1699 results about "Neodymium" patented technology

The invention discloses a low-cost high-cerium neodymium iron boron diffusion magnet and a preparation method and application thereof, and relates to the technical field of rare earth permanent magnet materials. Comprising the steps that a neodymium iron boron alloy casting piece Ce30 with the Ce content being 10 wt% and a neodymium iron boron alloy casting piece Ce50 with the Ce content being 15 wt% are prepared through burdening and smelting, after the Ce30 and Ce50 neodymium iron boron alloy casting pieces are evenly mixed, hydrogen decrepitation, jet milling, oriented pressing, cold isostatic pressing and vacuum sintering are sequentially carried out, and a high-cerium sintered neodymium iron boron matrix is obtained; carrying out grain boundary diffusion on the high-cerium sintered neodymium-iron-boron matrix to obtain a high-cerium neodymium-iron-boron diffused magnet; the performance of the blank prepared through the method is close to the N40 mark, the performance of the magnetic sheet after diffusion reaches the 38MT mark, the magnetic performance is kept at the high level, the Ce content is high, efficient utilization of the high-abundance element cerium is achieved, the production cost of the rare earth permanent magnet material is greatly reduced, industrial batch production can be achieved, and balanced utilization of rare earth resources is promoted.

The invention relates to the field of neodymium iron boron magnetic materials, in particular to a high intrinsic coercive force neodymium iron boron magnetic material and a preparation method thereof, and the high intrinsic coercive force neodymium iron boron magnetic material comprises the following raw materials in parts by weight: 52.5-57.2 parts of PrNd, 105-115.3 parts of Nd, 9.0-10.3 parts of B, 15-35 parts of Tb, 70-80 parts of Dy, 10-25 parts of Co and 650-680 parts of Fe. The two rare earth elements Tb and Dy are added into the neodymium-iron-boron magnetic material, so that the magnetocrystalline anisotropy field of the crystal is remarkably enhanced, and the intrinsic coercive force of the neodymium-iron-boron magnetic material is greatly improved.

The invention discloses a neodymium-iron-boron magnet, which comprises main phase crystal grains, a thin layer crystal boundary phase and a triangular region crystal boundary phase, and is characterized in that the neodymium-iron-boron magnet comprises 28 to 33 weight percent of R, 0.84 to 0.94 weight percent of B, 0.05 to 1 weight percent of Co, 0.05 to 0.55 weight percent of Cu, 0.3 to 0.6 weight percent of Ga, 0 to 0.55 weight percent of M2, 0.1 to 0.6 weight percent of M3, 66 to 70 weight percent of Fe and the balance of Fe, wherein R is a rare earth element and at least comprises PrNd; the triangular region grain boundary phase comprises an R6T13M1 phase, the element M in the R6T13M1 phase is selected from any two or more elements of Al, Cu, Ga, Ti, Sn and / or Zr, and the element T comprises Fe and / or Co; the sum of the areas of the R6T13M1 phases in the microscopic structure cross section of the neodymium-iron-boron magnet accounts for 5.2%-8.4% of the area of the microscopic structure cross section. The rare earth permanent magnet with high residual magnetism, high coercive force and good squareness consistency is obtained under the condition that no heavy rare earth is added or a small amount of heavy rare earth is added.

The invention discloses a neodymium iron boron composite magnet and a production process thereof, and belongs to the technical field of magnetic materials. Carrying out sand blasting and phosphoric acid treatment on the neodymium-iron-boron magnet to obtain a pretreated neodymium-iron-boron magnet; and mixing 50-60 parts of epoxy resin, 30-40 parts of polyurethane and 10-20 parts of polysiloxane, then adding 10-20 parts of a solvent, 8-16 parts of filler, 3-5 parts of an auxiliary agent and 1-3 parts of dibenzoyl peroxide, stirring to obtain a protective coating, then spraying the protective coating on the surface of the pretreated neodymium-iron-boron magnet, and curing to obtain the neodymium-iron-boron composite magnet. The auxiliary agent contains a hindered phenol structure, a benzotriazole structure and fluorine atoms, and a hybrid cross-linked network structure is formed among the auxiliary agent, the epoxy resin and the filler, so that the auxiliary agent and the filler can be highly dispersed and stably exist in the protective coating and fully play roles, and the protective coating has the advantages that the protective coating is more stable in performance due to the combined action of the other raw materials in the protective coating; the neodymium-iron-boron composite magnet has excellent and stable water resistance, aging resistance, corrosion resistance and the like.

