WO2022006973A1 - NdFeB 系磁粉、 NdFeB 系烧结磁体及制备方法 - Google Patents

NdFeB 系磁粉、 NdFeB 系烧结磁体及制备方法 Download PDF

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Publication number
WO2022006973A1
WO2022006973A1 PCT/CN2020/102617 CN2020102617W WO2022006973A1 WO 2022006973 A1 WO2022006973 A1 WO 2022006973A1 CN 2020102617 W CN2020102617 W CN 2020102617W WO 2022006973 A1 WO2022006973 A1 WO 2022006973A1
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ndfeb
magnetic powder
based magnetic
alloy
sintered magnet
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English (en)
French (fr)
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王明波
曾基灵
李犇
孙欢
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AAC Technologies Holdings Shenzhen Co Ltd
AAC Technologies Holdings Nanjing Co Ltd
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AAC Acoustic Technologies Shenzhen Co Ltd
AAC Technologies Holdings Nanjing Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0573—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes obtained by reduction or by hydrogen decrepitation or embrittlement
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0266—Moulding; Pressing

Definitions

  • the present application relates to the technical field of magnet materials, in particular to a NdFeB-based magnetic powder, an NdFeB-based sintered magnet and a preparation method.
  • NdFeB magnets are permanent magnets with the strongest magnetic force so far.
  • the maximum magnetic energy product (BH)max is more than 10 times higher than that of ferrite. In the state of bare magnetism, its magnetic force can reach about 3500 Gauss. .
  • the advantages of NdFeB magnets are high cost performance, small size, light weight, good mechanical properties and strong magnetic properties, and have been widely used in modern industry and electronic technology.
  • the purpose of this application is to provide a preparation method of NdFeB series magnetic powder, NdFeB series magnetic powder, NdFeB series sintered magnet and NdFeB series sintered magnet preparation method, to solve the problems in the prior art that are not conducive to improving the coercive force and mechanical properties of sintered magnets technical problem.
  • the problem that the oxidation of NdFeB magnets in the preparation process leads to the decline of magnet performance is effectively controlled; the high-temperature dehydrogenation process is cancelled, and the production cost is reduced; on this basis, the fine-grain technology is used to improve the coercivity and mechanical properties;
  • the problem of easy cracking of magnets with high hydrogen content during sintering is solved.
  • a preparation method of NdFeB-based magnetic powder including:
  • the NdFeB-based alloy raw material is heated to melt, and the molten NdFeB-based alloy raw material is shaken to form an alloy thin strip;
  • Hydrogen crushing process in which the alloy thin strip is subjected to hydrogen absorption under the first hydrogen pressure to carry out hydrogen crushing of the alloy thin strip to obtain alloy hydrogen crushed powder;
  • the alloy hydrogen pulverized powder is subjected to jet pulverization to obtain NdFeB-based magnetic powder.
  • the NdFeB-based alloy raw materials include 30-31.2 wt% Pr-Nd alloy, 0.008-0.012 wt% Dy-Tb alloy, 0.8-1.00 wt% Co, 0.90-1.10 wt% B, 0.19-19 wt% 0.23 wt% Al, 0.08-0.12 wt% Cu, and the balance Fe.
  • the NdFeB-based alloy raw materials include 30-31.2 wt% Pr-Nd alloy, 0.01wt% Dy-Tb alloy, 0.90wt% Co, 1.00wt% B, 0.21wt% Al, 0.10wt% % Cu and balance Fe.
  • the thickness of the alloy thin strip is 0.15-0.3 mm.
  • the first hydrogen pressure is greater than or equal to one atmospheric pressure and less than or equal to two atmospheric pressures, and the hydrogen absorption temperature is 5-35°C;
  • the value is less than the preset pressure value, it is judged that the hydrogen absorption of the alloy thin strip is completed, and it is maintained for 30 to 60 minutes.
  • the hydrogen pulverized powder and the first auxiliary agent are uniformly mixed to form a first mixture, and then the first mixture is subjected to jet pulverization to obtain the NdFeB-based magnetic powder, wherein the first
  • the adjuvants include one or more of methyl stearate, monochlorobenzene, tributyl borate, methyl laurate or n-hexane.
  • the NdFeB-based magnetic powder includes a main phase of a NdFeB crystal phase and a grain boundary phase of a rare-earth-rich phase, and a group of the NdFeB-based magnetic powder Divided into R a M b Co c B d Al e Cu f Fe balance , where,
  • R is selected from one or both of Nd and Pr;
  • M is selected from one or both of Dy and Tb;
  • the oxygen content of the NdFeB-based magnetic powder is less than 800 mass ppm, and the average particle size of the NdFeB-based magnetic powder is 1.8-2.3 ⁇ m.
  • the ratio of D90/D10 of the NdFeB-based magnetic powder is less than or equal to 4.5.
  • NdFeB-based sintered magnet the NdFeB-based sintered magnet is obtained by sequentially orienting and sintering NdFeB-based magnetic powder, and the intrinsic coercivity of the sintered magnet is greater than 14.0KOe, The bending strength of the sintered magnet is greater than 400 MPa, and the NdFeB-based magnetic powder is NdFeB-based magnetic powder prepared according to the above-mentioned preparation method.
  • the NdFeB magnetic powder is oriented and formed to obtain a green body
  • the temperature is raised to the sintering temperature at a heating rate of 0.5-2.5°C/min, and the green body is sintered to obtain a sintered magnet;
  • the NdFeB-based magnetic powder is NdFeB-based magnetic powder prepared according to the above-mentioned preparation method.
  • the heating and degassing adopts a gradient heating method, and the sintering process specifically includes:
  • the green body is placed in a sintering furnace, heated from room temperature to 250-350°C at a heating rate of 0.5-2.5°C/min, and kept for 60-120min;
  • the green body having a density of 3.2g / cm3 ⁇ 4.0g / cm 3 ;
  • the NdFeB-based magnetic powder and the second auxiliary agent are uniformly mixed to form a second mixture, and then the second mixture is oriented and shaped to obtain the green body, wherein the second auxiliary agent
  • the agent includes one or more of methyl stearate, monochlorobenzene, tributyl borate, methyl laurate or n-hexane.
