A sintered high-abundance rare earth Ce magnet and its preparation method

Abstract

The present invention relates to the technical field of rare earth permanent magnets, and in particular to a sintered high-abundance rare earth Ce magnet and a preparation method thereof. The present invention provides a sintered high-abundance rare earth Ce magnet, which is prepared by mixing and sintering RE1‑Fe‑M1‑B hard magnetic phase alloy powder, RE2‑Fe‑M2‑B hard magnetic phase alloy powder and PN alloy powder; the particle size ratio of the RE1‑Fe‑M1‑B hard magnetic phase alloy powder and the RE2‑Fe‑M2‑B hard magnetic phase alloy powder is 0.1-0.9; the particle size ratio of the PN alloy powder and the RE1‑Fe‑M1‑B hard magnetic phase alloy powder is 0.1-1. In the sintered high-abundance rare earth Ce magnet, Ce accounts for a high proportion of the total amount of rare earth elements added, and the cost of raw materials is significantly reduced; the microstructure is significantly optimized, the rare earth-rich phase is continuously distributed along the grain boundaries, effectively isolating the magnetic exchange coupling between the main phase grains, and at the same time, the magnetocrystalline anisotropy field strength of the surface layer of the main phase grains is increased, and the magnetic properties are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of rare earth permanent magnets, and in particular to a sintered high-abundance rare earth Ce magnet and a preparation method thereof. Background Art

[0002] The continued expansion of clean energy industries such as new energy vehicles, wind power generation, and variable-frequency air conditioners has significantly boosted demand for NdFeB permanent magnets. As the most intensive rare earth functional material, the NdFeB permanent magnet industry will drive a continued upward trend in rare earth demand, exacerbating the market's growing demand for raw rare earth metals such as Pr, Nd, Dy, and Tb. This will not only increase magnet production costs and reduce product profit margins, but also lead to a backlog of Ce, the highest-abundance co-existing rare earth element, which has abundant reserves but limited applications.

[0003] Ce is the most abundant rare earth element in nature. Among the world's proven rare earth minerals, Ce has the highest reserves, accounting for up to 50% of all rare earth minerals. Market supply exceeds demand, resulting in low prices and low added value for rare earth products. Replacing some of the rare earth raw materials Pr and Nd with Ce, the highest naturally abundant rare earth element, can not only significantly reduce magnet costs and improve the competitiveness of permanent magnet products, but also reduce the backlog of the highest naturally abundant rare earths and achieve high-quality utilization of rare earth elements.

[0004] Since Ce2Fe 14 B phase saturation magnetic polarization, magnetocrystalline anisotropy field, Curie temperature (4πM s =11.7 kGs, H a =26 kOe, T c =424 K) are significantly lower than Pr2Fe 14 Phase B (4πM s =15.6 kGs, H a =75 kOe, T c =565 K) and Nd2Fe 14 Phase B (4πM s =16.0 kGs, H a =73 kOe, T c =585 K), meaning that Ce substitution for Pr / Nd not only reduces the primary intrinsic magnetic properties of the hard magnetic phase but also weakens the temperature stability of high-abundance RE-Fe-B permanent magnets. Furthermore, an increase in Ce content or proportion within the magnet reduces the volume fraction of the hard magnetic phase and causes the grain boundary phase to clump, deteriorating the microstructure and significantly reducing magnetic properties.

[0005] Therefore, the existing high Ce content / ratio sintered high-abundance Ce magnets generally have poor microstructure and poor magnetic properties. Summary of the Invention

[0006] In view of the above analysis, the embodiments of the present invention aim to provide a sintered high-abundance rare earth Ce magnet and a preparation method thereof, so as to alleviate at least one of the problems such as the imbalance in the utilization of existing rare earth resources, the oversupply of raw material Ce, the high cost of sintered NdFeB permanent magnets, the lack of continuous grain boundary phase in the magnet due to high Ce content or proportion, the deterioration of microstructure, and the decline of magnetic properties.

[0007] The present invention provides a sintered high-abundance rare earth Ce magnet, which is prepared by mixing and sintering RE1-Fe-M1-B hard magnetic phase alloy powder, RE2-Fe-M2-B hard magnetic phase alloy powder and PN alloy powder;

[0008] The particle size ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder to the RE2-Fe-M2-B hard magnetic phase alloy powder is 0.1 to 0.9;

[0009] The particle size ratio of the PN alloy powder to the RE1-Fe-M1-B hard magnetic phase alloy powder is 0.1 to 1;

[0010] Preferably, the various powders are prepared by jet milling;

[0011] Among them, RE1 is neodymium element;

[0012] or RE1 contains neodymium and at least one of praseodymium, gadolinium, terbium, dysprosium, and holmium, preferably one or two of praseodymium and dysprosium;

[0013] Furthermore, the mass proportion of neodymium in RE1 is ≥50%;

[0014] RE2 is cerium;

[0015] or RE2 contains cerium and at least one of lanthanum, praseodymium, neodymium, gadolinium, terbium, dysprosium, and holmium, preferably one or more of lanthanum, neodymium, and praseodymium;

[0016] Furthermore, the mass proportion of cerium in RE2 is ≥50%;

[0017] PN includes at least one of praseodymium and neodymium elements;

[0018] Among them, the ratio of cerium to the total mass of rare earth elements is: Ce / (RE1+RE2+PN)=0.18~0.87;

[0019] M1 includes cobalt, copper, and gallium; or M1 includes cobalt, copper, gallium, and at least one of aluminum, titanium, and zirconium;

[0020] M2 includes cobalt, copper, and gallium; or M2 includes cobalt, copper, gallium, and at least one of aluminum, titanium, and zirconium.

[0021] Preferably, the compositions of M1 and M2 are exactly the same; particularly preferably, the mass proportions of the elements in the corresponding alloys are the same within a tolerance range, illustratively, the tolerance range is ±10%, for example, the mass content of an element X in the corresponding alloy is 1±0.1%.

[0022] Preferably, the particle size ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder to the RE2-Fe-M2-B hard magnetic phase alloy powder is 0.2 to 0.8; the particle size ratio of the PN alloy powder to the RE1-Fe-M1-B hard magnetic phase alloy powder is 0.2 to 0.8.

