A method for preparing anisotropic NdFeB magnet thin-walled rings using high-energy rays

Abstract

The invention provides a method for preparing anisotropic NdFeB magnet thin-walled rings by using high-energy rays. The method comprises the following steps: mixing epoxy resin with a solvent to prepare a uniform solution; immersing 20 parts of anisotropic NdFeB magnetic material powder in the solution; adding 0.05 parts of a curing agent; and after complete evaporation of the solvent, obtaining epoxy resin-coated anisotropic NdFeB magnetic material powder; dry-mixing 9.9 parts of the epoxy resin-coated anisotropic NdFeB magnetic material powder with 0.1 parts of triallyl isocyanurate to obtain a mixed powder; heating the mixed powder to 80°C and extruding it through an extruder to prepare a thin-walled ring; placing the thin-walled ring in a pulsed magnetic field with an intensity of 2T for magnetic field orientation; placing the oriented thin-walled ring in a high-energy ray irradiation device for irradiation treatment, and curing the thin-walled ring. The application can significantly improve the crosslinking degree of the epoxy resin, shorten the curing time, and quickly prepare a high-strength thin-walled ring sample.

Description

Technical Field

[0001] The present invention relates to the technical field of rare earth magnetic materials, in particular to a method for preparing anisotropic NdFeB magnet thin-walled rings by using high-energy rays. Background Art

[0002] Neodymium iron boron, as the permanent magnet material with the best magnetic properties currently, usually contains about 30% rare earth elements such as neodymium (Nd) and praseodymium (Pr). It is widely used in automobiles, industrial automation, consumer electronics, home appliances and other fields, especially in micro motors with power ranging from a few watts to several hundred watts.

[0003] In recent years, 3D printing technology has made great progress and has been widely used in the processing of metals, polymers and inorganic non-metallic materials. This technology can not only produce complex and special-shaped parts, but also overcome the problems of long cycle and high cost in the traditional mold opening process. It is also particularly suitable for the production needs of small batches and multiple varieties. However, the current magnetic materials used in motors have a wide variety of specifications. If a separate mold is opened for each size, it will lead to high costs and a long cycle.

[0004] Although existing 3D printing technologies, such as powder-sintering molding, printing filament laying process, slurry-sintering process, etc., have studied the rapid moldless 3D molding of NdFeB and its powder, these methods have not yet fully demonstrated the unique properties of HDDR anisotropic magnetic powder. First, existing 3D printing methods often require subsequent secondary processing to meet the requirements of installation testing. Second, the bonding process of anisotropic magnets allows their magnetic energy product to reach 12-20MGOe at the same size, while the maximum magnetic energy product of isotropic magnetic powder is only 12MGOe, showing its superiority in specific sizes (especially thin-walled circular ring parts). Third, 3D powders require ball milling and sintering in the later stage, which has some limitations in the preparation process.

[0005] Traditional UV 3D molding methods cannot meet the needs of rapid solidification of thin-walled magnets due to their weak energy and insufficient penetration, and still require long baking and secondary processing.

[0006] For example, patent CN102568730A discloses a high mechanical strength bonded NdFeB permanent magnet and a preparation method thereof, which has the aforementioned problems.

[0007] Therefore, it is particularly important to develop a rapid sample preparation process based on anisotropic magnetic powder and its composite materials. Summary of the Invention

[0008] In view of this, the present invention aims to propose a method for preparing anisotropic NdFeB magnet thin-walled rings using high-energy rays to solve the problem in the prior art that anisotropic NdFeB magnet thin-walled rings cannot be quickly prepared.

[0009] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0010] A method for preparing anisotropic NdFeB magnet thin-walled rings using high-energy rays comprises the following steps: mixing epoxy resin with a solvent to prepare a uniform solution; immersing 20 parts of anisotropic NdFeB magnetic material powder in the solution; adding 0.05 parts of a curing agent; and after complete evaporation of the solvent, obtaining epoxy resin-coated anisotropic NdFeB magnetic material powder; dry-mixing 9.9 parts of the epoxy resin-coated anisotropic NdFeB magnetic material powder with 0.1 parts of triallyl isocyanurate to obtain a mixed powder; heating the mixed powder to 80° C. and extruding it through an extruder to form a thin-walled ring; placing the thin-walled ring in a pulsed magnetic field with an intensity of 2T for magnetic field orientation; and placing the oriented thin-walled ring in a high-energy ray irradiation device for irradiation treatment to cure the thin-walled ring.

