Neodymium-iron-boron material, method for producing and use thereof

Abstract

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

Description

Technical Field

[0001] This invention relates to a neodymium iron boron material, its preparation method, and its application. Background Technology

[0002] Sintered NdFeB permanent magnets are widely used due to their ultra-high energy density. They not only possess high magnetic energy density and excellent temperature resistance, but also offer good cost-effectiveness, making them widely applicable in my country's pillar industries and emerging industries, such as rail transportation, military equipment, wind power generation, low-altitude flight, artificial intelligence, aerospace, medical devices, and precision manufacturing. With the miniaturization, lightweighting, efficiency improvement, and intelligentization of devices in various fields, increasingly higher demands are being placed on the performance of rare earth permanent magnets. In recent years, China has strengthened its control over rare earth exports, especially heavy rare earths, leading to significant price increases for both light and heavy rare earths this year. Coupled with cost pressures from downstream applications such as new energy, this places even greater demands on cost control for sintered NdFeB magnets. Against this backdrop, developing high-performance, low-cost sintered NdFeB magnets has become a key research direction for every NdFeB company and a core competitive advantage for profitability.

[0003] Technical solutions of existing technologies: At present, high-performance magnets are mainly obtained by adding heavy rare earth elements to the substrate and using grain boundary diffusion technology. Many neodymium iron boron companies and universities have conducted a lot of research and development on easily diffused substrates and alloy diffusion technology, grain refinement and other technologies. According to the current research results, to obtain, for example, 52UH magnets, the Tb content of existing technologies is generally above 0.5.

[0004] To obtain low-cost, high-performance magnets, it is essential to first obtain high-performance, easily diffusible substrates. These substrates must not only have high performance but also be easy to diffuse and possess good diffusion characteristics. Currently, many companies' research fails to systematically integrate substrate design with diffusion characteristics, resulting in low substrate performance, poor diffusion effects, or high substrate performance but difficulty in diffusion, high usage of heavy rare earth elements, and low performance improvement. Summary of the Invention

[0005] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies in fabricating low-cost, high-performance magnets, and to provide a neodymium iron boron (NdFeB) material, its preparation method, and its applications. The NdFeB material exhibits excellent remanence and coercivity, and good stability of its magnetic properties.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing neodymium iron boron materials, comprising the following steps:

[0008] S1. Melt and cast the main phase material and the auxiliary phase material respectively to obtain main phase rapid solidification sheet and auxiliary phase rapid solidification sheet;

[0009] S2. The main phase rapid solidification flakes and the auxiliary phase rapid solidification flakes are subjected to hydrogen rupture treatment to obtain main phase coarse powder and auxiliary phase coarse powder, respectively. They are then subjected to air jet milling to obtain main phase fine powder and auxiliary phase fine powder.

[0010] S3. Press the mixture containing the main phase fine powder and the auxiliary phase fine powder to obtain a green body, and sinter it to obtain a NdFeB material matrix;

[0011] S4. The neodymium iron boron material matrix is ​​subjected to diffusion treatment using a diffusion source;

[0012] The main phase material is R. a1 M (b1+c1+d1) T e1 B f1 R is a rare earth element selected from one or more of PrNd, Pr, Nd, Gd, Tb, Dy, and Ho, with a1 being 28.0 wt.%-31.0 wt.%; M is a metallic element selected from one or more of Ga, Al, Cu, Co, Ti, Zr, and Nb, wherein the total amount of Ga, Al, and Cu is b1, b1≤0.50 wt.%; Co is c1, 0.5 wt.%≤c1≤1.50 wt.%; the total amount of Ti, Zr, and Nb is d1, 0.10 wt.%≤d1≤0.30 wt.%; f1 is 0.90 wt.%-0.99 wt.%; T is Fe, e1=100 wt.%-a1-(b1+c1+d1)-f1, where the percentage is the mass percentage of each component in the total mass of the main phase material;

[0013] Wherein, the auxiliary phase material is R a2 M (b2+c2+d2) B f2 R is a rare earth element selected from one or more of PrNd, Pr, Nd, Gd, Tb, Dy, and Ho, with a2 being 30 wt.%-60 wt.%; M is a metallic element selected from one or more of Ga, Al, Cu, Co, Ti, Zr, and Nb, wherein the total amount of Ga, Al, and Cu is b2, 10 wt.% ≤ b2 ≤ 40 wt.%; Co is c2, 5 wt.% ≤ c2 ≤ 30 wt.%; the total amount of Ti, Zr, and Nb is d2, 5 wt.% ≤ d2 ≤ 10 wt.%; 0 ≤ f2 ≤ 0.5 wt.%, and the percentages are the mass percentages of each component relative to the total mass of the auxiliary phase material.

[0014] The diffusion source contains Dy and / or Tb elements.

[0015] In this invention, the PrNd can be a conventional PrNd alloy in the art. The mass ratio of Pr to Nd in the PrNd can be (10-25):(75-90), for example, 10:90, 20:80 or 25:75.

[0016] In some preferred embodiments, the main phase material satisfies the following condition: R is PrNd.

[0017] In some preferred embodiments, the main phase material satisfies the following: a1 is 29.0 wt.%-31.0 wt.%, for example, 30.0 wt.%.

[0018] In some preferred embodiments, the main phase material satisfies the following condition: M is Ga, Cu, Co, or Ti.

[0019] In some preferred embodiments, the main phase material satisfies the following condition: M is Co and Ti.

[0020] In some preferred embodiments, the main phase material satisfies: b1 ≤ 0.25 wt.%, or 0.10 wt.% ≤ b1 ≤ 0.50 wt.%.

[0021] In some preferred embodiments, the main phase material satisfies: c1 is, for example, 1.00 wt.%.

[0022] In some preferred embodiments, the main phase material satisfies: d1 is, for example, 0.12 wt.%.

[0023] In some preferred embodiments, the main phase material satisfies: f1 is, for example, 0.95 wt.%.

[0024] In some preferred embodiments, the main phase material satisfies: e1 is, for example, 67.68 wt.% or 67.93 wt.%.

[0025] In some preferred embodiments, the main phase material is PrNd. 30 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.68 B 0.95 or PrNd 30 Co 1.00 Ti 0.12 Fe 67.93 B 0.95 .

[0026] In some specific implementations, the main phase material is PrNd. 30 Ga 0.15 Cu 0.10 Co1.00 Ti 0.12 Fe 67.68 B 0.95 .