[0023] Furthermore, the mass ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder to the RE2-Fe-M2-B hard magnetic phase alloy powder is 1-9:1-9;

[0024] The PN alloy powder accounts for 0.1 to 5% of the total mass of the RE1-Fe-M1-B hard magnetic phase alloy powder, the RE2-Fe-M2-B hard magnetic phase alloy powder and the PN alloy powder.

[0025] Preferably, it is characterized in that the mass ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder to the RE2-Fe-M2-B hard magnetic phase alloy powder is 2-4.5:5.5-8;

[0026] The PN alloy powder accounts for 0.5-2% of the total mass of the RE1-Fe-M1-B hard magnetic phase alloy powder, the RE2-Fe-M2-B hard magnetic phase alloy powder and the PN alloy powder.

[0027] Preferably, the PN alloy is a PN-M3 alloy, wherein M3 is at least one of cobalt, copper, and gallium; and the proportion of PN is 60-100 wt.%, and the proportion of M3 is 0-40 wt.%.

[0028] Preferably, the specific composition of the RE1-Fe-M1-B hard magnetic phase alloy is: RE1: 25-35wt.%, Al: 0.0-1.5wt.%, Ti: 0.0-1.5wt.%, Co: 0.1-1.1wt.%, Cu: 0.1-1.1wt.%, Ga: 0.1-1.1wt.%, Zr: 0.0-1.5wt.%, B: 0.9-1.5wt.%, and the balance is transition metal Fe elements and impurity elements, wherein Al, Ti, Co, Cu, Ga, and Zr are elements in M1;

[0029] The specific composition of the RE2-Fe-M2-B hard magnetic phase alloy is: RE2: 25-35 wt.%, Al: 0.0-1.5 wt.%, Ti: 0.0-1.5 wt.%, Co: 0.1-1.1 wt.%, Cu: 0.1-1.1 wt.%, Ga: 0.1-1.1 wt.%, Zr: 0.0-1.5 wt.%, B: 0.9-1.5 wt.%, and the balance is transition metal Fe and impurity elements, wherein Al, Ti, Co, Cu, Ga, and Zr are elements in M2;

[0030] In the two types of hard magnetic alloys, the inaccurately measured La < 0.15 wt.%, and Ce < 0.15 wt.%, and the inaccurately measured La and Ce elements are considered impurities. It is worth noting that the inaccurately measured La and Ce elements refer to the extremely small amounts of La and Ce that are not included in the main components and are classified as impurities in the composition.

[0031] Furthermore, the specific composition of the magnet is calculated by mass percentage as follows:

[0032] RE1+RE2+PN: 25-38wt.%, Al: 0.0-1.5wt.%, Ti: 0.0-1.5wt.%, Co: 0.1-6.75wt.%, Cu: 0.1-3.05wt.%, Ga: 0.1-3.05wt.%, Zr: 0.0-1.5wt.%, B: 0.9-1.5wt.%, and the remainder is transition metal Fe and impurity elements.

[0033] Preferably, the average particle size of the RE1-Fe-M1-B hard magnetic phase alloy powder, the RE2-Fe-M2-B hard magnetic phase alloy powder and the PN alloy powder is 0.5 to 6.5 μm.

[0034] Preferably, the average particle size of the powder is 1 to 5 μm.

[0035] The present invention also provides a method for preparing the magnet.

[0036] First, RE1-Fe-M1-B hard magnetic phase alloy powder, RE2-Fe-M2-B hard magnetic phase alloy powder and PN alloy powder are prepared according to the preset formula and particle size ratio, with the average powder size of 0.5 to 6.5 μm;

[0037] The three powders are mixed in proportion, pressed into shape, sintered and subjected to aging heat treatment, and finally the sintered high-abundance rare earth Ce magnet is obtained.

[0038] Furthermore, the preparation method also includes a grain boundary diffusion treatment step, in which the surface of the sintered high-abundance rare earth Ce magnet after sintering aging heat treatment is ground and activated, and a diffusion source containing heavy rare earth elements is attached. After diffusion heat treatment, a grain boundary diffusion sintered high-abundance Ce magnet is obtained.

[0039] The present invention also discloses an application of the magnet, which is used in the manufacture of magnetic components in rare earth permanent magnet motors, smart consumer electronic products, and medical devices.

[0040] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0041] 1. The sintered high-abundance rare earth Ce magnet provided by the present invention has a high ratio of Ce to the amount of rare earth elements added, and the grain boundary phase can be continuously distributed between the grains. At the same time, the distribution of rare earth elements in the main phase grains is regulated, the magnetocrystalline anisotropy field strength in the surface area of the grains is enhanced, the coercive force is improved, and the magnet has excellent magnetic properties.

[0042] The present invention regulates the addition ratio and particle size ratio among RE1-Fe-M1-B hard magnetic phase alloy powder, RE2-Fe-M2-B hard magnetic phase alloy powder and PN-M3 alloy powder. On the one hand, it can optimize the number ratio and grain volume ratio between the two main phase grains with different intrinsic magnetic properties, RE1 main phase and RE2 main phase, in the dual main phase magnet, thereby constructing a magnetic energy potential difference between the grains of different main phases and hindering the expansion of the reversal magnetization domain.

[0043] On the other hand, the local relative distribution of PN (or PN-M3) alloy powder and high intrinsic magnetic properties RE1-Fe-M1-B hard magnetic phase alloy powder in the green body is increased, which is beneficial to the uniform distribution of RE-rich phase in the magnet and reduces the proportion of blocky RE-rich phase in the magnet after sintering heat treatment; it is beneficial to construct a continuous and uniformly distributed thin layer of RE-rich grain boundary phase in the magnet, such as Figure 2 The white rare earth-rich phase continuously distributed along the grain boundaries can effectively isolate the magnetic exchange coupling between the main phase grains, reduce grain boundary defects, and inhibit the nucleation of anti-magnetization domains; it is beneficial to significantly increase the concentration of rare earth elements with high intrinsic magnetic properties in the RE1-rich epitaxial layer and the RE2-rich epitaxial layer, thereby increasing the magnetocrystalline anisotropy field strength of the RE1-rich epitaxial layer and the RE2-rich epitaxial layer on the surface of the main phase grains, inhibiting the nucleation of anti-magnetization domains, and thus significantly improving the coercive force of the magnet, realizing the preparation of high-abundance Ce magnets sintered with high addition of dual main phases.

