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CN-122000159-A - High-resistant Wen iron-boron magnet and preparation method thereof

CN122000159ACN 122000159 ACN122000159 ACN 122000159ACN-122000159-A

Abstract

The application relates to the technical field of permanent magnet preparation, and particularly discloses a high-strength Wen iron-boron magnet and a preparation method thereof. The high-strength Wen-Fe-B magnet consists of Nd17.4-19.5 wt%, B0.66-0.72 wt%, fe 38.37-41.19 wt%, dy 0.36-4.8 wt%, nb0.18-0.3 wt%, al 0.18-0.3 wt%, cu 0.03-0.09 wt%, fast alloy sheet 29.1-34.8 wt% and other non-removable impurity, and the fast alloy sheet contains Pr, tb, bi, sn wt%, and is prepared through polishing the surface of fast alloy sheet, mixing with pretreated magnet block, adding zirconia balls, vacuumizing the reaction kettle, introducing argon gas, rotating at the rotation speed of 4-6r/min, rotating diffusion at 700-950 deg.c for 2-4 hr, tempering at 450-550 deg.c for 2-4 hr in vacuum environment. The Gao Wen-resistant magnet has the advantage of improving the defect that the heat resistance of the conventional neodymium-iron-boron magnet is still insufficient.

Inventors

  • ZHOU DIAN
  • XU YINZHOU

Assignees

  • 宁波晟誉磁电科技有限公司

Dates

Publication Date
20260508
Application Date
20241212

Claims (8)

  1. 1. A high-resistant Wen-Fe-B magnet is characterized by comprising, by mass, 17.4-19.5% of Nd17.66-0.72% of B, 38.37-41.19% of Fe, 0.36-4.8% of Dy, 0.18-0.3% of Nb, 0.18-0.3% of Al, 0.03-0.09% of Cu, 29.1-34.8% of alloy rapid hardening tablets and the balance of non-removable impurities, wherein the alloy rapid hardening tablets contain Pr, tb, bi, sn.
  2. 2. The high-strength Wen-resistant iron-boron magnet according to claim 1, wherein the alloy rapid-hardening sheet comprises 26-30% by mass of Pr, 0.7-1.3% by mass of Tb, 0.9-1.2% by mass of Bi0.8-1% by mass of Sn.
  3. 3. The high Wen Fe-B magnet according to claim 2, wherein the alloy rapid hardening sheet is added by a rotary diffusion mode.
  4. 4. The high Wen Fe-B magnet according to claim 3, wherein the alloy rapid hardening sheet further contains Mo and Ti.
  5. 5. The high-strength Wen-resistant ferroboron as set forth in claim 4, wherein the mass percentage of Mo is 0.6-0.9% and the mass percentage of Ti is 0.1-0.4%.
  6. 6. The high-Wen-resistant iron-boron magnet as set forth in claim 5, wherein the preparation method of the alloy rapid-hardening sheet comprises the steps of charging Pr, tb, bi, sn, mo and Ti into a rapid-hardening furnace according to a proportion, gradually vacuumizing, preheating with low power to remove water and adsorbed impurities of the furnace burden, continuously vacuumizing, charging argon, charging medium-frequency current to melt the furnace burden, heating, stirring for 3-5min, pouring the alloy liquid onto the surface of a water-cooled copper roller with the roller speed of 1.1-1.3m/s, and finally cooling to obtain the alloy rapid-hardening sheet.
  7. 7. The method for preparing the high Wen-resistant ferroboron magnet as claimed in any one of claims 1 to 6, which is characterized by comprising the following steps: S1, adding Nd, B, fe, dy, nb, al, cu into a vacuum atmosphere sintering furnace according to a proportion, introducing nitrogen, mixing and smelting to obtain a melt-spun sheet, and carrying out hydrogen crushing and air flow grinding to obtain neodymium iron boron magnetic powder; s2, placing neodymium iron boron magnetic powder in a forming die to be pressed to obtain a green body, and then pressing the green body in a hydrostatic press to obtain a pretreated magnet block; s3, pickling the pretreated magnet blocks in a nitric acid solution with the concentration of 3.5% -4.5%, ultrasonically cleaning the pretreated magnet blocks by deionized water, and pouring the pretreated magnet blocks into absolute ethyl alcohol for dehydration and blow-drying for later use; S4, polishing the surface of the alloy rapid hardening sheet, mixing the polished surface with the pretreated magnet blocks, adding zirconia balls, placing the mixture into a reaction kettle of a rotary diffusion furnace, vacuumizing the reaction kettle, introducing argon, rotating at a rotating speed of 4-6r/min, preserving heat for 3-7h at 700-704 ℃ for rotary diffusion, and then carrying out high-temperature diffusion at 850-950 ℃ for 2-4h and tempering heat treatment at 450-550 ℃ for 2-4h in a vacuum environment by using a vacuum tube furnace.
  8. 8. The method for preparing the high Wen Fe-B magnet according to claim 7, wherein the mass ratio of the alloy rapid hardening sheet, the pretreated magnet block and the zirconia balls is (1-3) (0.5-1.5).