The invention discloses a neodymium-iron-boron magnet with double main phases and light rare earth diffusion based on asymmetric cerium distribution and a preparation method, and relates to the technical field of neodymium-iron-boron magnets. The method comprises the steps that a diffusion matrix is prepared through a double-main-phase technology, in the double-main-phase technology, the components of a main-phase alloy and an auxiliary-phase alloy are RaCebFe100-a-b-c-dMcBd, R is PrNd alloy or Nd metal, M is at least one of Cu, Al, Zr, Co and Ga, the content of Ce in the main-phase alloy is larger than that of Ce in the auxiliary-phase alloy, then the upper surface and the lower surface of the diffusion matrix are coated with a diffusion source solution, and the diffusion matrix is obtained through heat treatment. Carrying out heat treatment and aging treatment to obtain a neodymium-iron-boron magnet; the diffusion source solution is formed by mixing a diffusion source and a solvent, and the diffusion source is (PrmNdn) aAlbCucZrdCoeMgf. The neodymium-iron-boron magnet obtained through the method has high residual magnetism and high coercive force at the same time, the diffusion efficiency of the diffusion source is high, and the rare earth utilization rate is increased.

The invention discloses a rare-earth metal arylamine group compound as well as preparation method and application thereof. The invention discloses the rare-earth metal arylamine group compound which is characterized in that a general formula of the rare-earth metal arylamine group compound is (2,6-R12PhNH)5LnLi2(THF)2, wherein Ln is a rear-earth metal selected from one of neodymium, samarium, ytterbium or yttrium; R1 is selected from one of hydrogen, methyl or isopropyl. The rare-earth metal arylamine group compound has the advantages that the rare-earth metal arylamine group compound has a definite structure; raw materials used in the preparation method are simple, easily obtained and cheap; the reaction process is simple and easily operated; the rare-earth metal arylamine group compound product is conveniently purified and the yield of the product is high; the rare-earth metal arylamine group compound has a high activity when acting as a single component catalyst to catalyze a hydrogen phosphine reaction of aldehyde or ketone and phosphite ester; the use amount of the catalyst is less; the yield is high; a substrate has wide universality; a new and simple method is provided for synthesis of a-hydroxyphosphonate.

The present invention discloses a medium-high performance neodymium iron boron and a preparation method thereof. Through the master-slave phase double alloy process, the master phase alloy is cerium iron boron with a low total rare earth content, and the slave phase is a neodymium iron boron alloy with a high total rare earth content, avoiding the entry of light rare earths in the master phase into the grain boundaries, while the surplus rare earths in the slave phase enter the grain boundaries and are recombined into rare earth-rich phases. The prepared magnet is processed into a thin magnetic sheet, and a low-melting-point HReM alloy is magnetron sputtered, realizing low-temperature grain boundary diffusion. This alloy improves the grain boundary wettability and also improves the fluidity of the rare earth-rich phase, enabling the cerium-containing neodymium iron boron master and slave phase grains to be quickly isolated during grain boundary diffusion. The low-temperature diffusion avoids the replacement of the diffused heavy rare earths by praseodymium, neodymium, and cerium elements, inhibits the exchange coupling between cerium iron boron grains, and makes the heavy rare earths free in the grain boundaries or interact with the rare earth-rich phase to form a core-shell structure on the surface layer of the master phase grains, enabling the rare earth-rich phase to be continuously and uniformly distributed, effectively enhancing the effectiveness of the grain boundary diffusion of heavy rare earth elements in improving the intrinsic coercivity of the cerium-containing magnet.

The invention discloses a neodymium-iron-boron quick-setting casting sheet, neodymium-iron-boron magnetic powder and a preparation method. The neodymium iron boron quick-setting casting piece is provided with a roller attaching surface and a free surface, and the neodymium iron boron quick-setting casting piece is composed of a Re2Fe14B main phase and an intergranular Re-rich phase and does not contain an alpha-Fe phase; the main phase has a columnar crystal morphology along the section in the direction from the roller attaching surface to the free surface, the width of the columnar crystal is 2.5-3.7 microns, dendritic crystals are distributed on the two sides of the columnar crystal, the width of the dendritic crystals is close to the width of the columnar crystal, Re-rich phases are attached to the two sides of the columnar crystal and the two sides of the dendritic crystals, and the Re-rich phases are uniformly distributed along the columnar crystal and the dendritic crystals. The neodymium-iron-boron quick-setting casting piece is beneficial to improving the yield of neodymium-iron-boron magnetic powder and improving the normal distribution of the granularity of the neodymium-iron-boron magnetic powder.