[0044] 2. The magnet preparation method provided by the present invention is relatively simple, and the microstructure characteristics of the magnet prepared are conducive to improving the grain boundary diffusion effect.

[0045] During the preparation process of the sintered high-abundance Ce magnet of the present invention, the wettability and fluidity of the grain boundary phase are improved by adding the low melting point PN-M3 alloy powder, and a continuous and uniformly distributed grain boundary phase is constructed. Figure 3 The continuous distribution of white rare earth-rich phases along the grain edges increases the grain boundary diffusion channels in high-addition, high-abundance sintered magnets, thereby promoting the diffusion depth and concentration of heavy rare earth elements into the magnet interior. This is beneficial for increasing the heavy rare earth content on the surface of the main phase grains within the magnet, promoting the formation of a composite phase with a high magnetocrystalline anisotropy field, and enhancing the reverse magnetization domain-shaped nucleation field on the surface of the main phase grains, thereby further improving the coercive force of the magnet. In addition, the composite phase microstructure formed on the surface of the main phase grains throughout the magnet has the same composition and structure as above.

[0046] 3. The present invention realizes the preparation of sintered high-abundance Ce magnets with low HRE and high coercivity by diffusion treatment of sintered high-abundance Ce magnets. At the same time, by using the highest naturally abundant rare earth element Ce to replace Pr / Nd elements to prepare sintered NdFeB permanent magnets, the raw material cost pressure of rare earth permanent magnets can be significantly reduced, the competitiveness of rare earth permanent magnet products can be improved, and the backlog of Ce can be reduced. The high-quality utilization of high-abundance rare earth elements can be realized, and the resource advantages of my country's high-abundance rare earths can be fully utilized to promote the balance and sustainable development of rare earth resources.

[0047] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. Throughout the drawings, the same reference symbols denote the same components.

[0049] Figure 1 Schematic diagram of the microstructure of sintered high-abundance Ce magnet;

[0050] Figure 2 This is a microscopic electron microscope photograph (10 μm level) of the sintered high-abundance Ce magnet in Example 1;

[0051] Figure 3 This is a microscopic electron microscope photograph (5μm level) of the sintered high-abundance Ce magnet in Example 1. DETAILED DESCRIPTION

[0052] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0053] Based on the current situation that an increase in Ce content or proportion in existing NdFeB permanent magnets can lead to negative effects such as loss of continuous grain boundary phase, deterioration of microstructure, and decreased magnetic properties, the researchers of this invention conducted in-depth research and analysis, identified the following defects, and proposed possible solutions:

[0054] (1) With the increase of Ce addition, the proportion of thin-layer grain boundary phase in RE-Fe-B rare earth permanent magnet decreases, the grain boundary defects increase, and the direct contact between the main phase grains enhances the magnetic exchange coupling between each other, resulting in a significant decrease in magnet performance. In addition, due to the La2Fe 14 B and Ce2Fe 14 The intrinsic magnetic properties of B are much lower than those of Pr2Fe 14 B and Nd2Fe 14 The increase of B and Ce content will further reduce the magnetocrystalline anisotropy field of the main phase grains of the magnet. Various reasons have seriously restricted the addition amount of high-abundance rare earth Ce elements in magnets and the scope of application of magnets.

[0055] (2) In the existing technology, some technicians have tried to adopt dual-main-phase or multi-main-phase processes, and through technical means such as rare earth element valence regulation, multi-permanent magnet main phase assembly composite magnets, grain boundary addition modification, and addition of heavy rare earth components, in order to improve the magnetic properties. However, since the microstructure and main phase intrinsic magnetic properties of sintered rare earth permanent magnets deteriorate sharply with the increase of Ce addition, it has become a key technical problem that needs to be solved urgently to ensure that the permanent magnet has a good microstructure and magnetic properties while increasing the Ce addition.

[0056] Therefore, the present invention is based on a dual-main-phase process. By designing a multi-element alloying system (selecting a suitable hard magnetic phase alloy and additionally adding a PN alloy), the alloy powder particle size and the addition ratio, the microstructure inside the magnet is regulated, the magnetic energy potential difference between different main phase grains is constructed, and the grain boundary structure is optimized. A sintered high-abundance Ce magnet with high cost-effectiveness and high addition amount is obtained. The proportion of high-abundance rare earth Ce content in the magnet to the total rare earth content can reach up to more than 80% (up to 87%). The rare earth-rich phase can be continuously distributed along the grain boundaries, separating adjacent main phase grains. At the same time, the proportion of grain boundary phases with blocky agglomeration distribution is reduced, and the magnetocrystalline anisotropy field of the main phase surface is improved, so that the magnetic properties are significantly improved compared with magnets prepared by traditional conventional processes.

[0057] The present invention provides a sintered high-abundance rare earth Ce magnet, which is prepared by mixing and sintering RE1-Fe-M1-B hard magnetic phase alloy powder, RE2-Fe-M2-B hard magnetic phase alloy powder and PN alloy powder;

[0058] The particle size ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder to the RE2-Fe-M2-B hard magnetic phase alloy powder is 0.1 to 0.9;

[0059] The particle size ratio of the PN alloy powder to the RE1-Fe-M1-B hard magnetic phase alloy powder is 0.1 to 1;

[0060] The present invention regulates the addition ratio and particle size ratio among RE1-Fe-M1-B hard magnetic phase alloy powder, RE2-Fe-M2-B hard magnetic phase alloy powder, and PN-M3 alloy powder to construct a continuous and uniformly distributed thin layer of RE-rich grain boundary phase in the magnet, isolates the magnetic exchange coupling between main phase grains, reduces grain boundary defects, promotes the uniform distribution of the RE-rich phase in the magnet, and reduces the proportion of blocky RE-rich phase in the magnet after sintering heat treatment, thereby effectively improving the remanence and coercive force of the high-addition and high-abundance Ce sintered magnet;

[0061] Preferably, the various powders are prepared by jet milling;

[0062] Among them, RE1 is neodymium element;

[0063] or RE1 contains neodymium and at least one of praseodymium, gadolinium, terbium, dysprosium, and holmium, preferably one or two of praseodymium and dysprosium;

[0064] Furthermore, the mass proportion of neodymium in RE1 is ≥50%;

[0065] RE2 is cerium;

[0066] or RE2 contains cerium and at least one of lanthanum, praseodymium, neodymium, gadolinium, terbium, dysprosium, and holmium, preferably one or more of lanthanum, neodymium, and praseodymium;

[0067] Furthermore, the mass proportion of cerium in RE2 is ≥50%;

[0068] PN includes at least one of praseodymium and neodymium elements;

[0069] M1 includes cobalt, copper, and gallium; or M1 includes cobalt, copper, gallium, and at least one of aluminum, titanium, and zirconium;

[0070] M2 includes cobalt, copper, and gallium; or M2 includes cobalt, copper, gallium, and at least one of aluminum, titanium, and zirconium.