[0011] The method for preparing anisotropic NdFeB magnet thin-walled rings using high-energy rays described in this application uses high-energy ray irradiation treatment, which can significantly improve the cross-linking degree of epoxy resin and shorten the curing time. Compared with traditional baking and secondary processing, high-strength thin-walled ring samples can be quickly prepared. At the same time, high-energy ray irradiation can effectively prevent the oxidation of powder during the magnetic alignment process, maintain the magnetic properties of the material, and ensure the magnetic indicators of the final product. Coating the anisotropic NdFeB magnetic material powder with epoxy resin can improve the lubricity of the powder, reduce friction during the processing process, and improve the quality of the product.

[0012] Furthermore, 1 part of epoxy resin is mixed with 4 parts of solvent to prepare a uniform solution, and the solvent is acetone.

[0013] This setting can significantly reduce the viscosity of the epoxy resin, improve its fluidity, and make it easier to mix evenly with the anisotropic NdFeB magnetic material powder, ensuring the uniformity and consistency of the finished product. The use of solvent can improve the wettability of the epoxy resin to the anisotropic NdFeB magnetic material powder, ensuring that the powder is fully coated, thereby improving the mechanical strength and magnetic properties of the final product. Acetone is a highly volatile solvent that can evaporate in a shorter time, shortening the production cycle.

[0014] Furthermore, the anisotropic NdFeB magnetic material is processed by using an HDDR furnace, and then the anisotropic NdFeB magnetic material is crushed by using a wheel mill to obtain anisotropic NdFeB magnetic material powder with a particle size of 30-100 μm.

[0015] HDDR (high temperature annealing and magnetic field orientation) furnace treatment can improve the crystal structure and magnetic orientation of NdFeB materials, enhance their magnetic properties, and make the final powder have higher coercive force and maximum magnetic energy product. Crushing treatment through a wheel mill can control the particle size of the powder within the range of 30-100μm, ensuring uniform particle size distribution of the powder, facilitating subsequent processing and application, and improving the consistency and performance of the finished product.

[0016] Furthermore, the initial magnetic properties of the anisotropic NdFeB magnetic material powder are Hcj=13kOe, (BH)max=38MGOe.

[0017] This setting gives the material strong anti-magnetization ability. When the external magnetic field is removed, the material can maintain its magnetism. The high magnetic energy product allows less material to provide strong magnetic force, effectively reducing the size and weight of the motor.

[0018] Furthermore, the irradiation dose in the high-energy ray irradiation device is 30 kG, and the irradiation time is 15 minutes.

[0019] This setting can effectively accelerate the cross-linking reaction of epoxy resin and increase the curing speed. High-energy ray irradiation can prevent the oxidation of powder during the alignment and curing process of magnetic materials to a certain extent, maintain the magnetic and chemical stability of the material, and ensure the quality of the final product. Irradiation treatment can also improve the lubricity of powder particles, reduce friction during the molding process, ensure the fluidity of powder during mixing and pressing, and improve molding efficiency.

[0020] Furthermore, 1 part of epoxy resin was mixed with 3.5 parts of solvent to prepare a uniform solution, and the solvent was acetone.

[0021] This setting can significantly reduce the viscosity of the epoxy resin, improve its fluidity, and make it easier to mix evenly with the anisotropic NdFeB magnetic material powder, ensuring the uniformity and consistency of the finished product. The use of solvent can improve the wettability of the epoxy resin to the anisotropic NdFeB magnetic material powder, ensuring that the powder is fully coated, thereby improving the mechanical strength and magnetic properties of the final product. Acetone is a highly volatile solvent that can evaporate in a shorter time, shortening the production cycle.

