A magnetic alloy binder, composite rare earth permanent magnetic material and preparation method thereof

Abstract

The present invention discloses a magnetic alloy binder, a composite rare earth permanent magnet material and a preparation method thereof. The magnetic alloy binder has a chemical formula expressed in atomic percentage as R x Fe 100‑x‑y‑z‑ v M1 y M2 z B v , where R is selected from at least one of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, and 10.0 < x < 14.0; M1 is selected from at least one of Al, Co, Si, Zr, Hf, Ta, Nb, Ti, V, Cr, Mn, Ni, W and Mo, and 0 ≤ y ≤ 15.0; M2 is at least one of Cu and Ga, 0 ≤ z ≤ 8.0, and 3 ≤ v ≤ 10.0. The present invention realizes the use of a magnetic binder with lower rare earth content, higher magnetic energy product, lower acquisition cost and wider composition range to bond Sm2Fe 17 N x , Nd(Fe,M) 12 N x , ThMn 12 -type Sm(Fe,M) 12 magnetic powder into a high-performance composite permanent magnet material.

Description

Technical field:

[0001] The present invention relates to rare earth permanent magnetic materials, in particular to a magnetic alloy binder, a composite rare earth permanent magnetic material and a preparation method thereof. Background technology:

[0002] Rare earth permanent magnet materials are important basic functional materials in modern society and are widely used in computers, automobiles, instruments, meters, home appliances, petrochemicals, healthcare, aerospace, new energy and other industries.

[0003] Sm-Co permanent magnets, invented in the 1960s, are the first generation of high-performance rare earth permanent magnets. However, their applications are limited due to their high concentration of the expensive and scarce strategic element Co.

[0004] In 1982, Masato Sagawa of Sumitomo Special Metals invented sintered Nd-Fe-B permanent magnets. These magnets have gained widespread application due to their high magnetic energy product, the absence of strategic metals, their high cost-effectiveness, and their simple preparation methods. They are currently the most widely used rare earth permanent magnet material. Bonded magnets, made from General Electric's rapidly quenched Nd-Fe-B magnetic powder and organic resin, have also gained widespread market recognition for their high dimensional accuracy and ease of fabrication for special-shaped magnets.

[0005] Following Nd-Fe-B compounds, Sm2Fe 17 N x (abbreviated as SmFeN), Nd(Fe,M) 12 N x (abbreviated as NdFeN), and ThMn12 type Sm(Fe,M) 12 Rare earth transition metal compounds such as Sm2Fe (abbreviated as 1:12 samarium iron) have also been found to have excellent intrinsic magnetic properties and are considered to be candidates for the next generation of rare earth permanent magnet materials. 17 N x (abbreviated as SmFeN), Nd(Fe,M) 12 N x (abbreviated as NdFeN) is a metastable phase that decomposes at temperatures above 600°C and cannot be formed by traditional high-temperature sintering processes. 12 Although 1:12 samarium iron (SmFe) is stable at high temperatures, it is difficult to achieve high coercivity in bulk. Currently, these magnetic materials can only be prepared into ultrafine single crystals or polycrystalline powders to achieve high coercivity and, therefore, high magnetic energy product. They are currently generally used to prepare resin or low-melting-point metal bonded magnets.

[0006] Anisotropic permanent magnets can be manufactured using organic resin bonding through injection molding or compression molding, but these processes generally require the addition of at least 30% organic resin. Using resin bonding and injection molding has three drawbacks: First, ensuring the volume fraction of the fluid resin exceeds 30% significantly reduces the magnet's remanence. Second, injection molding generally requires mixing and pelletizing magnetic powders, a process that must be performed at temperatures above the melting point of the bonding resin. Ultrafine particles are susceptible to oxidation, which can degrade magnetic properties. To mitigate this degradation, the magnetic powders require an anti-oxidation and corrosion-resistant coating, a demanding technique that adds significant cost. Third, the organic resin itself has a low melting point, and the operating temperature of the bonded composite magnet is limited by the strength of the resin. Similar issues exist with bonded magnets produced using compression molding.