The invention discloses an yttrium-rich neodymium-iron-boron magnet and a preparation method thereof, and belongs to the technical field of rare earth permanent magnet material preparation. The preparation method comprises the following steps: mixing yttrium-rich neodymium-iron-boron matrix alloy powder with grain boundary doped alloy powder containing Gd and / or Ho, and carrying out compression molding and sintering tempering treatment to obtain a first yttrium-rich neodymium-iron-boron magnet. According to the invention, the grain boundary doped alloy powder containing Gd and / or Ho is added into the yttrium-rich neodymium iron boron matrix alloy powder and then is sintered, so that a continuous and uniform non-magnetic thin-wall grain boundary phase structure is formed in the grain boundary, and the coercive force of the magnet is enhanced. Dy and / or Tb heavy rare earth element grain boundary diffusion is carried out based on the first yttrium-rich neodymium-iron-boron magnet after grain boundary modification, a second yttrium-rich neodymium-iron-boron magnet is obtained, the diffusion depth of Dy and / or Tb in the magnet can be increased, the utilization rate can be increased, the cost can be reduced, the coercivity of the magnet can be improved, and the adverse effect of Dy and / or Tb on residual magnetism can be reduced.

The invention discloses a high-adhesion super-hydrophobic protective coating process method and a coating. The high-adhesion super-hydrophobic protective coating process method comprises the following steps: S1, preparing magnetic nano iron oxide particles; s2, performing neodymium modification on the magnetic nano iron oxide particles to obtain ferromagnetic neodymium modified iron oxide; s3, preparing and spraying a neodymium modified iron oxide coating; s4, preparing and coating a negative charge modified polymer microsphere coating; s5, preparing and spraying a positive charge modified polymer microsphere coating; and S6, preparing and spraying a modified nano silicon dioxide super-hydrophobic coating. According to the method, neodymium-modified magnetic nanometer iron oxide serves as a first layer of the surface of a steel substrate and is sprayed and dried in a magnetic field, it is guaranteed that the neodymium-modified magnetic nanometer iron oxide is tightly adsorbed to the steel surface, a magnetic transition layer is formed, and then coatings with different charges are alternately coated through the electrostatic attraction effect; and finally, a high-adhesive-force super-hydrophobic coating is formed on the steel surface in a layer-by-layer self-assembly mode, and the problem that the adhesive force of the super-hydrophobic coating is poor is obviously solved.

The invention discloses a neodymium-iron-boron magnet and a preparation method and application thereof. The neodymium-iron-boron magnet comprises an easy-to-demagnetize area, a non-easy-to-demagnetize area and a bonding area, and the volume of the easy-to-demagnetize area accounts for 15%-50% of the total volume of the neodymium-iron-boron magnet; wherein the volume of the bonding area accounts for 0.5%-4.0% of the total volume of the neodymium-iron-boron magnet; wherein the ratio of the coercive force of the non-easy demagnetization area to the coercive force of the easy demagnetization area is 0.7-1. According to the neodymium-iron-boron magnet provided by the invention, the cost can be greatly reduced, and meanwhile, good demagnetization resistance is kept.

The invention provides a mixing device and a mixing method for neodymium-iron-boron magnet production, and belongs to the technical field of mixing devices.The mixing device comprises a mixing tank body, a detachable top cover is arranged at the top of the mixing tank body, a screening assembly and an airflow crushing assembly are arranged at the top of the top cover, the screening assembly comprises a screening box, and the screening box is arranged at the top of the top cover; the airflow crushing assembly comprises an airflow crushing bin, one side of the screening box is connected with the airflow crushing bin, a stirring cavity is formed in the mixing tank body, a stirring assembly is arranged in the stirring cavity, the stirring assembly comprises a separation cover and two sets of spiral material turning blades, and the separation cover divides the stirring cavity into an inner mixing cavity, a material turning cavity and a top mixing cavity. A plurality of groups of communicating grooves for communicating the inner mixing cavity with the material turning cavity are formed in the bottom end of the separation cover; the two groups of spiral material turning blades are positioned in the material turning cavity; through the arrangement of the airflow crushing assembly, large-particle materials can be crushed into fine particles; and through the arrangement of the stirring assembly, the materials can circulate in different chambers, and uniform mixing of the materials is ensured.

