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CN-122000157-A - Preparation method for improving performance of samarium cobalt magnet

CN122000157ACN 122000157 ACN122000157 ACN 122000157ACN-122000157-A

Abstract

The invention belongs to the technical field of rare earth permanent magnet materials, and particularly relates to a preparation method for improving performance of a samarium cobalt magnet. In order to simply and efficiently improve the magnetic performance of the samarium cobalt magnet, the sintering solid solution treated samarium cobalt magnet is subjected to vacuum plastic package, then is subjected to prestress treatment, and finally is subjected to aging treatment, so that the final-state samarium cobalt magnet is obtained.

Inventors

  • ZHOU XIANGLONG
  • WANG FANG
  • WEI ZHIYUAN
  • XU XIAOHONG
  • FAN SHAOHUA
  • QIN BIN
  • LI AOXIANG

Assignees

  • 山西师范大学
  • 湖北汽车工业学院

Dates

Publication Date
20260508
Application Date
20260324

Claims (8)

  1. 1. The preparation method for improving the performance of the samarium cobalt magnet is characterized by comprising the following steps of: step 1, performing vacuum plastic packaging on a sintered solid solution treated samarium cobalt magnet; Step 2, pre-stressing the samarium cobalt magnet subjected to vacuum plastic packaging; and step 3, performing aging treatment on the pre-stress treated samarium cobalt magnet to obtain the high-performance samarium cobalt magnet.
  2. 2. The method of claim 1, wherein the pre-stressing step 2 is cold isostatic pressing, hot isostatic pressing or applying a certain pressure by a pressurizing device.
  3. 3. The method for preparing the samarium cobalt magnet with improved performance according to claim 2, wherein the cold isostatic pressing condition is that pressure is maintained for 0.5-10 min under 50-300 MPa.
  4. 4. The method for preparing the samarium cobalt magnet with improved performance according to claim 1, wherein the sintered solution-treated samarium cobalt magnetic flux in the step1 is prepared by the following steps: (1) Removing surface oxide skin from metal raw materials including samarium, cobalt, iron, copper and zirconium, and then carrying out vacuum medium-frequency induction smelting to obtain alloy ingots or carrying out vacuum rapid hardening smelting to obtain rapid hardening tablets (2) Sequentially carrying out jaw coarse crushing, disc grinding fine crushing and air flow grinding on the alloy cast ingot or the rapid hardening sheet to obtain magnetic powder; (3) Orientation molding is carried out on the magnetic powder under a magnetic field, and then cold isostatic pressing is carried out to obtain a green body; (4) And sintering the green body, cooling to a certain temperature for solution treatment, and rapidly cooling to room temperature to obtain the sintered solution-treated samarium cobalt magnet.
  5. 5. The method for preparing samarium cobalt magnet according to claim 4, wherein the granularity of the magnetic powder in the step (2) is 3-6 μm.
  6. 6. The method for preparing the samarium cobalt magnet according to claim 4, wherein the strength of the magnetic field in the step (3) is 1-3T, the pressure of the cold isostatic pressing is 100-300 MPa, and the time is 0.5-1 min.
  7. 7. The method for preparing the samarium cobalt magnet according to claim 1, wherein the chemical formula of the samarium cobalt magnet is Sm (Co bal. Fe u Cu v Zr w ) z , wherein z represents an atomic ratio of a rare earth element Sm to a total of co+fe+cu+zr elements, z is 7-8, u=0.10-0.35, v=0.04-0.1, and w=0.01-0.08.
  8. 8. The method for preparing the samarium cobalt magnet according to claim 1, wherein the aging treatment in the step 3 is performed at 790-850 ℃ for 3-20 hours, then the temperature is slowly cooled to 400 ℃ at a cooling rate of 0.5-1.5 ℃ per minute, the temperature is continuously kept for 1-10 hours, and the temperature is cooled to room temperature to obtain the final-state magnet.