[0071] The functions of each element are as follows:

[0072] Fe and B are the main components of magnets and are essential elements for forming the hard magnetic main phase in RE-Fe-B alloys.

[0073] RE1: Neodymium is an essential element for forming the hard magnetic main phase in RE1-Fe-M1-B alloy, and has high intrinsic magnetic properties; the addition of other optional components such as praseodymium can reduce the cost of raw materials. The addition of elements such as gadolinium, terbium, dysprosium, and holmium can effectively improve the high-temperature resistance or coercive force of the magnet by enhancing the intrinsic magnetic properties of the hard magnetic phase.

[0074] M1, M2: can lower the melting point of the grain boundary phase, effectively improve the wettability of the molten grain boundary phase during heat treatment, and thus help optimize the distribution of the grain boundary phase.

[0075] RE2: Cerium is an essential element for the formation of the hard magnetic main phase in RE2-Fe-M2-B alloy; the addition of other optional components such as lanthanum can reduce the cost of raw materials. For example, the addition of elements such as praseodymium, neodymium, gadolinium, terbium, dysprosium, and holmium can effectively improve the high-temperature resistance or coercive force of the magnet by enhancing the intrinsic magnetic properties of the hard magnetic phase.

[0076] It is worth emphasizing that:

[0077] PN: The PN element is intended to further increase the content of praseodymium and neodymium elements in the surface layer of the main phase grains, promote magnetic hardening of the surface layer of the main phase grains, inhibit the nucleation of reverse magnetization domains, and thus improve the performance of the magnet.

[0078] M3 element: The addition of cobalt can increase the content of Co element in the main phase grains, increase the Curie temperature of the main phase, and improve the high temperature resistance of the magnet.

[0079] The copper and gallium elements in the PN alloy powder can directly play a role between the grains, significantly increasing the Cu and Ga element content in the grain boundaries, further improving the wettability of the molten grain boundary phase, and promoting the formation of a continuous and uniform thin layer of RE-rich phase in the magnet, thereby improving the grain boundary phase distribution, optimizing the microstructure, and enhancing the coercive force of the magnet.

[0080] In short, since the PN-M3 alloy powder is distributed between the hard magnetic phase grains and is the main source of the molten liquid grain boundary phase during the sintering process, adding Cu and Ga in this way allows the above elements to be preferentially concentrated and enriched in the grain boundaries, thereby obtaining better magnetic properties.

[0081] Preferably, M1 and M2 have exactly the same composition;

[0082] Particularly preferably, the mass proportion of each element in the corresponding alloy is the same within a tolerance range. For example, the tolerance range is ±10%, for example, the mass content of an element X in the corresponding alloy is 1±0.1%.

[0083] Preferably, the particle size ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder to the RE2-Fe-M2-B hard magnetic phase alloy powder is 0.2 to 0.8;

[0084] When the particle size ratio of RE1-Fe-M1-B hard magnetic phase alloy powder and RE2-Fe-M2-B hard magnetic phase alloy powder is lower than 0.2, the powder is extremely easy to oxidize and difficult to prepare and circulate, which not only reduces the performance of the magnet but also increases the manufacturing cost; when it exceeds 0.8, the proportion of low magnetic anisotropy Ce-rich epitaxial layer on the surface of RE1-Fe-MB hard magnetic phase grains in the sintered magnet increases, weakening the hard magnetism of the main phase grains and resulting in poor magnet performance.

[0085] The particle size ratio of the PN alloy powder to the RE1-Fe-M1-B hard magnetic phase alloy powder is 0.2 to 0.8;

[0086] When the particle size ratio of the PN alloy powder and the RE1-Fe-M1-B hard magnetic phase alloy powder is lower than 0.2, the powder is easily oxidized and difficult to prepare and circulate, which not only reduces the performance of the magnet but also increases the manufacturing cost; when it exceeds 0.8, the proportion of the agglomerated grain boundary phase in the sintered magnet increases, weakening the volume fraction of the hard magnetic phase and resulting in poor magnet performance.

[0087] Furthermore, the mass ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder to the RE2-Fe-M2-B hard magnetic phase alloy powder is 1-9:1-9;

[0088] The PN alloy powder accounts for 0.1 to 5% of the total mass of the RE1-Fe-M1-B hard magnetic phase alloy powder, RE2-Fe-M2-B hard magnetic phase alloy powder and PN alloy powder, for example, 0.1%, 0.5%, 1%, 1.5%, 2%, 3%, 4%, 5%.

[0089] Preferably, it is characterized in that the mass ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder to the RE2-Fe-M2-B hard magnetic phase alloy powder is 2-4.5:5.5-8;

[0090] The PN alloy powder accounts for 0.5-2% of the total mass of the RE1-Fe-M1-B hard magnetic phase alloy powder, the RE2-Fe-M2-B hard magnetic phase alloy powder and the PN alloy powder.

[0091] Preferably, the PN alloy is a PN-M3 alloy, wherein M3 is at least one of cobalt, copper, and gallium; and the proportion of PN is 60-100 wt.%, and the proportion of M3 is 0-40 wt.%.