[0007] To address the molding problem of metastable magnetic powders such as samarium iron nitride, invention patent CN111863369A discloses a method for using a nanocrystalline R-Fe-B alloy as a magnetic binder. This method lowers the melting point of the rare earth-rich grain boundary phase in the nanocrystalline neodymium iron boron magnetic powder and increases its content to improve its deformability. This allows the magnetic powder to contain a significant proportion of liquid phase at 400°C-550°C, thereby improving the binder's filling properties and creating a magnetic binder with excellent bonding ability. However, the method proposed in CN111863369A requires a significant increase in the rare earth content and a requirement that the melting point of the complex rare earth-rich grain boundary phase be lower than the temperature at which hot pressing is performed. This means that the binder contains a certain proportion of liquid phase during the hot pressing process. Binders that meet these requirements are expensive and have a limited range of ingredients. Because the rare earth-rich phase is non-magnetic, increasing its content inevitably increases the rare earth element content in the magnetic powder. This significantly increases the raw material cost of the binder and reduces its magnetic energy product. Patent CN111863369A limits the composition of the magnetic binder by lowering the melting point of the rare earth-rich phase and increasing its content, which inevitably increases binder cost and restricts the variety of binders. Summary of the invention:

[0008] In order to solve the problems existing in the prior art, the present invention proposes a magnetic alloy binder, a composite rare earth permanent magnet material and a preparation method thereof. The present invention realizes the use of a magnetic binder with lower rare earth content, higher magnetic energy product, lower acquisition cost and wider composition range to bind Sm2Fe 17 N x 、Nd(Fe,M) 12 N x ThMn 12 Type Sm(Fe,M) 12Magnetic powder is bonded into a high-performance composite permanent magnet material. In addition, the magnetic alloy binder and forming process proposed in the present invention can also bond magnetic powder of rare earth transition metal compounds such as SmCo5 (1:5 type Sm-Co), Sm(Co,Fe,Zr,Cu) z (2:17 type Sm-Co, 5 < z < 8.5), R2Fe 14 B, etc. into a dense magnet to prepare a high-performance composite permanent magnet material.

[0009] The first object of the present invention is to provide a magnetic alloy binder with a chemical formula expressed in atomic percentage as R x Fe 100-x-y-z-v M1 y M2 z B v where R is selected from at least one of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and yttrium (Y), 10.0 < x < 14.0; M1 is selected from at least one of Al, Co, Si, Zr, Hf, Ta, Nb, Ti, V, Cr, Mn, Ni, W, and Mo, 0 ≤ y ≤ 15.0; M2 is at least one of Cu and Ga, 0 ≤ z ≤ 8.0, 3 ≤ v ≤ 10.0.

[0010] [[ID=2OB>The described magnetic alloy binder has the following microstructure and morphological characteristics: It is composed of an R2Fe 14 B main phase with a grain size of 10 - 500 nm and a rare earth-rich phase distributed at the grain boundaries of the main phase. Among them, the atomic content occupied by the R2Fe 14 B main phase is 95% - 99%, and the atomic content occupied by the rare earth-rich phase is 0.1% - 5%; the magnetic alloy binder also contains impurities such as C, O, N, and their compounds that enter during the raw materials and preparation process, and the content of impurities is less than 3 wt%. The morphology of the magnetic alloy binder is powder particles with a size distribution between 0.1 - 10 μm.

[0011] The preparation method of the described magnetic alloy binder includes the following methods:

[0012] Method 1: Directly prepare an isotropic magnetic alloy binder using the melt spinning method, that is, an alloy binder with a chemical formula expressed in atomic percentage as R x Fe 100-x-y-z-v M1 y M2 z B vThe melt is poured onto a water-cooled copper roller to rapidly quench the alloy melt at a roller speed of 10 - 50 m / s to prepare amorphous or nanocrystalline rapidly quenched ribbons, and an isotropic magnetic binder is prepared. The main phase R2Fe 14 B grain size ranges from 10 - 120 nm, and the rare earth-rich phase is uniformly distributed at the grain boundaries of the main phase. The ribbons with permanent magnetic properties after heat treatment are ground into fine powder magnetic binders using a ball mill or a jet mill, and the powder diameter ranges from 0.1 - 10 μm. Commercially available rapidly quenched Nd-Fe-B magnetic powders prepared by rapid quenching process with the microstructural characteristics specified in the present invention can also be directly purchased. Commercially available rapidly quenched Nd-Fe-B magnetic powders are generally used as magnetic materials to manufacture resin or plastic bonded magnets or as raw materials to prepare high-performance permanent magnetic materials through hot pressing - hot deformation. Since rapidly quenched Nd-Fe-B magnetic powders generally have nanocrystalline structures, considering cost factors, commercially available magnetic powders can be directly purchased, ground into particles of 0.1 - 10 μm, and used as the magnetic alloy binder in the present invention. If the magnetic properties and filling ability of the directly purchased rapidly quenched magnetic powder are insufficient, an alloy binder with isotropic magnetic properties can be prepared by method two, which is to carry out grain boundary diffusion eutectic alloy on the rapidly quenched magnetic powder.

