CN-116313348-B - Neodymium iron boron magnet with high magnetic stability and manufacturing method and application thereof

CN116313348BCN 116313348 BCN116313348 BCN 116313348BCN-116313348-B

Abstract

The invention provides a neodymium iron boron magnet with high magnetic stability, a manufacturing method and application thereof. The neodymium iron boron magnet has a three-dimensional structure, wherein the three-dimensional structure comprises a length direction, a pressing direction and an orientation direction, and the orientation deflection angle of the neodymium iron boron magnet is smaller than or equal to 1 degree. The neodymium iron boron magnet and the manufacturing method thereof provided by the invention can effectively improve the magnetic stability of the magnet.

Inventors

PENG BUZHUANG
WANG SHUAI
WANG JIAO
LI GUANGJUN
YU DAYONG

Assignees

烟台正海磁性材料股份有限公司

Dates

Publication Date: 20260508
Application Date: 20211221

Claims (14)

1. The manufacturing method of the neodymium iron boron magnet is characterized by comprising the following steps of a rapid hardening sheet process, a powder process, a vertical compression molding process and a sintering process, and the neodymium iron boron magnet is manufactured; the vertical compression molding process specifically comprises the steps of carrying out vertical compression molding on neodymium iron boron powder under the action of a magnetic field to obtain a pressed compact, wherein the ratio of the dimension of the orientation direction of the pressed compact to the dimension of the length direction is 2.5-3.2; In the sintering process, a sintering protection material is also added, and the sintering protection material is uniformly distributed on the outer side of the green body, wherein the sintering protection material comprises rare earth-rich powder, and rare earth elements in the rare earth-rich powder are Nd, pr, la, ce; the neodymium iron boron magnet is of a three-dimensional structure, the three-dimensional structure comprises a length direction, a pressing direction and an orientation direction, and the orientation deflection angle of the neodymium iron boron magnet is smaller than or equal to 1 degree; The impurities of the neodymium iron boron magnet comprise: C, its content is lower than 700ppm; o, the content of which is less than 1000ppm; N, the content of which is less than 900ppm.
2. The method of claim 1, wherein the neodymium-iron-boron magnet comprises the following components: 25-35wt% of R, wherein R is one or more than two selected from Nd, pr, ce, dy or Tb; 0.8-1.5wt% of B; 1-5wt% of M selected from Ti, ga, cu, al, zr, nb, mn or more than two of Ni, and the balance of Fe and unavoidable impurities.
3. The method according to claim 1, wherein the impurity of the neodymium-iron-boron magnet is: the content of C is 100-650ppm; The content of O is 100-950ppm; The N content is 100-650ppm.
4. The method according to claim 1, wherein the rapid hardening sheet process comprises adding the required raw materials in the stoichiometric amount of the components of the NdFeB magnet, sufficiently melting into molten alloy under vacuum or inert gas atmosphere, rapidly cooling to form an alloy sheet, and cooling again to obtain the rapid hardening sheet.
5. The method according to claim 1, wherein the pulverizing step comprises subjecting the rapid hardening sheet to hydrogen embrittlement and air jet milling to obtain neodymium iron boron powder; the average grain diameter of the neodymium iron boron powder is 1-5 mu m; The gas ground by the jet mill is selected from inert gas, wherein the inert gas is selected from nitrogen, argon and helium; the oxygen content in the inert gas is not more than 30ppm; The inert gas is circularly used after being filtered after being ground by an air flow mill.
6. The method according to claim 5, wherein the average particle size of the NdFeB powder is 2 to 4. Mu.m.
7. The method according to claim 1, wherein the ratio of the dimension in the orientation direction to the dimension in the longitudinal direction of the compact is 2.5 to 3.
8. The method according to claim 1, wherein the vertical press molding step further comprises performing an isostatic pressing operation after the completion of the pressing; The isostatic pressure is 100Mpa-300Mpa.
9. The method of claim 1, wherein an additive is further added to the neodymium iron boron powder prior to vertical compression molding; the additives include lubricants and/or antioxidants.
10. The method according to claim 1, wherein the sintering step comprises sintering the compact at a high temperature, tempering at a low temperature, and cooling to obtain a neodymium iron boron magnet; The high-temperature sintering condition comprises that the vacuum degree is below 1.0X10 -3 Pa, the sintering temperature is 1000-1100 ℃ and the sintering time is 6-12h; the low-temperature tempering temperature is 450-600 ℃; The cooling rate is 5-15 ℃ per minute; The vertical compression molding step and the sintering step are both performed in a low-oxygen atmosphere, wherein the low-oxygen atmosphere means that the oxygen content is 50ppm or less.
11. The method of claim 10, wherein the cooling is at a rate of 6-10 ℃ per minute.
12. The method of manufacturing according to claim 1, wherein the rare earth element content in the rare earth-rich powder is more than 80%; the granularity of the rare earth-rich powder is not higher than 2 mu m; the sintering protection material is coated on the outer surface of the green body or in the cavity of the sintering material box.
13. The neodymium iron boron magnet obtained by the manufacturing method according to any one of claims 1 to 12, wherein the neodymium iron boron magnet has a three-dimensional structure, the three-dimensional structure comprises a length direction, a pressing direction and an orientation direction, and an orientation deflection angle of the neodymium iron boron magnet is less than or equal to 1 degree; The impurities of the neodymium iron boron magnet comprise: C, its content is lower than 700ppm; o, the content of which is less than 1000ppm; N, the content of which is less than 900ppm.
14. The use of the neodymium iron boron magnet of claim 13 in the field of electric automobiles.