[0022] Furthermore, it also includes SmFeN powder. The anisotropic NdFeB magnetic material is processed using an HDDR furnace, and the anisotropic NdFeB magnetic material and SmFeN material are crushed using a wheel mill to obtain anisotropic NdFeB magnetic material powder and SmFeN powder with a particle size of 30-100 μm. 80 parts of anisotropic NdFeB magnetic material powder are mixed with 18 parts of SmFeN powder to form a composite powder.

[0023] Mixing anisotropic NdFeB magnetic materials and SmFeN materials can achieve complementary performance and enhance the overall magnetic properties of the composite powder. At the same time, due to the low price of SmFeN materials, costs can also be reduced. SmFeN materials have good antioxidant properties and can improve the corrosion resistance of composite materials to a certain extent, extending the service life of the materials.

[0024] Furthermore, the initial magnetic properties of the anisotropic NdFeB magnetic material powder are Hcj=14kOe, (BH)max=39MGOe, and the initial magnetic properties of the SmFeN powder are Br=1.3-1.5T, (BH)max=38-40MGOe.

[0025] This setting gives the anisotropic NdFeB magnetic material powder a higher magnetic energy product, and less material can provide strong magnetic force. The SmFeN powder can maintain good magnetic properties at high temperatures and is suitable for applications in high-temperature environments. The addition of SmFeN material helps reduce the risk of demagnetization under high temperature or high load conditions, enhances the composite material's anti-demagnetization ability, and enables the final product to maintain good performance under different working conditions.

[0026] Furthermore, the irradiation dose in the high-energy ray irradiation device is 15 kG, and the irradiation time is 10 minutes.

[0027] Shorter irradiation time can significantly improve production efficiency, making the curing process of thin-walled rings faster and responding quickly to market demand. High-energy ray irradiation can effectively prevent the oxidation of powder during the alignment of magnetic materials, maintain the magnetic properties of the material, and avoid performance degradation caused by oxidation.

[0028] Furthermore, the thin-walled ring has an inner diameter of 10 mm, an outer diameter of 12 mm, a height of 2.0 mm, and a thickness of 1.0 mm.

[0029] This design can optimize the magnetic field distribution, improve the magnetic properties of the thin-walled ring, reduce the overall weight of the thin-walled ring, and improve energy efficiency.

[0030] Compared with the prior art, the method of preparing anisotropic NdFeB magnet thin-walled rings using high-energy rays described in the present invention has the following advantages:

[0031] 1) Using high-energy ray irradiation treatment can significantly increase the cross-linking degree of epoxy resin, shorten the curing time, and quickly prepare high-strength thin-walled ring samples;

[0032] 2) High-energy ray irradiation can effectively prevent the oxidation of powder during the magnetic alignment process, maintain the magnetic properties of the material, and ensure the magnetic indicators of the final product. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below.

[0034] Example 1

[0035] A method for preparing anisotropic NdFeB magnet thin-walled rings using high-energy radiation comprises treating anisotropic NdFeB magnetic material in an HDDR furnace and crushing the NdFeB magnetic material using a wheel mill to obtain anisotropic NdFeB magnetic material powder (HDDRNd-Fe-B) with a particle size of 30-100 μm and initial magnetic properties of Hcj = 13 kOe and (BH)max = 38 MGOe. One part epoxy resin is mixed with four parts solvent to form a uniform solution. 20 parts of the anisotropic NdFeB magnetic material powder are immersed in the solution, and 0.05 parts of a curing agent are added. After the solvent has completely evaporated, epoxy resin-coated anisotropic NdFeB magnetic material powder is obtained. The epoxy resin, solvent, anisotropic NdFeB magnetic material powder, and curing agent are all measured by weight.

[0036] Preferably, acetone is selected as the solvent.

