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CN-121983421-A - Preparation method of high-strength and high-toughness samarium cobalt permanent magnet

CN121983421ACN 121983421 ACN121983421 ACN 121983421ACN-121983421-A

Abstract

The invention belongs to the technical field of permanent magnet materials, and relates to a preparation method of a high-strength and high-toughness samarium cobalt permanent magnet, which comprises the following steps of batching, smelting, pulverizing, orientation molding, cold isostatic pressing, sintering, solid solution and aging treatment; the aging treatment comprises the following steps of carrying out heat treatment at 780-880 ℃ for 500-1500 min under the protection of inert gas, then closing the inert gas, cooling to 200-500 ℃ for carrying out secondary aging treatment, preserving heat for 30-600 min, applying an external magnetic field, and finally cooling to room temperature. The invention increases the external magnetic field in the secondary aging, cancels the gas protection, reduces the gas cost, and simultaneously ensures that the mechanical property of the samarium cobalt magnet is greatly improved under the condition that the magnetic property is basically unchanged.

Inventors

  • HU FANGQIN
  • Dai Bingde
  • SUN YINGLI
  • FU YONGHAO
  • DING YONG
  • LIU LEI
  • ZHOU BO
  • YAN ARU

Assignees

  • 中国科学院宁波材料技术与工程研究所

Dates

Publication Date
20260505
Application Date
20260206

Claims (10)

  1. 1. The preparation method of the high-strength and high-toughness samarium cobalt permanent magnet is characterized by comprising the following steps of: batching, smelting, pulverizing, orientation molding, cold isostatic pressing, sintering, solid solution and aging treatment; The aging treatment step comprises the following steps of carrying out heat treatment at 780-880 ℃ for 500-1500 min under the protection of inert gas, then closing the inert gas, cooling to 200-500 ℃ for carrying out secondary aging treatment, preserving heat for 30-600 min, applying an external magnetic field, and finally cooling to room temperature.
  2. 2. The preparation method according to claim 1, wherein the primary heat treatment has a heat preservation temperature of 800-840 ℃ and a heat preservation time of 600-1200 min.
  3. 3. The method according to claim 1, wherein the temperature is reduced at a rate of 0.5-1.2 ℃ per minute to the holding temperature of the secondary aging treatment.
  4. 4. The preparation method according to claim 1, wherein the heat preservation temperature of the secondary aging treatment is 350-500 ℃, and the heat preservation time of the secondary aging treatment is 50-500 min.
  5. 5. The method of claim 1, wherein the inert gas comprises nitrogen and/or argon.
  6. 6. The method according to claim 1, wherein the magnitude of the applied magnetic field is 3-50 koe.
  7. 7. The preparation method according to claim 1, wherein the applied magnetic field has a duration of 5 to 200 minutes.
  8. 8. The method of claim 1, wherein the direction of the externally applied magnetic field is at any angle to the magnet.
  9. 9. The method of claim 1, wherein the direction of the applied magnetic field is parallel to the easy axis of the magnet.
  10. 10. The high-strength and high-toughness samarium cobalt permanent magnet is characterized in that the high-strength and high-toughness samarium cobalt permanent magnet is prepared by the preparation method according to any one of claims 1 to 9, and the fracture toughness of the samarium cobalt permanent magnet is 3-10 Mpa-m 1/2 , and the bending strength is 120-300 Mpa.

Description

Preparation method of high-strength and high-toughness samarium cobalt permanent magnet Technical Field The invention belongs to the technical field of permanent magnet materials, and relates to a preparation method of a high-strength and high-toughness samarium cobalt permanent magnet. Background The samarium cobalt permanent magnet material has the advantages of high magnetic performance, high Curie temperature, high temperature resistance, low temperature coefficient and the like, and is a key material for developing the fields of consumer electronics, humanoid robots, intelligent manufacturing and the like. However, due to the intrinsic characteristics of small sliding system, anisotropy and the like, the samarium cobalt material causes unfilled corners and cracks in the processing or magnetizing process, and is more prone to failure under the action of external forces such as impact vibration, centrifugal force and the like in the using process. The samarium cobalt magnet has the bending strength of only 80-140 MPa and the fracture toughness of only 1.5-2.5 MPa.m 1/2, and the production loss is as high as 20-30% due to brittleness, so that the processing cost is greatly improved, and the application range and deep processing are severely restricted. In order to improve the mechanical properties of the samarium cobalt permanent magnet material, researchers explore various technical paths, namely firstly, cu powder with different contents is added in the powder preparation stage by a matrix reinforcing method, and the mechanical properties of the magnet are effectively improved by solid solution reinforcement, but the deterioration of remanence and magnetic energy product is obvious due to the magnetic dilution effect. Secondly, by a cryogenic treatment method, the method can reduce the residual stress in the magnet without sacrificing the magnetic performance, thereby improving the mechanical performance, but the improvement range of the mechanical performance is limited. In conclusion, synchronous improvement of magnetic performance and mechanical performance of the samarium cobalt permanent magnet material still faces significant challenges, and application requirements of the related fields on the material comprehensive performance are difficult to meet, so that development of a technical scheme capable of simultaneously optimizing the magnetic performance and mechanical performance of the samarium cobalt permanent magnet material has important significance. Disclosure of Invention The invention aims to provide a preparation method of a high-toughness samarium cobalt permanent magnet, so as to solve the problem that the magnetic property and the mechanical property are difficult to cooperatively improve in the prior art. The invention adopts the following technical scheme to realize the aim of the invention: The invention provides a preparation method of a high-toughness samarium cobalt permanent magnet, which comprises the following steps: batching, smelting, pulverizing, orientation molding, cold isostatic pressing, sintering, solid solution and aging treatment; The aging treatment step comprises the following steps of carrying out heat treatment at 780-880 ℃ for 500-1500 min under the protection of inert gas, then closing the inert gas, cooling to 200-500 ℃ for carrying out secondary aging treatment, preserving heat for 30-600 min, applying an external magnetic field, and finally cooling to room temperature. Inert gases herein include nitrogen and/or argon. Preferably, the heat preservation temperature of the primary heat treatment is 800-840 ℃, such as 800 ℃, 810 ℃, 820 ℃, 830 ℃ or 840 ℃, and the heat preservation time of the primary heat treatment is 600-1200 min, such as 600min, 700min, 800min, 900min, 1000min, 1100min or 1200min. Preferably, the temperature is reduced to the heat preservation temperature of the secondary aging treatment at the speed of 0.5-1.2 ℃ per minute. Preferably, the heat preservation temperature of the secondary aging treatment is 350-500 ℃, for example, 350-380 ℃, 400 ℃, 420 ℃, 450 ℃, 470 ℃ or 500 ℃, and more preferably 400-500 ℃. In a certain temperature range, as the secondary aging temperature is increased, the fracture toughness and the bending strength show a trend of gradually increasing, and excessive coarsening of a precipitated phase in the magnet can be caused by excessive secondary aging temperature, so that the fracture toughness and the bending strength are reduced, the pinning effect of the precipitated phase on the magnetic domain wall can be weakened, and the magnetic property is deteriorated. Preferably, the heat preservation time of the secondary aging treatment is 50-500 min. Preferably, the magnitude of the applied magnetic field is 3 to 50kOe, more preferably 5 to 20kOe, still more preferably 5 to 10kOe. In a certain range, as the magnetic field strength is increased, the fracture toughness and the bending strength are gradually increased, the magn