High-performance samarium-cobalt magnet and preparation method thereof

Abstract

The invention relates to a high-performance samarium-cobalt magnet and a preparation method thereof, and the preparation method of the high-performance samarium-cobalt magnet comprises the following steps: providing a main alloy and an auxiliary alloy; the main alloy and the auxiliary alloy are subjected to hydrogen breaking treatment together, hydrogen breaking powder is obtained, and the mass ratio of the main alloy to the auxiliary alloy is 97: 3-199: 1; the hydrogen broken powder is sequentially subjected to jet milling, forming and isostatic pressing, sintering, solid solution and aging treatment, the high-performance samarium-cobalt magnet is obtained, after solid solution is finished, the temperature is increased to 200-400 DEG C, heat preservation treatment is conducted for 2-6 h, and then aging treatment is conducted. The preparation method of the high-performance samarium-cobalt magnet is simple, low in production cost and high in production qualification rate, and the prepared high-performance samarium-cobalt magnet has high coercive force, residual magnetism and mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of rare earth permanent magnets, and particularly to high-performance samarium cobalt magnets and a preparation method thereof. Background Art

[0002] In order to obtain high-performance samarium cobalt magnets with good comprehensive magnetic properties, in the existing literature, Patent CN105304249A uses the method of separately hydrogenating and then mixing a high-iron alloy and a high-rare-earth alloy to improve the remanence. However, this method is too complicated, has many processes, and has a high production cost; for another example, Patent CN113205955A provides a method of mixing praseodymium copper powder and samarium cobalt powder to improve the comprehensive magnetic properties of samarium cobalt magnets. However, the process of preparing praseodymium copper alloy powder is relatively complex, there are too many production processes, and the crushing of samarium cobalt alloy uses mechanical crushing, which is not conducive to improving the magnet orientation and remanence; in addition, Patent CN115579205A mixes hydrogenated samarium cobalt alloy powder and (Pr 20 Nd 80 ) 75 Ti 15 Cu 10 alloy powder. Although the coercivity and remanence of samarium cobalt magnets are improved, its hydrogenation process is not described and is difficult to reproduce. At the same time, the added (Pr 20 Nd 80 ) 75 Ti 15 Cu 10 alloy powder accounts for 4%wt - 10%wt of the total powder weight, which is not conducive to reducing the raw material cost, and the sintering temperature is relatively high, which is not conducive to refining the grains and improving the mechanical properties. Summary of the Invention

[0003] Based on this, it is necessary to provide a high-performance samarium cobalt magnet and a preparation method thereof for the above problems. The preparation method of the high-performance samarium cobalt magnet not only has a simple preparation method, low production cost, and high production qualification rate, but also the prepared high-performance samarium cobalt magnet has high coercivity, remanence, and mechanical properties.

[0004] A preparation method of a high-performance samarium cobalt magnet includes the following steps:

[0005] Providing a main alloy and an auxiliary alloy, wherein the molecular formula of the main alloy is (Sm a (M) 1-a )(Co 1-b-c- d Fe b Cu c Zr d)For z, a is 0.9 - 0.95, b is 0.25 - 0.35, c is 0.04 - 0.1, d is 0.02 - 0.06, z is 7.0 - 8.0, M is selected from at least one of Ce, La, Y, Pr, and Nd, the auxiliary alloy is an alloy containing R and Cu, and R is selected from Pr and / or Nd;

[0006] The master alloy and the auxiliary alloy are subjected to hydrogen decrepitation treatment together to obtain hydrogen-decrepitated powder, wherein the mass ratio of the master alloy to the auxiliary alloy is 97:3 - 199:1;

[0007] The hydrogen-decrepitated powder is successively subjected to jet milling, shaping and isostatic pressing, sintering, solution treatment and aging treatment to obtain a high-performance samarium-cobalt magnet. After the solution treatment is completed, the temperature is first raised to 200°C - 400°C, and after heat preservation treatment for 2h - 6h, aging treatment is carried out.

[0008] In one embodiment, the hydrogen content in the hydrogen-decrepitated powder is 800 ppm - 1800 ppm;

[0009] And / or, the average particle size of the hydrogen-decrepitated powder is 100 μm - 300 μm.

[0010] In one embodiment, in the step of hydrogen decrepitation treatment, the hydrogen absorption temperature is room temperature, the hydrogen absorption pressure is 0.1 MPa - 0.5 MPa, the hydrogen absorption time is 2h - 6h, the dehydrogenation temperature is 200°C - 250°C, and the dehydrogenation time is 2h - 4h.

[0011] In one embodiment, in the alloy containing R and Cu, the mass ratio of R to Cu is 3:7 - 7:3.

[0012] In one embodiment, the master alloy is a master alloy ingot or a master alloy sheet, and the auxiliary alloy is an auxiliary alloy ingot or an auxiliary alloy sheet.

[0013] In one embodiment, the thicknesses of the master alloy ingot and the auxiliary alloy ingot are independently selected from 1 cm - 3 cm;

[0014] Or, the thicknesses of the master alloy sheet and the auxiliary alloy sheet are independently selected from 0.2 mm - 0.8 mm.

[0015] In one embodiment, before the hydrogen-decrepitated powder is subjected to jet milling, the hydrogen-decrepitated powder is also subjected to mixing, wherein the mixing time is 2h - 4h;

[0016] And / or, in the step of jet milling, the average particle size of the jet-milled powder is 3 μm - 5 μm;

[0017] And / or, in the steps of forming and isostatic pressing, the isostatic pressing pressure is 200 MPa - 300 MPa, and the pressure holding time is 10 min - 20 min.