The utility model relates to the technical field of neodymium-iron-boron production detection equipment, in particular to a surface defect detection device for neodymium-iron-boron production, which comprises a working table, an inlet guide bar for vertically entering annular neodymium-iron-boron is arranged on one side of the top of the working table, and an annular neodymium-iron-boron vertical limiting conveying device is arranged on the working table on one side of an outlet of the inlet guide bar. An inner surface defect detection device for detecting the inner surface defect of the annular neodymium iron boron on the limiting conveying device is arranged at the top of the workbench on one side of the limiting conveying device; by detecting the inner surface of the annular neodymium iron boron, when the visual detector detects that the inner surface of the annular neodymium iron boron has defects, the visual detector sends a signal to the controller, and the controller receives and processes the signal and starts the alarm to give an alarm to remind a detector that the inner surface of the annular neodymium iron boron has the defects. The detection efficiency is high, the performance and reliability of neodymium iron boron products are guaranteed, and faults or damage in the using process is reduced.

Disclosed are a neodymium-iron-boron magnet material, a preparation method, use thereof and a motor. The neodymium-iron-boron magnet material has an amorphous RE-rich phase located in a grain boundary phase. The amorphous RE-rich phase, containing elements TM, RE, Cu and Ga at an atom ratio of TM:RE:Cu:Ga=(15-30):(40-60):(10-25):(10-30), accounts for 3-8% by volume of the grain boundary phase. TM is Fe and Co. RE is a rare earth element. The neodymium-iron-boron magnet material increases the coercivity using none or a small amount of heavy rare earth elements, while maintaining high remanence and magnetic energy.

The invention relates to the technical field of neodymium-iron-boron magnets, in particular to a neodymium-iron-boron rare earth magnet and a preparation method thereof.The neodymium-iron-boron rare earth magnet is a sintered neodymium-iron-boron permanent magnet and comprises a main phase, a two-particle grain boundary phase and a triangular area grain boundary phase; the main phase comprises an R2T14B phase, R refers to at least one of Nd and Pr, T refers to Fe, and Co at least contains Fe; the two-particle grain boundary phase comprises a grain boundary copper-rich phase, and / or a needle-shaped ZrBx phase with the width of 10-50 nm, and / or a needle-shaped TiBx phase with the width of 10-50 nm; the triangular region grain boundary phase comprises an FCC type NdOx phase, an RCu phase, an RGa phase, an R-rich phase, a 6: 14 phase and / or a needle-shaped ZrBx phase with the width of 10-50 nm and / or a needle-shaped TiBx phase with the width of 10-50 nm, the neodymium-iron-boron rare earth magnet does not contain heavy rare earth and is good in uniformity, and the coercive force and residual magnetism can be regulated and controlled through the design of the grain boundary phase.

The present application relates to the technical field of tungsten alloy materials, and in particular to a tungsten alloy wire, a preparation method therefor, and a use thereof in cutting of a semiconductor material. The tungsten alloy is composed of the following elements in percentage by mass: 0.4-1.1 wt% of L, 0.001-0.25 wt% of Z, and the balance of tungsten and inevitable impurities, wherein L is one or more than two of lanthanum, cerium, praseodymium, neodymium, gadolinium and erbium, and Z comprises oxygen and carbon. The wire diameter of the wire is 20-60 μm, the wire contains linear L or a compound of L along the wire axis direction, and the radial average width D of L or the compound of L is smaller than or equal to 5 nm. According to the present application, the linear L element is doped between tungsten base bodies, and the radial average width of L is controlled to be smaller than or equal to 5 nm, so that the wire has the tensile strength of 5000 MPa or above under the wire diameter of 20-60 μm, and the machining performance of the tungsten alloy wire is enhanced.

A preparation and diffusion treatment method for a high-performance diffusion coating used for a sintered neodymium-iron-boron magnet. The method comprises the following steps: the preparation of alloy powders, the preparation of glue, the preparation of a diffusion coating, a pretreatment, coating with the coating, surface drying, and a heat treatment. By controlling the components and particle size of the alloy powders, the compounding of the glue, an anti-bonding powder and an auxiliary agent ensures that under the condition of a relatively small usage amount of a diffusion heavy rare earth metal, the coercive force is greatly improved, the residual magnetism is almost not reduced or is slightly reduced, and the phenomena of the shedding of the coating and the bonding of magnetic sheets after diffusion are avoided.