[0027] In some specific implementations, the main phase material is PrNd. 30 Co 1.00 Ti 0.12 Fe 67.93 B 0.95 .

[0028] In this invention, the auxiliary phase material does not contain Fe.

[0029] In some preferred embodiments, the auxiliary phase material satisfies the following condition: R is PrNd.

[0030] In some preferred embodiments, the auxiliary phase material satisfies the following: a2 is 34.0 wt.%-45.0 wt.%, for example, 40.0 wt.% or 44.5%.

[0031] In some preferred embodiments, the auxiliary phase material satisfies the following condition: M is Ga, Al, Cu, Co, Ti, and Zr.

[0032] In some preferred embodiments, the auxiliary phase material satisfies: 20 wt.% ≤ b2 ≤ 35 wt.%, more preferably, 25 wt.% ≤ b2 ≤ 30 wt.%, for example, 28.6 wt.%.

[0033] In some preferred embodiments, the auxiliary phase material satisfies: 15 wt.% ≤ c2 ≤ 25 wt.%, where c2 is, for example, 20.0 wt.%.

[0034] In some preferred embodiments, the auxiliary phase material satisfies: 5 wt.% ≤ d2 ≤ 8 wt.%, where d2 is, for example, 6.6 wt.%.

[0035] In some preferred embodiments, the auxiliary phase material satisfies: f2 is, for example, 0.3 wt.%.

[0036] In some preferred embodiments, the auxiliary phase material is PrNd. 44.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 B 0.3 .

[0037] The auxiliary phase material accounts for 0.3 wt.%-5.0 wt.% of the NdFeB material by mass.

[0038] In some preferred embodiments, the auxiliary phase material accounts for 0.5 wt.% to 2.5 wt.% of the NdFeB material by mass.

[0039] In some embodiments, the average particle size X50 of the main phase fine powder is 2.5-4.5 μm, more preferably 2.5-3.5 μm, for example 4.02 μm, 3.10 μm or 3.03 μm.

[0040] In this invention, the average particle size X50 refers to the diameter of the powder particles corresponding to a cumulative volume percentage of 50%. Those skilled in the art will understand its specific meaning.

[0041] In some embodiments, the average particle size X50 of the auxiliary phase fine powder is 2.5-4.5 μm, more preferably 3.6-4.5 μm, for example 4.12 μm or 3.08 μm.

[0042] In some specific embodiments, the average particle size X50 of the main phase fine powder is 4.02 μm, and the average particle size X50 of the auxiliary phase fine powder is 4.12 μm.

[0043] In some specific embodiments, the average particle size X50 of the main phase fine powder is 4.02 μm, and the average particle size X50 of the auxiliary phase fine powder is 3.08 μm.

[0044] In some specific embodiments, the average particle size X50 of the main phase fine powder is 3.10 μm, and the average particle size X50 of the auxiliary phase fine powder is 4.12 μm.

[0045] In some specific embodiments, the average particle size X50 of the main phase fine powder is 3.10 μm, and the average particle size X50 of the auxiliary phase fine powder is 3.08 μm.

[0046] In some specific embodiments, the average particle size X50 of the main phase fine powder is 3.03 μm, and the average particle size X50 of the auxiliary phase fine powder is 3.08 μm.

[0047] In some implementations, in step S4, the Tb element in the diffusion source exists in the form of an element, an alloy, or a compound.

[0048] In some preferred embodiments, the mass percentage of Tb in the diffusion source to the total mass of the diffusion source is ≥30 wt.%, for example, 49.2 wt.%.

[0049] In some implementations, in step S4, the Dy element in the diffusion source exists in the form of an element, an alloy, or a compound.

[0050] In some preferred embodiments, the mass percentage of Dy in the diffusion source relative to the total mass of the diffusion source is ≤90 wt.%.

[0051] In some alternative embodiments, the diffusion source further comprises one or more elements selected from PrNd, Pr, Nd, Cu, Al, Ga, and Co.

[0052] In some preferred embodiments, the mass percentage of the sum of the masses of PrNd, Pr and Nd in the diffusion source to the total mass of the diffusion source satisfies: 0 < PrNd + Pr + Nd ≤ 40 wt.%, for example, 18.4 wt.%.

[0053] In some preferred embodiments, the mass percentage of Cu in the diffusion source relative to the total mass of the diffusion source satisfies: 0 < Cu ≤ 30 wt.%, for example, 18.3 wt.%.

[0054] In some preferred embodiments, the mass percentage of Al in the diffusion source relative to the total mass of the diffusion source satisfies: 0 < Al ≤ 10 wt.%, for example, 2.3 wt.%.

[0055] In some preferred embodiments, the mass percentage of Ga in the diffusion source relative to the total mass of the diffusion source satisfies: 0 ≤ Ga ≤ 10 wt.%, for example, 5.4 wt.%.

[0056] In some preferred embodiments, the mass percentage of Co in the diffusion source relative to the total mass of the diffusion source satisfies: 0 ≤ Co ≤ 30 wt.%, for example, 6.4 wt.%.

[0057] In some preferred embodiments, the diffusion source is TbH, Tb 49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 or Tb 58 PrNd9Cu 12 Al 8.5 Co 12.5 .

[0058] In some specific implementations, the diffusion source is TbH.

[0059] In some specific implementations, the diffusion source is Tb. 49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 .

[0060] In some specific implementations, the diffusion source is Tb. 58 PrNd9Cu 12 Al 8.5 Co 12.5 .

[0061] In some specific embodiments, in the preparation method of the neodymium iron boron material, the main phase material is PrNd. 30 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.68 B 0.95 The auxiliary phase material is PrNd. 44.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 B 0.3 The diffusion source is Tb. 49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 .

[0062] In some specific embodiments, in the preparation method of the neodymium iron boron material, the main phase material is PrNd. 30 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.68 B 0.95 The auxiliary phase material is PrNd. 44.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 B 0.3 The diffusion source is Tb. 58 PrNd9Cu 12 Al 8.5 Co 12.5 .

[0063] In some specific embodiments, in the preparation method of the neodymium iron boron material, the main phase material is PrNd. 30 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.68B 0.95 The auxiliary phase material is PrNd. 34.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 Fe10B 0.3 The diffusion source is Tb. 49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 .

[0064] In some specific embodiments, in the preparation method of the neodymium iron boron material, the main phase material is PrNd. 30 Co 1.00 Ti 0.12 Fe 67.93 B 0.95 The auxiliary phase material is PrNd. 44.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 B 0.3 The diffusion source is Tb. 49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 .