[0037] 9.9 parts of anisotropic NdFeB magnetic material powder and 0.1 parts of triallyl isocyanurate are dry-mixed. Here, the dried anisotropic NdFeB magnetic material powder is used. The mixed powder is heated to 80°C and extruded through an extruder to form a thin-walled ring with an inner diameter of 10 mm, an outer diameter of 12 mm, a height of 2.0 mm, and a thickness of 1.0 mm. The ring is then oriented in a 2T pulsed magnetic field. The oriented thin-walled ring is placed in a high-energy ray irradiation device and irradiated at an energy of 30 kGy for 15 minutes to solidify the thin-walled ring.

[0038] The anisotropic NdFeB magnet prepared by the above method has Hcj=12.8kOe and (BH)max=17MGOe. The use of high-energy ray irradiation not only increases the crosslinking degree of the epoxy resin and improves the lubricity of the powder particles, but also effectively prevents oxidation of the powder during the magnetic alignment process.

[0039] The preparation method of this embodiment can quickly respond to customer needs, saving time in creating precision molds and quickly providing samples with high performance indicators. It also achieves a BHmax of 13-17 MGOe, a performance unattainable by isotropic NdFeB materials. Furthermore, due to its high resin content, it has excellent thermal corrosion resistance. The use of high-energy radiation curing shortens curing time, increases curing speed, and improves the product forming rate.

[0040] Example 2

[0041] Anisotropic NdFeB magnetic material was processed using an HDDR furnace, and then the anisotropic NdFeB magnetic material and SmFeN material were crushed using a wheel mill to obtain anisotropic NdFeB magnetic material powder and SmFeN powder with a particle size of 30-100 μm. The initial magnetic properties of the powder were Hcj=14kOe, (BH)max=39MGOe, and SmFeN powder had Br=1.3-1.5T and (BH)max=38-40MGOe. 80 parts of anisotropic NdFeB magnetic material powder were mixed with 18 parts of SmFeN powder to prepare a composite powder.

[0042] Preferably, anisotropic NdFeB magnetic material powder, SmFeN, SmCo and FeO are mixed to prepare composite powder.

[0043] Mix 1 part epoxy resin with 3.5 parts solvent to form a uniform solution. Immerse 20 parts of composite magnetic powder in the solution and add 0.05 parts of curing agent. After the solvent has completely evaporated, epoxy resin-coated NdFeB composite powder is obtained, with no acetone residue. The epoxy resin, solvent, anisotropic NdFeB magnetic material powder, SmFeN powder, and curing agent are all calculated by weight.

[0044] Preferably, acetone is selected as the solvent.

[0045] 9.9 parts of NdFeB composite powder and 0.1 parts of triallyl isocyanurate are dry-mixed. Here, the dried NdFeB composite powder is used. The mixed powder is heated to 80°C and extruded through an extruder to form a thin-walled ring with an inner diameter of 10 mm, an outer diameter of 12 mm, a height of 2.0 mm, and a thickness of 1.0 mm. The ring is then oriented in a 2T pulsed magnetic field. The oriented thin-walled ring is placed in a high-energy ray irradiation device and irradiated at an energy of 15 kGy for 10 minutes to solidify the thin-walled ring.

[0046] The anisotropic NdFeB magnet composite material prepared by the above method has Hcj=13.6kOe and (BH)max=12MGOe. The use of high-energy ray irradiation not only increases the crosslinking degree of the epoxy resin and improves the lubricity of the powder particles, but also effectively prevents the oxidation of the powder during the magnetic alignment process.

[0047] The preparation method of this embodiment can quickly respond to customer needs by saving time on precision mold creation and quickly providing samples with high performance indicators. A BHmax of 12MGOe is achieved. Although higher-grade isotropic NdFeB materials can also achieve this, the addition of SmFeN powder in this embodiment reduces the cost of the magnetic material. Furthermore, the higher resin content provides better thermal corrosion resistance, making this embodiment more advantageous for similar performance. Conventional technology requires re-molding whenever the customer's desired dimensions change. This thin-walled magnetic ring requires high-precision molds, which is time-consuming and expensive, making it difficult to quickly respond to customer needs.

[0048] The anisotropic magnetic material and its composite powder described in this application can fill the performance gap between isotropic NdFeB and sintered NdFeB, forming a complete performance system, which can make the motor smaller and save rare earth usage, so there is a huge market demand.

