca, a metal element A, a metal element R, Bi, Fe, and a metal element M are contained, the metal element A is at least one element selected from Sr, Ba, and Pb, the metal element R is at least one element selected from rare earth elements including Y and must contain La, the metal element M is at least one element selected from Co, Ni, Zn, Al, Cu, and Cr and must contain Co, and when atomic ratios of the metal elements are expressed by formula (1), in formula (1), c, a, r, b, f, and m satisfy the following formulae (2) to (8).

The preparation method comprises the steps that alloy raw materials are smelted, sheet throwing is carried out, heat treatment, hydrogen decrepitation, jet milling, magnetic field forming, cold isostatic pressing treatment and sintering are sequentially carried out, and a first sintered neodymium-iron-boron magnet is obtained; depositing a non-rare earth target material on one surface of the sintered neodymium-iron-boron magnet by using a molecular beam epitaxy technology; grain boundary diffusion and heat treatment; and depositing a heavy rare earth target material on the surface of the sintered magnet by using a molecular beam epitaxy technology to obtain a sintered neodymium-iron-boron magnet II, carrying out grain boundary diffusion and heat treatment, and then carrying out a tempering process to obtain the sintered neodymium-iron-boron magnet. According to the method, atomic-scale film layer control is achieved through the molecular beam epitaxy technology, the problem that a uniform thin diffusion layer is difficult to obtain through a traditional coating method is solved, diffusion materials can be efficiently utilized, the uniform diffusion depth of heavy rare earth elements in the magnet is increased, the ultrahigh-coercivity magnet is manufactured, and the industrial requirements of rare earth permanent magnet motors and the like are met.

To provide a rare earth magnet powder capable of sufficiently improving bulk density and suitable for manufacturing an anisotropic magnet.SOLUTION: A rare earth magnet powder has an average sphericity P1 defined by the formula (1) of P1=Ls / Ll of 0.65 or more. In the formula (1), Ll is the length of the long side of the circumscribing rectangle having the smallest area with respect to the rare earth magnet powder in a microscope image, and Ls in the formula (1) is the length of the short side of the circumscribing rectangle having the smallest area with respect to the rare earth magnet powder in the microscope image.SELECTED DRAWING: Figure 1A

Provided are Sm-Fe-N-based magnetic powder having high squareness, a Sm-Fe-N-based sintered magnet, and methods for producing the Sm-Fe-N-based magnetic powder and Sm-Fe-N-based sintered magnet. The Sm-Fe-N-based magnetic powder: contains particles containing samarium, iron, and nitrogen, and does not contain particles of an oxide of samarium having a particle diameter of 0.1 μm or more; or the number ratio of particles of an oxide of samarium having a particle diameter of 0.1 μm or more is 10% or less, and does not contain copper or contains 5 ppm or less of copper.

This magnetic material is an Sm-Fe-N-based magnetic material having a main phase with a Th2Zn17-type or Th2Ni17-type crystal structure, wherein the main phase has a molar formula (Sm(1-a-b)αaβb)6Fe51N9, where a is 0.01-0.20, and b is 0.01-0.20.

The invention discloses a rare earth dispersing agent, a high-performance neodymium-iron-boron permanent magnet and a preparation method and application of the high-performance neodymium-iron-boron permanent magnet. The dispersing agent comprises the following components: a rare earth R composition, a metal composition, an organic solvent and organic powder, wherein in terms of the total mass of the dispersing agent, the weight ratio of the rare earth R composition is 40-60 wt%, the weight ratio of the metal composition is 5-15 wt%, and the weight ratio of the organic solvent is 25-45 wt%; the weight ratio of the organic powder to the organic solvent is (10-20): 100. The neodymium-iron-boron permanent magnet is obtained by carrying out a diffusion process on a sintered magnet matrix by adopting the diffusant disclosed by the invention. By adopting the novel diffusant developed by the invention and optimizing diffusion process conditions, the high-performance neodymium-iron-boron permanent magnet is prepared, and the magnetic performance of the high-performance neodymium-iron-boron permanent magnet is effectively improved.

The application discloses an antioxidant composition, a rare earth permanent magnet, a sintered magnet material and a preparation method. The antioxidant composition comprises the following components: poly-alpha olefin 30mas% to 60mas%; butyl oleate 10mas% to 30mas%; fatty acid methyl ester 1mas% to 20mas%; and solvent oil 10mas% to 40mas%. The antioxidant composition can improve the dispersibility of the powder and the grinding efficiency, has excellent wettability, can well wrap the magnetic powder, prevents the contact between oxygen, nitrogen and the magnetic powder, plays an antioxidation role, reduces the nitrogen content, and ensures the high remanence and coercive force of the sintered magnet and the rare earth permanent magnet under the premise of high carbon content.

RTB-based sintered magnet with: R: 27.5 to 34.0 mass%, where R is at least one of the rare earth elements, and necessarily includes Nd and a heavy rare earth element RH, where RH is at least one of Dy, Tb, Gd and Ho, RH: 2 to 10 mass%, B: 0.89 to 0.95 mass%, Ti: 0.1 to 0.2 mass%, Ga: 0.3 to 0.7 mass%, Cu: 0.07 to 0.50 wt%, Al: 0.05 to 0.50 mass%, M: 0 to 0.3 mass%, where M is Nb and / or Zr, Remainder T and unavoidable impurities, where T is a transition metal element and necessarily includes Fe, satisfying the following inequalities (1), (2) and (3): [T] − 72.3 ([B] − 0.45 [Ti]) > 0 ([T] − 72.3 ([B] − 0.45 [Ti])) / 55.85 < 13 [Ga] / 69.72 [ Ga ] ≥ [ Cu ] where [T] is the content of T, expressed in mass%, [B] is the content of B, expressed in mass%, [Ti] is the content of Ti, expressed in mass%, [Ga] is the content of Ga, expressed in mass%, and [Cu] is the content of Cu, expressed in mass%.