[0065] In some specific embodiments, in the preparation method of the neodymium iron boron material, the main phase material is PrNd. 30 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.68 B 0.95 The auxiliary phase material is PrNd. 44.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 B 0.3 The diffusion source is TbH.

[0066] In this invention, in step S1, the smelting and casting can be performed using methods conventional in the art. The smelting and casting can be carried out in a continuous furnace.

[0067] In some embodiments, the melting temperature during the preparation of the main phase rapid solidification sheet is 1350°C-1500°C, for example, 1440°C.

[0068] In some embodiments, the melting temperature during the preparation of the auxiliary phase rapid solidification sheet is 1250°C-1450°C, for example, 1440°C.

[0069] In some implementations, in step S1, after the pouring is completed, the furnace is cooled to 40-60°C, for example, 45°C.

[0070] In some embodiments, the thickness of the main phase rapid-setting sheet is 0.20-0.35 mm, for example, 0.26 mm.

[0071] In some embodiments, the thickness of the auxiliary phase quick-setting sheet is 0.25-0.35 mm, for example, 0.26 mm.

[0072] In this invention, in step S2, the hydrogen destruction process can be carried out using a continuous hydrogen destruction furnace.

[0073] In some embodiments, in step S2, the reaction pressure of the hydrogen catalytic treatment is 0.08-0.12 MPa, for example 0.098 MPa.

[0074] In some implementations, during step S2, the dehydrogenation process is carried out at a temperature of 300-600°C, for example, 400°C.

[0075] In some embodiments of the present invention, in step S2, during the hydrogen destruction process, the hydrogen content after dehydrogenation is 500-3000 ppm, for example, 1600 ppm.

[0076] In some implementations, in step S2, after the hydrogen rupture process is completed, the furnace is cooled to 40-60°C, for example, 45°C.

[0077] In this invention, in step S2, the air jet mill can be performed using a multi-nozzle impact fluidized bed air jet mill.

[0078] In some implementations, in step S2, a powder additive is added to the main phase powder.

[0079] Preferably, the powder additive is added at a ratio of 1.5g of powder additive per kg of main phase coarse powder.

[0080] In some implementations, in step S2, a powder additive is added to the main phase fine powder.

[0081] Preferably, the powder additive is added at a ratio of 0.5g of powder additive per kg of main phase fine powder.

[0082] In some embodiments, in step S2, a powder additive is added to the coarse main phase powder before the air jet milling is performed, and the powder additive is added to the fine main phase powder obtained by the air jet milling. The powder additive may include one or more of petroleum ether, methyl acetate, calcium stearate, gasoline, oleamide, zinc stearate, tributyl borate, polyethylene glycol octane, pentane, hexane, turpentine, 120# solvent oil, 200# solvent oil, isopropanol, and cyclohexanone.

[0083] In some implementations, in step S2, a powder additive is added to the main phase powder.

[0084] Preferably, the powder additive is added at a ratio of 1.5g of powder additive per kg of main phase coarse powder.

[0085] In some implementations, in step S2, a powder additive is added to the auxiliary phase powder.

[0086] Preferably, the powder additive is added at a ratio of 0.5g of powder additive per kg of auxiliary phase fine powder.

[0087] In some embodiments, in step S2, powder additives are added to the coarse auxiliary phase powder before the air jet milling is performed, and powder additives are added to the fine auxiliary phase powder obtained by the air jet milling.

[0088] In this invention, adding powder additives during the air jet milling process is a conventional operation in the field. It can prevent particle agglomeration, control particle size distribution, improve grinding efficiency, reduce equipment wear, protect the grinding chamber, prevent oxidation or hydrolysis, improve product stability, and improve the adaptability to downstream processes.

[0089] In this invention, in step S3, the mixture comprising the main phase fine powder and the auxiliary phase fine powder is obtained by mixing the main phase fine powder and the auxiliary phase fine powder. The mixing is sufficient to ensure that the main phase fine powder and the auxiliary phase fine powder are mixed evenly.

[0090] In this invention, in step S3, the pressing can be performed using methods conventional in the art.

[0091] In some implementations, in step S3, the pressing is performed using a semi-automatic press or an automatic press.

[0092] In some implementations, step S3 includes orientation pressing.

[0093] Preferably, the process parameters for the orientation pressing include: pressing orientation direction dimension < 85mm, pressing blank weight < 1.5kg, pressing current ≥ 180A, minimum orientation field at the mold forming position > 1.6T, and oxygen content < 50ppm throughout the pressing process.

[0094] In some implementations, step S3 includes isostatic pressing.

[0095] Preferably, the isostatic pressure is 200 MPa.

[0096] In this invention, the sintering in step S3 can be performed using methods conventional in the art.

[0097] In some implementations, in step S3, the sintering uses one or more of a high-density graphite box, a molybdenum box, a tungsten box, and a carbon ceramic box; preferably, the sintering uses a combination of a high-density graphite box and a molybdenum box.

[0098] In some implementations, in step S3, the sintering process uses a combination of a high-density graphite box and a molybdenum box.

[0099] In some implementations, the sintering in step S3 is performed using a gradient heating method.

[0100] In some implementations, step S3 includes holding the sintering process at multiple temperature ranges, namely 100-200℃, 200-300℃, 350-450℃, 550-680℃, 730-850℃, 900-980℃, and 1000-1200℃.

[0101] Preferably, the heat preservation time at 1000-1200℃ is 4-15 hours.

[0102] In some specific implementations, step S3 includes sintering at 140°C, 260°C, 330°C, 440°C, 560°C, 640°C, 760°C, 830°C and 1068°C for 1h, 1h, 1h, 1.5h, 1.5h, 1.5h, 1.5h, 2.5h and 8h respectively.

[0103] In some implementations, in step S3, the heating rate during the sintering process is 1-3°C / min, for example, 1.5°C / min.

[0104] In some implementations, step S3 further includes an aging treatment after sintering. Preferably, the aging treatment is a two-stage aging treatment.

[0105] In some implementations, the two-stage aging treatment includes: holding at 880-930℃ for 3-10 hours, and then holding at 450-550℃ for 3-10 hours.

[0106] In some specific implementations, the two-stage aging treatment includes: holding at 900℃ for 3 hours, and then holding at 495℃ for 5 hours.

[0107] In this invention, the diffusion process in step S4 can be performed using methods conventional in the art.