[0049] The method for preparing anisotropic NdFeB magnet thin-walled rings using high-energy rays described in this application has the following advantages: the use of high-energy rays improves the curing speed of the anisotropic NdFeB magnet thin-walled rings during molding, shortens the curing time, and can quickly prepare high-strength thin-walled magnetic ring samples.

[0050] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A method for preparing anisotropic NdFeB magnet thin-walled rings using high-energy rays, characterized in that: An epoxy resin is mixed with a solvent to form a uniform solution, 20 parts of anisotropic NdFeB magnetic material powder are immersed in the solution, 0.05 parts of a curing agent are added, and after the solvent is completely evaporated, anisotropic NdFeB magnetic material powder coated with epoxy resin is obtained. Then, 9.9 parts of the anisotropic NdFeB magnetic material powder coated with epoxy resin are dry-mixed with 0.1 parts of triallyl isocyanurate to obtain a mixed powder, the mixed powder is heated to 80° C., and extruded through an extruder to form a thin-walled ring, the thin-walled ring is placed in a pulsed magnetic field with an intensity of 2T for magnetic field orientation, and the oriented thin-walled ring is placed in a high-energy ray irradiation device for irradiation treatment to cure the thin-walled ring.

2. The method for preparing anisotropic NdFeB magnet thin-walled rings by high-energy rays according to claim 1, characterized in that: Mix 1 part epoxy resin with 4 parts solvent to make a uniform solution. The solvent is acetone.

3. The method for preparing anisotropic NdFeB magnet thin-walled rings by high-energy rays according to claim 2, characterized in that: The anisotropic NdFeB magnetic material is processed by using an HDDR furnace, and then the anisotropic NdFeB magnetic material is crushed by using a wheel mill to obtain anisotropic NdFeB magnetic material powder with a particle size of 30-100 μm.

4. The method for preparing anisotropic NdFeB magnet thin-walled rings by high-energy rays according to claim 3, characterized in that: The initial magnetic properties of the anisotropic NdFeB magnetic material powder are Hcj=13kOe, (BH)max=38MGOe.

5. The method for preparing anisotropic NdFeB magnet thin-walled rings by high-energy rays according to claim 4, characterized in that: The irradiation dose in the high-energy ray irradiation device is 30 kG, and the irradiation time is 15 minutes.

6. The method for preparing anisotropic NdFeB magnet thin-walled rings by high-energy rays according to claim 1, characterized in that: Mix 1 part epoxy resin with 3.5 parts solvent to make a uniform solution. The solvent is acetone.

7. The method for preparing anisotropic NdFeB magnet thin-walled rings by high-energy rays according to claim 6, characterized in that: It also includes SmFeN powder. The anisotropic NdFeB magnetic material is processed using an HDDR furnace, and the anisotropic NdFeB magnetic material and SmFeN material are crushed using a wheel mill to obtain anisotropic NdFeB magnetic material powder and SmFeN powder with a particle size of 30-100 μm. 80 parts of anisotropic NdFeB magnetic material powder are mixed with 18 parts of SmFeN powder to form a composite powder.

8. The method for preparing anisotropic NdFeB magnet thin-walled rings by high-energy rays according to claim 7, characterized in that: The initial magnetic properties of the anisotropic NdFeB magnetic material powder are Hcj=14kOe, (BH)max=39MGOe, and the initial magnetic properties of the SmFeN powder are Br=1.3-1.5T, (BH)max=38-40MGOe.

9. The method for preparing anisotropic NdFeB magnet thin-walled rings by high-energy rays according to claim 8, characterized in that: The irradiation dose in the high-energy ray irradiation device is 15 kG, and the irradiation time is 10 minutes.

10. The method for preparing anisotropic NdFeB magnet thin-walled rings by high-energy rays according to claim 1, characterized in that: The thin-walled ring has an inner diameter of 10 mm, an outer diameter of 12 mm, a height of 2.0 mm, and a thickness of 1.0 mm.