Method for improving residual magnetism of neodymium iron boron and application thereof

Abstract

The invention discloses a method for improving residual magnetism of neodymium iron boron and application of the method. The method comprises the following steps: providing a multi-element neodymium iron boron main alloy and an auxiliary alloy; carrying out heat treatment on the auxiliary alloy; the multi-element neodymium-iron-boron main alloy and the auxiliary alloy subjected to heat treatment are subjected to hydrogen demolishing and jet milling in sequence, and multi-element neodymium-iron-boron main alloy fine powder and auxiliary alloy fine powder are obtained respectively; and after the multi-element neodymium iron boron main alloy fine powder and the auxiliary alloy fine powder are uniformly mixed, profiling, vacuum sintering, first tempering heat treatment and second tempering heat treatment are performed, so that the residual magnetism of neodymium iron boron is improved. According to the method, the alloy components are accurately controlled, and the organization structure of the precursor alloy is optimized through heat treatment, so that non-magnetic impure phases generated due to component deviation are reduced fundamentally. The coercive force of the prepared neodymium-iron-boron magnet is ensured while the residual magnetism is improved, and a key material support is provided for the field with the strict requirement for the magnetic performance.

Description

Technical Field

[0001] This invention belongs to the field of rare earth permanent magnet material production technology, specifically relating to a method for improving the remanence of neodymium iron boron magnets and its application. Background Technology

[0002] Sintered NdFeB magnets, due to their extremely high energy density, can meet the lightweighting requirements of modern industrial development and are essential core materials in fields such as new energy vehicles, wind power, rail transportation, and industrial robots. Remanence, as a specific indicator characterizing the strength of magnetic properties exhibited by permanent magnet materials, is of great guiding significance for the selection of permanent magnets in different application scenarios. Increasing remanence can directly drive further reduction in magnet size and lower the energy consumption of various electromechanical equipment, which has significant practical and strategic value for achieving national energy conservation and emission reduction goals and promoting green and low-carbon development.

[0003] According to ferromagnetic theory, the remanence of sintered Nd2Fe magnets is related to the magnetic properties of Nd2Fe. 14 The volume fraction of the B-phase grains is positively correlated with the remanence. Non-magnetic / weakly magnetic impurity phases (such as Nd-rich phases, Fe2B, FeB, α-Fe, etc.) dilute the proportion of the main phase, directly leading to a decrease in remanence. In actual production, to achieve better overall performance in sintered NdFeB magnets, non-magnetic trace elements such as Cu and Al are often introduced to replace the major elements Nd and Fe. These trace elements work synergistically to optimize the grain boundary phase and improve the uniformity of the microstructure. However, this process causes the elemental stoichiometry in the magnet to deviate from 2:14:1, essentially increasing coercivity at the expense of remanence. Conversely, to improve remanence, the use of trace elements can usually only be reduced. Thus, remanence and coercivity, two key permanent magnet performance parameters, become mutually restrictive. This not only limits the application scenarios of NdFeB but also adversely affects the development of related industries.

[0004] In the current technology, the remanence of NdFeB is mainly improved by increasing the orientation degree. For example, patent CN115602439A discloses a method to improve the remanence of NdFeB, which mainly adopts wet pressing and adds a large amount of lubricant to promote the rotation of magnetic powder, thereby improving the orientation degree and remanence. However, the disadvantage is that the use of a large amount of organic solvent will introduce impurity elements such as C, O, and N, which will damage other properties of the magnet.

[0005] Therefore, in the research and development and production of sintered NdFeB magnets, ensuring that other key performance indicators such as coercivity do not decline while improving remanence has become a highly challenging technical hurdle. Currently, the industry urgently needs to develop a simple and efficient new method to improve the remanence of NdFeB magnets. This method must possess two key characteristics: firstly, a breakthrough in composition design that reduces the "dilution" of non-magnetic impurities relative to the main phase, while simultaneously ensuring coercivity without sacrificing remanence through innovative grain boundary control mechanisms; secondly, an economical and feasible process route that eliminates the need for complex auxiliary processes (such as additional degreasing and multi-level magnetic field control), is compatible with existing production lines, and achieves increased efficiency in large-scale production. Summary of the Invention

[0006] The main objective of this invention is to provide a method for improving the remanence of neodymium iron boron and its application, so as to overcome the shortcomings of the prior art.

[0007] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0008] The first aspect of the present invention provides a method for improving the remanence of neodymium iron boron magnets, comprising:

[0009] We offer multi-element NdFeB main alloys and auxiliary alloys;

[0010] The auxiliary alloy is subjected to heat treatment;

[0011] The multi-element NdFeB main alloy and the heat-treated auxiliary alloy are subjected to hydrogen rupture and air jet milling respectively to obtain fine powder of multi-element NdFeB main alloy and fine powder of auxiliary alloy respectively.

[0012] After the fine powder of the multi-element NdFeB main alloy and the fine powder of the auxiliary alloy are mixed evenly, the mixture is subjected to molding, vacuum sintering, first tempering heat treatment and second tempering heat treatment, thereby improving the remanence of NdFeB.

[0013] In some embodiments, the molecular formula of the multi-element NdFeB master alloy is R a T b B c M d , where a, b, c, and d represent the weight percentages of R, T, B, and M in the total NdFeB main alloy, respectively.

[0014] In some embodiments, the molecular formula of the auxiliary alloy is R. e T f B g M h , where e, f, g, and h represent the weight percentages of R, T, B, and M in the total auxiliary alloy, respectively.

[0015] In some embodiments, R includes, but is not limited to, at least any one of Nd, Pr, La, Y, Ce, Dy, and Tb.

[0016] In some embodiments, T includes, but is not limited to, at least any one of Fe, Co, and Ni.

[0017] In some embodiments, B is elemental boron.

[0018] In some embodiments, M includes, but is not limited to, any one or a combination of several of Ga, Nb, Zr, Cu, Al, V, Ti, Mo, Si, and Mn.

[0019] In some embodiments, in the multi-component neodymium-iron-boron master alloy, a, b, c, and d satisfy the following conditions: 26.6 wt% ≤ a ≤ 34 wt%, 60 wt% ≤ b ≤ 75 wt%, 0.6 wt% ≤ c ≤ 1.1 wt%, 0.1 wt% ≤ d ≤ 3.5 wt%, and the total of a + b + c + d is 100.