[0108] In some embodiments, step S4 includes applying a diffusion source to the surface of the NdFeB substrate and performing a heat treatment.

[0109] In some preferred embodiments, the application is performed by screen printing, spraying, or magnetron sputtering.

[0110] In some implementations, the diffusion process in step S4 is performed using a segmented heat treatment process.

[0111] In some preferred embodiments, in step S4, the diffusion treatment is performed using a segmented heat treatment process, including:

[0112] First stage: Insulation temperature is 880-950℃, and the time is 5-36 hours;

[0113] The second stage: the insulation temperature is 450-550℃, and the time is 3-10 hours.

[0114] In some specific implementations, step S4, the segmented heat treatment process of the diffusion treatment includes:

[0115] First stage: Heat to 910℃ and keep warm for 16 hours;

[0116] Second stage: Cool down to 500℃ and keep warm for 4 hours.

[0117] Secondly, the present invention provides a neodymium iron boron material, which is prepared by the neodymium iron boron material preparation method described above.

[0118] In some preferred embodiments, the neodymium iron boron material includes a main phase grain and a grain boundary phase adjacent to the main phase grain, and the surface of the main phase grain is further provided with a shell layer;

[0119] The main phase grains contain (PrNd)₂Fe. 14 Phase B; the grain boundary phase comprises an alloy formed by at least two elements selected from Pr, Nd, Ga, Al, Cu, Ti, Zr, and Tb; the shell comprises Fe.

[0120] In some embodiments, the grain size of the main phase grains is 4-6 μm, preferably 4-5.5 μm.

[0121] In some embodiments, the main phase grains account for 91 wt.%-97 wt.% of the mass percentage of the NdFeB material, preferably 93.5 wt.%.

[0122] In some embodiments, the mass percentage of Tb element in the NdFeB material is less than 0.60 wt.%, preferably less than 0.50 wt.%.

[0123] In some embodiments, the Br content of the neodymium iron boron material is above 13.0 kGs.

[0124] In some embodiments, the Hcj of the neodymium iron boron material is above 20 kOe.

[0125] In some embodiments, the Hk / Hcj ratio of the neodymium iron boron material is above 95%.

[0126] Thirdly, the present invention also provides an application of the neodymium iron boron material as described above as a magnetic element.

[0127] In this invention, the neodymium iron boron magnet material can be used as a magnetic device in many fields such as rail transportation, military equipment, wind power generation, low-altitude flight, artificial intelligence, aerospace, medical devices, and precision manufacturing.

[0128] In this invention, the symbols for each element have conventional meanings in the art, specifically: "Pr" for praseodymium, "Nd" for neodymium, "Dy" for dysprosium, "Tb" for terbium, "Y" for yttrium, "Ho" for holmium, "Al" for aluminum, "Cu" for copper, "Ga" for gallium, "Co" for cobalt, "Ti" for titanium, "Zr" for zirconium, "Nb" for niobium, "W" for tungsten, "Mo" for molybdenum, "Fe" for iron, and "B" for boron.

[0129] The positive and progressive effects of this invention are as follows:

[0130] This invention employs a main phase to refine grain size and uses an iron-free grain boundary phase to control the composition of the grain boundary phase. Simultaneously, it controls appropriate grain size matching to obtain a substrate blank that possesses both high initial properties and good diffusion characteristics. Through alloy diffusion, the amount of heavy rare earth elements is significantly reduced, resulting in NdFeB materials with excellent remanence and coercivity, and good stability of magnetic properties. The NdFeB material preparation method of this invention can obtain low-cost, high-performance NdFeB materials. Attached Figure Description

[0131] Figure 1 The image shows the metallographic diagram of the M4 blank obtained in Example 3. Detailed Implementation

[0132] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0133] In the following examples and comparative examples, the powder additives used include Tianjin Yuesheng Agent and Dongyang Agent, which are used in a 1:1 mass ratio. Tianjin Yuesheng Agent was purchased from Tianjin Yuesheng New Materials Research Institute, model YSH-01; Dongyang Agent was purchased from Dongyang Antai Magnetic Materials Co., Ltd., model YKJ-10.

[0134] In the following examples and comparative examples, "PrNd" refers to praseodymium-neodymium metal alloys, where the ratio of Pr to Nd is 25:75.

[0135] Example 1

[0136] (1) Preparation of fine powder of main phase:

[0137] S1-1, Preparation of main phase rapid solidification sheets: Composition of main phase material X1: PrNd 30 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.6 8B 0.95 The melting and casting temperatures were 1440℃. The quick-setting sheets were produced in a continuous furnace and completely cooled to below 45℃ before being removed from the furnace. They were then placed in a sealed stainless steel container, and after thorough oxygen removal with argon gas, they were sealed. The thickness of the resulting main phase quick-setting sheets was 0.26mm.

[0138] S2-1. Hydrogenation treatment and air jet milling of the main phase rapid solidification flakes: Hydrogenation treatment is carried out in a continuous hydrogenation furnace at a reaction pressure of 0.098 MPa and dehydrogenation treatment is performed at 400℃ to obtain coarse powder of the main phase. The discharge process requires fully sealed oxygen-free operation. The hydrogen content after dehydrogenation is controlled to be about 1600 ppm. Powder additives are added to the coarse powder of the main phase at a ratio of 1.5 g of powder additives per kilogram of coarse powder of the main phase, and the powder is mixed and stirred for 120 min. Nitrogen gas is used to fully remove oxygen to below 2 ppm in a multi-nozzle impact fluidized bed air jet mill to prepare fine powder of the main phase with a particle size X50 of 4.02 μm. Powder additives are added to the receiving tank of fine powder of the main phase at a ratio of 0.5 g of powder additives per kilogram of fine powder of the main phase, and the fine powder of the main phase is stirred for 120 min after air jet milling.

[0139] (2) Preparation of auxiliary phase fine powder:

[0140] S1-2, Preparation of auxiliary phase rapid-setting sheets: Composition of auxiliary phase material Y1: PrNd 44.5 Ga 2.6 Al6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 B0 .3 The melting and casting temperatures were 1380℃, and the thickness of the resulting quick-setting auxiliary phase sheets was 0.30mm.