  • the beneficial effects of the present application are: in the preparation method of NdFeB-based magnetic powder of the present application, dehydrogenation treatment is not performed after the hydrogen crushing process, and the grain boundary phase of the obtained NdFeB-based magnetic powder is a rare earth-rich phase and has a low oxygen content, which is beneficial to reduce sintering.
  • the loss of rare earth elements in the magnet and the inhibition of grain growth during the sintering process can improve the structure of the sintered magnet, and improve the magnetic and mechanical properties of the sintered magnet. Mechanical properties of magnets.
  • Example 3 is a scanning electron microscope image of the NdFeB-based magnetic powder prepared in Example 1 of the application;
  • Example 4 is a scanning electron microscope image of another magnification of the NdFeB-based magnetic powder prepared in Example 1 of the application;
  • the "coercive force” mentioned in this specification also known as the intrinsic coercive force, refers to the state of magnetization from the saturation magnetization of the magnet, the magnetic field is monotonically reduced to zero and increased in the opposite direction, so that the magnetization is along the saturation magnetization state.
  • the “maximum magnetic energy product” mentioned in this specification refers to the maximum value of the product of Br and Hcj on the demagnetization curve, usually denoted as (BH)max, which is one of the important parameters to measure the energy stored by the magnet, and the unit is megaheight. Austria (MGOe).
  • the "orientation degree" mentioned in this specification is represented by Br/Bs, and the unit is %.
  • the "high-performance magnet” mentioned in this specification is a sintered magnet whose sum of the magnetic energy product (unit: MGsOe) and the intrinsic coercive force (unit: KOe) is greater than or equal to 65.
  • average particle size D10 refers to the equivalent diameter of the largest particle when the cumulative distribution in the particle size distribution curve is 10%, and its physical meaning is that particles with a particle size smaller than D10 account for 10%.
  • the average particle size D50 refers to the equivalent diameter of the largest particle when the cumulative distribution in the particle size distribution curve is 50%. Its physical meaning is that particles with a particle size smaller than D50 account for 50%, and particles with a particle size larger than D50. Also accounting for 50%, D50 is also known as the median particle size.
  • the "average particle size D90" mentioned in this specification represents the equivalent diameter of the largest particle in the particle size distribution curve when the cumulative distribution is 90%, and its physical meaning is that particles with a particle size smaller than D90 account for 90%.
  • D90/D10 represents the concentration of particle distribution.
  • the rare earth elements mentioned in this specification include but are not limited to praseodymium (Pr), neodymium (Nd) or heavy rare earth element RH.
  • the heavy rare earth element RH also known as the yttrium group element, includes yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), Nine elements including ytterbium (Yb) and lutetium (Lu).
  • a1-a2 means “greater than or equal to a1” and “less than or equal to a2", for example, x is 0-1, that is: 0 ⁇ x ⁇ 1.
  • the preparation method of NdFeB magnetic powder comprises the following steps:
  • the alloy flakes are made into NdFeB-based magnetic powder.
  • the NdFeB alloy raw materials include 30-31.2wt% Pr-Nd alloy, 0.008-0.012wt% Dy-Tb alloy, 0.8-01.00wt% Co, 0.90-1.10wt% B, 0.19-0.23wt% Al, 0.08-0.12wt% of Cu and the balance of Fe.
  • the NdFeB-based alloy raw materials include 30-31.2wt% Pr-Nd alloy, 0.01wt% Dy-Tb alloy, 0.90wt% Co, 1.00wt% B, 0.21 wt% wt% Al, 0.10 wt% Cu and balance Fe.
  • step S101 the smelting process adopts the rapid-setting casting process, and the NdFeB alloy raw material is heated to melting for smelting, and the smelted raw material is rapidly cooled and solidified, and is thrown into an alloy thin strip.
  • the smelting process is carried out in a vacuum or an inert atmosphere.
  • the thickness of the alloy thin strip is 0.15-0.3 mm, preferably 0.20-0.25 mm.
  • the columnar crystal width of the alloy flake prepared in step S101 is uniform and runs through the roller surface and the free surface, and the columnar crystal width is about 2.3 ⁇ m.
  • step S102 a hydrogen crushing process and an airflow crushing process are sequentially included.
  • the alloy ribbon is crushed into hydrogen crushed powder with relatively large particle size, and the hydrogen crushed powder is further crushed into magnetic powder with smaller particle size in the airflow crushing process.
  • the whole pulverizing process is carried out in a vacuum or an inert atmosphere.
  • the alloy ribbon is made to absorb hydrogen, and the alloy ribbon reacts with hydrogen to cause the volume expansion of the alloy ribbon lattice, and then the alloy ribbon is crushed along the crystal boundary to form alloy hydrogen powder.
  • the hydrogen pressure is greater than or equal to one atmospheric pressure and less than or equal to two atmospheric pressures, and the hydrogen absorption temperature is room temperature, such as 5-35°C. After the hydrogen absorption is completed, continue to maintain for 30min-60min. In this embodiment, the pressure in the hydrogen crushing furnace is detected to determine whether the hydrogen absorption is completed. Further, the first time is 5min, and the preset pressure value is 1Kpa.
  • the hydrogen content of the alloy hydrogen pulverized powder prepared by the hydrogen crushing process is greater than 3500ppm, while the hydrogen content of the dehydrogenated hydrogen pulverized powder in the prior art is generally 700-1200 ppm.
  • Carry out dehydrogenation directly enter the airflow pulverization process, and use the airflow to accelerate the alloy hydrogen pulverized powder to collide with each other and further crush.
  • the gas stream can be an inert gas stream, preferably a nitrogen gas stream, and the pressure of the gas stream can be 0.1-2.0 MPa, for example, 0.8-1.0 MPa.
  • the hydrogen pulverized powder and a first auxiliary agent are uniformly mixed to form a first mixture, and then the first mixture is subjected to jet pulverization, and the first auxiliary agent includes methyl stearate, monochlorobenzene , one or more of tributyl borate, methyl laurate or n-hexane.
  • the average particle size of the NdFeB-based magnetic powder prepared by jet milling is 1.8-2.3 ⁇ m, which is close to the width of the alloy ribbon columnar crystal.
  • the ratio of D90/D10 of the NdFeB-based magnetic powder is less than or equal to 4.5, and the particle size distribution concentration is good.
