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CN-121983403-A - Low-coercivity temperature coefficient sintered neodymium-iron-boron permanent magnet material for new energy automobile

CN121983403ACN 121983403 ACN121983403 ACN 121983403ACN-121983403-A

Abstract

The invention discloses a low-coercivity temperature coefficient sintered neodymium-iron-boron permanent magnet material for a new energy automobile, relates to the technical field of sintered neodymium-iron-boron permanent magnet materials, realizes the cooperative optimization of high remanence and high coercivity through the preparation of the sintered neodymium-iron-boron permanent magnet material, breaks through the performance bottleneck of the traditional sintered neodymium-iron-boron magnet material, and achieves double improvement in the aspects of magnet energy density and anti-demagnetizing capability, so that the sintered neodymium-iron-boron permanent magnet material is excellent in performance under high-temperature and high-intensity magnetic field environments.

Inventors

  • ZHANG ZHEN
  • XU JUAN

Assignees

  • 安徽省瀚海新材料股份有限公司

Dates

Publication Date
20260505
Application Date
20260225

Claims (10)

  1. 1. The preparation method of the sintered NdFeB permanent magnet material is characterized by comprising the following steps of: s1, vacuum smelting and melt-spinning are carried out according to the following raw material formula by weight percent, so as to obtain a melt-spun sheet; 25-30% of PrNd, 2-3% of Dy, 0.8-1% of B, 0.1-0.3% of Cu, 0.6-0.8% of Co, 0.15-0.35% of Tb, 0.1-0.3% of Zr, 0.1-0.3% of Ga and the balance of Fe; s2, crushing the melt-spun sheet by hydrogen and grinding the melt-spun sheet into powder by air flow to obtain neodymium iron boron powder; S3, uniformly mixing the neodymium iron boron powder with the additive to obtain magnetic powder; s4, carrying out orientation pressing and isostatic pressing on the magnetic powder to obtain a green body; and S5, carrying out vacuum sintering and aging treatment on the green body to obtain the sintered NdFeB permanent magnet material.
  2. 2. The method according to claim 1, wherein the additive is manganese fluosilicate, and preferably the additive is used in an amount of 0.3-0.5% by weight of the NdFeB powder.
  3. 3. The method of claim 1, wherein the vacuum melting temperature is 1400-1500 ℃.
  4. 4. The method of claim 1, wherein the magnetic powder has a D50 particle size of 3 to 4. Mu.m.
  5. 5. The method of claim 1, wherein the orientation pressing has a magnetic field strength of 1.5 to 3T.
  6. 6. The method of claim 1, wherein the isostatic pressure is 150-250 MPa.
  7. 7. The method of claim 1, wherein the vacuum sintering temperature is 1000-1100 ℃ and the vacuum sintering time is 5-15 hours.
  8. 8. The preparation method of the composite material is characterized in that the aging treatment is divided into two sections, wherein the temperature of the first section of aging treatment is 800-900 ℃ and the time is 2-5 hours, and the temperature of the second section of aging treatment is 400-500 ℃ and the time is 3-8 hours.
  9. 9. The sintered neodymium-iron-boron permanent magnet material prepared by the preparation method of any one of claims 1-8.
  10. 10. The use of the sintered neodymium iron boron permanent magnet material of claim 9 in new energy automobiles.

Description

Low-coercivity temperature coefficient sintered neodymium-iron-boron permanent magnet material for new energy automobile Technical Field The invention relates to the technical field of sintered NdFeB permanent magnet materials, in particular to a sintered NdFeB permanent magnet material with a low coercivity temperature coefficient, a preparation method thereof and application thereof in new energy automobiles. Background In recent years, the global new energy automobile industry has been in a state of rapid development. With the continuous enhancement of environmental protection awareness and the increasingly strict emission restrictions of traditional fuel automobiles, new energy automobiles are widely focused by various national governments and consumers as a green and efficient transportation means. In China, the new energy automobile industry is more rapid to develop, the yield of the new energy automobile in 2024 years reaches 1000 thousands, the sales volume is close to 950 thousands, and the new energy automobile continuously occupies the first world for many years. In a core component driving motor of a new energy automobile, the neodymium iron boron permanent magnet material plays a vital role. The driving motor is used as a power source of the new energy automobile, and the performance of the driving motor directly determines the power performance, economy and reliability of the automobile. By virtue of the excellent characteristics of high remanence, high coercivity, high magnetic energy product and the like, the neodymium iron boron permanent magnet material can generate a strong magnetic field under smaller volume and weight, so that the power density and the efficiency of the driving motor are remarkably improved. The coercive force temperature coefficient directly influences the high-temperature demagnetization resistance of the sintered NdFeB permanent magnetic material. The coercivity of the sintered NdFeB permanent magnet material is reduced along with the temperature rise, and the coercivity temperature coefficient of the common sintered NdFeB permanent magnet material is about-0.8 to-0.6%/DEGC ‌, so that the coercivity is possibly lower than the demagnetizing field intensity in a working environment under a high-temperature working condition (such as over 80-150 ℃), irreversible demagnetization is caused, and the equipment performance is permanently attenuated. Disclosure of Invention The technical problem to be solved by the invention is to provide the sintered NdFeB permanent magnet material and the preparation method thereof, and the obtained sintered NdFeB permanent magnet material has excellent magnetic performance, particularly low coercive force temperature coefficient, and can be applied to the field of new energy automobiles. The technical problems to be solved by the invention are realized by adopting the following technical scheme: the invention aims at providing a preparation method of a sintered NdFeB permanent magnet material, which comprises the following steps: s1, vacuum smelting and melt-spinning are carried out according to the following raw material formula by weight percent, so as to obtain a melt-spun sheet; 25-30% of PrNd, 2-3% of Dy, 0.8-1% of B, 0.1-0.3% of Cu, 0.6-0.8% of Co, 0.15-0.35% of Tb, 0.1-0.3% of Zr, 0.1-0.3% of Ga and the balance of Fe; s2, crushing the melt-spun sheet by hydrogen and grinding the melt-spun sheet into powder by air flow to obtain neodymium iron boron powder; S3, uniformly mixing the neodymium iron boron powder with the additive to obtain magnetic powder; s4, carrying out orientation pressing and isostatic pressing on the magnetic powder to obtain a green body; and S5, carrying out vacuum sintering and aging treatment on the green body to obtain the sintered NdFeB permanent magnet material. Further, the additive is manganese fluosilicate or nickel hypophosphite. The invention takes manganese fluosilicate or nickel hypophosphite as an additive, and mainly aims to reduce the coercivity temperature coefficient of the sintered NdFeB permanent magnet material. Further, the dosage of the additive is 0.3-0.5% of the weight of the neodymium iron boron powder. Further, the temperature of the vacuum melting is 1400-1500 ℃. The vacuum melting is used for improving the purity and uniformity of the alloy and preventing the oxidation of components by isolating air. Further, the D50 granularity of the magnetic powder is 3-4 mu m. The particle size distribution of the powder is accurately controlled through hydrogen crushing and air flow grinding, so that the particle size of the powder is more uniform, and the forming performance and compactness of the magnetic powder are improved. Further, the magnetic field strength of the orientation pressing is 1.5-3T. The magnetic field orientation forming is to arrange the easy magnetization direction of the powder particles by utilizing the interaction of the magnetic powder and an external magnetic field so a