[0141] S2-1. Hydrogenation treatment and air jet milling of the main phase rapid solidification flakes: Hydrogenation treatment is carried out in a continuous hydrogenation furnace at a reaction pressure of 0.098 MPa and dehydrogenation treatment is performed at 450℃ to obtain coarse auxiliary phase powder. The discharge process requires fully sealed oxygen-free operation. The hydrogen content after dehydrogenation is controlled to be about 1800 ppm. Powder additives are added to the coarse auxiliary phase powder at a ratio of 1.5 g of powder additives per kilogram of coarse auxiliary phase powder, and the powder is mixed and stirred for 120 min. Nitrogen gas is used to fully remove oxygen to below 2 ppm in a multi-nozzle impact fluidized bed air jet mill to prepare fine auxiliary phase powder with a particle size X50 of 4.12 μm. Powder additives are added to the receiving tank of fine auxiliary phase powder at a ratio of 0.5 g of powder additives per kilogram of fine auxiliary phase powder, and the fine auxiliary phase powder is stirred for 120 min after air jet milling.

[0142] (3) Preparation of NdFeB material matrix:

[0143] The main phase fine powder and auxiliary phase fine powder were mixed at a mass ratio of 98.5:1.5 and then pressed into shape. The pressing current was 210A, the minimum orientation field at the forming position of the mold was >1.6T, and the oxygen content throughout the pressing process was <50ppm. The pressed green body was then subjected to isostatic pressing at a pressure of 200MPa. Sintering was performed using a combination of high-density graphite box and molybdenum box. Before use, the green body required drying at a temperature above 250℃. During the sintering process, a vacuum was applied, and the green body was held at 140℃, 260℃, 330℃, 440℃, 560℃, 640℃, 760℃, 830℃, and 1068℃ for 1h, 1h, 1h, 1.5h, 1.5h, 1.5h, 1.5h, 2.5h, and 8h, respectively. After sintering, the green body underwent two-stage aging treatment under vacuum (900℃, 3h holding; 495℃, 5h holding). The neodymium iron boron material matrix (denoted as M2 blank) is obtained.

[0144] (4) Diffusion treatment: The M2 blank is processed to 30.8 mm. 12.1 4.6mm samples underwent surface activation treatments including degreasing and ultrasonic cleaning, with Tb 49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 Tb was applied to the magnet surface as a diffusion source using a screen printing process.49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 The film layer was subjected to heat treatment: 910℃ for 16 hours and 500℃ for 4 hours; the mass percentage of the film layer to the total mass of the obtained NdFeB material was 0.57 wt.%.

[0145] Example 2

[0146] The difference between this embodiment and Embodiment 1 is that: when preparing the auxiliary phase fine powder, an auxiliary phase fine powder with a particle size X50 of 3.08 μm is prepared; the neodymium iron boron material matrix prepared is denoted as M3 blank.

[0147] The remaining conditions and steps are the same as in Example 1.

[0148] Example 3

[0149] The difference between this embodiment and Embodiment 1 is that: when preparing the main phase fine powder, a main phase fine powder with a particle size X50 of 3.10 μm is prepared; the neodymium iron boron material matrix prepared is denoted as M4 blank.

[0150] The remaining conditions and steps are the same as in Example 1.

[0151] Example 4

[0152] The difference between this embodiment and Embodiment 3 is as follows: ① When preparing the auxiliary phase fine powder, an auxiliary phase fine powder with a particle size X50 of 3.08 μm is prepared; the neodymium iron boron material matrix prepared is denoted as M5 blank; ② When performing diffusion treatment, the M5 blank is subjected to diffusion treatment, wherein the heat treatment conditions are: 905℃ for 16h and 490℃ for 5h.

[0153] The remaining conditions and steps are the same as in Example 3.

[0154] Example 5

[0155] The difference between this embodiment and Embodiment 3 is that the mass ratio of the main phase fine powder to the auxiliary phase fine powder is 97.0:3.0. The prepared NdFeB material matrix is ​​designated as M7 blank.

[0156] The remaining conditions and steps are the same as in Example 3.

[0157] Example 6

[0158] The difference between this embodiment and Embodiment 3 is that the diffusion source is Tb during the diffusion process. 58 PrNd9Cu 12 Al 8.5 Co 12.5The mass percentage of the film layer to the total mass of the obtained NdFeB material was 0.43 wt.%.

[0159] The remaining conditions and steps are the same as in Example 3.

[0160] Example 7

[0161] The difference between this embodiment and Embodiment 2 is that: when preparing the main phase fine powder, ① the composition of the main phase material X3: PrNd 30 Co 1.00 Ti 0.12 Fe 67.93 B 0.95 ② The hydrogen content after dehydrogenation is controlled to be around 1500 ppm; ③ Fine powder with a particle size X50 of 3.03 μm is prepared. The prepared NdFeB material matrix is ​​designated as M9 blank.

[0162] The remaining conditions and steps are the same as in Example 2.

[0163] Example 8

[0164] The difference between this embodiment and Embodiment 1 is that the diffusion source is TbH, and the mass percentage of the film layer to the total mass of the obtained NdFeB material is 0.57 wt.%. The remaining conditions and steps are the same as in Embodiment 1.

[0165] Comparative Example 1

[0166] The preparation method of the NdFeB material in this comparative example includes the following steps:

[0167] First, M1 component quick-setting tablets were prepared separately using a melting method. The nominal component of M1 is: PrNd. 30.22 Ga 0.19 Al 0.09 Cu 0.40 Co 1.29 Ti 0.16 Zr 0.06 Fe 66.65 B 0.94The melting and casting temperature was 1430℃, and the thickness of the quick-setting sheet was 0.30mm. The quick-setting sheet was hydrogen-crushed in a continuous hydrogen-crushing furnace and dehydrogenated at 560℃ to obtain coarse powder. Powder additives were added to the coarse powder at a ratio of 1.5g per kilogram of coarse powder and stirred. Fine powder with a particle size of approximately 4.05μm (X50) was prepared using a nitrogen flow in a collision fluidized bed. Powder additives were added to the fine powder at a ratio of 0.5g per kilogram of fine powder and stirred. Semi-automatic pressing was used, with a minimum orientation field of >1.6T at the mold forming position and an oxygen content of <200ppm throughout the pressing process. After isostatic pressing of the green blank, it was sintered in a graphite box at 1085 for 6.5h. After sintering, it was subjected to two-stage aging treatments: holding at 900℃ for 3h and holding at 500℃ for 5h under vacuum. The resulting NdFeB material matrix was designated as M1-1 blank.

