Samarium-cobalt / aluminum-nickel-cobalt composite magnet and method for manufacturing the same

Abstract

The application provides a SmCo / AlNiCo composite magnet and a preparation method thereof. The preparation method comprises the following steps: mixing SmCo alloy powder and AlNiCo powder with specific compositions, and then sequentially performing orientation setting and cold isostatic pressing treatment to obtain a SmCo / AlNiCo composite magnet green body; and sequentially performing vacuum sintering, solid solution treatment and aging treatment on the SmCo / AlNiCo composite magnet green body to obtain the SmCo / AlNiCo composite magnet. In the application, SmCo-containing raw materials and AlNiCo alloy raw materials with specific compositions are selected to prepare the SmCo alloy powder and the AlNiCo powder, and through the steps of mixing the two, sequentially performing orientation setting, cold isostatic pressing treatment, vacuum sintering, solid solution treatment and aging treatment and the like, the advantages of the SmCo magnet and the AlNiCo magnet can be fully utilized, and a composite magnet material with good magnetic performance at high temperature can be obtained.

Description

Technical Field

[0001] This application relates to the field of rare earth permanent magnet materials, specifically to a samarium cobalt / alanine nickel cobalt composite magnet and its preparation method. Background Technology

[0002] Samarium cobalt rare-earth permanent magnets possess irreplaceable advantages such as corrosion resistance, high temperature resistance, and low temperature coefficient, making them indispensable functional metallic materials in aerospace, microwave communications, instrumentation, electrical engineering, and magnetic machinery. They are characterized by high energy product (BH)max, high coercivity, high Curie temperature, and good corrosion resistance. The maximum energy product (BH) of Samarium cobalt rare-earth permanent magnets is typically 25-30 MGOe; however, practical experience shows that above 350℃, the magnetic field of Samarium cobalt permanent magnets becomes unstable, and above 670℃, they may even completely demagnetize, making them unsuitable for some high-temperature applications. AlNiCo magnets have the advantages of high remanence and a low temperature coefficient. With a temperature coefficient of -0.02% / ℃, the maximum operating temperature can reach approximately 520℃. The disadvantages are very low coercivity and a non-linear demagnetization curve. Therefore, while AlNiCo magnets are easily magnetized, they are also easily demagnetized. Cast AlNiCo magnets are made by directly casting molten steel, resulting in good magnetic properties, but they are difficult to process.

[0003] The key to developing high-performance samarium cobalt aluminum nickel cobalt permanent magnets with high operating temperatures lies in improving their overall magnetic properties at high temperatures. To achieve this, researchers typically add heavy rare earth elements to compensate for the stability of the material's magnetic properties at high temperatures. However, adding heavy rare earth elements reduces the magnetization of the magnet, leading to a decrease in the maximum energy product. Furthermore, heavy rare earth elements are scarce and expensive, increasing the production cost of the magnets. While alloy composition design and microstructure control can improve the temperature stability of the magnets, the effects are not significant. Currently, research on such composite magnets is limited; therefore, developing high-performance samarium cobalt / aluminum nickel cobalt composite magnets with high operating temperatures has become a hot research topic. Summary of the Invention

[0004] This application provides a samarium cobalt / alanine nickel cobalt composite magnet and its preparation method to solve the problem of insufficient high-temperature magnetic properties of existing samarium cobalt permanent magnet materials. A method for preparing a samarium cobalt / alNico composite magnet includes: mixing samarium cobalt alloy powder and alNico powder, and then sequentially performing orientation shaping and cold isostatic pressing to obtain a samarium cobalt / alNico composite magnet green blank. The samarium cobalt alloy powder contains, by weight percentage, 24-25% Sm, 45-52% Co, 5-7% Cu, 16-19% Fe, and 2-5% Zr. The alNico alloy green blank contains, by weight percentage, 6-7% Al, 13-14% Ni, 30-35% Co, 2-4% Cu, 0.5-1% Nb, with the balance being Fe. The samarium cobalt / alNico composite magnet green blank is then sequentially subjected to vacuum sintering, solution treatment, and aging treatment to obtain the samarium cobalt / alNico composite magnet.

