Alloy binder, composite rare earth permanent magnet material and preparation method thereof

Abstract

This invention discloses an alloy binder, a composite rare-earth permanent magnet material, and a method for preparing the same. The alloy binder has the chemical formula Zn (expressed as atomic percentage). 100‑a‑b Mg a M b Wherein, 5≤a≤70; M is selected from at least one of Al, Cu, Fe, Co, Si, Zr, Hf, Ta, Nb, Ti, V, Cr, Mn, Ni, W, Mo, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and Sc, 0≤b≤80; the alloy binder contains at least one phase with a melting point below 420℃. The alloy binder proposed in this invention can bind Sm2Fe 17 N x Nd(Fe,M) 12 N x Magnetic powders can be bonded into dense magnets at temperatures below their decomposition temperature; utilizing this low-temperature bonding capability, ThMn12-type Sm(Fe,M) can also be bonded together. 12 , SmCo5 (1:5 type Sm‑Co), Sm (Co, Fe, Zr, Cu) z (2:17 type Sm-Co, 5) <z<8.5)、R2Fe 14 Rare earth transition metal compound magnetic powders such as B are bonded together to form a dense permanent magnet material.

Description

Technical fields:

[0001] This invention relates to rare earth permanent magnet materials, specifically to an alloy binder, a composite rare earth permanent magnet material, and a method for preparing the same. Background technology:

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

[0003] Invented in 1960, Sm-Co permanent magnets were the first generation of high-performance rare-earth permanent magnet materials. However, due to the presence of high proportions of the expensive and scarce strategic element Co, the application areas of Sm-Co were limited.

[0004] In 1982, Masato Sagawa of Sumitomo Special Metals invented sintered Nd-Fe-B permanent magnets. Due to their highest magnetic energy product to date, high cost-effectiveness because they do not contain strategic metals, and simple fabrication methods, they have gained widespread application and are currently the most widely used rare-earth permanent magnet material. Bonded magnets made using rapidly quenched Nd-Fe-B magnetic powder and organic resin invented by General Electric have also gained widespread market acceptance due to their high dimensional accuracy and ease of fabrication of irregularly shaped magnets.

[0005] Following Nd-Fe-B compounds, Sm2Fe 17 Nx (Samarium Iron Nitrogen), Nd(Fe,M) 12 N x (abbreviated as neodymium iron nitrogen), and ThMn12 type Sm(Fe,M) 12 Rare earth transition metal compounds such as Sm2Fe (short for 1:12 samarium iron) have also been found to possess superior intrinsic magnetic properties and are considered candidates for next-generation rare earth permanent magnet materials. 17 N x (abbreviated as samarium iron nitrogen), Nd(Fe,M) 12 Nx (neodymium iron nitrogen) is a metastable phase that decomposes at temperatures above 600°C, therefore it cannot be formed using traditional high-temperature sintering processes. Sm(Fe,M) 12 Although 1:12 samarium iron (SMI) is stable at high temperatures, it is difficult to form high coercivity in bulk materials. Currently, these magnetic materials can only be prepared into ultrafine single crystals or polycrystalline powders to achieve high coercivity and thus high energy product. They are 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. However, injection molding or compression molding generally requires the addition of more than 30% organic resin. Using resin bonding and injection molding has the following three drawbacks: First, to ensure flowability, the resin volume ratio must be higher than 30%, leading to a significant decrease in the remanence of the magnet. Second, injection molding generally requires the magnetic powder to be mixed and granulated, a process that needs to be carried out at temperatures above the melting point of the bonding resin. Ultrafine particles are prone to oxidation, causing a decrease in magnetic properties. To mitigate this, the magnetic powder needs to be coated with anti-oxidation and corrosion-resistant materials, a very demanding technique that adds extra cost. Third, the organic resin itself has a low melting point, and the operating temperature of the bonded composite magnet is limited by the resin's strength. Compression-molded bonded magnets also have similar problems.