[0020] In some embodiments, in the auxiliary alloy, e, f, g, and h satisfy the following conditions: 5 wt% ≤ e ≤ 30 wt%, 65 wt% ≤ f ≤ 90 wt%, 0 wt% ≤ g ≤ 1.1 wt%, 0 wt% ≤ h ≤ 2 wt%, and the total of e + f + g + h is 100.

[0021] In some embodiments, the method includes: mixing the multi-component neodymium-iron-boron master alloy powder and the auxiliary alloy powder in a ratio of x:y and subjecting them to compacting and sintering, where 80 wt.% ≤ x ≤ 99.9 wt.%, 0.1 wt.% ≤ y ≤ 20 wt.%, and the total of x + y is 🌐100. <🌐

[0022] In some embodiments, if the content of R in the multi-component neodymium-iron-boron master alloy and the auxiliary alloy is a < e, then the content of B is c > g; if the content of R in the multi-component neodymium-iron-boron master alloy and the auxiliary alloy is a > e, then the content of B is c < g; and after mixing the multi-component neodymium-iron-boron master alloy and the auxiliary alloy, 26.6 ≤ xa + ye ≤ 34, 0.9 ≤ xc + yg ≤ 1.05.

[0023] The second aspect of the present invention provides a high-remanence neodymium-iron-boron magnet prepared by the above method.

[0024] The third aspect of the present invention provides an application of the high-remanence neodymium-iron-boron magnet in the fields of consumer electronics, auxiliary motors for new energy vehicles, or in-vehicle magnetic components.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] (1) This invention implements precise and refined control of the magnet composition through dual alloys, focusing on optimizing and calibrating the stoichiometric ratio of main elements such as neodymium (Nd), iron (Fe), and boron (B) to make it strictly approach the ideal 2:14:1 ratio (i.e., Nd2Fe). 14 (Stoichiometry of phase B). This regulation mechanism can significantly reduce non-magnetic or weakly magnetic impurity phases such as neodymium-rich phase and α-Fe phase generated inside the magnet due to compositional deviation, and greatly improve the strong magnetic properties of Nd2Fe. 14 The volume ratio of the BB principal phase in the magnet is brought infinitely close to the theoretical design value. Based on this technological advantage, this invention can stably prepare ultra-high remanent NdFeB magnets with remanent magnetic properties that surpass conventional levels, providing key material support for fields with stringent magnetic performance requirements.

[0027] (2) The method for improving the remanence of NdFeB magnets provided by this invention has significant advantages for industrial production while ensuring the high remanence of the magnets: First, the production process of this invention is consistent with the basic process of existing industrial production, the core steps are clear and controllable, and there is no need to add complex special equipment or additional production processes. The production operation is simple and convenient, which helps to reduce the equipment investment and labor costs of enterprises and improve production efficiency. Second, in the entire preparation process, through the control of raw material purity and optimization of the process environment, no additional organic solvents are used, and no impurity elements such as carbon and nitrogen are introduced. This avoids the damage of impurities to the crystal structure of the magnet and the deterioration of magnetic properties, ensuring that the intrinsic magnetism of the magnet is not disturbed from the source, and providing a pure material basis for the stable performance of high remanence. This method takes into account performance, consistency and industrial feasibility, and provides a practical and feasible technical path for the large-scale application of high remanence magnets. Detailed Implementation

[0028] In view of the problems existing in the prior art, the inventors of this invention have conducted extensive and in-depth research and have provided a method for improving the remanence of neodymium iron boron and its application.

[0029] The following will provide a further explanation of the technical solution, its implementation process, and its principles.

[0030] The first aspect of the present invention provides a method for improving the remanence of NdFeB magnets, comprising:

[0031] We offer multi-element NdFeB main alloys and auxiliary alloys;

[0032] The auxiliary alloy is subjected to heat treatment;

[0033] The multi-element NdFeB main alloy and the heat-treated auxiliary alloy are subjected to hydrogen rupture and air jet milling respectively to obtain fine powder of multi-element NdFeB main alloy and fine powder of auxiliary alloy respectively.

[0034] After the fine powder of the multi-element NdFeB main alloy and the fine powder of the auxiliary alloy are mixed evenly, the mixture is subjected to molding, vacuum sintering, first tempering heat treatment and second tempering heat treatment, thereby improving the remanence of NdFeB.

[0035] In this invention, heat treatment of the auxiliary alloy can eliminate disordered agglomerates and uniform rare-earth-enriched phases, and avoid sintering crystal boundary defects. Simultaneously, it can suppress the precipitation of soft magnetic impurities, relax rapid quenching internal stress, alleviate brittleness, and optimize powder preparation and forming processability. This auxiliary alloy has a low Nd content and a high Fe content, and the prepared grains are mostly dot-like, strip-like agglomerates, or discontinuous flakes.

[0036] Two tempering heat treatments can optimize the morphology, decompose the segregated blocky Nd-rich phase and spread it uniformly along the main phase grain boundaries, transforming it into a continuous, thin and lustrous nanoscale grain boundary film; at the same time, tempering can eliminate soft magnetic impurities such as α-Fe and Fe3B.

[0037] In some implementations, the method specifically includes: using high-vacuum induction melting technology to melt and rapidly solidify the raw materials of the multi-element NdFeB main alloy and auxiliary alloy respectively, to form multi-element NdFeB main alloy castings and auxiliary alloy castings respectively;

[0038] The auxiliary alloy casting is heat-treated;

[0039] The multi-element NdFeB main alloy casting and the heat-treated auxiliary alloy casting were subjected to hydrogen rupture and air jet milling respectively to obtain the multi-element NdFeB main alloy fine powder and the auxiliary alloy fine powder respectively.

[0040] The fine powder of the multi-element NdFeB main alloy and the fine powder of the auxiliary alloy are mixed evenly, and then subjected to molding, vacuum sintering, first tempering heat treatment and second tempering heat treatment, thereby improving the remanence of NdFeB.

[0041] In some more specific implementations, the method specifically includes: using the high-vacuum induction melting technology to melt the raw materials of the multi-element NdFeB main alloy and auxiliary alloy respectively, and then pouring them onto a water-cooled copper roller for rapid solidification to form the multi-element NdFeB main alloy casting and auxiliary alloy casting respectively.

[0042] In some implementations, the method specifically includes: heat-treating the auxiliary alloy casting at 820–980°C for 2–6 hours.