[0018] In one embodiment, in the steps of sintering and solution treatment, the sintering temperature is 1160 °C - 1200 °C, the sintering time is 2 h - 4 h, the solution treatment temperature is 1130 °C - 1170 °C, and the solution treatment time is 4 h - 20 h.

[0019] In one embodiment, the aging treatment process includes: first heating to 800 °C - 850 °C, holding for 10 h - 20 h, then cooling to 380 °C - 420 °C at a rate of 0.3 °C / min - 0.7 °C / min, holding for 2 h - 6 h, and then cooling to room temperature.

[0020] A high-performance samarium-cobalt magnet prepared by using the preparation method of the high-performance samarium-cobalt magnet as described above.

[0021] The preparation method of the high-performance samarium-cobalt magnet of the present invention can effectively control the hydrogen absorption rate of the master alloy and reduce the difference in hydrogen absorption rate between the master alloy and the auxiliary alloy by using the master alloy with a specific formula and alloy doping. The master alloy and the auxiliary alloy are subjected to hydrogen breaking, jet milling, forming and isostatic pressing, sintering, solution treatment and aging treatment together, omitting the separate powder making and fine powder mixing processes of the auxiliary alloy, effectively simplifying the preparation process of the samarium-cobalt magnet, reducing the production cost, and effectively avoiding powder oxidation, improving the production efficiency and safety; in sintering, solution treatment and aging, the rare earth elements and copper elements in the auxiliary alloy jointly optimize the grain boundary structure of the samarium-cobalt magnet, synchronously improving the remanence and coercivity of the cerium-containing magnet. Moreover, since the materials of the auxiliary alloy are all low-melting-point alloys, it is beneficial to reduce the melting point of the blank, lower the sintering temperature, and is beneficial to grain refinement, thereby improving the mechanical properties of the samarium-cobalt magnet and increasing the sintering qualification rate; at the same time, by adding a holding section after the solution treatment and before the aging treatment, it is beneficial to eliminate the internal stress generated by rapid air cooling after the solution treatment, and can further improve the mechanical properties of the samarium-cobalt magnet. Therefore, the preparation method of the high-performance samarium-cobalt magnet of the present invention not only has a simple preparation method, low production cost and high sintering qualification rate, but also the prepared high-performance samarium-cobalt magnet has high coercivity, remanence and mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1Metallographic photograph of the high-performance samarium cobalt magnet prepared in Example 1 of the present invention;

[0024] Figure 2 Grain size distribution diagram of the high-performance samarium cobalt magnet prepared in Example 1 of the present invention;

[0025] Figure 3 Metallographic photograph of the high-performance samarium cobalt magnet prepared in Comparative Example 6 of the present invention;

[0026] Figure 4 Grain size distribution diagram of the high-performance samarium cobalt magnet prepared in Comparative Example 6 of the present invention;

[0027] Figure 5 Metallographic photograph of the high-performance samarium cobalt magnet prepared in Comparative Example 7 of the present invention;

[0028] Figure 6 Grain size distribution diagram of the high-performance samarium cobalt magnet prepared in Comparative Example 7 of the present invention. Detailed implementation manners

[0029] For ease of understanding the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, these embodiments or examples are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments or examples and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of the related listed items, and the any and all combinations include any two related listed items, any more related listed items, or all related listed items.

[0031] In the process of preparing high-performance samarium cobalt magnets using master alloys and auxiliary alloys, due to the significant differences in composition and intrinsic properties between the master alloy and the auxiliary alloy, there are also large differences in the hydrogen decrepitation process between the auxiliary alloy and the master alloy. For example, the hydrogen absorption efficiency of the master alloy is low, while that of the auxiliary alloy is high, resulting in a large difference in the hydrogen decrepitation process between the two. Through exploration by the applicant, it is found that: generally, the samarium cobalt alloy as the master alloy needs to absorb hydrogen at high temperature for more than 20 hours to be broken into powder, while the auxiliary alloy (such as praseodymium-neodymium-copper alloy) can be broken into powder at room temperature in 2-4 hours. Therefore, in the prior art, when preparing the master alloy fine powder and the auxiliary alloy fine powder, the respective suitable hydrogen decrepitation process and jet milling process are carried out separately, and then mixed.

[0032] Through research, the applicant found that by optimizing the formula of the master alloy and doping rare earth elements, the hydrogen absorption rate of the master alloy can be effectively controlled, the difference in hydrogen absorption rate between the master alloy and the auxiliary alloy can be reduced, so that the master alloy can complete the hydrogen decrepitation process together with the auxiliary alloy at room temperature in a short time, and then mixed and jet milled to make mixed fine powder. This setting can not only simplify the process, reduce production costs, but also effectively avoid powder oxidation, improve production efficiency and safety.

[0033] Therefore, the preparation method of the high-performance samarium cobalt magnet provided by the present invention includes the following steps:

[0034] S1, providing a master alloy and an auxiliary alloy, wherein the molecular formula of the master alloy is (Sm a (M) 1-a )(Co 1-b-c- d Fe b Cu c Zr d ) z , a is 0.9 - 0.95, b is 0.25 - 0.35, c is 0.04 - 0.1, d is 0.02 - 0.06, z is 7.0 - 8.0, M is selected from at least one of Ce, La, Y, Pr, Nd, and the auxiliary alloy is an alloy containing R and Cu, and R is selected from Pr and / or Nd.