[0013] Method two: Carry out grain boundary diffusion eutectic alloy on the rapidly quenched magnetic powder to prepare an alloy binder with isotropic magnetic properties. Taking rare earth metals R, Cu, and Al with an impurity content of less than 1 wt% as raw materials as an example, according to the chemical formula R x Cu 100-x-y Al y (10 < x < 40, 0 ≤ y < 10) is proportioned to form an alloy with a melting point below 600 °C. The alloy is melted into a uniform melt and rapidly quenched at a roller speed of 10 - 50 m / s to prepare amorphous or nanocrystalline rapidly quenched ribbons. The ribbons are ground into eutectic alloy powders using a high-energy ball mill or a jet mill, and the powder diameter ranges from 1 - 200 μm. The eutectic alloy powders are mixed evenly with commercially available R-Fe-B rapidly quenched magnetic powders such as MQ magnetic powders, so that the mixed alloy powder mixture has the chemical formula R expressed in atomic percentage x Fe 100-x-y-z-v M1 y M2 z B v The composition. After the mixture is mixed evenly in a mixer under the protection of N2 gas or Ar gas, it is placed under vacuum or Ar protection for heat treatment. The heat treatment temperature is 520 °C - 750 °C, and the heat treatment time is 30 - 360 min, so that the eutectic alloy diffuses into the grain boundaries of the R-Fe-B rapidly quenched magnetic powder. The magnetic powder with permanent magnetic properties after heat treatment is ground into fine powder magnetic alloy binder using a ball mill or a jet mill, and the powder diameter ranges from 0.1 - 10 μm. The isotropic magnetic binder prepared by the above method, and in the alloy, R2Fe14 The B grain diameter ranges from 10 to 200 nm, and preferably the grain diameter ranges from 10 to 100 nm.

[0014] Method 3: Based on HDDR R-Fe-B magnetic powder, a eutectic alloy with grain boundary diffusion is prepared to obtain an anisotropic magnetic alloy binder. Using rare earth metal R, Cu, and Al with an impurity content of less than 1 wt% as raw materials, according to the chemical formula R x Cu 100-x-y Al y (10 < x < 40, 0 ≤ y < 10) for batching to form an alloy with a melting point below 600 °C. Load the metal raw materials into a crucible and induction melt them into a homogeneous melt. Pour the melt onto a water-cooled copper roller with a surface rotation speed of 10 - 40 m / s. That is, the alloy melt is rapidly quenched to prepare an amorphous or nanocrystalline rapidly quenched ribbon. Grind the ribbon into eutectic alloy powder with a diameter range of 1 - 200 μm using a high-energy ball mill or a jet mill. Mix the eutectic alloy powder and commercial anisotropic HDDR R-Fe-B magnetic powder evenly, so that the mixed alloy powder mixture has the chemical formula expressed in atomic percentage as R x Fe 100-x-y-z-v M1 y M2 z B v The composition stated. After the mixture is evenly mixed in a mixer under the protection of N2 gas or Ar gas, it is placed under vacuum or Ar protection for heat treatment. The heat treatment temperature is 500 °C - 850 °C, and the heat treatment time is 30 - 600 min, so that the eutectic alloy diffuses into the grain boundaries of the anisotropic HDDR R-Fe-B magnetic powder. Grind the magnetic powder with permanent magnetic properties after heat treatment into a fine powder state magnetic binder with a diameter range of 0.5 - 10 μm using a ball mill or a jet mill. The above method prepares an anisotropic magnetic binder, and the R2Fe 14 The B grain diameter ranges from 100 to 500 nm, and preferably the grain diameter ranges from 100 to 300 nm.

[0015] Preferably, the magnetic alloy binder has a chemical formula expressed in atomic percentage as R x Fe 100-x-y-z- v M1 y M2 z B vThe magnetic alloy binder, wherein, R is selected from one of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, 10.0 < x < 14.0; M1 is selected from one of Al, Co, Si, Zr, Hf, Ta, Nb, Ti, V, Cr, Mn, Ni, W and Mo, 0 ≤ y ≤ 15.0; M2 is one of Cu and Ga, 0 ≤ z ≤ 8.0, 3 ≤ v ≤ 10.0.

[0016] Preferably, the magnetic alloy binder has a chemical formula in atomic percentage as R x Fe 100-x-y-z- v M1 y M2 z B v The magnetic alloy binder, wherein, R is Pr and / or Nd, 11.8 ≤ x ≤ 13.9, M1 is one of Zr and Nb, y = 0.5 - 1.0, z = 0.2 - 1.6, v = 5.5 - 5.9.