[0043] In some implementations, the particle size of the multi-element NdFeB main alloy fine powder and auxiliary alloy fine powder is 1~5μm.

[0044] In some embodiments, the method further includes: mixing the multi-element NdFeB main alloy fine powder and auxiliary alloy fine powder evenly, adding 0.05~0.15wt% of orientation lubricant, and obtaining a magnet blank after pressing, and further densifying the magnet in a cold isostatic pressing environment.

[0045] Furthermore, the vacuum degree during the melting process is ≤5×10⁻⁶. -2 Pa.

[0046] Furthermore, during the rapid solidification process of the multi-element NdFeB main alloy casting, the linear velocity of the copper roller is 1.5 m / s to 3 m / s, and the thickness is 150 to 400 μm; during the rapid solidification process of the auxiliary alloy casting, the linear velocity of the copper roller is greater than 3 m / s, and the thickness is less than 150 μm.

[0047] Furthermore, the particle size of the main alloy fine powder and the auxiliary alloy fine powder of the multi-element NdFeB alloy is 1~4μm.

[0048] Furthermore, the ambient oxygen content during the molding process is ≤300ppm, the magnetic field strength is ≥1.8T, the orientation direction is ≤50mm, and the density of the molded magnet blank is 3.6 g / cm³. 3 ≤ρ≤4 g / cm 3 .

[0049] Furthermore, the isostatic pressure in the cold isostatic pressing environment is 180MPa~300MPa, and the density of the magnet blank after cold isostatic pressing is 4.2~4.7g / cm³. 3 .

[0050] Furthermore, the vacuum sintering temperature is 1010~1110℃, the time is 2~6h, and the vacuum degree is ≤9×10 -3 Pa.

[0051] Furthermore, the first tempering heat treatment is performed at a temperature of 850~950℃ for 1~4 hours, and the second tempering heat treatment is performed at a temperature of 450~600℃ for 1~4 hours. The first tempering (850~950℃) precipitates and reconstructs the Nd:N phase at the grain boundaries, causing the non-equilibrium solidified and unevenly distributed Nd:N liquid phase, which solidified during rapid cooling after sintering, to remelt and uniformly distribute around the main phase grains, forming a continuous and smooth thin layer. The second tempering (450~650℃) optimizes the structure and composition of the grain boundary phase, eliminates lattice defects, further adjusts the composition, distribution, and wettability of the Nd:N phase, and eliminates micro-stress and lattice defects within the main phase grains caused by rapid cooling or the first tempering.

[0052] In some more specific embodiments, the method of the present invention for improving the remanence of NdFeB magnets may include the following steps:

[0053] S1, the multi-element NdFeB main alloy A1, and the auxiliary alloy A2 are all prepared by high-vacuum induction melting. The raw materials for both are melted under high-frequency induction melting and then cast onto water-cooled copper rollers for rapid cooling, forming multi-element NdFeB main alloy A1 and auxiliary alloy A2 castings, respectively. Preferably, the vacuum degree of the equipment during the preparation process is ≤5×10⁻⁶. -2 Pa prepared the thickness of the multi-element NdFeB main alloy A1 casting between 150 and 400 μm, and the thickness of the auxiliary alloy A2 casting less than 150 μm.

[0054] The S2 and auxiliary alloy A2 castings are subjected to a heat treatment at a temperature of 820~980℃ for 2~6 hours, followed by argon purging and cooling to room temperature.

[0055] S3, the main NdFeB alloy A1 casting, and the auxiliary alloy A2 casting are respectively processed into coarse powder by a hydrogen crushing furnace, and then further processed into fine powder by an air jet mill. Preferably, the fine powder has a particle size of 1~4μm.

[0056] S4, fine powder of the main NdFeB alloy A1 and fine powder of the auxiliary alloy A2 are mixed evenly in proportion to obtain a mixed powder.

[0057] S5. Add 0.1% orientation lubricant to the mixed powder by mass, and then press it into a blank in a magnetic field orientation molding press under inert gas protection. The magnetic blank is vacuum-sealed in an inert gas environment and placed in a cold isostatic pressing device. Preferably, the oxygen content of the molding environment is ≤300ppm, the magnetic field strength is ≥1.8T, the orientation direction is ≤50mm, and the density of the molded blank is 3.6 g / cm³. 3 ≤ρ≤4 g / cm 3 The isostatic pressing pressure is 180MPa~300MPa, and the density of the blank after isostatic pressing is 4.2~4.7g / cm³. 3 .

[0058] S6. The magnet blank is sintered in a vacuum sintering furnace. After heating, argon gas is introduced, and the furnace is rapidly cooled to room temperature using a blower. Preferably, the blank is held at 1010~1110℃ for 2~6 hours, and the vacuum degree is ≤9×10⁻⁶. -3 Pa.

[0059] S7. After sintering, perform the first tempering heat treatment at 850~950℃ for 1~4 hours, followed by the second tempering heat treatment at 450~600℃ for 1~4 hours.

[0060] A second aspect of the present invention provides a high remanence neodymium iron boron magnet, which is prepared by the above method.

[0061] In some embodiments, the stoichiometric ratio of the elements in the high remanence NdFeB magnet is Nd:Fe:B = 26.6~34:64.1~72.5:0.9~1.05.

[0062] A third aspect of the invention provides the application of the high remanence neodymium iron boron magnet in the fields of consumer electronics, auxiliary motors for new energy vehicles, or automotive magnetic components.

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0064] For experiments not specifically described in the examples, the procedures or conditions can be performed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available. Other unmentioned raw materials and instruments are all conventionally chosen and do not involve the core technical means of this invention.

[0065] Example 1

[0066] Main alloy A1 composition: Nd 28.5 Co 0.1 Cu 0.1 Zr 0.1 Ti 0.1 B 0.9 Fe 70.2

[0067] Auxiliary alloy A2 composition: Nd 17.8 Fe 81.2 B1

[0068] A method to improve the remanence of NdFeB magnets:

[0069] S1 The main alloy A1 and the auxiliary alloy A2 are respectively prepared into castings by high vacuum induction rapid solidification melting. The linear speed of the copper roller during the rapid solidification of the A1 casting is 1.7m / s and the average thickness is 280μm. The linear speed of the copper roller during the rapid solidification of the A2 casting is 3.5m / s and the average thickness is 110μm.

[0070] The S2 auxiliary alloy A2 casting was held at 900℃ for 2 hours in a high vacuum heat treatment furnace.

