Re-Fe-B based permanent magnet powder and method for producing the same

Abstract

The application provides a Re-Fe-B permanent magnet powder and a preparation method thereof. Neodymium, praseodymium, cerium, yttrium, lanthanum, boron, M and iron are first made into an alloy rapid solidification ingot, wherein the M is selected from one or more of cobalt, zirconium, copper, aluminum, gallium, molybdenum, niobium, vanadium, titanium, silicon and manganese; the alloy rapid solidification ingot is then crushed into coarse powder by using an airflow mill, and then heated and hydrogenated in a hydrogen environment; subsequently, the hydrogen partial pressure is adjusted, secondary disproportionation is adopted, and the coercivity is further improved to prepare a disproportionated alloy; finally, the temperature of the disproportionated alloy is adjusted, the hydrogen partial pressure is reduced, and rapid cooling is performed in a vacuum or inert atmosphere, and mechanical fine crushing is performed. The high-abundance rare earth elements such as lanthanum, cerium and yttrium are added, so that the cost can be greatly reduced, and the coercivity and high-temperature stability can be improved. The application can balance the utilization of rare earth resources, reduce the accumulation of high-abundance rare earth elements, keep the magnetic performance stable, improve the product competitiveness, and promote the sustainable development of the rare earth industry.

Description

Technical Field

[0001] This invention relates to the field of rare earth magnetic materials, specifically to a Re-Fe-B system permanent magnet powder and its preparation method. Background Technology

[0002] Neodymium iron boron (NdFeB) permanent magnets, often referred to as the "King of Permanent Magnets," are an indispensable core functional material in the development of modern high-tech. With their extremely high magnetic energy product, coercivity, and energy density, they have become the best-performing and most commercially successful permanent magnets to date. Their applications cover almost all high-end manufacturing and energy-saving technology fields, including electronic information and consumer electronics, electric drive systems and energy-saving motors, clean energy and high-end equipment, and transportation, directly determining the performance limits and energy efficiency levels of many core devices. Meanwhile, rare earth elements are an important national strategic resource for my country, and the rare earth permanent magnet industry is the largest consumer of rare earth resources. Its technological development and industrial application are directly related to the efficient and balanced utilization of rare earth resources and the security of national strategic resources.

[0003] Currently, several differentiated technical routes have emerged in the field of NdFeB permanent magnet materials. Among them, the HDDR (hydrogenation-disproportionation-dehydrogenation-recombination) process is a distinctive core technology for preparing high-performance NdFeB magnetic powder. This process can irreversibly transform the original coarse-grained ingot into magnetic powder with a uniform ultrafine nanocrystalline structure. During the dehydrogenation-recombination process, the easy magnetization direction of the magnetic powder grains can be aligned along the c-axis of the original ingot, forming an intragranular texture. The bonded magnet prepared with this magnetic powder can achieve a magnetic energy product that is 2-3 times that of isotropic bonded magnets. It occupies a technological high ground in the niche field of high-performance anisotropic bonded magnets, forming a differentiated complement to sintered NdFeB and possessing extremely high industrialization value. At the same time, in order to alleviate the pressure of consumption of scarce rare earth resources and promote the balanced utilization of rare earth resources, the industry has carried out a lot of research on the application of high-abundance rare earths in neodymium iron boron permanent magnet materials. Among them, (Ce-RE)-Fe-B based magnets with cerium as the core, which has the highest abundance, have become the mainstream research and development and production direction.