[0005] Furthermore, the vacuum sintering process is carried out in a vacuum sintering furnace, which includes: heating the vacuum sintering furnace to a first temperature under vacuum conditions and holding it at that temperature, followed by sintering to obtain a samarium cobalt / alNiCo composite magnet blank; preferably, the vacuum degree is 3×10⁻⁶. -3 ~5×10 -3 Pa, the heating rate of the heating process is 3~7℃ / min; the temperature of the heat preservation process is 450~550℃, and the heat preservation time is 1~2h; the temperature of the sintering process is 1050~1250℃, and the sintering time is 1~2h.

[0006] Furthermore, the solution treatment process includes: lowering the temperature of the vacuum sintering furnace to 1170~1185℃ and then holding it at that temperature for 4~6 hours.

[0007] Furthermore, the aging process includes: cooling the product of the solution treatment process to 200-400°C at a cooling rate of 6-15°C / min, and holding it at that temperature for 8-12 hours to obtain a samarium cobalt / alcobalt-aluminum composite magnet.

[0008] Furthermore, the vacuum melting process includes melting the samarium-cobalt raw material in an inert atmosphere, with a gauge pressure of 0.06±0.03Pa and a power of 60±10KW for 15-20 minutes until the surface of the alloy liquid turns greenish. Then, the power is adjusted to 45±10KW for 2-3 minutes of fine boiling. Finally, the power is adjusted to 20±2KW for 30-40 seconds of fine boiling before pouring into samarium-cobalt alloy ingots.

[0009] Furthermore, the preparation method of samarium cobalt alloy powder includes: vacuum melting samarium cobalt-containing raw materials under an inert atmosphere to obtain samarium cobalt alloy ingots; pulverizing samarium cobalt alloy ingots to obtain samarium cobalt alloy powder; preferably, before the vacuum melting process, the preparation method further includes: mixing samarium cobalt-containing raw materials with a lubricant.

[0010] Furthermore, the lubricant is added to the samarium-cobalt raw material in two batches during the mixing process; preferably, the amount of lubricant used is 0.5~1wt‰ of the samarium-cobalt raw material.

[0011] Furthermore, the weight ratio of samarium cobalt alloy powder to aluminum nickel cobalt powder is 1:(4~8); preferably, the particle size of samarium cobalt alloy powder and aluminum nickel cobalt powder is 4.0~4.5μm.

[0012] Furthermore, during the orientation and shaping process, the magnetic field strength is 2~4T; the pressure during the cold isostatic pressing process is 250~300Mpa.

[0013] Another aspect of this application provides a samarium cobalt / alNiCo composite magnet with a composition of Sm2Co. 17 / AlNiCo, and the samarium cobalt / alNiCo composite magnet is prepared using the preparation method provided in this application.

[0014] Studies have shown that this application uses samarium cobalt raw materials and aluminum nickel cobalt alloy raw materials with specific compositions to prepare samarium cobalt alloy powder and aluminum nickel cobalt powder. By mixing the two and then performing orientation shaping, cold isostatic pressing, vacuum sintering, solution treatment and aging treatment in sequence, the advantages of samarium cobalt magnets and aluminum nickel cobalt magnets can be fully utilized to obtain a composite magnet material with good magnetic performance at high temperature. Detailed Implementation

[0015] As described in the background art, this application provides a method for preparing a samarium cobalt / alNicobalt composite magnet, comprising: mixing samarium cobalt alloy powder and alNicobalt powder, and then sequentially performing orientation shaping and cold isostatic pressing to obtain a samarium cobalt / alNicobalt composite magnet green blank, wherein, by weight percentage, the raw materials for preparing the samarium cobalt alloy powder include Sm 24~25%, Co 45~52%, Cu 5~7%, Fe 16~19%, and Zr 2~5%; and by weight percentage, the raw materials for preparing the alNicobalt powder include Al 6~7%, Ni 13~14%, Co 30~35%, Cu 2~4%, Nb 0.5~1%, with the balance being Fe; and sequentially performing vacuum sintering, solution treatment, and aging treatment on the samarium cobalt / alNicobalt composite magnet green blank to obtain the samarium cobalt / alNicobalt composite magnet.