[0071] S3 castings are processed into coarse powder by a hydrogen crushing furnace, and then into fine powder by an air jet mill. During the powder making process, the oxygen content in the atmosphere is controlled below 10 ppm, and the powder particle size is 1~3 μm.

[0072] S4 Mix A1 and A2 fine powders at a ratio of 98%:2% to obtain a mixed powder.

[0073] S5 mixed powder, with 0.1% orientation lubricant added by mass, is pressed into a blank in a magnetic field orientation molding press under inert gas protection; wherein the magnetic field strength is 2T, the orientation direction is 48mm, and the density of the formed magnet blank is 3.85 g / cm³. 3 The blank was vacuum-sealed in an inert gas environment and then placed in a cold isostatic pressing apparatus for further densification under a pressure of 200 MPa. The density of the magnet blank after cold isostatic pressing was 4.4 g / cm³. 3 .

[0074] S6 magnet blanks are subjected to high vacuum heat treatment in a high vacuum furnace (vacuum degree 7.2 x 10⁻⁶). -3 The magnet was heated to 1090℃ for 5 hours and then cooled to room temperature with argon gas to obtain a sintered magnet.

[0075] S7. The temperature of the first tempering heat treatment is 890℃ and the time is 3h. The temperature of the second tempering heat treatment is 485℃ and the time is 2.5h.

[0076] The stoichiometric ratio of elements in the neodymium iron boron magnet prepared in this embodiment is R:Fe:B = 28.29:70.42:0.9.

[0077] Comparative Example 1-1

[0078] The difference between Comparative Example 1-1 and Example 1 is that step S2 is omitted, while the rest of the preparation process parameters are the same.

[0079] Comparative Examples 1-2

[0080] The difference between Comparative Examples 1 and 2 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 1, and the single alloy is directly melted and smelted, with a specific composition of Nd. 28.29 Co 0.1 Cu 0.1 Zr 0.1 Ti 0.1 B 0.9 Fe 70.42 All other preparation process parameters are the same.

[0081] Comparative Examples 1-3

[0082] The difference between Comparative Examples 1-3 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 1, and the single alloy is directly melted and smelted, with a specific composition of Nd. 28.29 Co 0.1 Cu 0.1 Zr 0.1 Ti 0.1B 0.9 Fe 70.42 Furthermore, step S2 is omitted, while all other preparation process parameters remain the same.

[0083] The magnetic properties of the sintered magnets of Embodiment 1 and Comparative Examples 1-1, 1-2, and 1-3 of the present invention are shown in Table 1.

[0084] Table 1. Magnetic properties of sintered magnets in Example 1 and the comparative example.

[0085] As can be seen from Table 1, adding high-speed iron auxiliary alloy and heat-treating the rapid solidification sheet of the auxiliary alloy can effectively improve the remanence of NdFeB sintered magnets without damaging other properties.

[0086] Example 2

[0087] Main alloy A1 composition: Nd 28.2 Tb 0.3 Co 0.1 Cu 0.1 Zr 0.1 B 0.95 Fe 70.25

[0088] Auxiliary alloy A2 composition: Nd 13 Fe 85.7 Ga 0.3 B1

[0089] A method to improve the remanence of NdFeB magnets:

[0090] S1 The main alloy A1 and the auxiliary alloy A2 are respectively prepared into castings by high vacuum induction rapid solidification melting. The copper roller linear speed of the A1 casting is 2.5m / s and the average thickness is 220μm. The copper roller linear speed of the A2 casting is 3.3m / s and the average thickness is 130μm.

[0091] The S2 auxiliary alloy A2 casting was held at 880℃ for 2 hours in a high vacuum heat treatment furnace.

[0092] S3 castings are processed into coarse powder by a hydrogen crushing furnace, and then into fine powder by an air jet mill. During the powder making process, the oxygen content in the atmosphere is controlled below 10 ppm, and the powder particle size is ~2.5 μm.

[0093] S4 Mix A1 and A2 fine powders at a ratio of 95%:5% to obtain a mixed powder.

[0094] S5 mixed powder, with 0.1% orientation lubricant added by mass, is pressed into a blank in a magnetic field orientation molding press under inert gas protection; wherein the magnetic field strength is 2.3T, the orientation direction is 45mm, and the density of the formed magnet blank is 3.88 g / cm³.3 The blank was vacuum-sealed in an inert gas environment and then placed in a cold isostatic pressing apparatus for further densification under a pressure of 180 MPa. The density of the magnet blank after cold isostatic pressing was 4.2 g / cm³. 3 .

[0095] S6 magnet blanks are subjected to high vacuum heat treatment in a high vacuum furnace (vacuum degree 7.2 x 10⁻⁶). -3 The magnet was heated to 1090℃ for 5 hours and then cooled to room temperature with argon gas to obtain a sintered magnet.

[0096] S7. The temperature of the first tempering heat treatment is 900℃ and the time is 3h. The temperature of the second tempering heat treatment is 500℃ and the time is 2h.

[0097] The stoichiometric ratio of elements in the neodymium iron boron magnet prepared in this embodiment is R:Fe:B = 27.7:71:0.95.

[0098] Comparative Example 2-1

[0099] The difference between Comparative Example 2-1 and Example 2 is that step S2 is omitted, while the other preparation process parameters are the same.

[0100] Comparative Example 2-2

[0101] The difference between Comparative Example 2-2 and Example 2-2 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 2, and the single alloy is directly melted and smelted, with a specific composition of Nd. 27.44 Tb 0.29 Co 0.1 Cu 0.1 Ga 0.02 Zr 0.1 B 0.95 Fe 71 All other preparation process parameters are the same.

[0102] Comparative Examples 2-3

[0103] The difference between Comparative Examples 2 and 3 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 2, and the single alloy is directly melted and smelted, with a specific composition of Nd. 27.44 Tb 0.29 Co 0.1 Cu 0.1 Ga 0.02 Zr 0.1 B 0.95 Fe 71 Furthermore, step S2 is omitted, while all other preparation process parameters remain the same.

[0104] The magnetic properties of the sintered magnets of Embodiment 2 and Comparative Examples 2-1, 2-2, and 2-3 of the present invention are shown in Table 2.

[0105] Table 2. Magnetic properties of sintered magnets in Example 2 and the comparative example.

[0106] As can be seen from Table 2, adding high-speed iron auxiliary alloy and heat-treating the rapid solidification sheet of the auxiliary alloy can effectively improve the remanence of NdFeB sintered magnets without damaging other properties.