Description

Neodymium iron boron magnet with high magnetic stability and manufacturing method and application thereof Technical Field The invention relates to the technical field of rare earth permanent magnets, in particular to a neodymium iron boron magnet with high magnetic stability, a manufacturing method and application thereof. Background The neodymium-iron-boron permanent magnet material is widely applied to a plurality of technical fields, such as wind power, household appliances, elevators, EPS and the like, on large equipment, the neodymium-iron-boron magnet is large in size, the corresponding magnetic performance requirement of a product is lower, the requirement on the orientation deflection angle consistency of the product is lower, but as the electric automobile field is continuously developed and is strong, the usage amount of the neodymium-iron-boron permanent magnet material is increased year by year, the electric automobile field is more prone to small and light development directions, the weight of the electric automobile is reduced, the flexible operation of the electric automobile is increased, and therefore the use size of the neodymium-iron-boron permanent magnet material on the electric automobile is required to be smaller and smaller, and the stability requirement on the magnetic performance of the neodymium-iron-boron permanent magnet material is higher and higher. In the process of magnetic orientation forming, the orientation direction of the product is not parallel to the orientation magnetic field direction to generate an orientation deflection angle, or in the process of product delivery, the product is not aligned when clamped, so that the orientation deflection angle is generated between the geometric symmetry axis of the product and the magnetic axis of the product. That is, the orientation bias angle of the permanent magnet refers to the bias angle of the final magnetization vector direction and the orientation direction of the permanent magnet. Due to the existence of the orientation deflection angle, the non-magnetization direction of the magnet generates a magnetic field to form a stray magnetic field. As permanent magnet applications continue to go deep, the orientation bias angle becomes an important contributor to the performance of precision magnetic devices. The consistency of the orientation deflection angle of the product is improved, and the stability of the product is enhanced. Disclosure of Invention The invention aims to provide a neodymium iron boron magnet with high magnetic stability, and a manufacturing method and application thereof. The technical scheme of the invention is as follows: The neodymium-iron-boron magnet has a three-dimensional structure, as shown in fig. 2, wherein the three-dimensional structure comprises a length direction, a pressing direction and an orientation direction, and the orientation deflection angle of the neodymium-iron-boron magnet is less than or equal to 1 degree. In the invention, the orientation bias angle of the neodymium-iron-boron magnet specifically means that magnetic flux values of the product in three directions of length, pressing and orientation are measured respectively, wherein the length direction, the pressing direction and the orientation direction are orthogonal in pairs, vector sum of the three directions is taken to obtain the total magnetic flux value and the final magnetized vector direction of the neodymium-iron-boron magnet, and then an included angle between the final magnetized vector direction and the orientation direction of the neodymium-iron-boron magnet is measured to define the orientation bias angle. According to an embodiment of the invention, the neodymium iron boron magnet comprises the following components: 25-35wt% of R, wherein R is one or more than two selected from Nd, pr, ce, dy or Tb; 0.8-1.5wt% of B; 1-5wt% of M selected from Ti, ga, cu, al, zr, nb, mn or more than two of Ni, and the balance of Fe and unavoidable impurities. According to an embodiment of the present invention, the impurities of the neodymium iron boron magnet include at least one of the following elements: c, the content of which is less than 700ppm, preferably from 100 to 650ppm; o in an amount of less than 1000ppm, preferably 100-950ppm; N is less than 900ppm, preferably 100-650ppm. The invention also provides a manufacturing method of the neodymium iron boron magnet, which comprises the following steps of rapid hardening sheet procedure, powder preparation procedure, vertical compression molding procedure and sintering procedure, and the neodymium iron boron magnet is prepared. According to the embodiment of the invention, the rapid hardening sheet process specifically comprises the steps of adding required raw materials according to the stoichiometric number of components of the neodymium-iron-boron magnet, fully melting into molten alloy under vacuum or inert gas atmosphere, rapidly cooling to form an alloy sheet, and th