[0016] This application uses samarium-cobalt raw materials and aluminum-nickel-cobalt alloy raw materials with specific compositions to prepare samarium-cobalt alloy powder and aluminum-nickel-cobalt powder. By mixing the two and then performing orientation shaping, cold isostatic pressing, vacuum sintering, solution treatment and aging treatment in sequence, the advantages of samarium-cobalt magnets and aluminum-nickel-cobalt magnets can be fully utilized to obtain a composite magnet material with good magnetic performance at high temperature.

[0017] The samarium cobalt alloy powder and aluminum nickel cobalt powder used in this application can be commercially available products or can be prepared in-house.

[0018] In a preferred embodiment, the method for preparing samarium-cobalt alloy powder includes: vacuum melting samarium-cobalt raw materials under an inert atmosphere to obtain samarium-cobalt alloy ingots; and pulverizing the samarium-cobalt alloy ingots to obtain samarium-cobalt alloy powder. In a preferred embodiment, the method for preparing aluminum-nickel-cobalt powder includes: processing aluminum-nickel-cobalt alloy blanks in a vacuum rapid solidification belt spinning device to obtain aluminum-nickel-cobalt belts; and pulverizing the aluminum-nickel-cobalt belts to obtain aluminum-nickel-cobalt powder.

[0019] To suppress surface oxidation, decarburization, alloy element depletion, hydrogen permeation, and oxygen permeation during the formation of samarium-cobalt alloy ingots, and to increase ingot density and reduce vertical wrinkles and cracks, the preparation method of the samarium-cobalt alloy powder further includes mixing samarium-cobalt-containing raw materials with a lubricant before the vacuum melting process. Preferably, the lubricant is added to the samarium-cobalt-containing raw materials in two stages during the mixing process, and the amount of lubricant used is 0.5~1 wt‰ of the samarium-cobalt-containing raw materials. Adding the lubricant in two stages and limiting the amount of lubricant within the above range is beneficial to further reduce vertical wrinkles and cracks in the samarium-cobalt alloy ingots, improve ingot quality and the stability of elemental composition in the ingots, and ultimately improve the magnetic performance stability of samarium-cobalt / AlNiCo composite magnets at high temperatures.

[0020] In order to obtain composite magnet materials with better performance, this application also specifically studied the temperature and time process control conditions of vacuum sintering, solution treatment and aging heat treatment.

[0021] Vacuum sintering removes impurities from samarium-cobalt raw materials, purifying the material. It also improves the alloy's microstructure, thereby enhancing the magnet's magnetic properties at high temperatures. In a preferred embodiment, the vacuum sintering process is carried out in a vacuum sintering furnace. The process includes: heating the furnace to a first temperature under vacuum conditions and holding it thereafter, followed by sintering to obtain a samarium-cobalt / AlNiCo composite magnet blank. Preferably, the vacuum level is 3 × 10⁻⁶. -3 ~5×10 -3 The heating rate during the heating process is 3~7℃ / min; the holding temperature during the heat treatment process is 450~550℃, and the holding time is 1~2h; the sintering temperature is 1050~1250℃, and the sintering time is 1~2h. This vacuum sintering process helps to further improve the impurity removal rate, suppress the influence of impurities on the magnetic properties of the subsequently prepared samarium cobalt / alNiCo composite magnets, and improve their magnetic properties; it also helps to further improve the high-temperature resistance of the final samarium cobalt / alNiCo composite magnets.

[0022] Solution treatment can obtain grains of suitable size, thereby improving the high-temperature resistance and high-temperature creep resistance of samarium cobalt / alNiCo composite magnets. In a preferred embodiment, the solution treatment process includes: lowering the temperature of the vacuum sintering furnace to 1170~1185℃ and holding it at that temperature for 4~6 hours. The temperature and time of the solution treatment include, but are not limited to, the above-mentioned ranges, and limiting them within these ranges is beneficial for further refining the grains and improving the high-temperature resistance and high-temperature creep resistance of the samarium cobalt / alNiCo composite magnets.