[0107] Example 3

[0108] Main alloy A1 composition: Nd 28 Co1Al 0.15 Cu 0.1 Zr 0.1 B 1.05 Fe 69.6

[0109] Auxiliary alloy A2 composition: Nd 30 Fe 69.2 B 0.8

[0110] A method to improve the remanence of NdFeB magnets:

[0111] S1 The main alloy A1 and the auxiliary alloy A2 are respectively prepared into castings by high vacuum induction rapid solidification melting. The linear speed of the copper roller during the rapid solidification of the A1 casting is 2.4 m / s and the average thickness is 230 μm. The linear speed of the copper roller during the rapid solidification of the A2 casting is 3.2 m / s and the average thickness is 140 μm.

[0112] The S2 auxiliary alloy A2 casting was held at 9200℃ for 2 hours in a high vacuum heat treatment furnace.

[0113] S3 castings are processed into coarse powder by a hydrogen crushing furnace, and then into fine powder by an air jet mill. During the powder making process, the oxygen content in the atmosphere is controlled below 10 ppm, and the powder particle size is ~2.5 μm.

[0114] S4 Mix A1 and A2 fine powders at a ratio of 95%:5% to obtain a mixed powder.

[0115] S5 mixed powder, with 0.1% orientation lubricant added by mass, is pressed into a blank in a magnetic field orientation molding press under inert gas protection; wherein the magnetic field strength is 2.3T, the orientation direction is 45mm, and the density of the formed magnet blank is 3.95 g / cm³. 3 The blank was vacuum-sealed in an inert gas environment and then placed in a cold isostatic pressing apparatus for further densification under a pressure of 180 MPa. The density of the magnet blank after cold isostatic pressing was 4.2 g / cm³. 3 .

[0116] S6 magnet blanks are subjected to high vacuum heat treatment in a high vacuum heat treatment furnace (vacuum degree 5.3◊10). -3The magnet was heated to 1100℃ for 5 hours and then cooled to room temperature with argon gas to obtain a sintered magnet.

[0117] S7. The temperature of the first tempering heat treatment is 920℃ and the time is 2.5h. The temperature of the second tempering heat treatment is 510℃ and the time is 4h.

[0118] The stoichiometric ratio of elements in the neodymium iron boron magnet prepared in this embodiment is R:Fe:B = 28.1:69.58:1.04.

[0119] Comparative Example 3-1

[0120] The difference between Comparative Example 3-1 and Example 3 is that step S2 is omitted, while the rest of the preparation process parameters are the same.

[0121] Comparative Example 3-2

[0122] The difference between Comparative Examples 3-2 and Example 3-2 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 3, and the single alloy is directly melted and smelted, with a specific composition of Nd. 28.1 Co 0.95 Cu 0.1 Al 0.12 Zr 0.1 B 1.04 Fe 69.58 All other preparation process parameters are the same.

[0123] Comparative Example 3-3

[0124] The difference between Comparative Examples 3-3 and Example 3-3 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 3, and the single alloy is directly melted and smelted, with a specific composition of Nd. 28.1 Co 0.95 Cu 0.1 Al 0.12 Zr 0.1 B 1.04 Fe 69.58 Furthermore, step S2 is omitted, while all other preparation process parameters remain the same.

[0125] The magnetic properties of the sintered magnets of Embodiment 3 and Comparative Examples 3-1, 3-2, and 3-3 of the present invention are shown in Table 3.

[0126] Table 3. Magnetic properties of sintered magnets in Example 3 and the comparative example.

[0127] As can be seen from Table 3, adding high-speed iron auxiliary alloy and heat-treating the rapid solidification sheet of the auxiliary alloy can effectively improve the remanence of NdFeB sintered magnets without damaging other properties.

[0128] Example 4

[0129] Main phase alloy A1 composition: Nd 27 Ce2Co 0.15 Cu 0.1 Zr 0.05 Al 0.15 B 0.98 Fe 69.57

[0130] Auxiliary phase alloy A2 composition: Nd 10 Dy 5.5 Fe 83.5 B1

[0131] A method to improve the remanence of NdFeB magnets:

[0132] S1 The main alloy A1 and the auxiliary alloy A2 are respectively prepared into castings by high vacuum induction rapid solidification melting. The copper roller linear speed of the A1 casting is 1.9m / s and the average thickness is 260μm during the rapid solidification process. The copper roller linear speed of the A2 casting is 3.3m / s and the average thickness is 130μm during the rapid solidification process.

[0133] The S2 auxiliary alloy A2 casting was held at 940℃ for 2 hours in a high vacuum heat treatment furnace.

[0134] S3 castings are processed into coarse powder by a hydrogen crushing furnace, and then into fine powder by an air jet mill. During the powder making process, the oxygen content in the atmosphere is controlled below 10 ppm, and the powder particle size is ~2.2 μm.

[0135] S4. Mix fine powders A1 and A2 at a ratio of 93%:7% to obtain a mixed powder.

[0136] S5 mixed powder, with 0.1% orientation lubricant added by mass, is pressed into a blank in a magnetic field orientation molding press under inert gas protection; wherein the magnetic field strength is 2.5T, the orientation direction is 35mm, and the density of the formed magnet blank is 3.95 g / cm³. 3 The blank was vacuum-sealed in an inert gas environment and then placed in a cold isostatic pressing apparatus for further densification under a pressure of 200 MPa. The density of the magnet blank after cold isostatic pressing was 4.4 g / cm³. 3 .

[0137] S6 magnet blanks are subjected to high vacuum heat treatment in a high vacuum furnace (vacuum degree 5.9 x 10⁻⁶). -3 The magnet was heated to 1080℃ for 5 hours and then cooled to room temperature with argon gas to obtain a sintered magnet.

[0138] S7. The temperature of the first tempering heat treatment is 950℃ and the time is 1 hour. The temperature of the second tempering heat treatment is 450℃ and the time is 4 hours.

[0139] The stoichiometric ratio of elements in the neodymium iron boron magnet prepared in this embodiment is R:Fe:B = 28.06:70.54:0.98.

[0140] Comparative Example 4-1

[0141] The difference between Comparative Example 4-1 and Example 4 is that step S2 is omitted, while the other preparation process parameters are the same.