The invention provides a neodymium-iron-boron magnet surface treatment method and a neodymium-iron-boron magnet, and belongs to the technical field of rare earth permanent magnet material preparation. The surface treatment method comprises the steps that a to-be-electroplated magnet with the clean and rough surface is prepared; connecting with a power supply, soaking in a plating solution, and forming a corrosion-resistant plating layer on the surface of the to-be-electroplated magnet through an ion exchange electrodeposition method; wherein the ion exchange electrodeposition method comprises a first stage of synchronously applying a constant magnetic field and a variable-frequency electric field and a second stage of synchronously applying a rotating magnetic field and a variable-frequency electric field, the intensity of the constant magnetic field and the rotating magnetic field is 1000-3000 gs, and the rotating speed of the rotating magnetic field is 20-100 rpm / min. According to the neodymium-iron-boron magnet surface treatment method provided by the invention, a variable-frequency electric field and magnetic field synergistic enhanced ion exchange deposition technology is adopted to improve the deposition efficiency and corrosion resistance of a plating layer, and the neodymium-iron-boron magnet with an excellent corrosion resistance effect is efficiently prepared.

The invention provides a method for strengthening the coercive force of a neodymium-iron-boron magnet through composite reduction grain boundary diffusion, which comprises the following steps of: (1) mixing a reducing agent, a dispersing agent and a composite rare earth diffusion source to obtain mixed powder; the composite rare earth diffusion source comprises a multi-element rare earth compound diffusion source and / or a composite compound diffusion source; (2) coating the mixed powder obtained in the step (1) on the surface of a neodymium-iron-boron magnet to obtain a coating layer magnet; and (3) carrying out sectional composite reduction-grain boundary diffusion heat treatment and tempering treatment on the coated magnet in the step (2) to obtain the neodymium iron boron diffusion magnet. According to the method, the composite rare earth diffusion source is adopted, the preparation cost of the neodymium iron boron diffusion magnet is reduced, meanwhile, the grain boundary diffusion efficiency is improved, and the large-scale market application prospect is achieved.

The present invention relates to the technical field of tungsten alloy materials, and in particular to a tungsten alloy wire, and a preparation method therefor and a use thereof. The tungsten alloy is composed of the following elements in percentage by mass: 0.45-0.9 wt% of L, 0.05-0.2 wt% of oxygen, and the balance being tungsten and inevitable impurities, wherein L is one or more of lanthanum, cerium, praseodymium, neodymium, gadolinium, and samarium, the wire has a wire diameter of 20-60 μm, in the wire, L or compounds of L exist in the axial direction of the wire in a linear shape, and the average width D of L or the compounds of L in the radial direction is less than or equal to 5 nm. The element L is controlled to be doped between the tungsten base materials in a linear shape, and the average width D of L in the radial direction to be less than or equal to 5 nm, so that cracks and wire breakage caused by second-phase particles in the subsequent pressure machining process are greatly reduced, thereby guaranteeing the mechanical strength of the tungsten alloy wire, and thus the wire has a tensile strength of 5000 MPa or above under a wire diameter of 20-60 μm, and the machining performance of the tungsten alloy wire is enhanced.

The invention provides a method for preparing a high-coercivity sintered neodymium-iron-boron magnet, and belongs to the technical field of rare earth permanent magnet material preparation, and the method comprises the following steps: 1, taking the sintered neodymium-iron-boron magnet as a base material, and removing an oxide layer through alkali washing deoiling, ultrasonic water washing and acid pickling cleaning; 2, taking the Pr-Dy-Cu-Ga quaternary alloy as a diffusion source, and cutting the Pr-Dy-Cu-Ga quaternary alloy into slices; 3, attaching the thin sheet to the surface of a base material for diffusion heat treatment; fourthly, low-temperature tempering is conducted; 5, testing a room temperature demagnetization curve of the sample; light rare earth Pr replaces a part of heavy rare earth Dy and is matched with Cu and Ga elements in a certain proportion to be smelted to obtain quaternary alloy, the quaternary alloy with low heavy rare earth serves as a diffusion source, the microscopic characteristics of the magnet are improved, grain boundary phase distribution is optimized, and under the condition that residual magnetism and the maximum magnetic energy product are slightly reduced, the coercive force of the sintered neodymium-iron-boron magnet is improved; and terbium and dysprosium are not used, so that the use amount of heavy rare earth elements and the production cost are reduced.