[0035] In the present invention, according to the molecular formula of the master alloy, it can be seen that the formula of the master alloy contains a high iron content, which is beneficial to the hydrogen absorption and crushing of the master alloy; at the same time, it contains a specific doping amount of rare earth elements. On the one hand, it can enhance the hydrogen absorption ability of the master alloy, reduce the difference in hydrogen absorption rate between the master alloy and the auxiliary alloy, and lay a foundation for the subsequent hydrogen decrepitation of the master alloy and the auxiliary alloy together; on the other hand, it can, under the synergistic effect with the auxiliary alloy, reduce the raw material cost without affecting the magnetic properties of the samarium cobalt magnet.

[0036] Meanwhile, in the subsequent sintering, solutionizing, and aging stages, the rare earth element R will enter the 2:17 phase of the master alloy to replace the samarium element, further increasing the remanence of the samarium cobalt magnet. At this time, the copper element will enter the grain boundaries of the 1:5 phase of the master alloy to make up for the copper element in the copper-depleted grain boundary region of the samarium cobalt magnet, thereby increasing the coercivity of the samarium cobalt magnet.

[0037] In the present invention, the type of the doped rare earth element M can be adjusted according to requirements. From the type of the rare earth element M, it can be seen that the master alloy can be doped only with high-abundance rare earth elements, such as at least one of Ce, La, and Y, or only with light rare earth elements, such as at least one of Pr and Nd, or both high-abundance rare earth elements (at least one of Ce, La, and Y) and light rare earth elements (at least one of Pr and Nd) are doped simultaneously. Preferably, both high-abundance rare earth elements (at least one of Ce, La, and Y) and light rare earth elements (at least one of Pr and Nd) are doped simultaneously in the master alloy. With such a setting, it is possible to better ensure that while not increasing the raw material cost, the remanence of the samarium cobalt magnet is not affected.

[0038] Optionally, in the alloy containing R and Cu, the mass ratio of R to Cu is 3:7 - 7:3. With such a setting, an appropriate amount of rare earth element R and copper element can be provided, better improving the coercivity and remanence of the samarium cobalt magnet and enhancing the comprehensive magnetic properties of the samarium cobalt magnet.

[0039] In step S1, the master alloy is a master alloy ingot or a master alloy sheet, preferably a master alloy sheet, and the auxiliary alloy is an auxiliary alloy ingot or an auxiliary alloy sheet, preferably an auxiliary alloy sheet. With such a setting, it is beneficial to increase the subsequent hydrogen disproportionation rate and shorten the hydrogen disproportionation time.

[0040] When the master alloy is a master alloy ingot and the auxiliary alloy is an auxiliary alloy ingot, the thicknesses of the master alloy ingot and the auxiliary alloy ingot are independently selected from 1 cm - 3 cm.

[0041] When the master alloy sheet and the auxiliary alloy sheet, their thicknesses are independently selected from 0.2 mm - 0.8 mm.

[0042] In one embodiment, the preparation method of the master alloy includes the following steps: using the molecular formula of the master alloy as (Sm a (M) 1-a )(Co 1-b-c-d Fe b Cu c Zr d ) z, taking a as 0.9 - 0.95, b as 0.25 - 0.35, c as 0.04 - 0.1, d as 0.02 - 0.06, z as 7.0 - 8.0, and M selected from at least one of Ce, La, Y, Pr, and Nd as a reference, ingredients are proportioned according to the ratios of each element, and then melted in an intermediate frequency induction furnace or a vacuum rapid solidification furnace to form a master alloy solution. Then, the master alloy solution is cast into a copper mold or on the surface of a copper roller, and cooled for a certain time to obtain a master alloy ingot or a master alloy sheet.

[0043] Similarly, taking the auxiliary alloy as an alloy containing R and Cu, and R selected from Pr and / or Nd as a reference, the mass ratio of R and Cu is adjusted according to requirements, and the auxiliary alloy ingot or the auxiliary alloy sheet can be obtained by referring to the preparation method of the master alloy.

[0044] S2, subject the master alloy and the auxiliary alloy to hydrogen decrepitation treatment together to obtain hydrogen decrepitated powder, wherein the mass ratio of the master alloy to the auxiliary alloy is 97:3 - 199:1.

[0045] In step S2, during the hydrogen decrepitation treatment, by using the rare earth element M with a specific doping amount in the master alloy, the hydrogen absorption rate of the master alloy can be effectively increased, thereby greatly reducing the difference in hydrogen absorption rate between the master alloy and the auxiliary alloy. As a result, the master alloy and the auxiliary alloy can complete hydrogen decrepitation together at room temperature, under low hydrogen pressure, and in a short time. Moreover, by adjusting the mass ratio of the master alloy and the auxiliary alloy, the coercivity and remanence of the high-performance samarium cobalt magnet can be controlled. Compared with the conventional methods of preparing master alloy fine powder and auxiliary alloy fine powder, this setting can not only simplify the process, reduce production costs, but also effectively avoid powder oxidation, improve production efficiency and safety.

[0046] Optionally, the hydrogen content in the hydrogen decrepitated powder is 800 ppm - 1800 ppm. With this setting, by controlling the hydrogen content in the hydrogen decrepitated powder, on the one hand, the hydrogen decrepitated powder can contain corresponding internal stresses, which are more easily broken in the subsequent jet mill stage, facilitating the improvement of the powder output efficiency of the jet mill and further enhancing the production efficiency of the entire process flow; on the other hand, hydrogen will be discharged from the samarium cobalt green compact during the degassing stage before sintering, and within a certain range of hydrogen content, the production efficiency of the sintering process will not be reduced.