[0017] The second object of the present invention is to protect a preparation method of a composite rare earth permanent magnet material, including the following steps: using the magnetic alloy binder with the chemical formula in atomic percentage as R x Fe 100-x-y-z-v M1 y M2 z B v to bond raw material magnetic powder into a magnet to prepare a composite rare earth permanent magnet material, and the raw material magnetic powder is selected from one or more of rare earth transition metal compound magnetic powders such as Sm2Fe 17 N x , Nd(Fe,M) 12 N x , ThMn 12 type Sm(Fe,M) 12 , SmCo5 (1:5 type Sm-Co), Sm(Co,Fe,Zr,Cu)z, R2Fe 14 B single crystal, oriented polycrystalline HDDR-R2Fe 14 B. The specific Sm(Co,Fe,Zr,Cu)z is 2:17 type Sm-Co, � < z < 8.5. The average particle diameter of the raw material magnetic powder is 1 - 200 μm. The function of the raw material magnetic powder is to provide magnetic properties for the composite magnet, and the type and proportion of the raw material magnetic powder can be adjusted according to the cost and the design goal of magnetic properties, and multiple magnetic powders can also be used in combination.

[0018] Preferably, the volume ratio of the raw material magnetic powder in the composite rare earth permanent magnet material is 60% - 95%, and the volume ratio of the magnetic alloy binder is 5% - 40%.

[0019] More preferably, the volume proportion of the raw material magnetic powder in the composite rare earth permanent magnet material is 80%-90%, and the volume proportion of the magnetic alloy binder is 10%-20%.

[0020] Preferably, the preparation method of the composite rare earth permanent magnet material comprises the following specific steps: uniformly mixing the raw magnetic powder and the magnetic alloy binder under vacuum or inert gas protection, orienting and pressing the compact into a green compact in a magnetic field greater than 15 kOe, wherein the pressure loading direction is perpendicular to the magnetic field direction and the pressure is 20-100 MPa, transferring the compact into a pressure sintering furnace, heating to 400°C-600°C in vacuum or under inert gas protection, applying a pressure of 50-400 MPa, and maintaining the pressure for 10-360 min, and pressing the compact into the composite rare earth permanent magnet material.

[0021] The present invention uses the Archimedean method to test the density of a dense bulk magnetic alloy binder and the actual density of a composite rare earth permanent magnet material (composite magnet). The theoretical density of a composite magnet = the density of the bulk magnetic alloy binder * the volume ratio of the magnetic alloy binder + the theoretical density of the raw magnetic powder * the volume ratio of the raw magnetic powder. The relative density of the composite magnet = (actual density of the composite magnet / theoretical density of the composite magnet) * 100%. The low-temperature filling performance of the magnetic alloy binder is measured by the relative density of the composite magnet.

[0022] In the present invention, the filling of the binder and the formation of the composite magnet can be achieved by extending the hot pressing or hot isostatic pressing time under conditions where the temperature is lower than the melting point of the rare earth-rich phase in the binder. During the hot pressing or hot isostatic pressing process of the composite magnet, the binder particles having a nanocrystalline structure can slip through the grain boundaries under the action of asymmetric stress, causing the binder particles to creep and enter the gaps between the magnetic powders, thereby achieving densification of the composite magnet. The hot pressing can be carried out in a vacuum or high-purity argon gas using equipment such as a uniaxial hot pressing furnace, a hot isostatic pressing furnace, or a spark plasma sintering furnace.

[0023] The present invention also protects the composite rare earth permanent magnetic material prepared by the preparation method of the composite rare earth permanent magnetic material.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. The present invention utilizes a magnetic binder with lower rare earth content, higher magnetic energy product, lower cost and wider composition range to bind Sm2Fe 17 N x 、Nd(Fe,M) 12 N x ThMn 12 Type Sm(Fe,M) 12, SmCo5 (1:5 type Sm-Co), Sm (Co, Fe, Zr, Cu)z (2:17 type Sm-Co, 5 <z<8.5)、R2Fe 14 B and other rare earth transition metal compound magnetic powders are bonded together to form a dense magnet. The present invention utilizes binder particles with fine grain size characteristics and containing a low melting point phase to deform through grain boundary sliding under stress, causing the binder particles to creep deform at temperatures above the melting point of the rare earth-rich phase and enter the gaps between the magnetic powders, thereby achieving densification of the composite magnet and increasing the relative density of the composite magnet to 90%-99%, thereby preparing a high-performance composite permanent magnet material. The present invention reduces the restrictions on the type, melting point, and volume ratio of the rare earth-rich phase in the magnetic binder, broadening the composition range and magnetic performance range of the magnetic binder. The present invention solves the problems of the prior art magnetic binder having an excessively high rare earth phase content, resulting in excessively high costs, and the requirement to press at a temperature above the melting point of the rare earth-rich phase of the binder when preparing the composite permanent magnet material, which is too stringent and limits the range of magnetic binder composition selection. It also avoids the decrease in binder magnetic properties caused by increasing the rare earth content, thereby facilitating an improvement in the magnetic energy product of the composite magnet.