[0007] When using low-melting-point alloys for bonding, the low fluidity of the metal means that both known room-temperature pressing and high-temperature pressing techniques suffer from low magnet density and high porosity, resulting in poor internal sealing, oxidation resistance, and corrosion resistance. To date, no commercially available products exist. In metal binders, metallic Zn can bind with Sm₂Fe. 17 N x To improve coercivity, current processes typically involve hot pressing or heat treatment at around 419°C, the melting point of metallic Zn. However, at this temperature, excessive reaction between Zn and magnetic powder leads to the formation of numerous non-magnetic Zn-Fe compounds, further reducing remanence. Therefore, although Zn-bonded Sm₂Fe₁₇Nx generally exhibits high coercivity, its remanence is often very low, making it unsuitable for fabricating permanent magnets with high energy products.

[0008] For the reasons mentioned above, Sm2Fe 17 N x (abbreviated as samarium iron nitrogen), Nd(Fe,M) 12 N x (abbreviated as neodymium iron nitrogen), and ThMn12 type Sm(Fe,M) 12 Among (abbreviated as 1:12 samarium iron) permanent magnet materials, only samarium iron nitrogen anisotropic magnetic powder has entered the stage of small-batch industrial production for injection molding bonded magnets. The other compounds have not yet entered the industrialization stage. Summary of the Invention:

[0009] To address the problems existing in the prior art, this invention proposes an alloy binder, a composite rare-earth permanent magnet material, and a method for preparing the same. This invention introduces a novel alloy binder and molding process for Sm2Fe... 17 N x Nd(Fe,M) 12 N x ThMn12 type Sm(Fe,M) 12Magnetic powder is bonded into high-performance magnets. Furthermore, the alloy binder and molding process proposed in this invention can also bond SmCo5 (1:5 type Sm-Co) and Sm(Co,Fe,Zr,Cu). z (2:17 type Sm-Co, 5) <z<8.5)、R2Fe 14 High-performance composite permanent magnet materials are prepared by bonding rare earth transition metal compound magnetic powders such as B together to form a dense magnet.

[0010] The first object of this invention is to provide an alloy binder with the chemical formula Zn, expressed in atomic percentage. 100-a-b Mg a M b Wherein, 5≤a≤70; M is selected from at least one of Al (aluminum), Cu (copper), Fe (iron), Co (cobalt), Si (silicon), Zr (zirconium), Hf (hafnium), Ta (tantalum), Nb (niobium), Ti (titanium), V (vanadium), Cr (chromium), Mn (manganese), Ni (nickel), W (tungsten), Mo (molybdenum), La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), Lu (lutetium), Y (yttrium), and Sc (scandium), 0≤b≤80; the alloy binder contains at least one phase with a melting point below 420℃.

[0011] This binder exhibits good filling ability at lower temperatures, enabling it to bind Sm2Fe 17 N x Nd(Fe,M) 12 N x ThMn12 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 Rare earth transition metal compound magnetic powders such as B are bonded together to form a dense composite permanent magnet material.

[0012] Preferably, the above-mentioned alloy binder has the chemical formula Zn, expressed as an atomic percentage. 100-a-b-c Mg a Al b N c Where 5≤a≤70, 0≤b≤70; N is selected from at least one of Cu, Fe, Co, Si, Zr, Hf, Ta, Nb, Ti, V, Cr, Mn, Ni, W, Mo, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y and Sc, and 0≤c≤10.

[0013] Further preferably, the above-mentioned alloy binder has the chemical formula Zn, expressed as an atomic percentage. 100-a-b-c Mg a Al b N c Where 18≤a≤43, 0≤b≤2, and N is Cu and / or Si, 0≤c≤2.