[0047] Optionally, in the steps of hydrogen decrepitation treatment, the hydrogen absorption temperature is room temperature, the hydrogen absorption pressure is 0.1 MPa - 0.5 MPa, the hydrogen absorption time is 2 h - 6 h, the dehydrogenation temperature is 200 °C - 250 °C, and the dehydrogenation time is 2 h - 4 h. With this setting, the hydrogen content in the hydrogen decrepitated powder can be effectively controlled, facilitating the improvement of the efficiency of the jet mill process and the entire production process.

[0048] Optionally, the average particle size of the hydrogen decrepitated powder is 100 μm - 300 μm. With such a setting, it is beneficial to adapt to the jet milling process, thereby increasing the single crystal ratio and the integrity of the grains in the powder, enhancing the orientation of the samarium cobalt magnet, and improving the remanence and comprehensive magnetic properties of the high-performance samarium cobalt magnet.

[0049] S3. Subject the hydrogen decrepitated powder to jet milling, molding and isostatic pressing, sintering, solution treatment and aging treatment in sequence to obtain a high-performance samarium cobalt magnet. After the solution treatment, first heat up to 200°C - 400°C, keep it warm for 2 h - 6 h, and then conduct the aging treatment.

[0050] In step S3, the hydrogen decrepitated powder is milled by jet milling. During the jet milling process, the main alloy powder and the auxiliary alloy powder can collide and mix more fully, so that the auxiliary alloy powder is evenly distributed at the grain boundaries of the main alloy. Subsequently, in the sintering, solution treatment and aging processes, the rare earth elements in the auxiliary alloy can better enter the 2:17 phase of the main alloy to replace the samarium element, which is beneficial to improving the remanence of the samarium cobalt magnet. And the copper element will enter the grain boundaries of the 1:5 phase to make up for the copper element in the copper-deficient grain boundary region of the samarium cobalt magnet, so as to achieve the purpose of simultaneously improving the coercivity and remanence of the samarium cobalt magnet, and also increasing the production qualified rate of the samarium cobalt magnet.

[0051] Moreover, after the solution treatment, keeping it warm at 200°C - 400°C for 2 h - 6 h and then conducting the aging treatment is beneficial to eliminating the internal stress generated by rapid air cooling after the solution treatment and improving the mechanical properties of the samarium cobalt magnet.

[0052] In addition, since the auxiliary alloy is a low-melting-point alloy such as praseodymium copper, neodymium copper or praseodymium-neodymium copper, mixing it with the main alloy will reduce the melting point of the overall blank, lower the sintering temperature, which is beneficial to refining the grains of the samarium cobalt magnet, improving the mechanical properties of the samarium cobalt magnet, thereby reducing the probability of cracking of the high-performance samarium cobalt magnet, and further increasing the sintering qualified rate of the high-performance samarium cobalt magnet.

[0053] It can be understood that in the present invention, by adopting a master alloy with a specific formula and a secondary alloy with specific components, and defining the mass ratio of the master alloy and the secondary alloy, the hydrogen absorption rates of the master alloy and the secondary alloy can be effectively controlled, the difference in hydrogen absorption rates between the master alloy and the secondary alloy can be reduced, so that the master alloy can be subjected to hydrogen breaking, mixing, jet milling, forming, isostatic pressing, sintering, solution treatment and aging treatment together with the secondary alloy, eliminating the separate powder making and fine powder mixing processes for the secondary alloy, effectively simplifying the preparation process of the samarium-cobalt magnet, reducing the production cost, and effectively avoiding powder oxidation, improving the production efficiency and safety; then, in the sintering, solution treatment and aging processes, the rare earth elements and copper elements in the secondary alloy jointly optimize the grain boundary structure of the samarium-cobalt magnet, synchronously improving the remanence and coercivity of the cerium-containing magnet, and since the materials of the secondary alloy are all low-melting alloys, it is beneficial to reduce the melting point of the blank, lower the sintering temperature, and is beneficial to grain refinement, thereby improving the mechanical properties of the samarium-cobalt magnet and increasing the production qualification rate; at the same time, by adding a heat preservation section after the solution treatment and before the aging treatment, it is beneficial to eliminate the internal stress generated by rapid air cooling after the solution treatment, and can further improve the mechanical properties of the samarium-cobalt magnet. Therefore, the preparation method of the high-performance samarium-cobalt magnet of the present invention not only has a simple preparation method, low production cost and high production qualification rate, but also the prepared high-performance samarium-cobalt magnet has high coercivity, remanence and mechanical properties.

[0054] Optionally, before jet milling the hydrogenated powder, mixing the hydrogenated powder is further included, wherein the mixing time is 2 h - 4 h; with such a setting, the hydrogenated powder is first mixed and then jet milled to make powder. During the jet milling process, the master alloy powder and the secondary alloy powder can collide and mix more fully, further improving the mixing uniformity of the two alloys.

[0055] Optionally, in the step of jet milling, the average particle size of the jet milled powder is 3 μm - 5 μm. With such a setting, it is beneficial to improve the magnetic properties of the samarium-cobalt magnet.

[0056] Optionally, in the step of forming and isostatic pressing, the isostatic pressing pressure is 200 MPa - 300 MPa, and the pressure holding time is 10 min - 20 min. With such a setting, it is beneficial to ensure the density of the samarium-cobalt magnet and a stable sintering process.