[0004] However, existing technologies still face numerous core bottlenecks that are difficult to overcome, making it impossible to simultaneously balance the utilization of rare earth resources and meet the high-performance requirements of magnets. Firstly, there is a significant structural contradiction in the utilization of rare earth resources. The current production of NdFeB magnets requires the large-scale consumption of scarce rare earth elements such as neodymium, praseodymium, dysprosium, and terbium, while high-abundance rare earth elements such as cerium, lanthanum, and yttrium have long been in a state of oversupply in the market. The price differences between various rare earth elements are substantial, and the continued large-scale consumption of scarce rare earths not only significantly increases the production cost of magnetic powder but also exacerbates the imbalance in rare earth resource utilization, hindering the healthy and sustainable development of the entire rare earth industry chain. Secondly, high-abundance rare earth doping has significant performance limitations. The introduction of high-abundance rare earth elements triggers a strong magnetic dilution effect, directly reducing the intrinsic magnetic properties of NdFeB materials and severely restricting the large-scale application of high-abundance rare earths in NdFeB systems. In particular, the cerium-based NdFeB system not only has relatively low intrinsic magnetic properties, but also easily precipitates high-melting-point Laves phase. The large-scale precipitation and aggregation of this phase will severely weaken the demagnetizing coupling effect of rare-earth-rich grain boundaries relative to the main phase grains, further hindering the improvement of the hard magnetic properties of the magnet. Thirdly, existing technologies cannot be adapted to HDDR processes to achieve synergistic optimization of performance and resource utilization. Current modification schemes for high-abundance rare-earth NdFeB systems are difficult to simultaneously achieve multiple objectives such as suppressing harmful precipitates, optimizing intrinsic magnetic properties, and improving thermal stability and coercivity. They cannot synergize with the grain refinement characteristics of the HDDR process, resulting in the continued limitation of the application of high-abundance rare earths in the preparation of HDDR NdFeB magnetic powder.

[0005] In conclusion, a new technical solution is urgently needed to address the problems existing in the current technology. Summary of the Invention

[0006] To address the shortcomings and deficiencies of the existing technologies, this invention provides a Re-Fe-B system permanent magnet powder and its preparation method. This invention employs a core strategy of Ce-Y-La multi-high-abundance rare earth synergistic doping modification combined with an improved HDDR preparation process involving a secondary disproportionation step. This strategy enables the invention to effectively suppress the precipitation and aggregation of harmful REFe2 phases, optimize grain boundary phase distribution and intrinsic magnetic properties of the main phase, significantly improve the coercivity and high-temperature thermal stability of the magnetic powder, and greatly alleviate the magnetic dilution problem caused by high-abundance rare earth doping. Simultaneously, it significantly improves the resource utilization rate of high-abundance rare earths such as Ce, La, and Y, achieving balanced and efficient utilization of rare earth resources, significantly reducing the raw material cost of permanent magnet powder. The prepared anisotropic permanent magnet powder exhibits excellent magnetic properties and can be directly adapted to the industrial preparation needs of various bonded magnets such as molding, injection molding, and calendering.

[0007] One object of the present invention is to provide a Re-Fe-B based permanent magnet powder, wherein the chemical formula of the Re-Fe-B based permanent magnet powder is Nd by mass percentage. x Pr y Ce z Yu La v Fe 100-x-y-z-u-v-w-t B w M t : Wherein, M is selected from one or more of Co, Zr, Cu, Al, Ga, Mo, Nb, V, Ti, Si, and Mn; x, y, z, u, v, w, t represent the mass percentage of each element; 0≤x≤30.0, 0≤y≤30.0, 5≤z≤30, 1≤u≤25, 0.5≤v≤5, 0.8≤w≤1.3, 0.1≤t≤1.5.

[0008] Another object of the present invention is to provide a method for preparing Re-Fe-B based permanent magnet powder, the method comprising the following steps: S1. Prepare raw materials, melt and spun in an inert atmosphere to obtain alloy rapid solidification casting sheets; S2. In an inert atmosphere, the rapidly solidified alloy casting sheet is crushed into coarse powder using an air jet mill, transferred to a hydrogen environment, and heated for hydrogenation to obtain hydrogenated alloy powder. S3. Adjust the hydrogen partial pressure, heat the hydrogenated alloy powder to the final temperature, hold it at the temperature for disproportionation, and obtain the intermediate product. S4. The intermediate product is depressurized and then hydrogen is introduced into the system for secondary disproportionation to obtain the disproportionated alloy. S5. The disproportionated alloy is heated to reduce the hydrogen partial pressure, cooled, and pulverized in a vacuum or inert atmosphere to obtain Re-Fe-B permanent magnet powder.