[0023] In a preferred embodiment, the aging process includes: cooling the product from the solution treatment process to 200–400°C at a cooling rate of 6–15°C / min, and holding at that temperature for 8–12 hours to obtain a samarium cobalt / alNiCo composite magnet. The cooling rate, temperature, and time during the aging process include, but are not limited to, the ranges described above. Limiting these ranges is beneficial for further improving the microstructure of the magnet, thereby significantly enhancing the coercivity of the samarium cobalt / alNiCo composite magnet.

[0024] Samarium-cobalt alloy ingots can be prepared using methods commonly used in the art. In a preferred embodiment, the vacuum melting process includes melting the samarium-cobalt raw material in an inert atmosphere at a gauge pressure of 0.06±0.03 Pa and a power of 60±10 kW for 15-20 minutes until the surface of the alloy melt has a greenish sheen. Then, the power is adjusted to 45±10 kW for refining for 2-3 minutes, and finally, the power is adjusted to 20±2 kW for refining for 30-40 seconds before pouring into the samarium-cobalt alloy ingot. Preparing samarium-cobalt alloy ingots under the above conditions helps to further reduce the content of impurity elements in the ingot while shortening the process time.

[0025] To further improve the high-temperature resistance and magnetic properties of samarium cobalt / alNiCo composite magnets, the weight ratio of samarium cobalt alloy powder to alNiCo powder is preferably 1:(4~8). The weight ratio of samarium cobalt alloy powder to alNiCo powder includes, but is not limited to, the above range. Limiting it to this range helps to better leverage the synergistic effect of the two materials, thereby further improving the high-temperature resistance and magnetic properties of the samarium cobalt / alNiCo composite magnets.

[0026] In a preferred embodiment, the particle size of the samarium cobalt alloy powder and the alnico powder is 4 μm. The particle size of the samarium cobalt alloy powder and the alnico powder affects the efficiency of vacuum sintering and the mechanical properties of the final composite magnet. The particle size of the samarium cobalt alloy powder and the alnico powder includes, but is not limited to, the range mentioned above. Limiting them to the range is beneficial in two ways: firstly, it helps to increase the sintering rate in the vertical direction, allowing the samarium cobalt alloy powder and the alnico powder to be sintered more thoroughly; secondly, it also helps to further improve the coercivity and other magnetic properties of the final composite magnet at high temperatures.

[0027] In a preferred embodiment, during the orientation and shaping process, the magnetic field strength is 2-4T, and the pressure during the cold isostatic pressing process is 250-300 MPa. The magnetic field strength during the orientation and shaping process and the pressure during the cold isostatic pressing process include, but are not limited to, the above ranges. Limiting them to these ranges is beneficial for further improving the orientation degree of the composite magnet, thereby further improving the coercivity and other magnetic properties of the composite magnet at high temperatures.

[0028] Another aspect of this application provides a samarium cobalt / alNiCo composite magnet with a composition of Sm2Co. 17 / AlNiCo, and the samarium cobalt / alNiCo composite magnet is prepared using the preparation method provided in this application.

[0029] This application selects samarium cobalt-containing raw materials and aluminum nickel cobalt alloy raw materials with specific compositions. By mixing the two materials and then performing orientation shaping, cold isostatic pressing, vacuum sintering, solution treatment and aging treatment in sequence, the advantages of samarium cobalt magnets and aluminum nickel cobalt magnets can be fully utilized to obtain a composite magnet material with good magnetic performance at high temperature.

[0030] The following description of the embodiments and comparative examples is used to further illustrate this application.

[0031] Example 1

[0032] A method for preparing a samarium cobalt / alNiCo composite magnet includes:

[0033] Step 1: Weigh out the following alloy powders: Sm: 24%, Cu: 7%, Co: 49%, Fe: 18%, Zr: 2%. Mix all the powders together and add 0.5‰ of the total weight of the alloy powders in zinc stearate. After mixing for 2 hours, add another 0.5‰ of the total weight of the alloy powders in zinc stearate and continue mixing for 10-30 minutes.

[0034] Step 2: Place the above powder in a vacuum melting furnace and melt it for 15 minutes under vacuum conditions of 0.06 Pa and 60 KW until the surface of the alloy liquid turns greenish. Then adjust the power to 45 KW and refine for 2 minutes. Finally, adjust the power to 20 KW and refine for 30 seconds before casting to obtain the samarium cobalt alloy ingot.