[0142] Comparative Example 4-2

[0143] The difference between Comparative Examples 4-2 and 4-2 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 4, and the single alloy is directly melted and smelted, with a specific composition of Nd. 25.81 Ce 1.86 Dy 0.39 Co 0.14 Cu 0.09 Zr 0.05 Al 0.14 B 0.98 Fe 70.54 All other preparation process parameters are the same.

[0144] Comparative Example 4-3

[0145] The difference between Comparative Examples 4 and 3 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 4, and the single alloy is directly melted and smelted, with a specific composition of Nd. 25.81 Ce 1.86 Dy 0.39 Co 0.14 Cu 0.09 Zr 0.05 Al 0.14 B 0.98 Fe 70 . 54 Furthermore, step S2 is omitted, while all other preparation process parameters remain the same.

[0146] The magnetic properties of the sintered magnets of Embodiment 4 and Comparative Examples 4-1, 4-2, and 4-3 of the present invention are shown in Table 4.

[0147] Table 4. Magnetic properties of sintered magnets in Example 4 and the comparative example.

[0148] As can be seen from Table 4, adding high-speed iron auxiliary alloy and heat-treating the rapid solidification sheet of the auxiliary alloy can effectively improve the remanence of NdFeB sintered magnets without damaging other properties.

[0149] Example 5

[0150] Main alloy A1 composition: Nd 26 Y3Co 0.1 Ga0.2 Cu 0.1 Ti 0.1 Al 0.15 B 0.9 Fe 69.45

[0151] Auxiliary alloy A2 composition: Nd 12.4 Tb3Fe 83.6 B1

[0152] A method to improve the remanence of NdFeB magnets:

[0153] S1 The main alloy A1 and the auxiliary alloy A2 are respectively prepared into castings by high vacuum induction rapid solidification melting. The copper roller linear speed of the A1 casting is 2.5m / s and the average thickness is 220μm. The copper roller linear speed of the A2 casting is 3.3m / s and the average thickness is 130μm.

[0154] The S2 auxiliary alloy A2 casting was held at 880℃ for 2 hours in a high vacuum heat treatment furnace.

[0155] S3 castings are processed into coarse powder by a hydrogen crushing furnace, and then into fine powder by an air jet mill. During the powder making process, the oxygen content in the atmosphere is controlled below 10 ppm, and the powder particle size is ~2.7 μm.

[0156] S4 Mix A1 and A2 fine powders at a ratio of 95%:5% to obtain a mixed powder.

[0157] S5 mixed powder, with 0.1% orientation lubricant added by mass, is pressed into a blank in a magnetic field orientation molding press under inert gas protection; wherein the magnetic field strength is 2T, the orientation direction is 40mm, and the density of the formed magnet blank is 3.88 g / cm³. 3 The blank was vacuum-sealed in an inert gas environment and then placed in a cold isostatic pressing apparatus for further densification under a pressure of 190 MPa. The density of the magnet blank after cold isostatic pressing was 4.3 g / cm³. 3 .

[0158] S6 magnet blanks are subjected to high vacuum heat treatment in a high vacuum furnace (vacuum degree 4.6 x 10⁻⁶). -3 The magnet was heated to 1100℃ for 5 hours and then cooled to room temperature with argon gas to obtain a sintered magnet.

[0159] S7. The temperature of the first tempering heat treatment is 850℃ and the time is 4h. The temperature of the second tempering heat treatment is 550℃ and the time is 2h.

[0160] The stoichiometric ratio of elements in the neodymium iron boron magnet prepared in this embodiment is R:Fe:B = 28.32:70.16:0.91.

[0161] Comparative Example 5-1

[0162] The difference between Comparative Example 5-1 and Example 5 is that step S2 is omitted, while the other preparation process parameters are the same.

[0163] Comparative Example 5-2

[0164] The difference between Comparative Examples 5-2 and Example 5-2 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 5, and the single alloy is directly melted and smelted, with a specific composition of Nd. 25.32 Tb 0.15 Y 2.85 Co 0.1 Ga 0.19 Cu 0.1 Ti 0.1 Al 0.14 B 0.91 Fe 70.16 All other preparation process parameters are the same.

[0165] Comparative Example 5-3

[0166] The difference between Comparative Examples 5-3 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 5, and the single alloy is directly melted and smelted, with a specific composition of Nd. 25.32 Tb 0.15 Y 2.85 Co 0.1 Ga 0.19 Cu 0.1 Ti 0.1 Al 0.14 B 0.91 Fe 70.16 Furthermore, step S2 is omitted, while all other preparation process parameters remain the same.

[0167] The magnetic properties of the sintered magnets of Embodiment 5 and Comparative Examples 5-1, 5-2, and 5-3 of the present invention are shown in Table 5.

[0168] Table 5. Magnetic properties of sintered magnets from Example 5 and the comparative example.

[0169] As can be seen from Table 5, adding high-iron auxiliary alloys and heat-treating the rapid solidification sheets of the auxiliary alloys can effectively improve the remanence of NdFeB sintered magnets without compromising other properties.

[0170] Example 6

[0171] Main alloy A1 composition: Nd 27.5 Co 0.17 Ga 0.28 Cu 0.1 Ti 0.15 Al 0.15 B 1.1Fe 70.55

[0172] Auxiliary alloy A2 composition: Nd 30 Fe 70

[0173] A method to improve the remanence of NdFeB magnets:

[0174] S1 The main alloy A1 and the auxiliary alloy A2 are respectively prepared into castings by high vacuum induction rapid solidification melting. The linear speed of the copper roller during the rapid solidification of the A1 casting is 2.1 m / s, and the average thickness is 250 μm. The linear speed of the copper roller during the rapid solidification of the A2 casting is 3.2 m / s, and the average thickness is 140 μm.

[0175] The S2 auxiliary alloy A2 casting was held at 900℃ for 2 hours in a high vacuum heat treatment furnace.

[0176] S3 castings are processed into coarse powder by a hydrogen crushing furnace, and then into fine powder by an air jet mill. During the powder making process, the oxygen content in the atmosphere is controlled below 10 ppm, and the powder particle size is ~2.5 μm.

[0177] S4 Mix A1 and A2 fine powders at a ratio of 85%:15% to obtain a mixed powder.