[0057] Optionally, in the steps of sintering and solution treatment, the sintering temperature is 1160 °C - 1200 °C, the sintering time is 2 h - 4 h, the solution treatment temperature is 1130 °C - 1170 °C, and the solution treatment time is 4 h - 20 h. With such a setting, it is beneficial to further homogenize the composition and stabilize the structure, improving the magnetic properties and the stability of the magnetic properties of the samarium-cobalt magnet.

[0058] In one of the embodiments, the aging treatment process includes: first heating to 800°C - 850°C, holding for 10h - 20h, then cooling to 380°C - 420°C at a rate of 0.3°C / min - 0.7°C / min, holding for 2h - 6h after that, and then cooling to room temperature. With such settings, it is beneficial to further improve the coercivity of the samarium cobalt magnet.

[0059] Meanwhile, the present invention also provides a high-performance samarium cobalt magnet prepared by using the preparation method of the high-performance samarium cobalt magnet as described above. This high-performance samarium cobalt magnet has high coercivity, remanence, and mechanical properties, and the preparation method is simple with low production cost, which is beneficial to improving the sintering qualification rate.

[0060] Hereinafter, the high-performance samarium cobalt magnet and its preparation method will be further described through the following specific embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specifying specific conditions in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For those reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0061] Example 1

[0062] Based on the main alloy molecular formula: (Sm 0.94 Ce 0.06 )(Co 0.57 Fe 0.34 Cu 0.06 Zr 0.03 ) 7.2 as a reference, the auxiliary alloy is PrCu alloy, in which the mass ratio of Pr and Cu is 4:6 as a reference, and the main alloy batching and auxiliary alloy batching are carried out respectively; then the obtained main alloy batching is placed in an intermediate frequency induction furnace, evacuated to below Pa, filled with argon to 0.03MPa and then heated and melted. When a green light appears on the surface of the alloy liquid, the alloy liquid is cast into a water-cooled splint copper mold, and after waiting for 1h to cool, it is taken out of the furnace to obtain a main alloy ingot with an average thickness of 2.4 cm; similarly, the obtained auxiliary alloy batching is placed in an intermediate frequency induction furnace, and a praseodymium copper alloy ingot with an average thickness of 2.4 cm is prepared according to the above method.

[0063] The obtained main alloy ingot and praseodymium copper alloy ingot are placed together in a hydrogenation crusher. Among them, the mass ratio of the main alloy ingot to the praseodymium copper alloy ingot is 99:1, and hydrogenation and crushing are carried out at room temperature. Among them, the hydrogenation pressure is 0.2MPa, the hydrogenation time is 4h. After the hydrogenation and crushing are completed, dehydrogenation treatment is carried out. Among them, the dehydrogenation temperature is 230°C, the dehydrogenation time is 3h, and hydrogenated powder is obtained. Among them, the average particle size of the hydrogenated powder is 150μm, and the content in the hydrogenated powder is 1200ppm.

[0064] The hydrogen-crushed powder is placed in a mixer for mixing for 3 hours, and then sent to a jet mill for further crushing to obtain a powder with an average particle size of 4.0μm; the powder after the jet mill is sent to a molding press, molded under a magnetic field of 2T, and then cold isostatically pressed under a pressure of 250MPa, and after holding the pressure for 10 minutes, a green body is obtained; the isostatically pressed green body is placed in a sintering furnace, first heated to 1185℃ for sintering for 3h, and then solid solution treated at 1145℃ for 6h, and finally quickly air-cooled to room temperature; then the solid solution blank is heated to 300℃, kept warm for 4h, then heated to 820℃, kept warm for 12h, then cooled to 400℃ at a rate of 0.4℃ / min, kept warm for 4h, and then cooled to room temperature with the furnace to obtain a high-performance samarium cobalt magnet.

[0065] Example 2

[0066] Main alloy formula: (Sm 0.90 La 0.1 )(Co 0.60 Fe 0.26 Cu 0.09 Zr 0.05 ) 7.5 The auxiliary alloy is NdCu alloy, wherein the mass ratio of Nd to Cu is 7:3, and the main alloy ingredients and the auxiliary alloy ingredients are prepared respectively; then the main alloy ingredients obtained above are placed in a medium frequency induction furnace and evacuated to Pa, fill with argon to 0.03MPa and then heat and melt. When green light appears on the surface of the alloy liquid, cast the alloy liquid in a water-cooled clamping copper mold, wait for cooling for 1 hour and then take it out of the furnace to obtain a main alloy ingot with an average thickness of 2cm; similarly, place the auxiliary alloy ingredients obtained above in a medium frequency induction furnace, and prepare a praseodymium-copper alloy ingot with an average thickness of 2cm according to the above method.

[0067] The main alloy ingot and the praseodymium-copper alloy ingot obtained above are placed together in a hydrogen crushing furnace, wherein the mass ratio of the main alloy ingot to the praseodymium-copper alloy ingot is 97:3, and hydrogen absorption crushing is carried out at room temperature, wherein the hydrogen absorption pressure is 0.1 MPa, and the hydrogen absorption time is 5 hours. After the hydrogen absorption crushing is completed, dehydrogenation treatment is carried out, wherein the dehydrogenation temperature is 210°C, and the dehydrogenation time is 3 hours, to obtain hydrogen-crushed powder, wherein the average particle size of the hydrogen-crushed powder is 250 μm, and the hydrogen content in the hydrogen-crushed powder is 1500 ppm.