[0026] 2. The magnetic alloy binder provided by the present invention deforms primarily through creep. Therefore, high deformation can be achieved by extending the processing time at temperatures below the melting point of the rare-earth-rich phase in the magnetic binder and pressures below 400 MPa. This achieves a high fill rate while minimizing the reaction between the binder and the magnetic powder, thereby reducing magnetic performance loss caused by the reaction between the binder and the raw magnetic powder. Furthermore, the lower processing temperature and pressure facilitate mold selection and reduce mold wear, thereby reducing mold costs while achieving the same densification conditions.

[0027] 3. The magnetic alloy binder proposed by the present invention can 17 N x 、Nd(Fe,M) 12 N x The magnetic powder is bonded into a dense magnet below the decomposition temperature (600℃); ThMn 12 Type Sm(Fe,M) 12 , SmCo5 (1:5 type Sm-Co), Sm (Co, Fe, Zr, Cu)z (2:17 type Sm-Co, 5 <z<8.5)、R2Fe 14B and other rare earth transition metal compound magnetic powders are bonded together to form a dense permanent magnet material. Therefore, the appropriate magnetic powder can be selected based on the magnetic properties and cost requirements of the composite magnet to produce high-performance, low-cost composite permanent magnet materials, or magnets with specific magnetic properties. Furthermore, a more corrosion-resistant binder can be selected based on the service environment requirements of the composite magnet. Furthermore, the use of magnetic binders to produce dense magnets is also a highly efficient method for recycling and reusing waste magnets and debris generated during magnet processing. Specific implementation method:

[0028] The following is a further description of the present invention, but not a limitation of the present invention.

[0029] Example 1

[0030] MQ-UF rapid quenching magnetic powder (composition Nd 13.6 Fe 73.6 Ga 0.6 Co 6.6 B 5.6 , magnetic performance parameters: Br = 0.77T, (BH) max =12.4, Hcj=19.8kOe) is used as magnetic alloy binder. MQ-UF rapid quenching magnetic powder is ground into fine powder with an average particle diameter of 3μm using air flow milling equipment. 17 N3 anisotropic magnetic powder is used as the raw material magnetic powder, the coercive force of the magnetic powder is 9.2kOe, and the maximum magnetic energy product of the magnetic powder is 33.2MGOe. MQ-UF rapid quenching magnetic powder is used as the magnetic alloy binder, and the mass ratio of the magnetic alloy binder to the magnetic powder is 20:80. The raw material magnetic powder and the magnetic alloy binder are loaded into a three-dimensional mixer and mixed evenly under the protection of high-purity argon. The mixture is oriented and pressed into a green compact in a magnetic field greater than 20kOe, with the pressure loading direction perpendicular to the magnetic field direction and the pressure being 100MPa. The green compact is transferred to a pressure sintering furnace with the pressure loading direction perpendicular to the orientation direction. -3 Pa vacuum is heated to 480 ° C, loaded with a pressure of 240 MPa, and the pressure is maintained for 10-360 min, and the green compact is pressed into a dense composite magnet. Table 1 shows the magnetic alloy binder and Sm2Fe 17 Effect of hot pressing process on the density and magnetic properties of composite magnets when the mass ratio of N3 magnetic powder is 20:80.

[0031] Table 1

[0032] Composite magnet number Hot pressing process Relative density / % Coercive force / kOe Maximum magnetic energy product / MGOe SUF-1 240Mpa*10min 85 10.3 22.2 SUF-2 240Mpa*20min 88 10.4 25.3 SUF-3 240Mpa*30min 93 10.5 26.7 SUF-4 240Mpa*40min 95 10.4 27.3 SUF-5 240Mpa*60min 96 10.3 27.6

[0033] Example 2

[0034] The same as Example 1, except that the mass ratio of the magnetic alloy binder to the magnetic powder is 5-40:60-95, and the hot pressing process is 240 MPa*60 minutes. The effect of the magnetic alloy binder ratio on the magnetic properties of the composite magnet when the hot pressing process is 240 MPa*60 minutes is shown in Table 2.