Description

Preparation method for improving performance of samarium cobalt magnet Technical Field The invention belongs to the technical field of rare earth permanent magnet materials, and particularly relates to a preparation method for improving performance of a samarium cobalt magnet. Background As a second-generation rare earth permanent magnet material, the samarium cobalt magnet is the permanent magnet material with the strongest high-temperature magnetism, and is difficult to replace by other permanent magnet materials in the high-temperature application fields of aerospace, national defense industry, microwave communication technology and the like. In recent years, along with the rapid development of rail transit in China and the increasing of industrial energy conservation and consumption reduction, the demand for only samarium cobalt magnets capable of meeting the use requirements of the magnets is rapidly increased, and the magnets are promoted to develop towards high performance. At present, researchers not only obtain high magnetic performance by improving the Fe content in the magnet and properly reducing the Cu and Zr contents of non-ferromagnetic elements through formula component design, but also further explore the magnetic performance potential of the samarium cobalt magnet through process optimization, equipment upgrading and technical innovation. Patent CN112927920a discloses a method for preparing high-performance samarium cobalt permanent magnet by applying compressive stress in isothermal aging process, which not only can improve magnetic property of the magnet, but also can shorten preparation flow of the same-grade magnet, but also has relatively complex preparation process and higher requirement on shape and size of the magnet. Patent CN118156014a adopts ultra-high pressure pre-ageing treatment to improve the coercive force of samarium cobalt magnets, and is also limited by the shape and size of magnets, and also requires investment in new equipment (hexahedral press). The patent CN113539596A prepares a high-performance samarium cobalt magnet by a microwave heating mode, and the method can greatly shorten the preparation period of the magnet, but the coercive force is still low without long-time aging treatment, and meanwhile, a new equipment microwave sintering furnace is introduced, so that the production cost is increased. The prior art has the defects of low production efficiency and large equipment investment. Therefore, the invention is based on the continuous deepening of the understanding of the phase change mechanism of the samarium cobalt magnet, proposes that the samarium cobalt magnet is subjected to cold isostatic pressing and other prestress treatments after being sintered and subjected to solution treatment so as to change the defects in the material, thereby accelerating the solid phase change process and obviously improving the magnetic performance of the samarium cobalt magnet. Disclosure of Invention The invention provides a preparation method for improving performance of a samarium cobalt magnet aiming at the problems. The method is based on the pre-stressing of the magnet through pre-stressing before aging treatment so as to promote the desolventizing, decomposing and converting of 1:7 phases in a solid solution treatment state to form a complete nano cellular tissue, thereby improving the coercive force and magnetic energy product of the magnet. The invention adopts the following technical scheme to achieve the aim: the invention discloses a preparation method for improving performance of a samarium cobalt magnet, which comprises the following steps of: step 1, performing vacuum plastic packaging on a sintered solid solution treated samarium cobalt magnet; Step 2, pre-stressing the samarium cobalt magnet subjected to vacuum plastic packaging; and step 3, performing aging treatment on the pre-stress treated samarium cobalt magnet to obtain the high-performance samarium cobalt magnet. Further, the pre-stressing in step 2 is cold isostatic pressing, hot isostatic pressing or applying a certain pressure by a pressurizing device (various hydraulic presses). Further, the cold isostatic pressing condition is that the pressure is maintained for 0.5-10 min under 50-300 MPa. Further, the sintered solid solution treated samarium cobalt magnetic flux in the step 1 is prepared by the following steps: (1) Removing surface oxide skin from metal raw materials including samarium (Sm), cobalt (Co), iron (Fe), copper (Cu) and zirconium (Zr), and then carrying out vacuum medium-frequency induction smelting to obtain alloy cast ingots or carrying out vacuum rapid hardening smelting to obtain rapid hardening tablets (2) Sequentially carrying out jaw coarse crushing, disc grinding fine crushing and air flow grinding on the alloy cast ingot or the rapid hardening sheet to obtain magnetic powder; (3) Orientation molding is carried out on the magnetic powder under a magnetic field, and then cold