[0168] The M1-1 blank is machined to 30.8 mm. 12.1 The 4.6 mm sample underwent surface activation treatments such as degreasing and ultrasonic cleaning. TbH was then applied to the magnet surface using screen printing. The sample was then heat-treated: 910℃ for 16 h and 500℃ for 4 h. The mass percentage of the film layer to the total mass of the obtained NdFeB material was 0.57 wt.%.

[0169] Comparative Example 2

[0170] The preparation method of the NdFeB material in this comparative example includes the following steps:

[0171] First, M1 component quick-setting tablets were prepared separately using a melting method. The nominal component of M1 is: PrNd. 30.22 Ga 0.19 Al 0.09 Cu 0.40 Co 1.29 Ti 0.16 Zr 0.06 Fe 66.65 B 0.94The melting and casting temperature was 1430℃, and the thickness of the quick-setting sheet was 0.30mm. The quick-setting sheet was hydrogen-crushed in a continuous hydrogen-crushing furnace and dehydrogenated at 560℃ to obtain coarse powder. Powder additives were added to the coarse powder at a ratio of 1.5g per kilogram of coarse powder and stirred. Fine powder with a particle size of approximately 3.00μm (X50) was prepared using a nitrogen flow in a collision fluidized bed. Powder additives were added to the fine powder at a ratio of 0.5g per kilogram of fine powder and stirred. Semi-automatic pressing was used, with a minimum orientation field of >1.6T at the die forming position and an oxygen content of <200ppm throughout the pressing process. After isostatic pressing of the green blank, it was sintered in a graphite box at 1085 for 6.5h. After sintering, it was subjected to two-stage aging treatments: holding at 900℃ for 3h and holding at 500℃ for 5h under vacuum. The resulting NdFeB material matrix was designated as M1-2 blank.

[0172] The M1-2 blank is machined to 30.8 mm. 12.1 The 4.6mm sample underwent surface activation treatments including degreasing and ultrasonic cleaning. Tb was then applied to the magnet surface using a screen printing process. 49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 The material was subjected to heat treatment: 910℃ for 16 hours and 500℃ for 4 hours; the film layer accounted for 0.57 wt.% of the total mass of the obtained NdFeB material.

[0173] Comparative Example 3

[0174] The difference between this comparative example and Example 1 is that: when preparing the main phase fine powder, ① the composition of the main phase material X2: La 0.5 Ce 0.5 PrNd 29 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.68 B 0.95 ② The melting and casting temperatures were 1430℃; ③ Fine powder with a particle size X50 of 3.01μm was prepared. The resulting NdFeB material matrix is ​​designated as M8 blank.

[0175] The remaining conditions and steps are the same as in Example 1.

[0176] Comparative Example 4

[0177] The preparation method of the NdFeB material in this comparative example includes the following steps:

[0178] First, M1 component quick-setting tablets were prepared separately using a melting method. The nominal component of M1 is: PrNd. 30.22 Ga 0.19 Al 0.09 Cu 0.40 Co 1.29 Ti 0.16 Zr 0.06 Fe 66.65 B 0.94 The melting and casting temperature was 1430℃, and the thickness of the rapid-setting sheet was 0.30mm. The rapid-setting sheet was hydrogen-crushed in a continuous hydrogen-crushing furnace and dehydrogenated at 560℃ to obtain coarse powder. Powder additives were added to the coarse powder at a ratio of 1.5g per kilogram of coarse powder and stirred. Fine powder with a particle size of approximately 4.05μm (X50) was prepared using a collision fluidized bed nitrogen gas flow. Powder additives were added to the fine powder at a ratio of 0.5g per kilogram of fine powder and stirred. Semi-automatic pressing was used, with a minimum orientation field of >1.6T at the die forming position and an oxygen content of <200ppm throughout the pressing process. After isostatic pressing of the green blank, it was sintered in a graphite box at 1085 for 6.5h. After sintering, it underwent two-stage aging treatments: holding at 900℃ for 3h and holding at 500℃ for 5h under vacuum. The resulting NdFeB material matrix was designated as M1-1 blank.

[0179] The M1-1 blank is machined to 30.8 mm. 12.1 The 4.6mm sample underwent surface activation treatments including degreasing and ultrasonic cleaning. Tb was then applied to the magnet surface using a screen printing process. 49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 The material was subjected to heat treatment: 910℃ for 16 hours and 500℃ for 4 hours; the mass percentage of the film layer to the total mass of the obtained NdFeB material was 0.57 wt.%.

[0180] Comparative Example 5

[0181] The difference between this comparative example and Example 1 is that the composition of the auxiliary phase material Y2:PrNd is different when preparing the auxiliary phase fine powder. 34.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 Fe 10 B 0.3The melting and casting temperatures were 1390℃, and the average thickness of the cast sheets was 0.30mm. Dehydrogenation treatment was performed at 450℃, and the hydrogen content after dehydrogenation was controlled to be approximately 1800ppm. Fine powder with a particle size X50 of 4.05 was prepared. The resulting NdFeB material matrix is ​​designated as M6 blank.

[0182] The remaining conditions and steps are the same as in Example 1.

[0183] The preparation process conditions for some of the examples 1-8 and comparative examples 1-5 are shown in Tables 1 and 3.

[0184] Example 1

[0185] 1. Average particle size X50

[0186] The particle size of the main phase fine powder, auxiliary phase fine powder and the fine powder obtained in Examples 1-8 and Comparative Examples 3 and 5, and Comparative Examples 1-2 and 4 were tested using a laser particle size analyzer (HELOS-RODOS, New Patek).

[0187] 2. Magnetic properties

[0188] The NdFeB substrates (blanks) prepared in Examples 1-8 and Comparative Examples 1-5 were respectively processed into ø10 The magnetic properties of a 10mm standard sample column were tested using the NIM62000tb permanent magnet material precision measurement system at a constant temperature of 20℃. The test data are shown in Table 2 below.

[0189] 3. Metallographic diagram

[0190] Metallographic images were obtained by taking microscopic photographs of the neodymium iron boron material substrates (blanks) prepared in Examples 1-8 and Comparative Examples 1-5, respectively.

[0191] The metallographic image of the M4 blank prepared in Example 3 is shown below. Figure 1 As shown.

[0192] Depend on Figure 1 It can be seen that in Example 3, the main phase grains in the M4 blank are mostly distributed between 4-5.5 μm in size; the auxiliary phase material is added at a conventional particle size, which better dissolves and precipitates out to coat the surface of the main phase grains, resulting in a clearer surface interface. Referring to Table 2, the obtained M4 blank maintains good magnetic shielding while refining the grains, exhibiting not only a good Hcj enhancement effect but also excellent diffusion characteristics.