[0035] Table 2

[0036] Composite magnet number Magnetic alloy binder ratio wt% Relative density / % Coercive force / kOe Maximum magnetic energy / MGOe SUF-7 5 88 9.1 26.4 SUF-8 10 94 9.5 28.2 SUF-9 15 95 10.3 27.6 SUF-10 20 96 10.4 27.6 SUF-11 25 97 10.5 26.3 SUF-12 40 98 12.3 23.5

[0037] Example 3

[0038] MQ-16-9HD rapid quenching magnetic powder (composition Nd 10.6 Fe 82.1 Zr 0.9 B 6.4 , magnetic performance parameters: Br = 0.87T, (BH) max =15.5, Hcj=9.4kOe) is used as magnetic alloy binder. The rapidly quenched magnetic powder is ground into fine powder with an average particle diameter of 3μm using air flow milling equipment. 17 N3 anisotropic magnetic powder is used as the raw material magnetic powder, the coercive force of the magnetic powder is 9.2kOe, and the maximum magnetic energy product of the magnetic powder is 33.2MGOe. Rapidly quenched magnetic powder is used as the magnetic alloy binder, and the mass ratio of the magnetic alloy binder to the magnetic powder is 20:80. The raw material magnetic powder and the magnetic alloy binder are loaded into a three-dimensional mixer and mixed evenly under the protection of high-purity argon. The mixture is oriented and pressed into a green compact in a magnetic field greater than 20kOe, with the pressure loading direction perpendicular to the magnetic field direction and the pressure being 100MPa. The green compact is transferred to a pressure sintering furnace with the pressure loading direction perpendicular to the orientation direction. -3 The green compact was heated to 500°C in a vacuum at 1000 MPa and subjected to a pressure of 300 MPa for a period of 10-360 minutes. Table 3 shows the effect of the hot pressing process on the density and magnetic properties of the composite magnet when the mass ratio of magnetic alloy binder to magnetic powder is 20:80.

[0039] Table 3

[0040] Composite magnet number Hot pressing process Relative density / % Coercive force / kOe Maximum magnetic energy product / MGOe SHD-1 300Mpa*10min 83 9.1 24.0 SHD-2 300Mpa*20min 85 9.2 24.6 SHD-3 300Mpa*30min 90 9.2 26.1 SHD-4 300Mpa*40min 92 9.1 26.6 SHD-5 300Mpa*60min 93 9.2 27.0

[0041] Example 4

[0042] The same as Example 3, except that the mass ratio of the magnetic alloy binder to the magnetic powder was 5-40:60-95, and the hot pressing process was 300 MPa*60 minutes. The effect of the magnetic alloy binder ratio on the magnetic properties of the composite magnet when the hot pressing process was 300 MPa*60 minutes is shown in Table 4.

[0043] Table 4

[0044] Composite magnet number Magnetic alloy binder ratio wt% Relative density / % Coercive force / kOe Maximum magnetic energy product / MGOe SHD-7 5 84 9.1 26.5 SHD-8 10 90 9.2 27.6 SHD-9 15 92 9.1 27.4 SHD-10 20 93 9.2 27.0 SHD-11 25 95 9.1 26.7 SHD-12 40 97 9.2 24.8

[0045] Example 5

[0046] The impurity content of metal PrNd (Pr 20 Nd 80 ), Cu as raw materials, with atomic ratio (PrNd) 70 Cu 30 Ingredients are used to prepare low melting point diffusion source alloy powder. The metal raw materials are placed in a crucible and induction melted into a uniform melt. The melt is poured onto a water-cooled copper roller with a surface speed of 30m / s to prepare a quick-quenching thin strip. The quick-quenching thin strip is ground into a powder with a particle diameter of 10-30μm using a jet mill. MQ-16-9HD quick-quenching magnetic powder purchased from Magnequench (composition Nd10.6Fe82.1Zr0.9B6.4, magnetic properties parameters: Br=0.87T, (BH) max =15.5, Hcj = 9.4 kOe) was mixed with PrNdCu alloy powder, with the PdNdCu ratio in the mixture ranging from 1 to 4 at.% (as shown in Table 5). After uniform mixing, the mixture was subjected to diffusion heat treatment in a vacuum at 620°C for 30 minutes. The magnetic properties of the quenched strip after diffusion heat treatment were tested using PPMS. Table 5 shows the test results of the PrNdCu alloy content in the mixed magnetic powder, the melting point of the rare earth-rich phase, the coercivity of the binder magnetic powder, and the maximum magnetic energy product.