[0178] S5 mixed powder, with 0.1% orientation lubricant added by mass, is pressed into a blank in a magnetic field orientation molding press under inert gas protection; wherein the magnetic field strength is 2.5T, the orientation direction is 38mm, and the density of the formed magnet blank is 3.9 g / cm³. 3 The blank was vacuum-sealed in an inert gas environment and then placed in a cold isostatic pressing apparatus for further densification under a pressure of 200 MPa. The density of the magnet blank after cold isostatic pressing was 4.4 g / cm³. 3 .

[0179] S6 magnet blanks are subjected to high vacuum heat treatment in a high vacuum heat treatment furnace (vacuum degree 3.8◊10). -3 The magnet was heated to 1110℃ for 5 hours and then cooled to room temperature with argon gas to obtain a sintered magnet.

[0180] S7. The temperature of the first tempering heat treatment is 910℃ and the time is 3h. The temperature of the second tempering heat treatment is 480℃ and the time is 2.5h.

[0181] The stoichiometric ratio of elements in the neodymium iron boron magnet prepared in this embodiment is Nd:Fe:B = 27.875:70.468:0.935.

[0182] Comparative Example 6-1

[0183] The difference between Comparative Example 6-1 and Example 6 is that step S2 is omitted, while the other preparation process parameters are the same.

[0184] Comparative Example 6-2

[0185] The difference between Comparative Examples 6-2 and Example 6-2 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 6, and the single alloy is directly melted and smelted, with a specific composition of Nd. 27.875 Co 0.145 Ga 0.238 Cu 0.085 Ti 0.128 Al 0.128 B 0.935 Fe 70.468 All other preparation process parameters are the same.

[0186] Comparative Example 6-3

[0187] The difference between Comparative Examples 6-3 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 6, and the single alloy is directly melted and smelted, with a specific composition of Nd. 27.875 Co 0.145 Ga 0.238 Cu 0.085 Ti 0.128 Al 0.128 B 0.935 Fe 70.468 Furthermore, step S2 is omitted, while all other preparation process parameters remain the same.

[0188] The magnetic properties of the sintered magnets of Embodiment 6 of the present invention and Comparative Examples 6-1, 6-2, and 6-3 are shown in Table 6.

[0189] Table 6. Magnetic properties of sintered magnets in Example 6 and the comparative example.

[0190] As can be seen from Table 6, adding high-iron auxiliary alloys and heat-treating the rapid solidification sheets of the auxiliary alloys can effectively improve the remanence of NdFeB sintered magnets without compromising other properties.

[0191] Example 7

[0192] Main alloy A1 composition: Pr 8.5 Nd 25.5 Co 0.5 Ga 0.15 Cu 0.15 Ti 0.1 Al 0.05 B 0.95 Fe 64.1

[0193] Auxiliary alloy A2 composition: Nd9Fe 90 B1

[0194] A method to improve the remanence of NdFeB magnets:

[0195] S1 The main alloy A1 and the auxiliary alloy A2 are respectively prepared into castings by high vacuum induction rapid solidification melting. The copper roller linear speed of the A1 casting is 1.5m / s and the average thickness is 310μm. The copper roller linear speed of the A2 casting is 3m / s and the average thickness is 150μm.

[0196] The S2 auxiliary alloy A2 casting was held at 820℃ for 2 hours in a high vacuum heat treatment furnace.

[0197] S3 castings are processed into coarse powder by a hydrogen crushing furnace, and then into fine powder by an air jet mill. During the powder making process, the oxygen content in the atmosphere is controlled below 10 ppm, and the powder particle size is ~3 μm.

[0198] S4. Mix fine powders A1 and A2 at a ratio of 99.9%:0.1% to obtain a mixed powder.

[0199] S5 mixed powder, with 0.05% orientation lubricant added by mass, is pressed into a blank in a magnetic field orientation molding press under inert gas protection; wherein the magnetic field strength is 2.2T, the orientation direction is 3.8mm, and the density of the formed magnet blank is 3.9 g / cm³. 3 The blank was vacuum-sealed in an inert gas environment and then placed in a cold isostatic pressing apparatus for further densification under a pressure of 200 MPa. The density of the magnet blank after cold isostatic pressing was 4.4 g / cm³. 3 .

[0200] S6 magnet blanks are subjected to high vacuum heat treatment in a high vacuum heat treatment furnace (vacuum degree 8.2 x 10⁻⁶). -3 The magnet was heated to 1110℃ for 5 hours and then cooled to room temperature with argon gas to obtain a sintered magnet.

[0201] S7. The temperature of the first tempering heat treatment is 890℃ and the time is 3h. The temperature of the second tempering heat treatment is 510℃ and the time is 4h.

[0202] The stoichiometric ratio of elements in the neodymium iron boron magnet prepared in this embodiment is R:Fe:B = 33.976:64.126:0.95.

[0203] Comparative Example 7-1

[0204] The difference between Comparative Example 7-1 and Example 7 is that step S2 is omitted, while the rest of the preparation process parameters are the same.

[0205] Comparative Example 7-2

[0206] The difference between Comparative Examples 7-2 and Example 7-2 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 7, and the single alloy is directly melted and smelted, with a specific composition of Pr. 8.492 Nd25.484 Co 0.5 Ga 0.15 Cu 0.15 Ti 0.1 Al 0.05 B 0.95 Fe 64.126 All other preparation process parameters are the same.

[0207] Comparative Example 7-3

[0208] The difference between Comparative Examples 7-3 is that the chemical formula mass percentage of the magnet is the nominal composition of the alloy after mixing in Example 7, and the single alloy is directly melted and smelted, with a specific composition of Pr. 8.492 Nd 25.484 Co 0.5 Ga 0.15 Cu 0.15 Ti 0.1 Al 0.05 B 0.95 Fe 64.126 Furthermore, step S2 is omitted, while all other preparation process parameters remain the same.

[0209] The magnetic properties of the sintered magnets of Embodiment 7 and Comparative Examples 7-1, 7-2, and 7-3 of the present invention are shown in Table 7.

[0210] Table 7. Magnetic properties of sintered magnets in Example 7 and the comparative example.

[0211] As can be seen from Table 7, adding high-speed iron auxiliary alloy and heat-treating the rapid solidification sheet of the auxiliary alloy can effectively improve the remanence of NdFeB sintered magnets without damaging other properties.