[0014] The second objective of this invention is to protect the preparation method of the aforementioned alloy binder, using metallic raw materials or intermediate alloys with an impurity content of less than 1 wt% as raw materials, and the chemical formula Zn expressed as atomic percentage. 100-a-b Mg a M b The process involves loading metal raw materials or intermediate alloys into a reaction vessel and induction melting them into a homogeneous melt. The melt is then rapidly quenched to prepare amorphous or nanocrystalline rapidly quenched ribbons. The rapidly quenched ribbons are then heat-treated under an inert gas atmosphere at 200℃-380℃ for 10-120 minutes to obtain rapidly quenched ribbons with a grain size range of 10-2000nm. The heat-treated rapidly quenched ribbons are then ground in an inert gas atmosphere to obtain the alloy binder.

[0015] The alloy binder contains at least one intermetallic compound or other brittle phase, making the alloy strip easy to break. The above-mentioned alloy binder powder has the following microstructure characteristics: the alloy binder is composed of polycrystalline particles with fine grains of 10-2000 nm, and the size of the polycrystalline particles is distributed between 0.1-20 μm.

[0016] Preferably, the specific steps of the rapid quenching are as follows: pouring the melt onto a water-cooled copper roller, wherein the surface rotation speed of the copper roller is 5-50 m / s.

[0017] Preferably, the alloy binder is composed of polycrystalline particles with fine grains having a particle size of 10-2000 nm.

[0018] This invention also protects a method for preparing a composite rare-earth permanent magnet material, comprising the following steps: using the above-mentioned atomic percentages to express the chemical formula Zn 100-a-b Mg a M bThe alloy binder uses rare earth transition metal compound magnetic powder with an average particle size of 1-200 μm as raw material magnetic powder, and prepares composite permanent magnet materials through mixing, orientation pressing and hot pressing; wherein, 5≤a≤70; M is selected from at least one of Al, Cu, Fe, Co, Si, Zr, Hf, Ta, Nb, Ti, V, Cr, Mn, Ni, W, Mo, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y and Sc, 0≤b≤80; the volume ratio of raw material magnetic powder in the composite permanent magnet material is 60%-98%, and the volume ratio of alloy binder is 2%-40%.

[0019] The purpose of raw material magnetic powder is to provide magnetic properties for composite rare earth permanent magnet materials (composite magnets). The type and proportion of raw material magnetic powder can be adjusted according to the design goals of cost and magnetic properties, and multiple magnetic powders can also be mixed and used.

[0020] Preferably, the volume ratio of the raw material magnetic powder in the composite permanent magnet material is 80%-95%, and the volume ratio of the binder is 5%-20%.

[0021] Preferably, the preparation method of the above-mentioned composite rare earth permanent magnet material includes the following specific steps: The raw material magnetic powder and alloy binder are mixed uniformly under vacuum or inert gas protection, and then oriented and pressed into a compact in a magnetic field greater than 15 kOe. The pressure loading direction is perpendicular to the magnetic field direction, and the pressure is 20-200 MPa. The compact is transferred to a pressure sintering furnace and heated to 300℃-650℃ under vacuum or inert gas protection, with a pressure of 30-500 MPa applied for 20-360 min. The compact is then pressed into the composite rare earth permanent magnet material. The specific pressure sintering temperature is determined based on the decomposition temperature of the raw material magnetic powder and the melting point of the low-melting-point phase in the magnetic alloy binder: the pressure sintering temperature is not lower than 70% of the melting point (absolute temperature) of the low-melting-point phase in the metal or binder.

[0022] Further optimization involves transferring the compact to a pressure sintering furnace, heating it to 350℃-380℃ in a vacuum or under inert gas protection, applying a pressure of 200 MPa, and holding the pressure for 10-40 minutes to press the compact into the composite rare earth permanent magnet material.