[0047] Table 5

[0048] Binder No. PrNdCu alloy contains / at.% Melting point of rare earth-rich phase / ℃ Coercive force / kOe Maximum magnetic energy product / MGOe MQ-B 0 - 8.9 15.0 PN-2 1 516 9.6 14.9 PN-3 2 516 10.3 14.6 PN-4 3 516 12.4 14.3 PN-5 4 516 13.7 14.1

[0049] The diffusion heat treated quenched strip was ground into fine powder with an average particle diameter of 3 μm using air flow milling equipment. 17 N3 anisotropic magnetic powder is used as the raw material magnetic powder, the coercive force of the magnetic powder is 10.2kOe, and the maximum magnetic energy product of the magnetic powder is 33.2MGOe. The NdFeB-based alloy powder prepared as above (as shown in Table 5) is used as the magnetic alloy binder, and the volume ratio of the magnetic alloy binder to the magnetic powder is 20:80. The raw material magnetic powder and the binder are loaded into a three-dimensional mixer and mixed evenly under the protection of high-purity argon. The mixture is oriented and pressed into a green compact in a magnetic field greater than 20kOe, and the pressure loading direction is perpendicular to the magnetic field direction, and the pressure is 100MPa. The green compact is transferred to a pressure sintering furnace, and the pressure loading direction is perpendicular to the orientation direction. -3 Pa vacuum was heated to 480 ° C, loaded with a pressure of 300 MPa, and the pressure was maintained for 60 min to press the green compact into a dense composite magnet. Table 6 shows the magnetic alloy binder and Sm2Fe17 Relative density, coercive force and maximum magnetic energy product of composite magnets prepared from N3 magnetic powder.

[0050] Table 6

[0051] Composite magnet number Magnetic alloy binder Relative density / % Coercive force / kOe Maximum magnetic energy product / MGOe SMQ-B MQ-B 88 9.1 26.5 SPN-2 PN-2 91 10.2 28.3 SPN-3 PN-3 92 10.4 28.8 SPN-4 PN-4 94 10.4 30.0 SPN-5 PN-5 95 10.5 30.6

[0052] Example 6

[0053] Using Nd, Fe, Mn, Cu, and a boron-iron alloy with an impurity content of less than 1 wt%, the raw materials are formulated according to the chemical formulas expressed in elemental proportions as shown in Table 7. A 1% burnout compensation is added to the rare earth Nd. The raw metals are placed in a crucible and induction melted into a uniform melt. Table 7 shows the composition of the NdFeB-based alloy binder, the melting point of the rare earth-rich phase, the coercivity of the binder magnetic powder, and the maximum magnetic energy product test results. The melt is poured onto a water-cooled copper roller at a surface speed of 25 m / s. The alloy melt is then rapidly quenched to produce amorphous or nanocrystalline rapidly quenched ribbons. The ribbons are heat treated in a vacuum at 630°C for 15 minutes. The rapidly quenched ribbons are ground into a fine powder with an average particle diameter of 3 μm using a jet mill. Sm2Fe17N3 anisotropic magnetic powder with an average particle diameter of 3μm is used as the raw magnetic powder. The coercive force of the magnetic powder is 10.2kOe, and the maximum magnetic energy product of the magnetic powder is 36.9MGOe. The NdFeB-based alloy powder in Table 7 is used as the magnetic alloy binder. The volume ratio of the magnetic alloy binder and the magnetic powder is 20:80. The raw magnetic powder and the magnetic alloy binder are loaded into a three-dimensional mixer and mixed evenly under the protection of high-purity argon. The mixture is oriented and pressed into a green compact in a magnetic field greater than 20kOe. The pressure loading direction is perpendicular to the magnetic field direction, and the pressure is 100MPa. The green compact is transferred to a pressure sintering furnace with the pressure loading direction perpendicular to the orientation direction. -3 Pa vacuum was heated to 480℃, loaded with 300Mpa pressure, and the pressure was maintained for 60min, and the compact was pressed into a dense composite magnet. Table 8 shows the rapid quenching of NdFeB binder and Sm2Fe 17 Test data table of relative density, coercive force and maximum magnetic energy product of composite magnets prepared from N3 magnetic powder.