  • Figures 3 and 4 are taken in the scanning electron microscope backscattering mode.
  • the dark part is the NdFeB crystal phase
  • the white part is the rare-earth-rich phase.
  • the alloy flakes will be fractured intergranularly to the greatest extent, and the NdFeB crystal phase in the magnetic powder is the main phase, and the rare earth-rich phase is the grain boundary phase.
  • step S102 the hydrogen content of the hydrogen pulverized alloy prepared by the hydrogen pulverization process is greater than 3500 ppm, the hydrogen pulverized alloy is not dehydrogenated, and the hydrogen pulverized alloy is directly subjected to airflow pulverization. If the content is high, the alloy hydrogen pulverized powder has strong oxidation resistance, and the oxygen content of the NdFeB series magnetic powder formed after jet pulverization is less than 800ppm.
  • the NdFeB-based magnetic powder prepared in this embodiment has the following characteristics: (1) The average particle size of the NdFeB-based magnetic powder is 1.8-2.3 ⁇ m, and the relatively small average particle size can greatly improve the coercive force of the sintered magnet prepared from the magnetic powder.
  • the oxygen content of the NdFeB magnetic powder is less than 800ppm, and the magnetic powder with low oxygen content can reduce the loss of rare earth elements during the sintering process;
  • the grain boundary phase on the surface of the NdFeB magnetic powder is Rare earth-rich phase, the increase of rare earth element content on the surface of NdFeB magnetic powder is beneficial to the subsequent sintering of the magnet, which can improve the structure of the sintered magnet, thereby improving the magnetic properties and mechanical properties of the sintered magnet;
  • NdFeB magnetic powder is not desorbed during the preparation process.
  • the hydrogen content of NdFeB-based magnetic powder is relatively high, and hydrogen will be slowly released in the process of sintering to form a sintered magnet, which can inhibit the problem of easy oxidation caused by the small average particle size of NdFeB-based magnetic powder to a certain extent, which is beneficial to reduce the problem of easy oxidation.
  • Oxygen content of the prepared sintered magnets is relatively high, and hydrogen will be slowly released in the process of sintering to form a sintered magnet, which can inhibit the problem of easy oxidation caused by the small average particle size of NdFeB-based magnetic powder to a certain extent, which is beneficial to reduce the problem of easy oxidation.
  • the NdFeB-based magnetic powder prepared according to the above preparation method includes the main phase of the NdFeB crystal phase and the grain boundary phase of the rare-earth-rich phase. Further, the composition of the NdFeB-based magnetic powder is the remainder of RaMbCocBdAleCufFe, wherein, R is selected from one or both of Nd and Pr, and M is selected from one or both of Dy and Tb; a% is R in The mass percentage of all elements of NdFeB-based magnetic powder, a is 30-31.2; b% is the mass percentage of M in all elements of NdFeB-based magnetic powder, b is 0.008-0.012; c% is the mass of Co in all elements of NdFeB-based magnetic powder Percentage, c is 0.8 ⁇ 01.00; d% is the mass percentage of B in all elements of NdFeB magnetic powder, d is 0.90 ⁇ 1.10; e% is the mass percentage of Al in all elements of NdFeB magnetic
  • the embodiment of the present application also provides a method for preparing a NdFeB-based sintered magnet, comprising the following steps:
  • NdFeB-based magnetic powder is prepared.
  • the temperature is raised to a sintering temperature at a heating rate of 0.5-2.5° C./min, and the green body is sintered to obtain a sintered magnet.
  • step S202 the NdFeB-based magnetic powder is placed in an orientation magnetic field to perform a molding process.
  • the molding process is performed in a vacuum or an inert atmosphere.
  • the forming process is compression forming followed by isostatic pressing to obtain a green body.
  • the forming process is vibration forming without isostatic pressing.
  • the strength of the orientation magnetic field can be selected according to actual needs, for example, the strength of the magnetic field is 1-5T, preferably 1-3T or 3-5T.
  • step S202 in an optional embodiment, the NdFeB-based magnetic powder and the second auxiliary agent are uniformly mixed to form a second mixture, and then the second mixture is subjected to orientation molding, and the second auxiliary agent includes methyl stearate , one or more of monochlorobenzene, tributyl borate, methyl laurate or n-hexane.
  • the orientation degree (Br/Bs) of the sintered magnet prepared in this example can reach more than 90%.
  • the hydrogen content of the NdFeB-based magnetic powder is relatively high.
  • the density of the green body and/or the density of the green body can be appropriately reduced. The size of the green body is controlled.
  • the density of the green body is 3.2g/cm3 to 4.0g/cm3; in another optional embodiment, the size of the green body is less than or equal to 26*22 *9.7cm, that is, the length of the green body is less than or equal to 26cm, the width is less than or equal to 22cm, and the height is less than or equal to 9.7cm.
  • Step S203 in order to suppress the formation of cracks inside the magnet during the sintering process, the time of heating and degassing can be appropriately extended, and the heating and degassing is performed by a gradient heating method.
  • Step S203 specifically includes:
  • the green body is placed in a sintering furnace, heated from room temperature to 250-350°C at a heating rate of 0.5-2.5°C/min, and kept for 60-120min;
  • the heating rate in step S203 is 1°C/min
  • the temperature of the first gradient is 300°C
  • the temperature of the second gradient is 800°C.
  • the grain size of the sintered magnet prepared in this example does not grow significantly, indicating that the surface of the NdFeB-based magnetic powder is covered with rare earth-rich phase. , has a certain inhibitory effect on the grain growth during the sintering process, and the boundaries between the grains of the sintered magnet are clear, which is beneficial to improve Hcj and mechanical properties.
  • the present embodiment provides a method for preparing a NdFeB based sintered magnet, comprising the following steps:
  • the alloy thin strip absorbs hydrogen at room temperature under normal pressure or 2 atmospheres to form hydrogen powder.
  • the standard for determining the completion of hydrogen absorption is that the pressure change in the hydrogen crushing furnace is less than 1KPa in 5 minutes, and it is maintained for 30min ⁇ 60min.
  • D10 D50 D90 The average particle size D90/D10 Particle size ( ⁇ m) 1.16 3.00 5.17 2.07 4.46
  • the magnetic powder after jet pulverization is mixed with the second auxiliary agent, it is oriented and formed into a green body with a density of 3.2 ⁇ 4g/cm 3 and a size of about 26*22*9.7cm.