[0212] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0213] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A method for improving the remanence of neodymium iron boron magnets, characterized in that, It includes: Providing a multi - element neodymium - iron - boron master alloy and a subsidiary alloy; Performing heat treatment on the subsidiary alloy; Subjecting the multi - element neodymium - iron - boron master alloy and the heat - treated subsidiary alloy to hydrogen desorption and jet milling in sequence, respectively obtaining multi - element neodymium - iron - boron master alloy fine powder and subsidiary alloy fine powder; After uniformly mixing the multi - element neodymium - iron - boron master alloy fine powder and the subsidiary alloy fine powder, through compacting, vacuum sintering, first tempering heat treatment, and second tempering heat treatment, thereby improving the remanence of neodymium - iron - boron.

2. The method according to claim 1, characterized in that: The molecular formula of the multi-element NdFeB master alloy is R a T b B c M d , where a, b, c, and d represent the weight percentages of R, T, B, and M in the total NdFeB main alloy, respectively; And / or, the molecular formula of the auxiliary alloy is R e T f B g M h , where e, f, g, and h represent the weight percentages of R, T, B, and M in the total auxiliary alloy, respectively; And / or, R includes at least any one of Nd, Pr, La, Y, Ce, Dy, Tb; And / or, T includes at least any one of Fe, Co, Ni; And / or, B is elemental boron; And / or, M includes any one or a combination of several of Ga, Nb, Zr, Cu, Al, V, Ti, Mo, Si, Mn.

3. The method according to claim 2, characterized in that: In the multi - element neodymium - iron - boron master alloy, a, b, c, d satisfy the following conditions: 26.6wt% ≤ a ≤ 34wt%, 60wt% ≤ b ≤ 75wt%, 0.6wt% ≤ c ≤ 1.1wt%, 0.1wt% ≤ d ≤ 3.5wt%, and the total amount of a + b + c + d is 100; And / or, in the subsidiary alloy, e, f, g, h satisfy the following conditions: 5wt.% ≤ e ≤ 30wt%, 65wt.% ≤ f ≤ 90wt%, 0wt.% ≤ g ≤ 1.1wt%, 0wt.% ≤ h ≤ 2wt%, and the total amount of e + f + g + h is 100; And / or, the method includes: mixing the multi - element neodymium - iron - boron master alloy powder and the subsidiary alloy powder in a ratio of x:y and compacting and sintering, where 80wt.% ≤ x ≤ 99.9wt%, 0.1wt.% ≤ y ≤ 20wt%, and the total amount of x + y is 100.

4. The method according to claim 3, characterized in that: If the content of R, a < e, in the multi - element neodymium - iron - boron master alloy and the subsidiary alloy, then the content of B, c > g; if the content of R, a > e, in the multi - element neodymium - iron - boron master alloy and the subsidiary alloy, then the content of B, c < g; and after mixing the multi - element neodymium - iron - boron master alloy and the subsidiary alloy, 26.6 ≤ xa+ye ≤ 34, 0.9 ≤ xc+yg ≤ 1.

05.

5. The method according to claim 1, characterized in that, Specifically, it includes: Using high - vacuum induction melting technology, melting and rapidly solidifying the raw materials of the multi - element neodymium - iron - boron master alloy and the subsidiary alloy respectively to form multi - element neodymium - iron - boron master alloy cast sheets and subsidiary alloy cast sheets; Performing heat treatment on the subsidiary alloy cast sheets; Subjecting the multi - element neodymium - iron - boron master alloy cast sheets and the heat - treated subsidiary alloy cast sheets to hydrogen desorption and jet milling in sequence, respectively obtaining the multi - element neodymium - iron - boron master alloy fine powder and the subsidiary alloy fine powder; Mixing the multi - element neodymium - iron - boron master alloy fine powder and the subsidiary alloy fine powder evenly, and through the compacting, vacuum sintering, first tempering heat treatment and second tempering heat treatment, thereby improving the remanence of neodymium - iron - boron.

6. The method according to claim 5, characterized in that, Specifically, it includes: Using the high - vacuum induction melting technology, melting the raw materials of the multi - element neodymium - iron - boron master alloy and the subsidiary alloy respectively, and then pouring them onto a water - cooled copper roller for rapid solidification to form the multi - element neodymium - iron - boron master alloy cast sheets and the subsidiary alloy cast sheets; And / or, the method specifically includes: performing heat treatment on the subsidiary alloy cast sheets at 820 - 980°C for 2 - 6h; And / or, the particle size of the multi-element NdFeB main alloy fine powder and auxiliary alloy fine powder is 1~5μm; And / or, the method further includes: mixing the multi-element NdFeB main alloy fine powder and auxiliary alloy fine powder evenly, adding 0.05~0.15wt% of orientation lubricant, obtaining a magnet blank after pressing, and further densifying the magnet in a cold isostatic pressing environment.

7. The method according to claim 6, characterized in that, The vacuum degree during the melting process is ≤5×10 -2 Pa; And / or, during the rapid solidification process of the multi-element NdFeB main alloy casting, the linear velocity of the copper roller is 1.5 m / s to 3 m / s, and the thickness is 150 to 400 μm; during the rapid solidification process of the auxiliary alloy casting, the linear velocity of the copper roller is greater than 3 m / s, and the thickness is less than 150 μm. And / or, the particle size of the multi-element NdFeB main alloy fine powder and auxiliary alloy fine powder is 1~4μm; And / or, the ambient oxygen content during the molding process is ≤300ppm, the magnetic field strength is ≥1.8T, the orientation direction is ≤50mm, and the density of the formed magnet blank is 3.6 g / cm³. 3 ≤ρ≤4 g / cm 3 ; And / or, the isostatic pressure in the cold isostatic pressing environment is 180MPa~300MPa, and the density of the magnet blank after cold isostatic pressing is 4.2~4.7g / cm³. 3 ; And / or, the vacuum sintering temperature is 1010~1110℃, the time is 2~6h, and the vacuum degree is ≤9×10 -3 Pa; and / or, the temperature of the first tempering heat treatment is 850~950℃, the time is 1~4h, and the temperature of the second tempering heat treatment is 450~600℃, the time is 1~4h.

8. A high remanence neodymium iron boron magnet, characterized in that, It is prepared by the method of any one of claims 1-7.

9. The high remanence neodymium iron boron magnet according to claim 8, characterized in that: The stoichiometric ratio of the elements in the high remanence NdFeB magnet is Nd:Fe:B = 26.6~34: 64.1~72.5: 0.9~1.

05.

10. The application of the high remanence neodymium iron boron magnet of claim 8 or 9 in the fields of consumer electronics, auxiliary motors for new energy vehicles, or on-board magnetic components.

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