The utility model provides an inductor. The inductor comprises a sintered magnet, a copper coil sleeved on the surface of the sintered magnet, a first bonding layer between the sintered magnet and the copper coil, and a shielding layer coated on the surface of the copper coil, the distance between the side surface of the sintered magnet and the inner side wall of the copper coil is 0.1-0.2 mm; the length of the sintered magnet is smaller than that of the copper coil, and the distance between the end faces of the two ends of the sintered magnet and the end face, close to the end faces, of the copper coil ranges from 0.1 mm to 0.2 mm. The distance between every two adjacent coils on the copper coil ranges from 0.01 mm to 5 mm. The copper coil is obtained through laser etching of a copper pipe, and electrode areas are arranged at the two ends of the copper pipe. Compared with an existing integrated inductor, under the condition of the same inductance value, the inductor has the advantages that the number of turns is smaller, the temperature rise rated current is higher, the direct-current resistance is lower, and therefore the inductor has higher rated power.

A rare earth sintered magnet (1) comprises: a main phase (10) containing crystal grains satisfying the general formula (Nd, Pr, RH, R)-Fe-B and based on an Nd2Fe14B crystal structure, where RH denotes a heavy rare earth element containing at least one of Dy and Tb, and R denotes one or more rare earth elements selected from other than Nd, Pr, Dy, and Tb; and a subphase (20) present among a plurality of the main phases. The main phase has core sections (11c, 12c) and shell sections (11s, 12s) covering the core sections. The main phase has a first main phase (11) in which CNd > CPr and a second main phase (12) in which CNd < CPr, where CNd denotes the concentration of Nd in the core section and CPr denotes the concentration of Pr in the core section. The concentration of the heavy rare earth element RH in the core section of the first main phase is higher than the concentration of the heavy rare earth element RH in the core section of the second main phase. The first and second main phases are mixed and heavy rare earth elements are present on at least a part of the surfaces in the first main phase and the second main phase.

The production method for a rare-earth sintered magnet according to the present disclosure comprises: a step for producing a molded article by compression-molding a slurry containing a rare-earth element-containing alloy powder and a dispersion medium using a wet-molding device; and a step for sintering the molded article. When the slurry is being poured into the inside of a space forming a cavity of the wet-molding device, a magnetic field is not applied. By pressing of the slurry, the dispersion medium contained in the slurry starts to be removed from the inside of the space.

This sintered magnet comprises a first phase having a main phase of Sm-Fe-N-based crystal grains with a Th2Zn17-type structure and a second phase consisting of an alloy containing at least one or more elements selected from Group 2 elements and rare earth elements, the alloy having a temperature range of 180-620°C, wherein a residual magnetization is 10.0 kG or more.

A method for cleaning rare earth alloy powder, includes the steps of: mixing rare earth oxides, metals, and metal compounds as raw materials, and reducing the rare earth oxides chemically to produce alloy powder that contains the reduced rare earth elements in alloy form; and cleaning the alloy powder, where the cleaning step include the steps of adding the alloy powder in a solution containing an aliphatic organic acid and an organic acid ammonium salt and removing components other than those constituting the alloy powder from the added alloy powder by the organic acid ammonium salt.

A rare-earth sintered magnet (1) comprises: a main phase (10) satisfying a general formula (Nd, Pr, R)-Fe-B, where R represents one or more rare-earth elements selected to exclude Nd and Pr, wherein the main phase (10) consists of crystal grains based on an Nd2Fe 14 The B-crystal structure contains a subphase (20) that is present between a multitude of main phases (10). The main phase (10) includes a core section (11c, 12c) and a shell section (11s, 12s) that covers the core section (11c, 12c). The main phase (10) includes a first main phase (11) that satisfies CNd>CPr and a second main phase (12) that satisfies CNd

An R-T-B sintered magnet containing 26.5 mass% or more and 31.5 mass% or less of R (R is a rare earth element and contains at least one or two elements selected from the group consisting of Nd and Pr), 0.40 mass% or more and 1.50 mass% or less of M (M is at least one element selected from the group consisting of Ga, Cu, Zn, Al and Si and must contain Cu), 0.85 mass% or more and 0.94 mass% or less of B, 61.5 mass% or more of T (T is Fe and Co, 90% or more of T is Fe in mass ratio), and the balance of Fe and unavoidable impurities. The Nd / Pr alloy satisfies the following conditions: 0.05-0.30% by mass of O, 0.20% by mass or less of Tb, and 0.30% by mass or less of Dy, and satisfies the following formula: the concentration of one or both selected from the group consisting of Nd and Pr and the concentration of Cu gradually decrease from the surface toward the depth direction within a range from the surface to a depth of 200 [mu] m. 26.0 mass% < = ([Nd] + [Pr] + [Ce] + [La] + [Dy] + [Tb])-12 ([O] + [C]) < = 27.7 mass%