[0193] Table 1

[0194]

[0195] Table 2

[0196]

[0197] In Table 2, Br represents remanence; Hcj represents intrinsic coercivity; Hk represents knee point. The ratio of Hk to intrinsic coercivity (Hcj) (Hk / Hcj) is used to quantify the rectangularity of the demagnetization curve. The larger the ratio, the closer the curve is to a rectangle, and the more stable the magnetic properties are.

[0198] As shown in Table 2, the innovative design of the main and auxiliary phase compositions in this embodiment of the invention allows for further control of grain size. Through microscopic optimization and grain boundary phase composition combination, the magnet obtained by the optimized preparation process exhibits a 480 Oe increase in Hcj compared to the conventional single-alloy magnets in Comparative Examples 1-2. This may be because the special design of the auxiliary phase composition in this invention provides a superior grain boundary-like phase composition, effectively achieving a demagnetizing coupling effect. Further refinement of the main phase composition by grain size and matching auxiliary phases of different sizes revealed that a finer main phase matched with a coarser main phase exhibits optimal magnetic properties. For example, in the blank of Example 3, the Hcj was increased by 1.32 Koe compared to the blank in Comparative Example 1.

[0199] In Examples 1-8, Examples 1-2 employed a main-auxiliary alloying process, with the main phase using a normal particle size of 4.02 μm, resulting in a blank performance superior to Comparative Example 1. Examples 3-5 employed a main-auxiliary alloying process, with the main phase using a finer particle size of 3.10 μm, and the auxiliary phase, regardless of its particle size, exhibited performance superior to Comparative Example 2. Among these examples, Example 3 showed the best performance when the main phase particle size of 3.10 μm was combined with the auxiliary phase particle size of 4.05 μm.

[0200] As can be seen from Comparative Example 3 and Example 4, after La and Ce were introduced into the main phase in Comparative Example 3, Br and Hcj were significantly reduced, resulting in poor magnetic properties.

[0201] As shown in Examples 5 and 3, in the preparation method of NdFeB materials, the mass ratio of the main phase fine powder to the auxiliary phase fine powder has a significant impact on the magnetic properties of the obtained NdFeB material matrix. Reducing the auxiliary phase ratio decreases Hcj, increases Br, and decreases the Hk / Hcj ratio.

[0202] As shown in Examples 3 and 7, the main phase composition has a significant impact on the magnetic properties of the obtained NdFeB material matrix. In Example 3, the main phase material contains Ga and Cu, which improves Hcj to a certain extent. This may be because the presence of metallic elements such as Ga, Cu, and Al in the main phase material is conducive to the formation of a more complete grain boundary phase.

[0203] Example 2

[0204] 1. Metallographic diagram

[0205] Microscopic images of the NdFeB materials prepared in Examples 1-8 and Comparative Examples 1-5 were obtained by taking metallographic photographs using a metallographic microscope. The average grain size range of the main phase grains in the NdFeB materials was determined based on these metallographic images. The results are shown in Table 3.

[0206] 2. The mass percentage of Tb element in NdFeB materials

[0207] The percentage of Tb in the NdFeB materials obtained in Examples 1-8 and Comparative Examples 1-5 was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the results are shown in Table 3.

[0208] 3. Magnetic properties

[0209] The neodymium iron boron materials obtained in Examples 1-8 and Comparative Examples 1-5 were processed into ø10 standard cylinders, and the test results were shown in Table 3 using the NIM62000tb permanent magnet material precision measurement system in a constant temperature environment of 20℃.

[0210] Table 3

[0211]

[0212] In Table 3, Br represents remanence; Hcj represents intrinsic coercivity; Hk represents knee point. The ratio of Hk to intrinsic coercivity (Hcj) (Hk / Hcj) is used to quantify the rectangularity of the demagnetization curve. The larger the ratio, the closer the curve is to a rectangle, and the more stable the magnetic properties are.

[0213] As shown in Table 3, in this invention, by controlling the composition and microstructure of the grain boundary phase of the NdFeB material matrix, and through finer main phase grains, the Hcj of the magnet can be further improved, and it possesses good diffusion channels. By matching the diffusion source with the NdFeB material matrix of this invention, the resulting NdFeB material exhibits excellent magnetic properties. Specifically, the Hcj of the NdFeB materials obtained in Examples 1-7 can reach above 25 kOe, and on this basis, the Br of the NdFeB material can reach above 14 kGs, and the Hk / Hcj of the NdFeB material can reach above 96%.

[0214] The neodymium iron boron (NdFeB) material prepared by the method of this invention can achieve superior magnetic properties with lower Tb content. In Example 6 of this invention, the Tb content is only 0.43%, and the Hcj reaches 25.88 kOe, which is 1.42 kOe higher than that of Comparative Example 1 with a Tb content of 0.57%.

[0215] Compared to Comparative Example 1, Example 8 also used TbH as the diffusion source, and the resulting NdFeB material exhibited superior Hcj.

[0216] Compared to Example 3, Example 7 lacks low-melting-point elements in its main phase, which significantly affects diffusion efficiency. In Example 3, the Hcj of the NdFeB material increased by 0.9 kOe compared to Example 7.