[0068] After mixing the hydrogenated powder in a mixer for 4 hours, it is sent to a jet mill for further crushing to obtain a powder with an average particle size of 3.2 μm. The powder after the jet mill is sent to a molding press and molded under a magnetic field of 2 T, and then cold isostatically pressed under a pressure of 200 MPa. After holding the pressure for 18 minutes, a green compact is obtained. The green compact after isostatic pressing is placed in a sintering furnace, first heated to 1180 °C for sintering for 4 hours, then solution-treated at 1140 °C for 10 hours, and finally rapidly air-cooled to room temperature. Then the solution-treated blank is heated to 220 °C, heat-treated for 6 hours, then heated to 850 °C and held for 10 hours, and then cooled to 420 °C at a rate of 0.4 °C / min and held for 2 hours, and then furnace-cooled to room temperature and taken out of the furnace to obtain a high-performance samarium cobalt magnet.

[0069] Example 3

[0070] Based on the main alloy molecular formula: (Sm 0.92 Pr 0.08 )(Co 0.59 Fe 0.30 Cu 0.04 Zr 0.02 ) 8.0 as a reference, the auxiliary alloy is NdCu alloy, in which the mass ratio of Nd and Cu is 3:7 as a reference, and the main alloy batching and auxiliary alloy batching are carried out respectively; then the main alloy batching obtained above is placed in an intermediate frequency induction furnace, evacuated to below Pa, filled with argon to 0.03 MPa and then heated and melted. When a green light appears on the surface of the alloy liquid, the alloy liquid is cast into a water-cooled splint copper mold, and after waiting for 1 hour to cool, it is taken out of the furnace to obtain a main alloy ingot with an average thickness of 2 cm; similarly, the auxiliary alloy batching obtained above is placed in an intermediate frequency induction furnace, and a praseodymium copper alloy ingot with an average thickness of 2 cm is prepared according to the above method.

[0071] The main alloy ingot and the praseodymium copper alloy ingot obtained above are placed together in a hydrogenation and crushing furnace, in which the mass ratio of the main alloy ingot to the praseodymium copper alloy ingot is 95:5, and hydrogen absorption and crushing are carried out at room temperature. Among them, the hydrogen absorption pressure is 0.5 MPa, the hydrogen absorption time is 2 hours, and dehydrogenation treatment is carried out after hydrogen absorption and crushing. Among them, the dehydrogenation temperature is 250 °C and the dehydrogenation time is 3 hours to obtain hydrogenated powder, in which the average particle size of the hydrogenated powder is 300 μm and the hydrogen content in the hydrogenated powder is 1000 ppm.

[0072] After mixing the hydrogenated powder in a mixer for 4 hours, it is sent to a jet mill for further crushing to obtain a powder with an average particle size of 5.0 μm. The powder after the jet mill is sent to a molding press and molded under a magnetic field of 2T, and then cold isostatically pressed under a pressure of 300 MPa. After holding the pressure for 10 minutes, a green compact is obtained. The green compact after isostatic pressing is placed in a sintering furnace, first heated to 1190 °C for sintering for 2 hours, then solution-treated at 1130 °C for 18 hours, and finally rapidly air-cooled to room temperature. Then the solution-treated blank is heated to 400 °C, held for 2 hours, then heated to 800 °C and held for 20 hours, and then cooled to 380 °C at a rate of 0.7 °C / min and held for 4 hours, and then furnace-cooled to room temperature and taken out of the furnace to obtain a high-performance samarium-cobalt magnet.

[0073] Example 4

[0074] Compared with Example 1, Example 4 is only different in that, taking the main alloy molecular formula: (Sm 0.94 Ce 0.04 Pr 0.02 )(Co 0.57 Fe 0.34 Cu 0.06 Zr 0.03 ) 7.2 as a reference, and the other conditions are the same, a high-performance samarium-cobalt magnet is obtained.

[0075] Example 5

[0076] Compared with Example 1, Example 5 is only different in that the dehydrogenation temperature is 290 °C, the dehydrogenation time is 4 hours, and the hydrogen content in the hydrogenated powder is 400 ppm. The other conditions are the same, and a high-performance samarium-cobalt magnet is obtained.

[0077] Example 6

[0078] Compared with Example 1, Example 6 is only different in that the dehydrogenation temperature is 200 °C, the dehydrogenation time is 2 hours, and the hydrogen content in the hydrogenated powder is 2600 ppm. The other conditions are the same, and a high-performance samarium-cobalt magnet is obtained.

[0079] Comparative Example 1

[0080] Compared with Example 1, Comparative Example 1 is only different in that, taking the main alloy molecular formula: Sm(Co 0.57 Fe 0.34 Cu 0.06 Zr 0.03 ) 7.2 as a reference, and the other conditions are the same. In this comparative example, since the main alloy does not contain rare earth elements, the hydrogen absorption efficiency is low under the hydrogenation and crushing process of Example 1, and it cannot be crushed into powder, so a high-performance samarium-cobalt magnet cannot be made.

[0081] Comparative Example 2

[0082] Comparative Example 2 is different from Example 1 only in that, taking the master alloy molecular formula: (Sm 0.8 Ce 0.2 )(Co 0.57 Fe 0.34 Cu 0.06 Zr 0.03 ) 7.2 as a reference, with all other conditions being the same, a high-performance samarium-cobalt magnet is obtained.