[0009] Specifically, in step S1, the oxides and inclusions on the metal surface are cleaned before melting to reduce the introduction of impurities into the alloy. Since rare earth elements and boron elements are subject to burn-off or volatilization, 3-5 wt% burn-off is considered when preparing the alloy.

[0010] Specifically, in step S1, the purpose of smelting is to obtain (Ce-Y-La-RE)2Fe 14 The base master alloy of phase B.

[0011] Further, in step S1, "slinging" refers to pouring the refined (Ce-Y-La-RE)-Fe-B alloy molten steel onto the surface of a rotating copper roller. The surface linear velocity of the copper roller is 1-5 m / s, and the rapidly cooled (Ce-Y-La-RE)-Fe-B alloy is slinged off the surface of the copper roller in the form of scales with a thickness of 0.2-0.4 mm.

[0012] Furthermore, in step S2, the hydrogen partial pressure of the hydrogen environment is 0.05-0.3 MPa.

[0013] Furthermore, in step S2, the heating temperature is 25-650°C.

[0014] Furthermore, in step S3, the hydrogen partial pressure is 10-50 kPa.

[0015] Furthermore, in step S3, the heating rate is 5-15℃ / h; the final temperature is 750-900℃.

[0016] Further, in step S4, the rate of pressure reduction is 1-5 kPa / min; the vacuum degree of pressure reduction is 10. -1 -10 -2 Pa.

[0017] Furthermore, in step S4, the rate at which hydrogen gas is introduced is 1-5 kPa / min.

[0018] Specifically, in step S4, secondary disproportionation can make the nano-disproportionated phase grains smaller and more homogeneous, which is beneficial for forming uniform, fine, and homogeneous (Ce-Y-La-RE)2Fe after dehydrogenation and recombination. 14 Phase B effectively eliminates the impurity phase REFe2, thereby improving the coercivity of the magnetic powder.

[0019] Furthermore, in step S5, the heating temperature is 750-900℃; the cooling temperature is room temperature.

[0020] Furthermore, in step S5, the rate of reducing the hydrogen partial pressure is 0.05-1.0 kPa / min.

[0021] The present invention has the following beneficial effects: (1) This invention provides a Re-Fe-B permanent magnet powder and its preparation method. Based on the HDDR process, neodymium, praseodymium, cerium, yttrium, lanthanum, boron, M, and iron are first made into alloy rapid solidification castings, wherein M is selected from one or more of cobalt, zirconium, copper, aluminum, gallium, molybdenum, niobium, vanadium, titanium, silicon, and manganese; then the alloy rapid solidification castings are crushed into coarse powder by air jet mill, and then heated and hydrogenated in a hydrogen environment. Subsequently, the hydrogen partial pressure is adjusted and the temperature is raised to perform high-temperature disproportionation; the hydrogen partial pressure is reduced and held for a period of time, and then hydrogen is introduced for secondary disproportionation to prepare a disproportionated alloy; finally, the temperature of the disproportionated alloy is adjusted, the hydrogen partial pressure is reduced, and the mixture is rapidly cooled to complete the dehydrogenation-recombination. After that, it is mechanically crushed in a vacuum or inert atmosphere to obtain Re-Fe-B permanent magnet powder.