[0035] Step 3: The above-mentioned samarium cobalt alloy ingot is initially crushed to obtain alloy powder with a particle size of less than 10 mm. The powder is then sieved, air-jet milled, and then further crushed to less than 1 mm. Finally, it is ball-milled into fine powder to obtain samarium cobalt material powder with a particle size of about 4 μm.

[0036] Step 4: Take an aluminum-nickel-cobalt alloy blank with the following elemental composition: Al: 7%; Ni: 14%; Co: 30%; Cu: 3%; Nb: 0.8%; balance Fe. Clean it and add it to a vacuum rapid solidification belt casting furnace. Add 0.5% aluminum by weight of the total alloy. After complete melting, cast the belt casting sheet. Coarsely crush the resulting belt casting sheet, sieve it, and then grind it into powder using an air jet mill to obtain aluminum-nickel-cobalt fine powder with an average particle size of 4μm.

[0037] Step 5: The two powders prepared above are added at a weight ratio of 1:4 for samarium cobalt alloy powder and aluminum nickel cobalt powder. 0.5‰ zinc stearate is added under inert gas protection. After mixing for 2 hours, the powder is oriented and shaped in a magnetic field with a magnetic field strength of 2T. The oriented composite powder is then subjected to cold isostatic pressing in a fluid at 250 MPa to obtain a samarium cobalt / aluminum nickel cobalt composite magnet green blank.

[0038] Step 6: Place the pressed green body into a vacuum sintering furnace and adjust the vacuum level to 3×10⁻⁶. -3 Pa was heated to 450℃ at a heating rate of 3℃ / min and held for 1.5h, then heated to the sintering temperature of 1200℃ and sintered for 2h, and then cooled to room temperature.

[0039] Step 7: The product obtained in Step 6 is subjected to solution treatment and aging treatment. The specific operation is as follows: after reducing the furnace temperature to 1185℃, solution treatment is performed for 6 hours, and finally rapid cooling to room temperature is performed. The aging conditions are to cool down to 400℃ at a cooling rate of 7℃ / min and hold for 8 hours to obtain a cooled magnet.

[0040] Step 8: The surface of the cooling magnet is finely ground and cleaned, and the finished product is obtained after passing the inspection.

[0041] Example 2

[0042] The difference from Example 1 is that in step six, the pressed green body is placed in a vacuum sintering furnace, and the vacuum level is adjusted to 3×10⁻⁶. -3 Pa was heated to 450℃ at a heating rate of 5℃ / min and held for 1.5h, then heated to the sintering temperature of 1205℃ and sintered for 2h, and then cooled to room temperature.

[0043] Example 3

[0044] The difference from Example 2 is that the temperature of the solution treatment process is 1180°C.

[0045] Example 4

[0046] The difference from Example 3 is that the solution treatment process takes 4 hours.

[0047] Example 5

[0048] The difference from Example 3 is that the aging process takes 6 hours.

[0049] Example 6

[0050] The difference from Example 1 is that the heating rate of the vacuum sintering process is 7°C / min.

[0051] Example 7

[0052] The difference from Example 1 is that the sintering temperature of the vacuum sintering process is 1050℃.

[0053] Example 8

[0054] The difference from Example 1 is that the heating rate of the vacuum sintering process is 10℃ / min, and the sintering temperature is 950℃.

[0055] Example 9

[0056] The difference from Example 1 is that the solution treatment process is carried out at a temperature of 1170°C for 4 hours.

[0057] Example 10

[0058] The difference from Example 1 is that the solution treatment process is carried out at a temperature of 1185°C for 6 hours.

[0059] Example 11

[0060] The difference from Example 1 is that the solution treatment temperature is 1165°C and the holding time is 8 hours.

[0061] Example 12

[0062] The difference from Example 1 is that the cooling rate of the aging process is 15°C / min.

[0063] Example 13

[0064] The difference from Example 1 is that the cooling rate of the aging process is 5°C / min.

[0065] Example 14

[0066] The difference from Example 1 is that the temperature of the aging process is 200°C.