[0083] Comparative Example 3

[0084] Comparative Example 3 is different from Example 1 only in that, taking the master alloy molecular formula: (Sm 0.98 Ce 0.02 )(Co 0.57 Fe 0.34 Cu 0.06 Zr 0.03 ) 7.2 as a reference, with all other conditions being the same, a high-performance samarium-cobalt magnet is obtained.

[0085] Comparative Example 4

[0086] Comparative Example 4 is different from Example 1 only in that the mass ratio of the master alloy ingot to the praseodymium-copper alloy ingot is 92:8, the sintering temperature is 1175 °C, the solution temperature is 1135 °C, and all other conditions are the same, and a high-performance samarium-cobalt magnet is obtained.

[0087] Comparative Example 5

[0088] Comparative Example 5 is different from Example 1 only in that the mass ratio of the master alloy ingot to the praseodymium-copper alloy ingot is 99.99:0.01, the sintering temperature is 1190 °C, the solution temperature is 1150 °C, and all other conditions are the same, and a high-performance samarium-cobalt magnet is obtained.

[0089] Comparative Example 6

[0090] Comparative Example 6 is different from Example 1 only in that it does not contain a praseodymium-copper alloy ingot, the sintering temperature is 1190 °C, the solution temperature is 1150 °C, and all other conditions are the same, and a high-performance samarium-cobalt magnet is obtained.

[0091] Comparative Example 7

[0092] Comparative Example 7 is different from Example 1 only in that aging treatment is directly carried out after solution treatment, that is, the solution-treated blank is heated to 820 °C, held for 12 h, and then cooled to 400 °C at a rate of 0.4 °C / min and held for 4 h, and all other conditions are the same, and a high-performance samarium-cobalt magnet is obtained.

[0093] Comparative Example 8

[0094] Prepare the master alloy ingot and the praseodymium copper alloy ingot respectively according to the method of Example 1.

[0095] Place the obtained master alloy ingot in a hydrogen crushing furnace for hydrogen breaking treatment. Among them, the hydrogen absorption temperature is 200 °C, the hydrogen absorption pressure is 0.5 MPa, the hydrogen absorption time is 20 h, the dehydrogenation temperature is 300 °C, and the dehydrogenation time is 3 h to obtain the master alloy hydrogen broken powder. Then, send the master alloy hydrogen broken powder into a jet mill for further crushing to obtain a master alloy powder with an average particle size of 4.0 μm.

[0096] Place the obtained praseodymium copper alloy ingot in a hydrogen crushing furnace for hydrogen breaking treatment. Among them, the hydrogen absorption temperature is room temperature, the hydrogen absorption pressure is 0.2 MPa, the hydrogen absorption time is 2 h, the dehydrogenation temperature is 200 °C, and the dehydrogenation time is 2 h to obtain the praseodymium copper alloy hydrogen broken powder. Then, send the praseodymium copper alloy hydrogen broken powder into a jet mill for further crushing to obtain a praseodymium copper alloy powder with an average particle size of 4.0 μm.

[0097] Place the obtained master alloy powder and praseodymium copper alloy powder in a mixer according to a mass ratio of 99:1, and the other conditions are the same as those in Example 1 to obtain a high-performance samarium cobalt magnet.

[0098] Perform magnetic property and bending strength tests on the high-performance samarium cobalt magnets prepared in Examples 1-6 and Comparative Examples 1-8 respectively. The test results are shown in Table 1. Among them, the specific test methods are as follows: For the magnetic property test, use a 7×10 samarium cobalt small cylinder and test it with a permanent magnetic material measuring instrument; for the bending strength test, first process the sintered and aged samarium cobalt blank into a block of 20×6×5, and the direction with a thickness of 5 is the magnetization direction. Test it according to the three-point bending method. Place the processed samarium cobalt block on the fixture of a universal testing machine, and the indenter loads downward at a speed of 0.5 mm / min until the samarium cobalt block breaks. At this time, the instrument automatically displays the value of the bending strength. Test 20 pieces for each type and take the average value. 7×10 samarium cobalt small cylinders can be tested with a permanent magnetic material measuring instrument; for the bending strength test, first process the sintered and aged samarium cobalt blank into a block of 20×6×5, and the direction with a thickness of 5 is the magnetization direction. Test it according to the three-point bending method. Place the processed samarium cobalt block on the fixture of a universal testing machine, and the indenter loads downward at a speed of 0.5 mm / min until the samarium cobalt block breaks. At this time, the instrument automatically displays the value of the bending strength. Test 20 pieces for each type and take the average value.

[0099] Table 1 Typical magnetic properties and bending strengths of each example and comparative example

[0100]

[0101] It can be seen from the data in Table 1 that compared with Examples 1-6 and Comparative Examples 1-8, in the present invention, a master alloy with a specific formula and a secondary alloy with specific components are used, and the mass ratio of the master alloy and the secondary alloy is limited, which can effectively control the hydrogen absorption rate of the master alloy, so that the master alloy can be hydrogen broken together with the secondary alloy, and a heat preservation section is added between the end of solid solution and before aging treatment. These conditions have a synergistic relationship, making the high-performance samarium cobalt magnet of the present invention have high coercivity, remanence and mechanical properties, and the preparation method is simple, the production cost is low, and the production qualification rate is high.