[0022] (2) The present invention adds cerium to Re-Fe-B system permanent magnet powder, which can not only balance the consumption of high-abundance rare earth elements, but also significantly reduce the cost of magnetic materials. Yttrium is mainly enriched in the 2:14:1 main phase of the alloy, while lanthanum and cerium are abundant in the grain boundary phase. Analysis shows that the introduction of yttrium can stabilize the tetragonal phase, preventing lanthanum and cerium from damaging the permanent magnet phase structure and giving it certain enrichment characteristics at the grain boundaries. Simultaneously, yttrium can suppress the precipitation and aggregation of REFe2-rich phases. The presence of REFe2 phases hinders the improvement of magnet performance, while the addition of yttrium can disrupt the structural stability of REFe2 phases, reduce their content, and make the grain boundary phase distribution more uniform, which is beneficial for decoupling between permanent magnet grains, thereby improving coercivity. Furthermore, due to the lack of 4f electrons in yttrium atoms, the 2:14:1 phase formed has a positive anisotropic temperature coefficient over a wide temperature range, effectively suppressing the significant decrease in coercivity caused by the deterioration of the intrinsic properties of cerium magnets at high temperatures, exhibiting good temperature stability in the 300-400 K temperature range. This invention, by adding lanthanum atoms, on the one hand, leads to lattice expansion, making Ce... 3+ The proportion of Ce increased, while Ce 4+ The proportion of lanthanum is reduced accordingly, thereby enhancing the magnetic moment and increasing the remanent magnetic induction of the magnet. On the other hand, by utilizing the property of lanthanum to segregate towards the grain boundary, the structure of the grain boundary phase is optimized, the formation of non-magnetic phase is suppressed, and the distribution of RE-enriched phase on the grain boundary becomes clearer, more uniform and continuous, increasing the difficulty of irreversible reversal nucleation during the demagnetization process of the magnet, thereby obtaining higher coercivity.

[0023] (3) The present invention employs a two-stage disproportionation process, which can reduce the size of coarse (Ce-Y-La-RE)2Fe. 14 The formation of nano-disproportionated phases from BHx micron-sized phases, with secondary disproportionation exhibiting a more pronounced grain-refining effect, also facilitates the diffusion and uniform distribution of Ce, Y, La, and RE atoms. This results in finer, more homogeneous nano-disproportionated phase grains, further promoting the formation of uniform and fine (Ce-Y-La-RE)2Fe. 14 B. In terms of magnetic properties, the magnitude of coercivity is most strongly affected by the change in grain size. Within a certain range, coercivity increases as the grain size decreases. Uniform atomic distribution avoids the deterioration effect of grain defects on coercivity. At the same time, secondary disproportionation can effectively eliminate the impurity phase REFe2, thereby improving the coercivity of magnetic powder.

[0024] (4) The La, Ce and Y selected in this invention are high-abundance rare earth elements with relatively low prices. By adding these high-abundance rare earth elements in combination with the characteristics of HDDR process, this invention partially replaces expensive rare earth elements such as Nd and Pr. The magnetic properties of the magnet decay relatively slowly, which can better maintain the stability of the magnetic properties, reduce the raw material cost of NdFeB magnets, improve the market competitiveness of the product, help to achieve balanced utilization of rare earth resources, reduce the accumulation of high-abundance rare earth elements, and promote the sustainable development of the rare earth industry. Attached Figure Description

[0025] Figure 1 A process flow diagram of the method of the present invention is shown. Detailed Implementation

[0026] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0027] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0028] It should be understood that, except in any operational instance or otherwise indicated, the amounts or all figures representing ingredients used, for example, in the specification and claims, should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​varying according to the desired performance to be obtained according to the invention.

[0029] Example 1 A Re-Fe-B based permanent magnet powder, wherein the chemical formula of the Re-Fe-B based permanent magnet powder is Nd6Ce by mass percentage. 15 Y5LaFe 70.75 B 1.05 CoNb 0.2 ; The preparation method of the Re-Fe-B permanent magnet powder includes the following steps: S1. Prepare raw materials according to the above mass fraction, melt and refine them into an alloy in an argon atmosphere, and cast the alloy onto the surface of a rotating copper roller with a surface linear velocity of 3 m / s for slinging to obtain an alloy rapid solidification casting sheet with a thickness of 0.3±0.1 mm. S2. In an argon atmosphere, the alloy rapid solidification casting sheet is crushed into coarse powder with a particle size of D90:15 mm by an air jet mill, transferred to a hydrogen environment with a hydrogen partial pressure of 0.08 MPa, and heated to 500℃ for 1 h to obtain hydrogenated alloy powder. S3. Adjust the hydrogen partial pressure to 30 kPa, heat the hydrogenated alloy powder to 800℃ at a heating rate of 10℃ / h, and hold for disproportionation for 1 h to obtain the intermediate product. S4. Continuously reduce the hydrogen partial pressure at a rate of 2.5 kPa / min until the vacuum degree reaches 10. -1 At Pa, maintain for 30 min, then introduce hydrogen gas at a rate of 2.5 kPa / min and maintain the hydrogen partial pressure at 30 kPa for 1 h to complete the secondary disproportionation and obtain the disproportionated alloy. S5. The disproportionated alloy is heated to 810°C, and the hydrogen partial pressure is continuously reduced at a rate of 0.5 kPa / min for 0.9 h. It is then rapidly cooled to room temperature in the furnace and mechanically pulverized in an argon atmosphere until the particle size D90: 160 μm is obtained to obtain Re-Fe-B permanent magnet powder.