  • Comparative Example 1 is a magnet of N52 grade produced by a Japanese manufacturer, and the mechanical properties of the magnet are shown in Table 4.
  • Comparative example 2 is a magnet of N52 grade produced by domestic supplier 1, and the mechanical properties of the magnet are shown in Table 4.
  • Comparative example 3 is a magnet of N52 grade produced by domestic supplier 2, and the mechanical properties of the magnet are shown in Table 4.

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Abstract

涉及磁体材料技术领域，尤其涉及一种NdFeB系磁粉、NdFeB系烧结磁体及制备方法。NdFeB系磁粉及制备方法对NdFeB系磁粉的组分进行了改进，并在氢破碎工序之后没有进行脱氢处理，所得NdFeB系磁粉的晶界相为富稀土相且氧含量较低，有利于降低烧结磁体稀土元素的损失以及抑制烧结过程中晶粒长大，改善烧结磁体的组织结构，提升烧结磁体的磁性能和力学性能；同时，所得NdFeB系磁粉的平均粒径较小，有利于进一步提升烧结磁体的力学性能。

Description

NdFeB系磁粉、NdFeB系烧结磁体及制备方法 技术领域
本申请涉及磁体材料技术领域，尤其涉及一种NdFeB系磁粉、NdFeB系烧结磁体及制备方法。
 背景技术
钕铁硼（NdFeB）系磁体是目前为止具有最强磁力的永久磁体，其最大磁能积(BH)max高过铁氧体10倍以上，在裸磁的状态下，其磁力可达到3500高斯左右。钕铁硼系磁体的优点是性价比高，体积小、重量轻、良好的机械特性和磁性强等特点，在现代工业和电子技术中获得了广泛的应用。
现有技术中利用钕铁硼系磁粉烧结形成钕铁硼系磁体的过程中，由于氢气的析出容易产生微裂纹，要解决这一问题会增加烧结时间及难度。目前较难稳定量产中位径D50为3微米的稀土磁体，主要原因为磁粉粒径越小，越易氧化，且难取向，且矫顽力随粒径的减小而增大。
为解决上述问题需要一种新的高性能NdFeB磁粉的制备方法，及其制得的高性能NdFeB磁粉，以及基于所述NdFeB磁粉制得的高性能NdFeB磁体。
 技术问题
本申请的目的在于提供一种NdFeB系磁粉的制备方法、NdFeB系磁粉、NdFeB系烧结磁体及NdFeB系烧结磁体的制备方法，解决现有技术中不利于提高烧结磁体的矫顽力和力学性能的技术问题。有效控制了NdFeB磁体在制备过程中的氧化导致磁体性能下降的问题；取消了高温脱氢工序，降低了生产成本；在此基础上利用细晶技术，提高了矫顽力和力学性能；同时解决了高含氢量磁体在烧结过程中易开裂的问题。
 技术解决方案
本申请的技术方案如下：提供一种NdFeB系磁粉的制备方法，包括：
合金熔炼工序，将NdFeB系合金原料加热至熔融，将熔融态的NdFeB系合金原料甩制形成合金薄带；
氢破碎工序，将所述合金薄带于第一氢压下吸氢以对所述合金薄带进行氢破碎，得到合金氢碎粉；
气流粉碎工序，将所述合金氢碎粉进行气流粉碎，得到NdFeB系磁粉。
优选地，所述NdFeB系合金原料包括30～31.2 wt%的Pr‑Nd合金、0.008～0.012 wt%的Dy-Tb合金、0.8～1.00 wt%的Co、0.90～1.10 wt%的B、0.19～0.23 wt%的Al、0.08～0.12 wt%的Cu以及余量的Fe。
优选地，所述NdFeB系合金原料包括30～31.2 wt%的Pr‑Nd合金、0.01wt%的Dy-Tb合金、0.90wt%的Co、1.00wt%的B、0.21wt%的Al、0.10wt%的Cu以及余量的Fe。
优选地，所述合金薄带的厚度为0.15～0.3mm。
优选地，所述氢破碎工序中，所述第一氢压大于或等于一个大气压且小于或等于两个大气压，吸氢温度为5～35℃；当第一时间内氢破碎炉内压力的变化值小于预设压力值时，判断所述合金薄带吸氢完成，继续保持30min～60min。
优选地，所述气流粉碎工序中，将所述氢碎粉与第一助剂均匀混合形成第一混合物，再将第一混合物进行气流粉碎以得到所述NdFeB系磁粉，其中，所述第一助剂包括硬脂酸甲酯、一氯代苯、硼酸三丁酯、月桂酸甲酯或正己烷中的一种或多种。
本申请的另一技术方案如下：提供一种采样上述制备方法得到的NdFeB系磁粉，所述NdFeB系磁粉包括NdFeB晶体相的主相以及富稀土相的晶界相，所述NdFeB系磁粉的组分为R aM bCo cB dAl eCu fFe 余量，其中，
R选自Nd和Pr中的一种或两种；
M选自Dy和Tb中的一种或两种；
所述NdFeB系磁粉的氧含量小于800质量ppm，所述NdFeB系磁粉平均粒径为1.8～2.3μm。
优选地，所述NdFeB系磁粉的D90/D10的比值小于或等于4.5。
本申请的另一技术方案如下：提供一种NdFeB系烧结磁体，所述NdFeB系烧结磁体为NdFeB系磁粉依次进行取向成型和烧结得到的，所述烧结磁体的内禀矫顽力大于14.0KOe，所述烧结磁体的弯曲强度大于400MPa，所述NdFeB系磁粉为按照上述的制备方法制备的NdFeB系磁粉。
本申请的另一技术方案如下：提供一种NdFeB系烧结磁体的制备方法，包括：
取向成型工序，将NdFeB系磁粉进行取向成型，得到生坯；
烧结工序，在所述生坯加热脱气完成后，以0.5～2.5℃/min的升温速度升温至烧结温度，将生坯进行烧结以得到烧结磁体；
其中，所述NdFeB系磁粉为按照上述的制备方法制备的NdFeB系磁粉。
优选地，所述加热脱气采用梯度升温方式，所述烧结工序具体包括：