[0092] Preferably, the specific composition of the RE1-Fe-M1-B hard magnetic phase alloy is: RE1: 25-35wt.%, Al: 0.0-1.5wt.%, Ti: 0.0-1.5wt.%, Co: 0.1-1.1wt.%, Cu: 0.1-1.1wt.%, Ga: 0.1-1.1wt.%, Zr: 0.0-1.5wt.%, B: 0.9-1.5wt.%, and the balance is transition metal Fe elements and impurity elements, wherein Al, Ti, Co, Cu, Ga, and Zr are elements in M1;

[0093] The specific composition of the RE2-Fe-M2-B hard magnetic phase alloy is: RE2: 25-35 wt.%, Al: 0.0-1.5 wt.%, Ti: 0.0-1.5 wt.%, Co: 0.1-1.1 wt.%, Cu: 0.1-1.1 wt.%, Ga: 0.1-1.1 wt.%, Zr: 0.0-1.5 wt.%, B: 0.9-1.5 wt.%, and the balance is transition metal Fe and impurity elements, wherein Al, Ti, Co, Cu, Ga, and Zr are elements in M2;

[0094] Wherein, in the two types of hard magnetic alloys, La<0.15wt.%, Ce<0.15wt.%, and both La and Ce elements are regarded as impurity elements.

[0095] Furthermore, the specific composition of the magnet is calculated by mass percentage as follows:

[0096] RE1+RE2+PN: 25~38wt.%, of which Ce / (RE1+RE2+PN)=0.18~0.87; Al: 0.0~1.5wt.%, Ti: 0.0~1.5wt.%, Co: 0.1~6.75wt.%, Cu: 0.1~3.05wt.%, Ga: 0.1~3.05wt.%, Zr: 0.0~1.5wt.%, B: 0.9~1.5wt.%, and the remainder is transition metal Fe element and impurity elements.

[0097] Preferably, the average particle size of the RE1-Fe-M1-B hard magnetic phase alloy powder, the RE2-Fe-M2-B hard magnetic phase alloy powder and the PN alloy powder is 0.5 to 6.5 μm.

[0098] Preferably, the average particle size of the powder is 1 to 5 μm.

[0099] The present invention also provides a method for preparing the magnet.

[0100] First, RE1-Fe-M1-B hard magnetic phase alloy powder, RE2-Fe-M2-B hard magnetic phase alloy powder and PN alloy powder are prepared according to the preset formula and particle size ratio, and the average particle size of the powder is 0.5 to 6.5 μm;

[0101] The three powders are mixed in proportion, pressed into shape, sintered and subjected to aging heat treatment, and finally the sintered high-abundance rare earth Ce magnet is obtained.

[0102] Specifically, the various alloy powders can be purchased directly, customized, or prepared by oneself. When preparing the above powders by oneself, various powders with more uniform texture and better performance can be obtained by preparing them according to the following preparation methods.

[0103] A method for preparing various alloy powders, specifically comprising the following steps:

[0104] (1) First, prepare RE1-Fe-M1-B hard magnetic phase alloy sheet, RE2-Fe-M2-B hard magnetic phase alloy sheet and PN-M3 alloy sheet respectively;

[0105] Among them, RE1-Fe-M1-B hard magnetic phase alloy is prepared by mixing raw materials containing Nd element, Fe element, M1 element and B element through batching, smelting, rapid solidification and cooling to form alloy sheets;

[0106] RE2-Fe-M2-B hard magnetic phase alloy sheet is prepared by mixing raw materials containing Ce element, Fe element, M2 element and B element through batching, smelting, rapid solidification and cooling.

[0107] Optionally, the preparation process of the two hard magnetic phase alloy sheets is as follows: weighing and mixing raw materials in proportion, smelting under inert gas protection, casting the molten alloy liquid onto a quenching roller rotating at a certain speed at a certain casting temperature, and preparing the alloy sheet after cooling;

[0108] Furthermore, the inert gas is nitrogen or argon, preferably argon; the casting temperature is 1050-1550°C, preferably 1150-1500°C; the speed of the chill roll is 15-70 rpm, preferably 25-55 rpm; the average thickness of the alloy sheet is 80-450 μm;

[0109] Preferably, the raw material is a pure metal / substance or alloy containing RE1, RE2, Fe, M1, M2, and B. More preferably, the raw material of the B element is an alloy containing B.

[0110] It is worth noting that the preparation processes of the RE1-Fe-M1-B hard magnetic phase alloy sheet and the RE2-Fe-M2-B hard magnetic phase alloy sheet can be the same or different.

[0111] Exemplarily, the RE1-Fe-M1-B hard magnetic phase alloy sheet and the RE2-Fe-M2-B hard magnetic phase alloy sheet are prepared by vacuum induction melting and rapid solidification strip spinning furnace.

[0112] PN-M3 alloy flakes are prepared by batching, smelting, rapid solidification, and cooling raw materials. More specifically, the raw materials are weighed and batched according to proportion, smelted under inert gas protection, and the molten alloy liquid is cast onto a chill roll rotating at a certain speed at a certain casting temperature. The alloy flakes are prepared after cooling.

[0113] Furthermore, the inert gas is nitrogen or argon, preferably argon; the casting temperature is 600-1200°C, preferably 650-1100°C; the speed of the chill roll is 0.5-50 m / s, preferably 1-40 m / s; the average thickness of the alloy sheet is 50-800 μm;

[0114] Exemplarily, the PN-M3 alloy sheet is prepared by vacuum induction melting and rapid solidification furnace;

[0115] Or after being prepared into an ingot through batching, smelting, casting and cooling, it is processed into an alloy sheet with a thickness of ≤2mm by machining;

[0116] Preferably, the raw material is a pure metal or alloy containing PN and M3. More preferably, the raw material is a pure metal containing PN and M3.

[0117] (2) The RE1-Fe-M1-B hard magnetic phase alloy sheet, the RE2-Fe-M2-B hard magnetic phase alloy sheet and the PN-M3 alloy sheet in step (1) are respectively subjected to hydrogen crushing and air flow grinding to form alloy powders and then mixed according to proportion.

[0118] Specifically, the pressing step includes magnetic field orientation pressing; further, isostatic pressing. Experimental verification shows that the isostatic pressing step has little effect on magnet performance. Considering cost, it is preferred that the pressing step only involves magnetic field orientation pressing to produce the green compact.

[0119] The specific parameters of the magnetic field orientation pressing molding are: the magnetic field intensity is 1.0 to 6.0 T, preferably 2.0 to 5.0 T; the isostatic pressing pressure is 120 to 270 MPa, preferably 150 to 240 MPa.