[0030] Figure 1 A process flow diagram of the method of the present invention is shown.

[0031] Example 2 A Re-Fe-B based permanent magnet powder, wherein the chemical formula of the Re-Fe-B based permanent magnet powder is Nd5Ce by mass percentage. 10 Y10La2Fe 71.37 B 1.03 Co 0.5 Cu 0.1 ; The preparation method of the Re-Fe-B permanent magnet powder includes the following steps: S1. Prepare raw materials, melt and refine them into an alloy in an argon atmosphere, and cast the alloy onto the surface of a rotating copper roller with a surface linear velocity of 3 m / s to produce an alloy rapid solidification casting sheet with a thickness of 0.3±0.1 mm. S2. In an argon atmosphere, the rapidly solidified alloy casting sheet is crushed into coarse powder with a particle size of D90:15mm using an air jet mill. The powder is then transferred to a hydrogen environment with a hydrogen partial pressure of 0.15 MPa and heated to 125°C for 1.5 h to obtain hydrogenated alloy powder. S3. Adjust the hydrogen partial pressure to 40 kPa, heat the hydrogenated alloy powder to 780℃ at a heating rate of 10℃ / h, and hold for disproportionation for 0.5 h to obtain the intermediate product. S4. Continuously reduce the hydrogen partial pressure at a rate of 2.5 kPa / min until the vacuum degree reaches 10. -1At a pressure of 40 kPa, maintain for 30 min, then introduce hydrogen gas at a rate of 2.5 kPa / min and maintain the hydrogen partial pressure at 40 kPa for 0.5 h to complete the secondary disproportionation and obtain the disproportionated alloy. S5. The disproportionated alloy is heated to 810°C, and the hydrogen partial pressure is continuously reduced at a rate of 0.5 kPa / min for 0.9 h. It is then rapidly cooled to room temperature in the furnace and mechanically pulverized in an argon atmosphere until the particle size D90: 160 μm is obtained to obtain Re-Fe-B permanent magnet powder.

[0032] Example 3 A Re-Fe-B based permanent magnet powder, wherein the chemical formula of the Re-Fe-B based permanent magnet powder is Nd3Ce by mass percentage. 16 Y6La2Fe 70.75 B 1.05 CoGa 0.1 Ti 0.1 The preparation method of the Re-Fe-B permanent magnet powder includes the following steps: S1. Prepare raw materials, melt and refine them into an alloy in an argon atmosphere, and cast the alloy onto the surface of a rotating copper roller with a surface linear velocity of 3 m / s to produce an alloy rapid solidification casting sheet with a thickness of 0.3±0.1 mm. S2. In an argon atmosphere, the rapidly solidified alloy casting sheet is crushed into coarse powder with a particle size of D90:15mm using an air jet mill. The powder is then transferred to a hydrogen environment with a hydrogen partial pressure of 0.15 MPa and heated to 125°C for 1.5 h to obtain hydrogenated alloy powder. S3. Adjust the hydrogen partial pressure to 40 kPa, heat the hydrogenated alloy powder to 780℃ at a heating rate of 10℃ / h, and hold for disproportionation for 0.5 h to obtain the intermediate product. S4. Continuously reduce the hydrogen partial pressure at a rate of 2.5 kPa / min until the vacuum degree reaches 10. -1 At a pressure of 40 kPa, maintain for 30 min, then introduce hydrogen gas at a rate of 2.5 kPa / min and maintain the hydrogen partial pressure at 40 kPa for 0.5 h to complete the secondary disproportionation and obtain the disproportionated alloy. S5. The disproportionated alloy is heated to 810°C, and the hydrogen partial pressure is continuously reduced at a rate of 0.5 kPa / min for 0.9 h. It is then rapidly cooled to room temperature in the furnace and mechanically pulverized in an argon atmosphere until the particle size D90: 160 μm is obtained to obtain Re-Fe-B permanent magnet powder.