[0054] Table 7

[0055] Binder No. Binder ingredients rare earth-rich phase melting point Coercive force / kOe Maximum magnetic energy product / MGOe N-1 Nd11.8FebalB5.9Cu0.2 / 678 9.4 139 N-2 Nd12.5FebalB5.9Cu0.2 534 12.3 13.6 N-3 Nd13.2FebalB5.9Cu0.2 534 13.6 13.42 N-4 Nd13.9FebalB5.9Cu0.2 534 14.2 13.1 N-5 Nd12.5FebalB5.9Cu0.2Zr0.5 534 14.4 12.8

[0056] Table 8

[0057]

[0058]

[0059] As can be seen from Table 8,.

[0060] Example 7

[0061] Referring to Example 1, the compact was transferred to a pressure sintering furnace, with the pressure loading direction perpendicular to the orientation direction. -3 Pa in a vacuum and heated to 400 ° C, loaded with a pressure of 400 MPa, the pressure is maintained for 10 minutes, and the green compact is pressed into a dense composite magnet.

[0062] Example 8

[0063] Referring to Example 1, the compact was transferred to a pressure sintering furnace, with the pressure loading direction perpendicular to the orientation direction. -3 Pa in a vacuum and heated to 600 ° C, loaded with a pressure of 50 MPa, the pressure is maintained for 360 minutes, and the green compact is pressed into a dense composite magnet.

[0064] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a composite rare earth permanent magnet material, characterized in that: It includes the following steps: using a magnetic alloy binder with a chemical formula expressed in atomic percentages as R x Fe 100-x-y-z-v M1 y M2 z B v to bond raw material magnetic powder into a magnet to prepare a composite rare earth permanent magnet material. The raw material magnetic powder is selected from one or more of rare earth transition metal compound magnetic powders such as Sm2Fe 17 N x , Nd(Fe,M) 12 N x , ThMn 12 -type Sm(Fe,M) 12 , SmCo5, Sm(Co,Fe,Zr,Cu)z, R2Fe 14 B single crystal, oriented polycrystalline HDDR-R2Fe 14 B. The Sm(Co,Fe,Zr,Cu)z is specifically 2:17-type Sm-Co, where 5 < z < 8.5; in the magnetic alloy binder, R is selected from at least one of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, 10.0 < x < 14.0; M1 is selected from at least one of Al, Co, Si, Zr, Hf, Ta, Nb, Ti, V, Cr, Mn, Ni, W, and Mo, 0 ≤ y ≤ 15.0; M2 is at least one of Cu and Ga, 0 ≤ z ≤ 8.0, 3 ≤ v ≤ 10.

0.

2. The method for preparing a composite rare earth permanent magnet material according to claim 1, wherein: The chemical formula expressed in atomic percentage is R x Fe 100-x-y-z-v M1 y M2 z B v of a magnetic alloy binder, wherein R is selected from one of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, 10.0 < x < 14.0; M1 is selected from one of Al, Co, Si, Zr, Hf, Ta, Nb, Ti, V, Cr, Mn, Ni, W and Mo, 0 ≤ y ≤ 15.0; M2 is one of Cu and Ga, 0≤z≤8.0, 3≤v≤10.

0.

3. The method for preparing a composite rare earth permanent magnet material according to claim 1, wherein: The chemical formula expressed in atomic percent is R x Fe 100-x-y-z-v M1 y Cu z B v A magnetic alloy binder, wherein R is Pr and / or Nd, 11.8≤x≤13.9, M1 is one of Zr and Nb, y=0.5-1.0, z=0.2-1.6, and v=5.5-5.

9.

4. The method for preparing a composite rare earth permanent magnet material according to claim 1, wherein: The volume proportion of raw material magnetic powder in the composite rare earth permanent magnetic material is 60%-95%, and the volume proportion of magnetic alloy binder is 5%-40%.

5. The method for preparing a composite rare earth permanent magnet material according to claim 4, wherein: The volume proportion of raw material magnetic powder in the composite rare earth permanent magnetic material is 80%-90%, and the volume proportion of magnetic alloy binder is 10%-20%.

6. The method for preparing a composite rare earth permanent magnet material according to claim 1, wherein: The specific steps are as follows: mixing raw magnetic powder and magnetic alloy binder uniformly under vacuum or inert gas protection, orienting and pressing the green compact in a magnetic field greater than 15kOe, with the pressure loading direction perpendicular to the magnetic field direction and the pressure being 20-100MPa, transferring the green compact to a pressure sintering furnace, heating to 400°C-600°C in vacuum or under inert gas protection, applying a pressure of 50-400MPa, and maintaining the pressure for 10-360min, and pressing the green compact into the composite rare earth permanent magnet material.

7. The composite rare earth permanent magnet material prepared by the method for preparing the composite rare earth permanent magnet material according to claim 1.

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