[0120] Specifically, the sintering and aging heat treatment includes: vacuum liquid phase sintering and aging treatment.

[0121] The sintering temperature of the vacuum liquid phase sintering is 900-1170° C., preferably 925-1120° C.; the sintering time of the vacuum liquid phase sintering is 0.5-9 h, preferably 1-8.5 h.

[0122] The aging treatment includes a primary aging treatment and optionally includes or excludes a secondary aging treatment. Preferably, the aging treatment includes a secondary aging treatment.

[0123] The aging temperature of the primary aging treatment is 600-1000° C., preferably 650-980° C.; the aging time is 0.5-8 hours, preferably 0.5-7.5 hours.

[0124] The aging temperature of the secondary aging treatment is 400-650° C., preferably 410-640° C.; the aging time is 0.5-15 hours, preferably 0.5-10 hours.

[0125] After the vacuum liquid phase sintering and the aging treatment are completed, the process is cooled to room temperature by at least one of water cooling, air cooling and wind cooling.

[0126] Furthermore, the preparation method also includes a grain boundary diffusion treatment step, in which the surface of the sintered high-abundance rare earth Ce magnet after sintering aging heat treatment is ground and activated, and a diffusion source containing heavy rare earth elements is attached. After diffusion heat treatment, a grain boundary diffusion sintered high-abundance Ce magnet is obtained.

[0127] Preferably, the diffusion treatment includes applying a diffusion source material to the magnet surface, performing vacuum heating diffusion heat treatment, diffusion cooling, and diffusion aging treatment. The diffusion treatment method can improve the diffusion efficiency of the sintered magnet during grain boundary diffusion, thereby further improving the magnet performance.

[0128] Specifically, one or more of pure metals, alloys, and compounds containing heavy rare earth elements (Dy and Tb) can be attached to the surface of the high-abundance NdFeB permanent magnet by spraying, sputtering, evaporation, etc. Exemplary materials include at least one of an alloy composed of Dy and / or Tb and optionally containing or excluding at least one of Al, Co, Cu, and Ga, pure metal of Dy and / or Tb, hydrides of Dy and / or Tb, oxides of Dy and / or Tb, and fluorides of Dy and / or Tb, such as dysprosium fluoride.

[0129] Specifically, the diffusion treatment can be performed in a vacuum heat treatment furnace.

[0130] Preferably, the temperature of the vacuum heating diffusion treatment is 750-1000° C., and the time of the vacuum heating diffusion treatment is 2-40 hours.

[0131] Preferably, the diffusion cooling temperature is below 100°C.

[0132] Preferably, the temperature of the diffusion aging treatment is 400-650°C, for example, 400, 450, 500, 550, 600, 650°C, and the time of the diffusion aging treatment is 2-15h, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15h.

[0133] Preferably, after the sintering process and before the diffusion treatment, the magnet can be processed into a target finished product size.

[0134] Specifically, the above-mentioned sintered high-abundance Ce magnet can be used to manufacture magnetic components in the fields of rare earth permanent magnet motors, smart consumer electronic products, medical equipment, etc.

[0135] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0136] In the following examples of the present invention, PrNd is added in the form of an alloy, the other metals are added in the form of simple elements, and B is provided by a B-Fe alloy.

[0137] Example 1

[0138] (1) According to the designed composition ratio: PrNd: 30.5 wt.%, Co: 0.5 wt.%, Ga: 0.1 wt.%, Al: 0.1 wt.%, Cu: 0.1 wt.%, Zr: 0.1 wt.%, B: 0.95 wt.%, Fe balance, weigh the raw material of RE1-Fe-M1-B hard magnetic phase alloy, use a vacuum induction melting furnace to melt it under the protection of Ar gas atmosphere, cast the molten steel onto a water-cooled copper roller with a rotation speed of 32 rpm, and the casting temperature of the steel liquid is 1380 ° C to obtain RE1-Fe-M1-B hard magnetic phase alloy sheets with an average thickness of 0.28 mm;

[0139] (2) According to the designed composition ratio of PrNd: 6.10 wt.%, Ce: 24.40 wt.%, Co: 0.5 wt.%, Ga: 0.1 wt.%, Al: 0.1 wt.%, Cu: 0.1 wt.%, Zr: 0.1 wt.%, B: 0.95 wt.%, and Fe as the balance, the raw materials of RE2-Fe-M2-B hard magnetic phase alloy were weighed and melted in a vacuum induction melting furnace under the protection of Ar gas atmosphere. The molten liquid was cast onto a water-cooled copper roller with a rotation speed of 36 rpm and the liquid casting temperature was 1320 ° C to obtain RE2-Fe-M2-B hard magnetic phase alloy sheets with an average thickness of 0.26 mm;

[0140] (3) According to the designed composition ratio of PrNd: 75 wt.%, Cu: 10 wt.%, Ga: 15 wt.%, PN-M3 alloy raw materials were weighed and melted in a vacuum induction melting furnace under Ar gas protection. The molten liquid was cast onto a water-cooled copper roller with a rotation speed of 30 rpm. The liquid casting temperature was 1100 °C, and PN-M3 alloy sheets with an average thickness of 0.35 mm were obtained;

[0141] (4) The RE1-Fe-M1-B, RE2-Fe-M2-B hard magnetic phase alloy and PN-M3 alloy sheets were subjected to hydrogen crushing, dehydrogenation and air flow grinding to prepare alloy powders with average particle sizes of 2.8 μm, 3.5 μm and 2.0 μm, respectively. 37.5 wt.% of RE1-Fe-M1-B hard magnetic phase alloy powder and 62.5 wt.% of RE2-Fe-M2-B hard magnetic phase alloy powder were weighed and mixed in proportion; PN-M3 alloy powder was weighed according to the mixing mass percentage of PN-M3 alloy to RE1-Fe-M1-B hard magnetic phase alloy and RE2-Fe-M2-B hard magnetic phase alloy powder of 1.5:98.5. Mix under the protection of N2 gas atmosphere, add 0.1 wt% of anti-oxidation lubricant (conventional anti-oxidation lubricant known in the art), and stir to mix evenly;

[0142] (5) The mixed powder was filled into the mold cavity of the pressing equipment under the protection of N2 gas atmosphere, and the oriented magnetic field strength was 2.5T for orientation molding and pressing. Then, the isostatic pressing was carried out at a pressure of 175 MPa in a cold isostatic press to obtain a density of 4.5 g / cm 3 of the compact (calculated by weighing and measuring the size of the compact);

[0143] (6) The compact was placed in a vacuum sintering furnace under N2 atmosphere and sintered at 1015°C for 3 h. The sintering vacuum was maintained at 1×10 -2 After the heat preservation is completed, Ar gas is filled and cooled to below 65°C before being taken out of the furnace. The density is 7.58g / cm 3 sintered blank.