[0067] Example 15

[0068] The difference from Example 1 is that the aging process temperature is 600°C.

[0069] Comparative Example 1

[0070] The difference from Example 1 is that the temperature of the solution treatment process is 1165°C.

[0071] Comparative Example 2

[0072] The difference from Example 1 is that the cooling rate of the aging process is 20°C / min.

[0073] Comparative Example 3

[0074] The difference from Example 1 is that the aging process takes 12 hours.

[0075] Comparative Example 4

[0076] The difference from Example 1 is that the composition of the samarium-cobalt raw material is Sm: 24%, Co: 47%, Cu: 1%, Fe: 24%, Zr: 4%.

[0077] Comparative Example 5

[0078] The difference from Example 1 is that the composition of the aluminum-nickel-cobalt alloy blank is Al: 6%, Ni: 13%, Co: 33%, Cu: 4%, Nb: 1%, Fe: 43%.

[0079] Performance testing

[0080] The performance of the composite magnets prepared in the examples and comparative examples was tested using the following methods: The samples were magnetized with an electromagnet using an ultra-high temperature measuring instrument, and a quasi-static scanning method was implemented. The purpose was to keep the change in magnetization current constant by slowly increasing it during the measurement process, thereby avoiding eddy currents and the phase angle between the magnetic field and magnetic polarization. The measuring device employed data acquisition technology to measure the hysteresis loops of the material at different temperature states. Then, based on the definitions, the magnetic properties of the prepared sintered samarium-cobalt magnets were calculated: remanence at 20℃, remanence at 500℃, intrinsic coercivity at 20℃, and intrinsic coercivity at 500℃.

[0081] The test results are shown in Table 1.

[0082] Table 1

[0083]

[0084] As shown in Table 1, comparing the samples from Examples 1-15 and Comparative Examples 1-5, it can be effectively observed that the magnetic properties of the samarium cobalt / alNicobalt composite magnets at a high temperature of 500°C are significantly lower than those at an operating temperature of 20°C, but still relatively good. The reason for this is that high-temperature samarium cobalt is very sensitive to composition and structure; the high-temperature phase region is a non-equilibrium phase, and after heat treatment, it needs to meet requirements such as high-temperature stability, high-temperature magnetic properties, low temperature coefficient, low magnetic properties, and low attenuation. Therefore, the process control window is very narrow. The disadvantages of AlNicobalt magnets are low density and poor magnetic properties, which greatly limits their application range. Cast AlNicobalt magnets are made by directly casting molten steel, resulting in high magnetic properties, but their disadvantages include poor toughness and high processing difficulty.

[0085] Rare earth element Sm is prone to volatilization and oxidation during sintering and solution treatment, resulting in a significant decrease in magnetic properties compared to the original magnet. Sm impurity gas reactions lead to higher internal C and O content, causing component segregation and severely affecting magnetic properties, especially high-temperature magnetic properties. Comparative examples and the control example demonstrate that sintering and aging temperatures and times significantly influence the coercivity and remanence of the material at both room and high temperatures.

[0086] Meanwhile, the cooling rate after heat treatment of composite materials also has a certain impact on their performance. The cooling rate that needs to be controlled during heat treatment mainly includes the cooling rate after solution treatment and after first-stage aging. Poor optimization of the cooling effect will affect the transformation mechanism of the 1:7 phase and the 2:17 phase at high temperatures, as well as the formation of the 1:5 phase, and thus affect the intrinsic coercivity temperature coefficient β.

[0087] The specific embodiments described in this invention are only some specific implementations of this invention, but the protection scope of this invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this invention should be included within the protection scope of this invention.

[0088] It should be noted that, according to the above embodiments of the present invention, those skilled in the art can fully realize the contents of the independent claims and dependent claims of the present invention, and the implementation process and method are the same as those in the above embodiments, and the parts of the present invention not described in detail belong to the well-known technology in the art.