The invention discloses a grain boundary diffusion method of a high-performance sintered neodymium-iron-boron magnet. The preparation method comprises the following steps: sequentially carrying out hydrogen decrepitation, jet milling, magnetic field forming, cold isostatic pressing and low-temperature presintering treatment on a neodymium-iron-boron alloy rapid hardening sheet to obtain a presintered neodymium-iron-boron magnet; depositing a non-rare earth metal or metal oxide film layer on the surface of the pre-sintered magnet by using a pulse laser deposition process; performing diffusion heat treatment on the neodymium-iron-boron magnet deposited with the non-rare earth metal or metal oxide film layer; depositing a heavy rare earth element film layer on the surface of the treated neodymium-iron-boron magnet by using the pulse laser deposition process again; and performing diffusion heat treatment and tempering treatment on the treated neodymium-iron-boron magnet. According to the method, the diffusion cost is reduced, meanwhile, the diffusion depth of heavy rare earth elements in the magnet is increased, the neodymium-iron-boron magnet with high coercive force and high magnetic energy product is prepared, and the urgent application requirements of emerging industries such as rare earth permanent magnet motors are met.

The invention discloses a neodymium-zirconium co-substituted M-type strontium ferrite wave-absorbing material and a preparation method thereof, the chemical formula of the neodymium-zirconium co-substituted M-type strontium ferrite wave-absorbing material is Sr1-xNdxZr0. 2Fe11.8 O19, and x is more than or equal to 0.1 and less than or equal to 0.4. The method comprises the following steps: (1) mixing strontium nitrate, ferric nitrate nonahydrate, neodymium nitrate hexahydrate, zirconium nitrate pentahydrate, citric acid monohydrate and deionized water, stirring and dissolving to obtain sol; (2) adjusting the pH value of the sol to 6.5-7.5, and then heating to carry out sol-gel reaction to obtain wet gel; (3) drying and grinding the wet gel to obtain precursor powder; and (4) performing heat treatment on the precursor powder in a box-type furnace, cooling and grinding to obtain the neodymium-zirconium co-substituted M-type strontium ferrite wave-absorbing material. According to the material, effective wave-absorbing frequency band broadening is achieved, the matching thickness corresponding to the effective wave-absorbing bandwidth is as thin as 0.55-0.7 mm, and meanwhile, the performance requirements of thinness, width and strength in the field of electromagnetic compatibility are met.

The invention discloses sintered neodymium-iron-boron magnet grinding machining equipment, and relates to the technical field of neodymium-iron-boron magnet machining, the sintered neodymium-iron-boron magnet grinding machining equipment comprises a machining table, the machining table is provided with a grinding assembly, a clamping assembly, a steering adjusting assembly and a cooling assembly, and the clamping assembly is used for clamping a magnet body; the grinding assembly is used for achieving grinding machining of a magnet body, the steering adjusting assembly is used for achieving rotation of the magnet body and achieving multi-directional machining of the magnet body in a matched mode, and the cooling assembly is used for cooling treatment when the magnet body is machined, so that machining is more stable. A plurality of through grooves are formed in the machining table, and a waste collecting assembly is arranged in the machining table and used for collecting machined waste. The problems that in the prior art, a grinding mechanism is directly driven by a feeding mechanism to conduct grinding, the microstructure of a magnet is easily damaged, and the magnetic performance is reduced are solved.

The invention relates to a high-flux selective diffusion agent and application thereof. The high-flux selective diffusion agent is obtained by mixing heavy rare earth-containing spherical powder and a solid organic binder and then melting and processing; the particle size of the heavy rare earth-containing spherical powder is 10-60 [mu] m, and the sphericity is greater than 85%. According to the method, the heavy rare earth-containing spherical powder with high sphericity degree and good fluidity and the raw material suitable for additive manufacturing are adopted, and the comprehensive magnetic performance of the subsequently prepared magnet can be remarkably improved by strictly controlling the morphology of the heavy rare earth-containing spherical powder. According to the method, the high-flux selected area dispersion technology is combined with the additive manufacturing means, selected area diffusion is conducted on the surface of the neodymium-iron-boron magnet, and the coercive force and high-temperature stability of the neodymium-iron-boron magnet can be greatly improved under the condition that the use amount of heavy rare earth is small. The method is suitable for multi-batch and small-batch production exploration and has the advantages of being high in technological process automation process and short in research and development period.