[0144] Example 2

[0145] The only difference between Example 2 and Example 1 is that in step (4), PN-M3 alloy powder is weighed according to the mixing mass percentage of the powders of PN-M3 alloy and RE1-Fe-M1-B hard magnetic phase alloy and RE2-Fe-M2-B hard magnetic phase alloy being 1.0:99.0.

[0146] Example 3

[0147] The only difference between Example 3 and Example 1 is that in step (4), the RE1-Fe-M1-B, RE2-Fe-M2-B hard magnetic phase alloy and PN-M3 alloy sheets are respectively hydrogen crushed, dehydrogenated, and air flow ground into alloy powders with average particle sizes of 3.2 μm, 4.0 μm, and 2.2 μm.

[0148] Example 4

[0149] The only difference between Example 4 and Example 1 is that in step (3), according to the designed composition ratio of PrNd: 75 wt.%, Cu: 10 wt.%, Ga: 15 wt.%, PN-M3 alloy raw materials are weighed, and smelted in a vacuum induction melting furnace under the protection of Ar gas atmosphere, and the molten liquid is atomized to obtain PN-M3 alloy powder with an average particle size of 1.0 μm (the PN-M3 alloy powder in this example is directly purchased and can be customized from relevant manufacturers as needed).

[0150] In step (4), 25 wt.% of RE1-Fe-M1-B hard magnetic phase alloy powder and 75 wt.% of RE2-Fe-M2-B hard magnetic phase alloy powder are weighed and mixed in proportion; PN-M3 alloy powder is weighed according to the mixing mass percentage of PN-M3 alloy, RE1-Fe-M1-B hard magnetic phase alloy and RE2-Fe-M2-B hard magnetic phase alloy powder being 1.0:99.

[0151] Example 5

[0152] The only difference between Example 5 and Example 1 is that in step (3), PN-M3 alloy raw materials are weighed according to the designed composition ratio of PrNd: 100 wt.%.

[0153] Example 6

[0154] The only difference between Example 6 and Example 1 is that in step (4), PN-M3 alloy powder is weighed according to the mixing mass percentage of the powders of PN-M3 alloy, RE1-Fe-M1-B hard magnetic phase alloy, and RE2-Fe-M2-B hard magnetic phase alloy being 3:97.

[0155] Comparative Example 1

[0156] The only difference between Comparative Example 1 and Example 1 is that in step (4), the RE1-Fe-M1-B, RE2-Fe-M2-B hard magnetic phase alloys and PN-M3 alloy sheets are respectively hydrogen crushed, dehydrogenated, and air flow ground into alloy powders with average particle sizes of 4 μm, 4 μm, and 4 μm.

[0157] Comparative Example 2

[0158] The only difference between Comparative Example 2 and Example 1 is that in step (4), the RE1-Fe-M1-B, RE2-Fe-M2-B hard magnetic phase alloys and PN-M3 alloy sheets are respectively hydrogen crushed, dehydrogenated, and air flow ground into alloy powders with average particle sizes of 2.8 μm, 3.5 μm, and 3.4 μm.

[0159] Comparative Example 3

[0160] The only difference between Comparative Example 3 and Example 1 is that in step (4), PN-M3 alloy powder is not added.

[0161] Comparative Example 4

[0162] The only difference between Comparative Example 4 and Comparative Example 1 is that in step (3), the PN-M3 alloy raw material is weighed according to the designed composition ratio of Cu: 50 wt.%, Ga: 50 wt.% (i.e., PN is not included).

[0163] The magnetic properties of the magnets prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were tested using a hysteresis loop measuring instrument. The results are shown in Table 1.

[0164]

[0165] Comparing Example 1 with Example 2, it can be seen that due to the reduction in the amount of PN alloy added, although the proportion of non-magnetic grain boundary phase in the magnet can be reduced, thereby improving the remanence and magnetic energy product of the magnet, it also inhibits the continuous distribution of the RE-rich phase in the magnet to a certain extent, causing the coercive force of the magnet to decrease by about 16%.

[0166] Comparison between Example 1 and Example 3 shows that when the particle size ratio between the powders remains unchanged, the average particle size of the RE2 powder particles increases, which leads to an increase in the average grain size of the magnet after sintering, a decrease in the number of grain boundaries, and a decrease in the magnetic properties of the magnet.

[0167] Since Ce2Fe 14 The intrinsic magnetic properties of B phase are lower than those of Nd2Fe 14 For phase B, when the Ce / RE content is increased to 60%, the remanence, magnetic energy product and coercive force of the magnet will be significantly reduced compared with the magnet with Ce / RE=50%. However, the coercive force of the magnet with Ce / RE=60% prepared by the present invention can reach the level of the magnet with Ce / RE=50%, as can be seen from the comparison between Example 4 and Comparative Example 3.

[0168] Comparison of Example 1 with Example 5 shows that the appropriate addition of the M3 metal element to the PN alloy can effectively lower the melting point of the grain boundary phase, improve fluidity, and facilitate the further formation of a continuously distributed grain boundary phase, thereby reducing the proportion of agglomerated non-magnetic rare earth-rich phases. The prepared magnet can have relatively high remanence and coercivity. Comparison with Comparative Example 4 shows that the PN metal element added to the PN alloy can be enriched in the surface layer of the main phase grains through the grain boundaries, thereby improving the intrinsic magnetic properties of the main phase in the grain surface region, such as the magnetocrystalline anisotropy field and saturation magnetic polarization intensity, and inhibiting the nucleation of the reverse magnetization field, thereby achieving relatively high magnetic properties, increasing the remanence by 0.24 kGs and the coercivity by 32%.