[0033] Comparative Example 1 A method for preparing Re-Fe-B permanent magnet powder. The difference between this comparative example and Example 1 is that this example only uses a single disproportionation process.

[0034] A Re-Fe-B based permanent magnet powder, wherein the chemical formula of the Re-Fe-B based permanent magnet powder is Nd6Ce by mass percentage. 15 Y5LaFe 70.75 B 1.05 CoNb 0.2 ; The preparation method of the Re-Fe-B permanent magnet powder includes the following steps: S1. Prepare raw materials according to the above mass fraction, melt and refine them into an alloy in an argon atmosphere, and cast the alloy onto the surface of a rotating copper roller with a surface linear velocity of 3 m / s for slinging to obtain an alloy rapid solidification casting sheet with a thickness of 0.3±0.1 mm. S2. In an argon atmosphere, the alloy rapid solidification casting sheet is crushed into coarse powder with a particle size of D90:15 mm by an air jet mill, transferred to a hydrogen environment with a hydrogen partial pressure of 0.08 MPa, and heated to 500℃ for 1 h to obtain hydrogenated alloy powder. S3. Adjust the hydrogen partial pressure to 30 kPa, heat the hydrogenated alloy powder to 800℃ at a heating rate of 10℃ / h, and hold for disproportionation for 1 h to obtain the intermediate product. S4. The intermediate product is heated to 810°C, and the hydrogen partial pressure is continuously reduced at a rate of 0.5 kPa / min for 0.9 h. It is then rapidly cooled to room temperature in the furnace and mechanically pulverized in an argon atmosphere until the particle size D90: 160 μm is obtained to obtain Re-Fe-B permanent magnet powder.

[0035] Comparative Example 2 A method for preparing Re-Fe-B series permanent magnet powder. The difference between this comparative example and Example 1 is that the alloy formula in this example does not contain La element.

[0036] A Re-Fe-B based permanent magnet powder, wherein the chemical formula of the Re-Fe-B based permanent magnet powder is Nd6Ce by mass percentage. 16 Y5Fe 70.75 B 1.05 CoNb 0.2 ; The preparation method of the Re-Fe-B permanent magnet powder includes the following steps: S1. Prepare raw materials according to the above mass fraction, melt and refine them into an alloy in an argon atmosphere, and cast the alloy onto the surface of a rotating copper roller with a surface linear velocity of 3 m / s for slinging to obtain an alloy rapid solidification casting sheet with a thickness of 0.3±0.1 mm. S2. In an argon atmosphere, the alloy rapid solidification casting sheet is crushed into coarse powder with a particle size of D90:15 mm by an air jet mill, transferred to a hydrogen environment with a hydrogen partial pressure of 0.08 MPa, and heated to 500℃ for 1 h to obtain hydrogenated alloy powder. S3. Adjust the hydrogen partial pressure to 30 kPa, heat the hydrogenated alloy powder to 800℃ at a heating rate of 10℃ / h, and hold for disproportionation for 1 h to obtain the intermediate product. S4. Continuously reduce the hydrogen partial pressure at a rate of 2.5 kPa / min until the vacuum degree reaches 10. -1 At Pa, maintain for 30 min, then introduce hydrogen gas at a rate of 2.5 kPa / min and maintain the hydrogen partial pressure at 30 kPa for 1 h to complete the secondary disproportionation and obtain the disproportionated alloy. S5. The disproportionated alloy is heated to 810°C, and the hydrogen partial pressure is continuously reduced at a rate of 0.5 kPa / min for 0.9 h. It is then rapidly cooled to room temperature in the furnace and mechanically pulverized in an argon atmosphere until the particle size D90: 160 μm is obtained to obtain Re-Fe-B permanent magnet powder.