将生坯放置于烧结炉中，以0.5～2.5℃/min的升温速度由室温升温至250～350℃，保温60～120min；
以0.5～2.5℃/min的升温速度继续升温至450～550℃，保温60～120min；
以0.5～2.5℃/min的升温速度继续升温至烧结温度，保温1～3h，其中，所述烧结温度为800～1200℃。
优选地，所述生坯的密度为3.2g/cm3～4.0g/cm 3；
在所述取向成型工序中，将所述NdFeB系磁粉与第二助剂均匀混合形成第二混合物，再将所述第二混合物进行取向成型以得到所述生坯，其中，所述第二助剂包括硬脂酸甲酯、一氯代苯、硼酸三丁酯、月桂酸甲酯或正己烷中的一种或多种。
 有益效果
本申请的有益效果在于：本申请的NdFeB系磁粉的制备方法，在氢破碎工序之后没有进行脱氢处理，所得NdFeB系磁粉的晶界相为富稀土相且氧含量较低，有利于降低烧结磁体稀土元素的损失以及抑制烧结过程中晶粒长大，改善烧结磁体的组织结构，提升烧结磁体的磁性能和力学性能；同时，所得NdFeB系磁粉的平均粒径较小，有利于进一步提升烧结磁体的力学性能。
 附图说明
图1为本申请实施例1的NdFeB系磁粉的制备方法中合金薄带的扫描电镜图（其中Pa2=4.742μm，Pa3=2.256μm）；
图2为本申请实施例1的NdFeB系磁粉的制备方法中合金薄带的另一放大倍数的扫描电镜图（其中Pa1=2.426μm）；
图3为本申请实施例1制备的NdFeB系磁粉的扫面电镜图；
图4为本申请实施例1制备的NdFeB系磁粉的另一放大倍数的扫面电镜图；
图5为本申请实施例1的NdFeB系烧结磁体的扫面电镜图（其中Pa1=3.568μm，Pa2=2.929μm，Pa3=6.463μm）。
 本发明的实施方式
为了使本申请的目的、技术方案及优点更加清楚明白，下面结合附图和具体实施例对本申请作进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本申请，并不用于限定本申请。
为了使本揭示内容的叙述更加详尽与完备，下文针对本申请的实施方式与具体实施例提出了说明性的描述；但这并非实施或运用本申请具体实施例的唯一形式。实施方式中涵盖了多个具体实施例的特征以及用以建构与操作这些具体实施例的方法步骤与其顺序。然而，亦可利用其它具体实施例来达成相同或均等的功能与步骤顺序。
本说明书中所提及的“剩磁”，是指饱和磁滞回线上磁场强度为零处所对应的磁通密度的数值，通常记作Br，单位为特斯拉(T)或高斯(Gs)，其中，1Gs＝0.0001T。
本说明书中所提及的“矫顽力”，也称为内禀矫顽力，是指从磁体的饱和磁化状态，把磁场单调地减小到零并反向增加，使其磁化强度沿饱和磁滞回线减小到零时的磁场强度，通常记作Hcj或MHc，单位为奥斯特(Oe)或KOe或安/米(A/m)，其中，1Oe＝79.6A/m。
本说明书中所提及的“最大磁能积”，指退磁曲线上Br与Hcj乘积的最大值，通常记作（BH）max，是衡量磁体所储存能量大小的重要参数之一，单位为兆高奥（MGOe）。
本说明书中所提及的“方形度”，采用Hk/Hcj表示，弯曲点磁场Hk为退磁曲线上J＝0.9Br时所对应的磁场，也称为膝点矫顽力；Hcj为室温时的内禀矫顽力。
本说明书中所提及的“取向度”，用Br/Bs表示，单位为%。
本说明书中所提及的“高性能磁体”，为磁能积（单位为MGsOe）与内禀矫顽力（单位为KOe）之和大于或等于65的烧结磁体。
本说明书中所提及“平均粒度D10”表示粒度分布曲线中累积分布为10％时的最大颗粒的等效直径，其物理意义是粒径小于D10的颗粒占10%。
本说明书中所提及“平均粒度D50”表示粒度分布曲线中累积分布为50％时的最大颗粒的等效直径，其物理意义是粒径小于D50的颗粒占50%，粒径大于D50的颗粒也占50%，D50也称为中位粒径。
本说明书中所提及“平均粒度D90”表示粒度分布曲线中累积分布为90％时的最大颗粒的等效直径，其物理意义是粒径小于D90的颗粒占90%。
本说明书中所提及“D90/D10”表示颗粒的分布集中程度，在磁性材料行业中，D90/D10的数值越小，粒度分布集中度越好。
本说明书中所提及的稀土元素包括但不限于镨（Pr）、钕（Nd）或重稀土元素RH。其中，重稀土元素RH，又称为钇族元素，包括钇（Y）、钆（Gd）、铽（Tb）、镝（Dy）、钬（Ho）、铒（Er）、铥（Tm）、镱（Yb）、镥（Lu）等九种元素。
在本说明书中，“a1～a2”的描述方式表示“大于或等于a1”且“小于或等于a2”，例如，x为0～1，即为：0≤x≤1。
为了便于理解本申请，在本申请实施例中，先对制备方法进行说明，再对产品进行说明。 
磁粉及磁粉制备实施例
NdFeB系磁粉的制备方法包括如下步骤：
S101，将NdFeB系合金原料进行熔炼获得合金薄片；
S102，将合金薄片制成NdFeB系磁粉。
其中，NdFeB系合金原料包括30～31.2wt%的Pr‑Nd合金、0.008～0.012wt%的Dy-Tb合金、0.8～01.00wt%的Co、0.90～1.10wt%的B、0.19～0.23wt%的Al、0.08～0.12wt%的Cu以及余量的Fe。进一步地，在一个可选的实施方式中，NdFeB系合金原料包括30～31.2wt%的Pr‑Nd合金、0.01wt%的Dy-Tb合金、0.90wt%的Co、1.00wt%的B、0.21wt%的Al、0.10wt%的Cu以及余量的Fe。
需要说明的是，在磁粉的制备过程中以及后续进一步制备烧结磁体的过程中，会不可避免地引入少量氧。
在步骤S101中，熔炼工艺采用速凝铸片工艺，将NdFeB系合金原料加热至熔融以进行熔炼，熔炼后的原料迅速冷却凝固并甩成合金薄带。为了防止NdFeB系合金原料以及制备的合金薄片被氧化，熔炼过程在真空或惰性气氛中进行。在步骤S101中，合金薄带的厚度为0.15～0.3mm，优选为0.20～0.25mm。请参阅图1和图2所示，步骤S101制备的合金薄片的柱状晶宽度均匀且贯穿贴辊面与自由面，柱状晶宽度约为2.3μm。