The invention provides a method for coating slurry on the surface of a sintered neodymium-iron-boron matrix, a preparation method of a sintered neodymium-iron-boron magnet and the slurry. The method for coating the surface of the sintered neodymium-iron-boron substrate with the slurry comprises the steps that the slurry is prepared; wherein the slurry comprises powder containing heavy rare earth elements, an organic solvent and a binder, and the viscosity of the slurry is 2000-5000 mPa.s; and coating the surface of the sintered neodymium-iron-boron substrate with the slurry by adopting a roller coater to form a coating layer. The slurry provided by the invention is low in viscosity, good in flowability, low in thixotropy, low in shear viscosity mutation rate and low in temperature sensitivity, the weight gain uniformity of magnets in each batch and between batches is good, and the coercive force is obviously improved.

The present application provides an entropy-regulated composite dielectric film, which comprises a polymer matrix; and fillers dispersed in the polymer matrix, wherein the fillers comprise Bi 4‑a M 1a Ti (3‑3b) M 2b O 12 , wherein M1 comprises at least one of lanthanum, neodymium, samarium and praseodymium, M2 comprises at least one of zirconium, hafnium and tin, 0 The entropy-regulated composite dielectric film has high temperature resistance, high breakdown strength, high polarization strength, high energy storage density and good stability.

The invention relates to a diffusion source for a neodymium-iron-boron magnet and a preparation method and application of the diffusion source. The invention discloses a rare-earth metal catalyst which comprises the following components in percentage by mass: 46%-49% of an organic solvent, 0.1%-2% of an adhesive, 0.1%-5% of a metal oxide and 46%-49% of rare-earth metal, and the melting point of the metal oxide is higher than that of the neodymium-iron-boron magnet. The specific organic solvent, the adhesive, the metal oxide and the rare earth metal are matched for use according to a specific matching relation, so that the diffusion source is more stable, the diffusion effect is improved, and when the magnet attached with the diffusion source is subjected to thermal diffusion treatment, the rare earth metal can be diffused into the magnet so as to improve the coercive force and other properties of the magnet. In the process, the high-melting-point metal oxide is adhered to the surface of the magnet and then serves as a spacer, the adhesion phenomenon of the magnet in the high-temperature sintering diffusion process is reduced or avoided, grain boundary diffusion is further promoted, and the performance of the magnet is improved.

The invention relates to the technical field of laser control, and discloses a 920nm femtosecond pulse fiber laser system based on a neodymium-doped fiber. The system comprises a seed laser source system, a pre-chirp system, an amplification system and a compression system, the output end of the seed laser source system is connected with the input end of the pre-chirp system, the output end of the pre-chirp system is connected with the input end of the amplification system, and the output end of the amplification system is connected with the input end of the compression system. Through a pre-chirp management method, the seed pulse can simultaneously realize the improvement of the pulse energy and the violent broadening of the spectrum in the amplification process. And a wider spectrum can obtain a narrower pulse width after being subjected to time domain compression. The narrower the width of the pulse means that the energy is more concentrated, so that the peak power of the laser pulse output after compression is higher, and the problem that narrow pulse width and high energy output cannot be simultaneously realized in the 920nm wave band in the existing fiber laser technology is solved.

The invention discloses a grain boundary diffusion method of a sintered neodymium-iron-boron magnet. The grain boundary diffusion method comprises the following steps: providing a magnet to be diffused; coating the surface of the magnet to be diffused with coating slurry containing heavy rare earth metal powder, and performing grain boundary diffusion after vacuum heat preservation and dehydrogenation; the vacuum heat preservation dehydrogenation process comprises the steps that under the vacuum condition, the temperature is increased to 220-250 DEG C from the normal temperature after 1-1.5 h, heat preservation is conducted for 2-3 h, then the temperature is increased to 520-560 DEG C after 1-2 h, and heat preservation is conducted for 1-2 h; the grain boundary diffusion process comprises the following steps: heating to 650-750 DEG C after 1-1.5 hours, and preserving heat for 24-30 hours for permeation; and finally, the temperature is increased to 970-1000 DEG C after 1-1.5 h, and heat preservation is conducted for 2-3 h. According to the grain boundary diffusion method, the coercive force of the center part of the sintered neodymium-iron-boron magnet with the high permeation thickness can be remarkably improved, and the intrinsic coercive force gradient difference of the surface layer and the center part of the magnet is reduced.