[0023] Preferably, the raw material magnetic powder is selected from Sm2Fe 17 N x Nd(Fe,M) 12 N x ThMn12 type Sm(Fe,M) 12 ,SmCo5,Sm(Co,Fe,Zr,Cu)z,R2Fe 14B Single Crystal and Oriented Polycrystalline HDDR-R2Fe 14 One or more of B, wherein Sm(Co,Fe,Zr,Cu)z is specifically type 2:17 Sm-Co, 5 <z<8.5。

[0024] To obtain a high magnetic energy product, the raw magnetic powder is generally required to possess magnetic anisotropy. (Sm₂Fe) 17 N x Nd(Fe,M) 12 N x ThMn12 type Sm(Fe,M) 12 SmCo5 (1:5 type Sm-Co), R2Fe 14 When B is used as a raw material magnetic powder, it is used in the form of a single crystal powder with an average particle diameter of 0.5-15 μm. (Sm(Co,Fe,Zr,Cu)) z (2:17 type Sm-Co, 5) <z<8.5)、HDDR-R2Fe 14 The average particle diameter of the beta-oriented polycrystalline magnetic powder is 10-200 μm. R2Fe 14 There are two types of magnetic powder used as raw material B: single-crystal magnetic powder and oriented polycrystalline powder prepared using the HDDR process. R2Fe 14 To reduce costs when using boron single crystals as raw material magnetic powder, discarded R-Fe-B sintered magnets or grinding debris can be used as raw materials, which are then ground into single crystal magnetic powder. The raw material magnetic powder particles should have a regular equiaxed shape and an oxygen content of less than 2 wt%.

[0025] Composite rare earth permanent magnet materials (composite magnets) have the following characteristics: The composite magnet is composed of an alloy binder and Sm2Fe 17 N x Nd(Fe,M) 12 N x ThMn12 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 14The composite magnet is composed of one or more rare earth transition metal compound magnetic powders, such as B. An alloy binder with fine grain size and containing low-melting-point phases undergoes deformation under heat and pressure, filling the gaps between the raw magnetic powder particles and promoting densification, resulting in a relative density of 90%-99%. Because the alloy binder can deform at temperatures of 250℃-400℃ and stresses below 500MPa, and its fine particle size facilitates uniform mixing of the solid binder and magnetic powder, the binder undergoes rheological changes during hot pressing and penetrates between the magnetic powder particles, playing a role in densification and bonding. Since the alloy binder is mainly composed of corrosion-resistant Al, Mg, and Zn, the composite magnet exhibits excellent corrosion resistance.

[0026] The alloy binder provided by this invention can achieve a high filling rate at temperatures below 400°C and under relatively low pressure. The Zn element in the alloy binder can react with the surface of the raw material magnetic powder, removing harmful impurities such as α-Fe and improving the coercivity of the composite magnet. The lower pressing temperature can also prevent excessive reaction between the binder and the magnetic powder, preventing a significant decrease in remanence while maintaining or improving coercivity. The lower processing temperature and lower pressure facilitate the selection of molds and reduce mold wear, thereby reducing mold costs under the same densification conditions.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. In terms of chemical composition, the alloy binder is mainly composed of abundant and readily available elements such as Al, Mg, and Zn, resulting in low raw material costs. Regarding the physicochemical properties of the material, the alloy binder exhibits a low melting point and good corrosion resistance. In terms of processing performance, the alloy binder contains at least one brittle phase, making it easy to efficiently crush into ultrafine powders smaller than 10 micrometers using mature equipment such as ball mills and air jet mills. The fine particle size facilitates uniform mixing of the solid binder and magnetic powder; the alloy binder can deform under temperatures of 250℃-400℃ and low stress, filling the gaps in the raw material magnetic powder, promoting the densification of the magnet, and achieving a relative density of 92-99% for the composite magnet. The components of the alloy binder themselves possess good corrosion resistance, helping to improve the corrosion resistance of the composite magnet and saving on anti-corrosion coating costs.