[0037] Test case The performance of the Re-Fe-B permanent magnet powders prepared in the examples and comparative examples was tested using a vibrating sample magnetometer (VSM).

[0038] The test results are shown in Table 1.

[0039] Table 1 Performance Test Results As shown in Table 1, the secondary disproportionation process and the addition of light rare earth composites are beneficial to improving the overall magnetic properties of magnetic powder, such as coercivity and temperature stability.

[0040] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0041] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A Re-Fe-B based permanent magnet powder, characterized in that, The chemical formula of the Re-Fe-B permanent magnet powder is Nd (by mass percentage). x Pr y Ce z Y u La v Fe 100-x-y-z-u-v-w-t B w M t : Wherein, M is selected from one or more of Co, Zr, Cu, Al, Ga, Mo, Nb, V, Ti, Si, and Mn; x, y, z, u, v, w, t represent the mass percentage of each element; 0≤x≤30.0, 0≤y≤30.0, 5≤z≤30, 1≤u≤25, 0.5≤v≤5, 0.8≤w≤1.3, 0.1≤t≤1.

5.

2. A method for preparing Re-Fe-B system permanent magnet powder, characterized in that, The preparation method of the Re-Fe-B permanent magnet powder includes the following steps: S1. Prepare raw materials, melt and spun in an inert atmosphere to obtain alloy rapid solidification casting sheets; S2. In an inert atmosphere, the rapidly solidified alloy casting sheet is crushed into coarse powder using an air jet mill, transferred to a hydrogen environment, and heated for hydrogenation to obtain hydrogenated alloy powder. S3. Adjust the hydrogen partial pressure, heat the hydrogenated alloy powder to the final temperature, hold it at the temperature for disproportionation, and obtain the intermediate product. S4. The intermediate product is depressurized and then hydrogen is introduced into the system for secondary disproportionation to obtain the disproportionated alloy. S5. The disproportionated alloy is heated to reduce the hydrogen partial pressure, cooled, and pulverized in a vacuum or inert atmosphere to obtain Re-Fe-B permanent magnet powder.

3. The method for preparing Re-Fe-B permanent magnet powder according to claim 2, characterized in that, In step S2, the hydrogen partial pressure of the hydrogen environment is 0.05-0.3 MPa.

4. The method for preparing Re-Fe-B permanent magnet powder according to claim 2, characterized in that, In step S2, the heating temperature is 25-650℃.

5. The method for preparing Re-Fe-B permanent magnet powder according to claim 2, characterized in that, In step S3, the hydrogen partial pressure is 10-50 kPa.

6. The method for preparing Re-Fe-B permanent magnet powder according to claim 2, characterized in that, In step S3, the heating rate is 5-15℃ / h; the final temperature is 750-900℃.

7. The method for preparing Re-Fe-B permanent magnet powder according to claim 2, characterized in that, In step S4, the pressure reduction rate is 1-5 kPa / min; the vacuum degree of the pressure reduction is 10. -1 -10 -2 Pa.

8. The method for preparing Re-Fe-B permanent magnet powder according to claim 2, characterized in that, In step S4, the rate at which hydrogen gas is introduced is 1-5 kPa / min.

9. The method for preparing Re-Fe-B permanent magnet powder according to claim 2, characterized in that, In step S5, the heating temperature is 750-900℃; the cooling temperature is room temperature.

10. The method for preparing Re-Fe-B permanent magnet powder according to claim 2, characterized in that, In step S5, the rate of reducing the hydrogen partial pressure is 0.05-1.0 kPa / min.

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