[0217] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for preparing neodymium iron boron material, characterized in that, It includes the following steps: S1. Melt and cast the main phase material and the auxiliary phase material respectively to obtain main phase rapid solidification sheet and auxiliary phase rapid solidification sheet; S2. The main phase rapid solidification flakes and the auxiliary phase rapid solidification flakes are subjected to hydrogen rupture treatment to obtain main phase coarse powder and auxiliary phase coarse powder, respectively. They are then subjected to air jet milling to obtain main phase fine powder and auxiliary phase fine powder. The average particle size X50 of the main phase fine powder is 2.5-3.5μm, and the average particle size X50 of the auxiliary phase fine powder is 3.6-4.5μm. S3. Press the mixture containing the main phase fine powder and the auxiliary phase fine powder to obtain a green body, and sinter it to obtain a NdFeB material matrix; S4. The neodymium iron boron material matrix is ​​subjected to diffusion treatment using a diffusion source; The main phase material is R. a1 M (b1+c1+d1) T e1 B f1 R is a rare earth element selected from one or more of Pr, Nd, Gd, Tb, Dy, and Ho, with a1 being 28.0 wt.%-31.0 wt.%; M is a metallic element selected from one or more of Ga, Al, Cu, Co, Ti, Zr, and Nb, wherein the total amount of Ga, Al, and Cu is b1, b1≤0.50 wt.%; Co is c1, 0.5 wt.%≤c1≤1.50 wt.%; the total amount of Ti, Zr, and Nb is d1, 0.10 wt.%≤d1≤0.30 wt.%; f1 is 0.90 wt.%-0.99 wt.%; T is Fe, e1=100 wt.%-a1-(b1+c1+d1)-f1, where the percentage is the mass percentage of each component in the total mass of the main phase material; Wherein, the auxiliary phase material is R a2 M (b2+c2+d2) B f2 R is a rare earth element selected from one or more of Pr, Nd, Gd, Tb, Dy, and Ho, with a2 being 30 wt.%-60 wt.%; M is a metallic element selected from one or more of Ga, Al, Cu, Co, Ti, Zr, and Nb, wherein the total amount of Ga, Al, and Cu is b2, 10 wt.% ≤ b2 ≤ 40 wt.%; Co is c2, 5 wt.% ≤ c2 ≤ 30 wt.%; the total amount of Ti, Zr, and Nb is d2, 5 wt.% ≤ d2 ≤ 10 wt.%; 0.3 wt.% ≤ f2 ≤ 0.5 wt.%, where percentages are the mass percentage of each component relative to the total mass of the auxiliary phase material; The diffusion source contains Dy and / or Tb elements.

2. The method for preparing NdFeB material as described in claim 1, characterized in that, In step S1, the main phase material satisfies one or more of the following conditions: (1) R is PrNd; (2) a1 is 29.0 wt.%-31.0 wt.%; (3) M is Ga, Cu, Co, and Ti; (4) M represents Co and Ti; (5) b1≤0.25 wt.%, or, 0.10 wt.%≤b1≤0.50 wt.%; (6) c1 is 1.00 wt.%; (7) d1 is 0.12 wt.%; (8) f1 is 0.95 wt.%; (9) e1 is 67.68 wt.% or 67.93 wt.%.

3. The method for preparing NdFeB material as described in claim 1, characterized in that, In step S1, the auxiliary phase material satisfies one or more of the following conditions: (1) R is PrNd; (2) a2 is 34.0 wt.%-45.0 wt.%; (3) M is Ga, Al, Cu, Co, Ti, and Zr; (4) 20 wt.%≤b2≤35 wt.%; (5)15 wt.%≤c2≤25 wt.%; (6) 5 wt.% ≤ d2 ≤ 8 wt.%; (7) f2 is 0.3 wt.%.

4. The method for preparing NdFeB material as described in claim 1, characterized in that, In step S4, the diffusion source satisfies one or more of the following conditions: (1) 30 wt.%≤Tb, where the percentage is the mass percentage of Tb element in the total mass of the diffusion source; (2) Dy≤90 wt.%, which is the mass percentage of Dy element in the total mass of the diffusion source; (3) The diffusion source further comprises one or more elements selected from Pr, Nd, Cu, Al, Ga and Co; (4) In the diffusion source, the Tb element exists in the form of an element, an alloy, or a compound; (5) In the diffusion source, the Dy element exists in the form of an element, an alloy or a compound.

5. The method for preparing NdFeB material as described in claim 1, characterized in that, The main phase material, the auxiliary phase material, and the diffusion source satisfy one or more of the following conditions: (1) The main phase material is PrNd 30 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.68 B 0.95 or PrNd 30 Co 1.00 Ti 0.12 Fe 67.93 B 0.95 ; (2) The auxiliary phase material is PrNd 44.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 B 0.3 ; (3) The diffusion source is TbH, Tb 49.2 PrNd 21.8 Cu 21.3 Al 2.3 Ga 5.4 Co 6.4 or Tb 58 PrNd9Cu 12 Al 8.5 Co 12.5 .

6. The method for preparing NdFeB material as described in claim 5, characterized in that, The main phase material, the auxiliary phase material, and the diffusion source satisfy one or more of the following conditions: (1) The main phase material is PrNd 30 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.68 B 0.95 The auxiliary phase material is PrNd. 44.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 B 0.3 The diffusion source is Tb. 49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 ; (2) The main phase material is PrNd 30 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.68 B 0.95 The auxiliary phase material is PrNd. 44.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 B 0.3 The diffusion source is Tb. 58 PrNd9Cu 12 Al 8.5 Co 12.5 ; (3) The main phase material is PrNd 30 Co 1.00 Ti 0.12 Fe 67.93 B 0.95 The auxiliary phase material is PrNd. 44.5 Ga 2.6 Al 6.0 Cu20Co 20 Ti 2.6 Zr 4.0 B 0.3 The diffusion source is Tb. 49.2 PrNd 18.4 Cu 18.3 Al 2.3 Ga 5.4 Co 6.4 ; (4) The main phase material is PrNd 30 Ga 0.15 Cu 0.10 Co 1.00 Ti 0.12 Fe 67.68 B 0.95 The auxiliary phase material is PrNd. 44.5 Ga 2.6 Al 6.0 Cu 20 Co 20 Ti 2.6 Zr 4.0 B 0.3 The diffusion source is TbH.

7. A neodymium iron boron material, characterized in that, It is prepared by the method for preparing neodymium iron boron material as described in any one of claims 1-6.

8. The neodymium iron boron material as described in claim 7, characterized in that, It includes a main phase grain and a grain boundary phase adjacent to the main phase grain, and the surface of the main phase grain is further provided with a shell layer; The main phase grains contain (PrNd)₂Fe. 14 Phase B; the grain boundary phase comprises an alloy formed by at least two elements selected from Pr, Nd, Ga, Al, Cu, Ti, Zr, and Tb; the shell comprises Fe.

9. The neodymium iron boron material as described in claim 8, characterized in that, The main phase grains have a grain size of 4-6 μm; And / or, the main phase grains account for 91%-97% of the mass percentage of the NdFeB material; And / or, the mass percentage of Tb element in the NdFeB material is less than 0.60 wt.% of the NdFeB material; And / or, the Br content of the neodymium iron boron material is 13.0 kGs or higher; And / or, the Hcj of the neodymium iron boron material is 20 kOe or higher; And / or, the Hk / Hcj of the neodymium iron boron material is 95% or more.

10. An application of the neodymium iron boron material as described in any one of claims 7-9 as a magnetic element.

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