[0029] 2. The alloy binder provided by this invention can achieve a high filling rate at temperatures below 400°C and under relatively low pressure. The Zn element in the binder can react with the surface of the magnetic powder to remove harmful impurities such as α-Fe and improve the coercivity of the composite magnet. The lower pressing temperature can also prevent excessive reaction between the binder and the magnetic powder, preventing a significant decrease in remanence while maintaining or improving coercivity. The lower processing temperature and lower pressure facilitate the selection of molds and reduce mold wear, thereby reducing the cost of molds under the same densification conditions.

[0030] 3. The alloy binder proposed in this invention can bind Sm2Fe 17 N x Nd(Fe,M) 12 N x Magnetic powders can be bonded into dense magnets at temperatures below their decomposition temperature; utilizing this low-temperature bonding capability, ThMn12-type Sm(Fe,M) can also be bonded together. 12 , SmCo5 (1:5 type Sm-Co), Sm (Co, Fe, Zr, Cu) z (2:17 type Sm-Co, 5) <z<8.5)、R2Fe 14 Rare earth transition metal compound magnetic powders such as B are bonded together to form a dense permanent magnet material. Therefore, according to the magnetic properties and cost requirements of the composite magnet, appropriate magnetic powders can be selected to prepare high-performance, low-cost magnets, or magnets with specific magnetic properties. Detailed implementation method:

[0031] The following is a further description of the invention, but not a limitation thereof.

[0032] Example 1

[0033] According to the chemical formulas listed in Table 1 (expressed as atomic percentages), raw materials with an impurity content of less than 1 wt% were prepared and placed in a crucible for induction melting to form a homogeneous melt. The melt was then poured onto a water-cooled copper roller at a surface rotation speed of 30 m / s. The alloy melt was then rapidly quenched to prepare amorphous or nanocrystalline rapidly quenched ribbons. The rapidly quenched ribbons were then heat-treated under argon protection at 320℃ for 60 min. The heat-treated rapidly quenched ribbons were then ground into fine powder with an average particle diameter of 3 μm using an air jet milling system; this powder served as the alloy binder.

[0034] Table 1

[0035] serial number Alloy binder composition alloy initial melting point / °C ZM-1 <![CDATA[Zn 30 Mg 70 ]]> 342 ZM-2 <![CDATA[Zn 55 Mg 45 ]]> 342 ZM-3 <![CDATA[Zn 70 Mg 30 ]]> 382 ZM-4 <![CDATA[Zn 80 Mg 20 ]]> 382 ZM-5 <![CDATA[Zn 85 Mg 15 ]]> 363 ZM-6 <![CDATA[Zn 88 Mg 12 ]]> 363 ZM-7 <![CDATA[Zn 95 Mg5]]> 363 ZM-8 <![CDATA[Zn 55 Mg 43 Al2]]> 345 ZM-9 <![CDATA[Zn 55 Mg 43 Cu2]]> 345 ZM-10 <![CDATA[Zn 55 Mg 43 Si2]]> 345 ZM-11 <![CDATA[Zn 80 Mg 18 Al2]]> 362 ZM-12 <![CDATA[Zn 80 Mg 18 Cu2]]> 364 ZM-13 <![CDATA[Zn 80 Mg 18 Si2]]> 366 ZM-14 <![CDATA[Zn 55 Mg 41 Al2Si2]]> 345

[0036] Table 1 shows the composition and initial melting point of the Zn-Mg based alloy binders. An alloy binder with an initial melting point of 342℃-345℃ was selected as the alloy binder for the subsequent composite magnet. Sm2Fe with an average particle diameter of 3μm was used as the binder. 17 N3 anisotropic magnetic powder was used as the raw material, with a coercivity of 9.1 kOe and a maximum energy product of 33.2 MGOe. Using alloy binders numbered ZM-1, ZM-2, ZM-8, ZM-9, ZM-10, and ZM-14 (20% by volume), the raw material and binders were loaded into a three-dimensional mixer and mixed uniformly under high-purity argon protection to obtain a mixture. The mixture was then oriented and pressed into a compact in a magnetic field greater than 20 kOe, with the pressure applied perpendicular to the magnetic field direction at a pressure of 100 MPa. The compact was then transferred to a pressure sintering furnace, with the pressure applied perpendicular to the orientation direction, at a pressure of 3*10... -3 The compact is heated to 350℃ in a vacuum and subjected to a pressure of 200 MPa for 20 minutes to form a dense composite magnet. Table 2 shows the effect of different alloy binder volume ratios (20%) on the density and magnetic properties of the composite magnets.