[0169] By comparing Example 1 with Comparative Examples 1 and 3, it can be seen that the magnet prepared by regulating the particle size of the alloy powder using the method of the present invention has excellent magnetic properties because the rare earth-rich phase can be more continuously distributed along the grain boundaries, the magnetocrystalline anisotropy field in the surface area of the main phase grains is improved, and the grain size after sintering is relatively consistent.

[0170] Comparison between Example 1 and Comparative Example 2 shows that the larger the particle size of the PN alloy powder than that of the RE2 main phase alloy, the higher the proportion of the bulk non-magnetic grain boundary phase in the magnet, which results in a significant decrease in magnetic properties.

[0171] As shown in Example 6, when the PN alloy addition level is too high, the remanence of the magnet decreases significantly due to the sharp increase in the proportion of the non-magnetic phase, making it difficult to achieve good magnetic properties. Therefore, the preferred range of the PN alloy addition in the present invention is 0.5-2 wt.%. Both too high and too low a level will lead to reduced magnetic properties.

[0172] In summary, the high-abundance Ce sintered magnet prepared by the present invention (taking Ce / RE total amount = 50 wt.% as an example) has Br≥12.47kGs, Hcj≥6.68kOe, and BH max ≥35.01MGOe, with relatively good magnetic properties.

[0173] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A sintered high-abundance rare earth Ce magnet, characterized in that: The sintered high-abundance rare earth Ce magnet is prepared by mixing and sintering RE1-Fe-M1-B hard magnetic phase alloy powder, RE2-Fe-M2-B hard magnetic phase alloy powder and PN alloy powder; The particle size ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder and the RE2-Fe-M2-B hard magnetic phase alloy powder is 0.2 to 0.8; The particle size ratio of the PN alloy powder to the RE1-Fe-M1-B hard magnetic phase alloy powder is 0.2 to 0.8; wherein RE1 is neodymium; or RE1 contains neodymium and at least one of praseodymium, gadolinium, terbium, dysprosium, and holmium and does not contain cerium; RE2 is cerium; or RE2 contains cerium and at least one of lanthanum, praseodymium, neodymium, gadolinium, terbium, dysprosium, and holmium; PN includes at least one of praseodymium and neodymium and does not contain iron; Among them, the ratio of cerium to the total mass of rare earth elements is: Ce / (RE1+RE2+PN)=0.18~0.87; M1 is cobalt, copper and gallium; or M1 includes cobalt, copper and gallium and at least one of aluminum, titanium and zirconium; M2 is cobalt, copper and gallium; or M2 includes cobalt, copper and gallium and at least one of aluminum, titanium and zirconium.

2. The magnet according to claim 1, wherein The mass ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder to the RE2-Fe-M2-B hard magnetic phase alloy powder is 1-9:1-9; The PN alloy powder accounts for 0.1 to 5% of the total mass of the RE1-Fe-M1-B hard magnetic phase alloy powder, the RE2-Fe-M2-B hard magnetic phase alloy powder and the PN alloy powder.

3. The magnet according to claim 1, characterized in that The mass ratio of the RE1-Fe-M1-B hard magnetic phase alloy powder to the RE2-Fe-M2-B hard magnetic phase alloy powder is 2-4.5:5.5-8; The PN alloy powder accounts for 0.5-2% of the total mass of the RE1-Fe-M1-B hard magnetic phase alloy powder, the RE2-Fe-M2-B hard magnetic phase alloy powder and the PN alloy powder.

4. The magnet according to claim 1, characterized in that The PN alloy is a PN-M3 alloy, wherein M3 is at least one of cobalt, copper, and gallium and is not iron; and the proportion of PN is 60-100 wt.%, and the proportion of M3 is 0-40 wt.%.

5. The magnet according to claim 1, wherein: The specific composition of the RE1-Fe-M1-B hard magnetic phase alloy is: RE1: 25-35wt.%, Al: 0.0-1.5wt.%, Ti: 0.0-1.5wt.%, Co: 0.1-1.1wt.%, Cu: 0.1-1.1wt.%, Ga: 0.1-1.1wt.%, Zr: 0.0-1.5wt.%, B: 0.9-1.5wt.%, and the balance is transition metal Fe and impurity elements; The specific composition of the RE2-Fe-M2-B hard magnetic phase alloy is: RE2: 25-35 wt.%, Al: 0.0-1.5 wt.%, Ti: 0.0-1.5 wt.%, Co: 0.1-1.1 wt.%, Cu: 0.1-1.1 wt.%, Ga: 0.1-1.1 wt.%, Zr: 0.0-1.5 wt.%, B: 0.9-1.5 wt.%, and the balance is transition metal Fe and impurity elements; Among them, the inaccurately measured La<0.15wt.%, and Ce<0.15wt.% in the two types of hard magnetic alloys, and the inaccurately measured La and Ce elements are regarded as impurity elements.

6. The magnet according to claim 1, characterized in that The specific composition of the magnet is calculated by mass percentage: RE1+RE2+PN: 25-38wt.%, Al: 0.0-1.5wt.%, Ti: 0.0-1.5wt.%, Co: 0.1-6.75wt.%, Cu: 0.1-3.05wt.%, Ga: 0.1-3.05wt.%, Zr: 0.0-1.5wt.%, B: 0.9-1.5wt.%, and the remainder is transition metal Fe and impurity elements.

7. The magnet according to claim 1, characterized in that The average particle size of the RE1-Fe-M1-B hard magnetic phase alloy powder, the RE2-Fe-M2-B hard magnetic phase alloy powder and the PN alloy powder is 0.5 to 6.5 μm.

8. A method for preparing the magnet according to any one of claims 1 to 7, characterized in that: First, RE1-Fe-M1-B hard magnetic phase alloy powder, RE2-Fe-M2-B hard magnetic phase alloy powder and PN alloy powder are prepared according to the preset formula and particle size ratio, and the average particle size of the powder is 0.5 to 6.5 μm; The three powders are mixed in proportion, pressed into shape, sintered and subjected to aging heat treatment, and finally the sintered high-abundance rare earth Ce magnet is obtained.

9. Use of the magnet according to any one of claims 1 to 7 or the magnet prepared by the preparation method according to claim 8, characterized in that: The magnet is used in the manufacture of magnetic components in rare earth permanent magnet motors, smart consumer electronic products or medical devices.

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