在步骤S102中，依次包括氢破碎工序和气流粉碎工序，氢破碎工序中合金薄带破碎成粒度相对较大的氢碎粉，气流粉碎工序中氢碎粉进一步破碎为粒度较小的磁粉。为了防止合金薄片以及由其破碎形成的氢碎粉和磁粉被氧化，整个制粉过程在真空或惰性气氛中进行。
在氢破碎工序中，使合金薄带吸氢，合金薄带与氢气反应引发合金薄带晶格的体积膨胀，进而使合金薄带沿着晶体边界破碎形成合金氢碎粉。
氢破碎工序中，氢压大于或等于一个大气压且小于或等于两个大气压，吸氢温度为室温，例如可以为5～35℃，吸氢完成后，继续保持30min～60min。在本实施例中，检测氢破碎炉内的压力以确定吸氢是否完成，当第一时间内氢破碎炉内压力的变化值小于预设压力值时，判断所述合金薄带吸氢完成。进一步地，第一时间为5min，预设压力值为1Kpa。
氢破碎工序制备的合金氢碎粉的氢含量大于3500ppm，而现有技术中经过脱氢的氢碎粉氢含量一般为700～1200ppm，本申请取消了高温脱氢工序，不对该合金氢碎粉进行脱氢，直接进入气流粉粹工序，利用气流使合金氢碎粉加速后相互碰撞而进一步破碎。气流可以为惰性气体气流，优选为氮气气流，气流的压力可以为0.1～2.0MPa，例如为0.8～1.0MPa。在一个可选的实施方式中，将氢碎粉与第一助剂均匀混合形成第一混合物，再将第一混合物进行气流粉碎，该第一助剂包括硬脂酸甲酯、一氯代苯、硼酸三丁酯、月桂酸甲酯或正己烷中的一种或多种。
气流粉碎制备的NdFeB系磁粉的平均粒径为1.8～2.3μm，该平均粒径与合金薄带柱状晶宽度接近。NdFeB系磁粉的D90/D10的比值小于或等于4.5，粒度分布集中度较好。
请参阅图3和图4所示，图3和图4为扫描电子显微镜背散射模式拍摄，其中，深色部分为NdFeB晶体相，白色部分为富稀土相，说明了当柱状晶宽度大小与气流粉碎后磁粉的粒径大小接近时，合金薄片将会最大程度的沿晶破碎，磁粉中NdFeB晶体相作为主相，富稀土相作为晶界相。
在步骤S102中，氢破碎工序制备的合金氢碎粉的氢含量大于3500ppm，不对该合金氢碎粉进行脱氢，直接将该合金氢碎粉进行气流粉粹，由于该合金氢碎粉的氢含量较高，该合金氢碎粉具有较强的抗氧化性，气流粉碎后形成的NdFeB系磁粉的氧含量小于800ppm。
本实施例制备的NdFeB系磁粉具有如下特点：（1）NdFeB系磁粉平均粒径为1.8～2.3μm，相对较小的平均粒径，可以使该磁粉制备的烧结磁体的矫顽力大幅提升，有利于提高烧结磁体的力学性能；（2）该NdFeB系磁粉的氧含量小于800ppm，低氧含量的磁粉可以降低烧结过程中稀土元素的损失；（3）该NdFeB系磁粉表面的晶界相为富稀土相，NdFeB系磁粉表面稀土元素含量的增加有利于后续磁体烧结，能够改善烧结磁体的组织结构，进而提升烧结磁体的磁性能和力学性能；（4）NdFeB系磁粉制备过程中没有进行脱氢，NdFeB系磁粉的氢含量较高，在烧结形成烧结磁体的过程中会缓慢释放氢气，可以在一定程度上抑制由于NdFeB系磁粉平均粒径较小导致的容易氧化的问题，有利于降低所制备的烧结磁体的氧含量。
按照上述制备方法制备的NdFeB系磁粉包括NdFeB晶体相的主相以及富稀土相的晶界相，该NdFeB系磁粉的氧含量小于800ppm，该NdFeB系磁粉平均粒径为1.8～2.3μm。进一步地，该NdFeB系磁粉的组分为RaMbCocBdAleCufFe余量，其中，R选自Nd和Pr中的一种或两种，M选自Dy和Tb中的一种或两种；a%为R在NdFeB系磁粉全部元素中的质量百分比，a为30～31.2；b%为M在NdFeB系磁粉全部元素中的质量百分比，b为0.008～0.012；c%为Co在NdFeB系磁粉全部元素中的质量百分比，c为0.8～01.00；d%为B在NdFeB系磁粉全部元素中的质量百分比，d为0.90～1.10；e%为Al在NdFeB系磁粉全部元素中的质量百分比，e为0.19～0.23；f%为Cu在NdFeB系磁粉全部元素中的质量百分比，f为0.08～0.12。更进一步地，a%为30～31.2%，b%为0.01%，c%为0.90%，d%为1.00%，e%为0.21%，f%为0.10%。
烧结磁体及烧结磁体制备实施例
本申请实施例还提供了一种NdFeB系烧结磁体的制备方法，包括如下步骤：
S201，制备NdFeB系磁粉。
NdFeB系磁粉的制备方法具体参见上述实施例，在此不进行一一赘述。
S202，将NdFeB系磁粉进行取向成型，得到生坯。
S203，在生坯加热脱气完成后，以0.5～2.5℃/min的升温速度升温至烧结温度，将生坯进行烧结以得到烧结磁体。
在步骤S202中，将NdFeB系磁粉置于取向磁场中进行成型处理，为了避免NdFeB系磁粉被氧化，成型过程在真空或惰性气氛中进行。在一个可选的实施方式中，成型处理为模压成型，随后经过等静压处理，得到生坯。在另一个可选的实施方式中，成型处理为振动成型，无需进行等静压处理。取向磁场的强度可以按照实际需求进行选择，例如，磁场强度为1～5T，优选为1～3T或3～5T。
在步骤S202中，在一个可选的实施方式中，将NdFeB系磁粉与第二助剂均匀混合形成第二混合物，再将第二混合物进行取向成型，该第二助剂包括硬脂酸甲酯、一氯代苯、硼酸三丁酯、月桂酸甲酯或正己烷中的一种或多种。
本实施例所制备的烧结磁体取向度(Br/Bs)可以达到90%以上。
由于本实施例中使用的NdFeB系磁粉在制备过程中没有进行脱氢操作，NdFeB系磁粉的氢含量较高，为了抑制后续烧结过程中磁体内部形成裂纹，可以适当降低生坯的密度和/或控制生坯的尺寸，在一个可选的实施方式中，生坯的密度为3.2g/cm3～4.0g/cm3；在另一个可选的实施方式中，生坯的尺寸小于或等于26*22*9.7cm，即：生坯的长度小于或等于26cm，宽度小于或等于22cm，高度小于或等于9.7cm。
在步骤S203中，为了抑制烧结过程中磁体内部形成裂纹，可以适当延长加热脱气的时间，加热脱气采用梯度升温方式进行，步骤S203具体包括：
将生坯放置于烧结炉中，以0.5～2.5℃/min的升温速度由室温升温至250～350℃，保温60～120min；