[0037] Table 2

[0038] serial number Alloy binder Relative density / % Coercivity / kOe Maximum magnetic energy product / MGOe SZM-1 <![CDATA[Zn 30 Mg 70 ]]> 97 11.6 20.2 SZM-2 <![CDATA[Zn 55 Mg 45 ]]> 94.5 13.4 21.8 SZM-3 <![CDATA[Zn 55 Mg 43 Al2]]> 95 13.7 22.4 SZM-4 <![CDATA[Zn 55 Mg 43 Cu2]]> 94.2 12.3 21.2 SZM-5 <![CDATA[Zn 55 Mg 43 Si2]]> 95.1 12.8 21.9 SZM-6 <![CDATA[Zn 55 Mg 41 Al2Si2]]> 95.2 13.5 22.3

[0039] From Table 2, we obtain Zn 55 Mg 43 Al2, Zn 55 Mg 43 Cu2, Zn 55 Mg 43 Si2 and Zn 55 Mg 41 Composite magnets obtained by using Al2Si2 as an alloy binder exhibit good performance. These alloys can all be used to prepare composite permanent magnet materials with excellent magnetic properties.

[0040] Example 3

[0041] The preparation method of the alloy binder is as described in Example 1, using Sm2Fe with an average particle diameter of 3 μm. 17 N3 anisotropic magnetic powder was used as the raw material magnetic powder. The coercivity of the raw material magnetic powder was 9.1 kOe, and the maximum energy product of the raw material magnetic powder was 33.2 MGOe. Zn powder numbered ZM-8 in Example 1 was used. 55 Mg 43Al2 is used as the alloy binder, with volume proportions of 5%, 10%, 15%, 20%, 25%, and 10%. The raw material magnetic powder and alloy binder are loaded into a three-dimensional mixer according to the above proportions and mixed uniformly under high-purity argon protection to obtain a mixture. The mixture is then oriented and pressed into a compact in a magnetic field greater than 20 kOe, with the pressure applied perpendicular to the magnetic field direction at a pressure of 100 MPa. The compact is then transferred to a pressure sintering furnace, with the pressure applied perpendicular to the orientation direction, at a pressure of 3*10... -3 Heating to 350℃ in a vacuum of 200 MPa and applying a pressure of 200 MPa for 20 minutes, the compact is pressed into a dense composite magnet. Table 3 shows the density and magnetic properties of composite magnets with an alloy binder volume ratio of 5%-40%.

[0042] Table 3

[0043] serial number Alloy binder volume ratio / % Relative density / % Coercivity / kOe Maximum magnetic energy product / MGOe SZM-7 5 87.3 10.3 26.8 SZM-8 10 92.1 12.7 26.1 SZM-9 15 94.5 13.1 24.4 SZM-10 20 95.0 13.7 22.4 SZM-11 25 96.5 14.3 20.5 SZM-12 40 98.5 16.4 14.4

[0044] Table 3 shows that Zn can be adjusted 55 Mg 43 The ratio of Al2 alloy binder to raw material magnetic powder can be adjusted to control the coercivity and magnetic energy product of the composite magnet, thereby preparing composite permanent magnet materials with high magnetic energy product or high coercivity.