Description

High-resistant Wen iron-boron magnet and preparation method thereof Technical Field The application relates to the technical field of permanent magnet preparation, in particular to a high-resistant Wen iron boron magnet and a preparation method thereof. Background The neodymium-iron-boron magnet is used as a rare earth permanent magnet material with the highest global comprehensive performance at present, has excellent performances such as high magnetic energy product and high remanence, is known as 'permanent magnet king' by industry, and has quite broad application prospect in the fields of information communication, new energy, medical appliances and the like. Along with the adjustment of economic structures in China and the promotion of energy conservation and emission reduction policies, new energy automobiles, wind power generation and other novel industries rapidly rise, the market demand for high-performance neodymium-iron-boron permanent magnets is greatly increased, meanwhile, the technology for preparing the neodymium-iron-boron magnets is innovated by a pusher, and especially the requirements for long-term service of the magnets at high working temperature are higher and higher, so that the whole magnetic performance of the neodymium-iron-boron magnets is required to be provided with new steps. The intrinsic coercivity (INTRINSIC COERCIVITY, H cj) is one of the most important technical parameters of rare earth permanent magnets, and it is generally considered that the higher the intrinsic coercivity H cj of a neodymium-iron-boron magnet at room temperature is, the better the stability at high temperature is, and further the neodymium-iron-boron magnet can work at higher temperature, in order to improve the intrinsic coercivity H cj of the neodymium-iron-boron magnet, heavy rare earth elements are usually added in a formula, and are used as rare resources, on one hand, unbalanced utilization of rare earth resources is caused, on the other hand, the cost of raw materials is increased, the temperature coefficient of the neodymium-iron-boron magnet is improved by adopting a mode of adding Co elements, and soft magnetic phases are easily formed on grain boundaries by adding Co elements, so that the intrinsic coercivity H cj of the magnet is reduced. Disclosure of Invention In order to improve the defect that the heat resistance of the conventional NdFeB magnet is still insufficient, the application provides a high-resistant Wen-iron-boron magnet and a preparation method thereof. In a first aspect, the application provides a high Wen iron boron resistant magnet, which adopts the following technical scheme: A high-resistant Wen-Fe-B magnet comprises, by mass, 17.4-19.5% of Nd, 0.66-0.72% of B, 38.37-41.19% of Fe, 0.36-4.8% of Dy, 0.18-0.3% of Nb, 0.18-0.3% of Al, 0.03-0.09% of Cu, 29.1-34.8% of alloy rapid hardening tablets, and the balance of non-removable impurities, wherein the alloy rapid hardening tablets contain Pr, tb, bi, sn. Because the production cost of the heavy rare earth element Tb serving as a rare resource is too high, the utilization rate is relatively low, and the magnetic property of the magnet at high temperature can be improved by adding Pr, so that the magnet can keep stable magnetic property in a wider temperature range, and the high-temperature stability of the neodymium-iron-boron magnet is not affected while the addition amount of the heavy rare earth element Tb is reduced by selecting Pr to replace Tb. Meanwhile, bi and Sn have the characteristic of low melting point, and the low melting point metal BiSn alloy is beneficial to promoting the uniform distribution of a grain boundary phase, enhancing the wettability of the grain boundary phase and promoting Tb to diffuse into a magnet, so that a core-shell structure with a high magnetocrystalline anisotropy field is formed, the coercive force of the magnet is improved, and the magnetic property degradation of the magnet at a high temperature is reduced. Preferably, the alloy rapid hardening sheet comprises 26-30% of Pr, 0.7-1.3% of Tb, 0.9-1.2% of Bi and 0.8-1% of Sn in percentage by mass. Preferably, the alloy rapid hardening sheet is added by a rotary diffusion mode. The essence of the rotary diffusion is vapor deposition diffusion, wherein the vapor deposition is to place heavy rare earth and a compound thereof and a flaky permanent magnet sample in a chamber of a vapor deposition furnace, high-temperature heating is utilized to enable the heavy rare earth element to be sublimated at high temperature, the heavy rare earth element is deposited on the surface of a diffusion sample under the induction of gas, meanwhile, the high-temperature environment promotes the heavy rare earth element to diffuse into the magnet, and the high-temperature treatment is favorable for stabilizing the internal structure of the magnet, and the magnetic property degradation after the heat treatment is reduced, so that the high coercive force is fav