以0.5～2.5℃/min的升温速度继续升温至450～550℃，保温60～120min；
以0.5～2.5℃/min的升温速度继续升温至烧结温度，保温1～3h，其中，烧结温度为800～1200℃。
在一个可选的实施方式中，步骤S203中的升温速度为1℃/min，第一梯度的温度为300℃，第二梯度的温度为800℃。
请参阅5所示，本实施例制备的烧结磁体的晶粒大小与上一实施例制备的NdFeB系磁粉的粒径相比，无明显长大，说明该NdFeB系磁粉由于表面覆盖有富稀土相，对烧结过程中的晶粒长大有一定的抑制作用，且烧结磁体的晶粒之间界限清晰，有利于提高Hcj和力学性能。
实施例1
本实施例提供一种NdFeB系烧结磁体的制备方法，包括如下步骤：
1、按照表1的配方准备NdFeB系合金原料，熔融后甩制成厚度在0.15~0.3mm后的合金薄带，合金薄带的组织结构见图1和图2所示。
表1 NdFeB系合金原料配方
合金成分 Nd+Pr Dy+Tb Co B Al Cu Fe
wt% 30~31.2 0.01 0.90 1.00 0.21 0.10 余量
2、合金薄带在常压或者2个大气压下室温吸氢形成氢碎粉，吸氢完成判定标准为5分种氢碎炉内压力变化小于1KPa，保持30min~60min。
3、氢碎粉与第一助剂混匀后气流粉碎成平均粒径在1.8~2.3um的磁粉，其粉末形貌见图3和图4所示，粒度分布见表2。
表2 NdFeB系磁粉的粒度分布结果
  D10 D50 D90 平均粒径 D90/D10
粒径（μm） 1.16 3.00 5.17 2.07 4.46
4、气流粉碎后的磁粉混合第二助剂后，经取向成型为密度在3.2~4g/cm 3、尺寸约为26*22*9.7cm的生坯。
5、将生坯装入烧结炉，以1℃/min的升温速率阶段性加热至300℃左右保温，再升温至500℃保温，最后升温至1000℃左右烧结，保温2h后降至室温取出测试性能，烧结磁体组织结构见图5所示，烧结磁体的磁性能见表3，磁体力学性能见表4。
表3 烧结磁体的磁体性能结果
Figure 407066dest_path_image001
对比例
对比例1为日本厂家生产的N52牌号的磁体，磁体力学性能见表4。
对比例2为国内供应商1生产的N52牌号的磁体，磁体力学性能见表4。
对比例3为国内供应商2生产的N52牌号的磁体，磁体力学性能见表4。
表4 烧结磁体力学性能结果
Figure 636053dest_path_image002
 [0101] 以上所述的仅是本申请的实施方式，在此应当指出，对于本领域的普通技术人员来说，在不脱离本申请创造构思的前提下，还可以做出改进，但这些均属于本申请的保护范围。

Claims (12)

1、一种NdFeB系磁粉的制备方法，其特征在于，包括：
合金熔炼工序，将NdFeB系合金原料加热至熔融，将熔融态的NdFeB系合金原料甩制形成合金薄带；
氢破碎工序，将所述合金薄带于第一氢压下吸氢以对所述合金薄带进行氢破碎，得到合金氢碎粉；
气流粉碎工序，将所述合金氢碎粉进行气流粉碎，得到NdFeB系磁粉。
2、根据权利要求1所述的NdFeB系磁粉的制备方法，其特征在于，所述NdFeB系合金原料包括30～31.2 wt%的Pr‑Nd合金、0.008～0.012 wt%的Dy-Tb合金、0.8～1.00 wt%的Co、0.90～1.10 wt%的B、0.19～0.23 wt%的Al、0.08～0.12 wt%的Cu以及余量的Fe。
3、根据权利要求2所述的NdFeB系磁粉的制备方法，其特征在于，所述NdFeB系合金原料包括30～31.2 wt%的Pr‑Nd合金、0.01wt%的Dy-Tb合金、0.90wt%的Co、1.00wt%的B、0.21wt%的Al、0.10wt%的Cu以及余量的Fe。
4、根据权利要求1所述的NdFeB系磁粉的制备方法，其特征在于，所述合金薄带的厚度为0.15～0.3mm。
5、根据权利要求1所述的NdFeB系磁粉的制备方法，其特征在于，所述氢破碎工序中，所述第一氢压大于或等于一个大气压且小于或等于两个大气压，吸氢温度为5～35℃；当第一时间内氢破碎炉内压力的变化值小于预设压力值时，判断所述合金薄带吸氢完成，继续保持30min～60min。
6、根据权利要求1所述的NdFeB系磁粉的制备方法，其特征在于，所述气流粉碎工序中，将所述氢碎粉与第一助剂均匀混合形成第一混合物，再将第一混合物进行气流粉碎以得到所述NdFeB系磁粉，其中，所述第一助剂包括硬脂酸甲酯、一氯代苯、硼酸三丁酯、月桂酸甲酯或正己烷中的一种或多种。
7、一种采用权利要求1至6任一项所述的制备方法得到的NdFeB系磁粉，其特征在于，所述NdFeB系磁粉包括NdFeB晶体相的主相以及富稀土相的晶界相，所述NdFeB系磁粉的组分为R aM bCo cB dAl eCu fFe 余量，其中，
R选自Nd和Pr中的一种或两种；
M选自Dy和Tb中的一种或两种；
所述NdFeB系磁粉的氧含量小于800质量ppm，所述NdFeB系磁粉平均粒径为1.8～2.3μm。
8、根据权利要求7所述的NdFeB系磁粉，其特征在于，所述NdFeB系磁粉的D90/D10的比值小于或等于4.5。
9、一种NdFeB系烧结磁体，其特征在于，所述NdFeB系烧结磁体为NdFeB系磁粉依次进行取向成型和烧结得到的，所述烧结磁体的内禀矫顽力大于14.0KOe，所述烧结磁体的弯曲强度大于400MPa，所述NdFeB系磁粉为按照权利要求1至6任一项所述的制备方法制备的NdFeB系磁粉。
10、一种NdFeB系烧结磁体的制备方法，其特征在于，包括：
取向成型工序，将NdFeB系磁粉进行取向成型，得到生坯；
烧结工序，在所述生坯加热脱气完成后，以0.5～2.5℃/min的升温速度升温至烧结温度，将生坯进行烧结以得到烧结磁体；
其中，所述NdFeB系磁粉为按照权利要求1至6任一项所述的制备方法制备的NdFeB系磁粉。
11、根据权利要求10所述的NdFeB系烧结磁体的制备方法，其特征在于，所述加热脱气采用梯度升温方式，所述烧结工序具体包括：