[0102] Specifically, compared with Example 1 and Comparative Examples 1-3, it can be seen that doping the master alloy with a specific content of rare earth elements is beneficial to controlling the hydrogen absorption rate of the master alloy. It can not only complete hydrogen breaking together with the auxiliary alloy in a short time at room temperature, but also be beneficial to improving the remanence of high-performance samarium cobalt magnets. Compared with Examples 1-4 and Comparative Examples 4-6, it can be seen that adding a specific amount of auxiliary alloy can improve the remanence and coercivity of high-performance samarium cobalt magnets simultaneously, and to a certain extent improve the mechanical properties of high-performance samarium cobalt magnets. Compared with Example 1 and Comparative Example 7, it can be seen that by setting an insulation section, it is beneficial to improving the mechanical properties of high-performance samarium cobalt magnets. Compared with Example 1 and Comparative Example 8, compared with the conventional means of preparing the master alloy fine powder and the auxiliary alloy fine powder, in the present invention, the master alloy and the auxiliary alloy are hydrogen broken, mixed and ground into powder by airflow together, which not only does not affect the magnetic properties of high-performance samarium cobalt magnets, but also improves compared with the conventional means. Compared with Example 1 and Examples 5-6, controlling the hydrogen content within 1800 ppm is beneficial to ensuring the mechanical properties of high-performance samarium cobalt magnets and reducing the cracking probability of samarium cobalt magnets.

[0103] Combined Figure 1-6 it can be seen that the grain size of the magnet in Example 1 is much lower than that in Comparative Example 6, and the distribution is also more concentrated. Therefore, the flexural strength is significantly improved. The reduction of the grain size is because the addition of the auxiliary alloy reduces the sintering temperature of the samarium cobalt magnet; the grain size of the magnet in Comparative Example 7 is not much different from that in Example 1, but the flexural strength is reduced. This is because the insulation section before aging in Example 1 reduces the internal stress in the magnet, which is beneficial to improving the mechanical properties of the magnet.

[0104] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0105] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A method for preparing a high-performance samarium cobalt magnet, characterized in that, It includes the following steps: Provide a master alloy and a subsidiary alloy, wherein the molecular formula of the master alloy is (Sm a (M) 1-a )(Co 1-b-c-d Fe b Cu c Zr d ) z , a is 0.9 - 0.95, b is 0.25 - 0.35, c is 0.04 - 0.1, d is 0.02 - 0.06, z is 7.0 - 8.0, M is selected from at least one of Ce, La, Y, Pr, Nd, and the subsidiary alloy is an alloy containing R and Cu, and R is selected from Pr and / or Nd; Hydrogen decrepitation treatment is carried out on the master alloy and the auxiliary alloy together to obtain hydrogen decrepitated powder, wherein the mass ratio of the master alloy to the auxiliary alloy is 97:3 - 199:1; The hydrogen decrepitated powder is successively subjected to jet milling, forming and isostatic pressing, sintering, solution treatment and aging treatment to obtain a high-performance samarium cobalt magnet. After the solution treatment, it is first heated to 200°C - 400°C, held for 2h - 6h and then subjected to aging treatment.

2. The preparation method of the high-performance samarium cobalt magnet according to claim 1, characterized in that, The hydrogen content in the hydrogen decrepitated powder is 800ppm - 1800ppm; And / or, the average particle size of the hydrogen decrepitated powder is 100μm - 300μm.

3. The preparation method of the high-performance samarium cobalt magnet according to claim 1 or 2, characterized in that, In the step of hydrogen decrepitation treatment, the hydrogen absorption temperature is room temperature, the hydrogen absorption pressure is 0.1MPa - 0.5MPa, the hydrogen absorption time is 2h - 6h, the dehydrogenation temperature is 200°C - 250°C, and the dehydrogenation time is 2h - 4h.

4. The preparation method of the high-performance samarium cobalt magnet according to claim 1, characterized in that In the alloy containing R and Cu, the mass ratio of R to Cu is 3:7 - 7:

3.

5. The preparation method of the high-performance samarium cobalt magnet according to claim 1, characterized in that, The master alloy is a master alloy ingot or a master alloy sheet, and the auxiliary alloy is an auxiliary alloy ingot or an auxiliary alloy sheet.

6. The preparation method of the high-performance samarium cobalt magnet according to claim 5, characterized in that, The thicknesses of the master alloy ingot and the auxiliary alloy ingot are independently selected from 1cm - 3cm respectively; Or, the thicknesses of the master alloy sheet and the auxiliary alloy sheet are independently selected from 0.2mm - 0.8mm respectively.

7. The preparation method of the high-performance samarium cobalt magnet according to claim 1, wherein Before jet milling the hydrogen decrepitated powder, it also includes mixing the hydrogen decrepitated powder, wherein the mixing time is 2h - 4h; And / or, in the step of jet milling, the average particle size of the jet milled powder is 3μm - 5μm; And / or, in the step of forming and isostatic pressing, the isostatic pressing pressure is 200MPa - 300MPa, and the pressure holding time is 10min - 20min.

8. The preparation method of the high-performance samarium cobalt magnet according to claim 1, characterized in that, In the steps of sintering and solution treatment, the sintering temperature is 1160°C - 1200°C, the sintering time is 2h - 4h, the solution treatment temperature is 1130°C - 1170°C, and the solution treatment time is 4h - 20h.

9. The preparation method of the high-performance samarium cobalt magnet according to claim 1, characterized in that, The aging treatment process includes: first heating to 800°C - 850°C, holding for 10h - 20h, then cooling at a rate of 0.3°C / min - 0.7°C / min to 380°C - 420°C, holding for 2h - 6h and then cooling to room temperature.

10. A high-performance samarium cobalt magnet prepared by using the preparation method of the high-performance samarium cobalt magnet according to any one of claims 1 - 9.

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