[0045] The above description of the embodiments is only for the purpose of helping to understand the technical solution and core idea of ​​the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An alloy binder characterized in that, Zn 100-a-b-c Mg a Al b N c wherein 5≤a≤70, 0≤b≤70; N is selected from at least one of Cu, Fe, Co, Si, Zr, Hf, Ta, Nb, Ti, V, Cr, Mn, Ni, W, Mo, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y and Sc, and 0≤c≤10; the alloy binder contains at least one phase with a melting point lower than 420℃; the preparation method of the alloy binder comprises the following steps: taking metal raw materials or intermediate alloys with impurity content lower than 1wt% as raw materials, and preparing the alloy binder according to the chemical formula Zn 100-a-b- c Mg a Al b N c charging, charging the metal raw materials or intermediate alloys into a reaction container, inductive smelting into a homogeneous melt, rapidly quenching the melt to prepare amorphous rapidly-quenched thin strips or nanocrystalline rapidly-quenched thin strips, heat treating the rapidly-quenched thin strips at 200-380℃ under inert gas protection for 10-120min to obtain rapidly-quenched thin strips with grain size ranging from 10-2000nm, and grinding the heat-treated rapidly-quenched thin strips in inert gas to obtain the alloy binder.

2. The alloy binder of claim 1, wherein, The chemical formula expressed in atomic percentage is Zn 100-a-b-c Mg a Al b N c wherein 18≤a≤43, 0≤b≤2, N is Cu and / or Si, and 0≤c≤2.

3. The alloy binder of claim 1, wherein, The rapid quenching is specifically implemented by pouring the melt onto a water-cooled copper roller, and the surface rotating speed of the copper roller is 5-50 m / s.

4. The alloy binder of claim 1, wherein, The alloy binder is a polycrystalline particle composed of grains with a particle size of 10-2000 nm.

5. A method for preparing a composite rare-earth permanent magnet material, characterized in that, comprising the following steps: using the alloy binder of claim 1, with the chemical formula of Zn 100-a-b-c Mg a Al b N c , and rare earth transition metal compound magnetic powder with an average particle size of 1-200 microns as raw material magnetic powder, a composite permanent magnetic material is prepared by mixing, orientation pressing and hot pressing; wherein, 5≤a≤70, 0≤b≤70, N is selected from at least one of Cu, Fe, Co, Si, Zr, Hf, Ta, Nb, Ti, V, Cr, Mn, Ni, W, Mo, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y and Sc, and 0≤c≤10; the volume ratio of the raw material magnetic powder in the composite permanent magnetic material is 60%-98%, and the volume ratio of the alloy binder is 2%-40%.

6. The method of producing a composite rare earth permanent magnet material according to claim 5, characterized by, The volume ratio of the raw material magnetic powder in the composite permanent magnetic material is 80%-95%, and the volume ratio of the binder is 5%-20%.

7. The method of producing a composite rare earth permanent magnet material according to claim 5 or 6, characterized in that, The specific steps are as follows: uniformly mixing the raw material magnetic powder and the alloy binder under vacuum or inert gas protection, orienting and pressing the mixture into a compact in a magnetic field with a magnetic field strength greater than 15 kOe, the pressure loading direction being perpendicular to the magnetic field direction, and the pressure being 20-200 MPa, transferring the compact into a pressure sintering furnace, heating the compact to 300-650 ℃ under vacuum or inert gas protection, loading a pressure of 30-500 MPa, and keeping the pressure for 20-360 min, and pressing the compact into the composite rare earth permanent magnetic material.

8. The method of producing a composite rare earth permanent magnet material according to claim 5, characterized by, The raw material magnetic powder is selected from Sm2Fe 17 N x , Nd(Fe, M) 12 N x , ThMn12 type Sm(Fe, M) 12 , SmCo5, Sm(Co, Fe, Zr, Cu)z, R2Fe 14 B single crystal and oriented polycrystalline HDDR-R2Fe 14 B, or one or more of the above, wherein Sm(Co, Fe, Zr, Cu)z is specifically 2:17 type Sm-Co, 5<z<8.5.