将生坯放置于烧结炉中，以0.5～2.5℃/min的升温速度由室温升温至250～350℃，保温60～120min；
以0.5～2.5℃/min的升温速度继续升温至450～550℃，保温60～120min；
以0.5～2.5℃/min的升温速度继续升温至烧结温度，保温1～3h，其中，所述烧结温度为800～1200℃。
12、根据权利要求10所述的NdFeB系烧结磁体的制备方法，其特征在于，所述生坯的密度为3.2g/cm3～4.0g/cm 3；
在所述取向成型工序中，将所述NdFeB系磁粉与第二助剂均匀混合形成第二混合物，再将所述第二混合物进行取向成型以得到所述生坯，其中，所述第二助剂包括硬脂酸甲酯、一氯代苯、硼酸三丁酯、月桂酸甲酯或正己烷中的一种或多种。
PCT/CN2020/102617 2020-07-10 2020-07-17 NdFeB 系磁粉、 NdFeB 系烧结磁体及制备方法 Ceased WO2022006973A1 (zh)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117444202A (zh) * 2023-11-23 2024-01-26 瑞声开泰科技(马鞍山)有限公司 填充成型模具及填充成型方法、烧结NdFeB磁体制备方法
CN120581319A (zh) * 2025-06-12 2025-09-02 浙江金硕磁铁有限公司 一种高电阻率烧结钕铁硼磁体及其制备方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114334422B (zh) * 2021-12-31 2024-06-18 湖南稀土新能源材料有限责任公司 钕铁硼磁体及其制备方法
CN117012486A (zh) 2022-04-29 2023-11-07 福建省长汀金龙稀土有限公司 一种钕铁硼磁体材料及其制备方法、应用

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1412328A (zh) * 2001-10-18 2003-04-23 山东中舜科技发展有限公司 铸态钕铁硼生产方法
US20110074530A1 (en) * 2009-09-30 2011-03-31 General Electric Company Mixed rare-earth permanent magnet and method of fabrication
CN103871701A (zh) * 2014-03-04 2014-06-18 南京信息工程大学 一种高剩磁镨铁磷永磁材料及制备方法
CN104599801A (zh) * 2014-11-25 2015-05-06 宁波同创强磁材料有限公司 一种稀土永磁材料及其制备方法
CN105206372A (zh) * 2011-12-27 2015-12-30 因太金属株式会社 NdFeB系烧结磁体
CN106463223A (zh) * 2014-06-02 2017-02-22 因太金属株式会社 RFeB系磁体及RFeB系磁体的制造方法

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060165550A1 (en) * 2005-01-25 2006-07-27 Tdk Corporation Raw material alloy for R-T-B system sintered magnet, R-T-B system sintered magnet and production method thereof
CN102586682B (zh) * 2011-01-17 2016-01-20 三环瓦克华（北京）磁性器件有限公司 一种高性能稀土永磁烧结磁体及其制造方法
WO2013146781A1 (ja) * 2012-03-30 2013-10-03 インターメタリックス株式会社 NdFeB系焼結磁石
JP6271425B2 (ja) * 2012-07-24 2018-01-31 インターメタリックス株式会社 ＮｄＦｅＢ系焼結磁石の製造方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1412328A (zh) * 2001-10-18 2003-04-23 山东中舜科技发展有限公司 铸态钕铁硼生产方法
US20110074530A1 (en) * 2009-09-30 2011-03-31 General Electric Company Mixed rare-earth permanent magnet and method of fabrication
CN105206372A (zh) * 2011-12-27 2015-12-30 因太金属株式会社 NdFeB系烧结磁体
CN103871701A (zh) * 2014-03-04 2014-06-18 南京信息工程大学 一种高剩磁镨铁磷永磁材料及制备方法
CN106463223A (zh) * 2014-06-02 2017-02-22 因太金属株式会社 RFeB系磁体及RFeB系磁体的制造方法
CN104599801A (zh) * 2014-11-25 2015-05-06 宁波同创强磁材料有限公司 一种稀土永磁材料及其制备方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117444202A (zh) * 2023-11-23 2024-01-26 瑞声开泰科技(马鞍山)有限公司 填充成型模具及填充成型方法、烧结NdFeB磁体制备方法
CN120581319A (zh) * 2025-06-12 2025-09-02 浙江金硕磁铁有限公司 一种高电阻率烧结钕铁硼磁体及其制备方法

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