Claims

1. A method for preparing a samarium cobalt / alNiCo composite magnet, characterized in that, The preparation method includes: Samarium cobalt alloy powder and AlNiCo powder are mixed and then subjected to orientation shaping and cold isostatic pressing to obtain a Samarium cobalt / AlNiCo composite magnet green blank. The Samarium cobalt alloy powder contains, by weight percentage, 24-25% Sm, 45-52% Co, 5-7% Cu, 16-19% Fe, and 2-5% Zr. The AlNiCo alloy green blank contains, by weight percentage, 6-7% Al, 13-14% Ni, 30-35% Co, 2-4% Cu, 0.5-1% Nb, with the balance being Fe. The samarium cobalt / alNico composite magnet green blank is subjected to vacuum sintering, solution treatment and aging treatment in sequence to obtain the samarium cobalt / alNico composite magnet; The vacuum sintering process is carried out in a vacuum sintering furnace, and includes: heating the vacuum sintering furnace to a first temperature under vacuum conditions and holding it at that temperature, followed by sintering to obtain a samarium cobalt / alNiCo composite magnet blank. The vacuum degree of the vacuum conditions is 3×10⁻⁶. -3 ~5×10 -3 Pa, the temperature of the sintering process is 1050~1250℃; The solution treatment process includes: lowering the temperature of the vacuum sintering furnace to 1170~1185℃ and then holding it at that temperature for 4~6 hours; The aging process includes: cooling the product of the solution treatment process to 200-400°C at a cooling rate of 6-15°C / min, and holding it at that temperature for 8-12 hours to obtain the samarium cobalt / alcobalt-aluminum nickel-cobalt composite magnet.

2. The method for preparing the samarium cobalt / alNiCo composite magnet according to claim 1, characterized in that, The heating rate of the heating process is 3~7℃ / min; the temperature of the heat preservation process is 450~550℃, and the heat preservation time is 1~2h; the sintering time of the sintering process is 1~2h.

3. The method for preparing the samarium cobalt / alNiCo composite magnet according to claim 1, characterized in that, The preparation method of the samarium-cobalt alloy powder includes: The samarium-cobalt raw material was vacuum melted under an inert atmosphere to obtain a samarium-cobalt alloy ingot. The samarium-cobalt alloy ingot is pulverized to obtain samarium-cobalt alloy powder.

4. The method for preparing the samarium cobalt / alNiCo composite magnet according to claim 3, characterized in that, Before carrying out the vacuum melting process, the preparation method further includes mixing the samarium-cobalt raw material with a lubricant.

5. The method for preparing the samarium cobalt / alNiCo composite magnet according to claim 3, characterized in that, The vacuum melting process includes melting the samarium-cobalt raw material in an inert atmosphere, with a gauge pressure of 0.06±0.03 Pa and a power of 60±10 KW for 15-20 minutes until the surface of the alloy liquid has a greenish sheen. Then, the power is adjusted to 45±10 KW for 2-3 minutes of refining. Finally, the power is adjusted to 20±2 KW for 30-40 seconds of refining before casting to obtain the samarium-cobalt alloy ingot.

6. The method for preparing the samarium cobalt / alNiCo composite magnet according to claim 4, characterized in that, The lubricant is added to the samarium-cobalt-containing raw material in two stages during the mixing process.

7. The method for preparing the samarium cobalt / alNiCo composite magnet according to claim 6, characterized in that, The amount of the lubricant used is 0.5~1wt‰ of the samarium-cobalt raw material.

8. The method for preparing the samarium cobalt / alNiCo composite magnet according to claim 1, characterized in that, The weight ratio of the samarium cobalt alloy powder to the aluminum nickel cobalt powder is 1:(4~8).

9. The method for preparing the samarium cobalt / alNiCo composite magnet according to claim 8, characterized in that, The samarium cobalt alloy powder and the aluminum nickel cobalt powder have a particle size of 4.0~4.5μm.

10. The method for preparing the samarium cobalt / alNiCo composite magnet according to claim 1, characterized in that, During the orientation and shaping process, the magnetic field strength is 2~4T; the pressure during the cold isostatic pressing process is 250~300Mpa.

11. A samarium cobalt / alNiCo composite magnet, characterized in that, The composition of the samarium cobalt / alNiCo composite magnet is Sm2Co 17 / AlNiCo, and the samarium cobalt / alNiCo composite magnet is prepared by any one of claims 1 to 10.

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