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Preparation of an organic slurry coated on NdFeB magnets and high coercivity NdFeB magnets

A high coercive force, neodymium-iron-boron technology, applied in the direction of magnetic objects, magnetic materials, inductors/transformers/magnets, etc., can solve the problems of uneven magnet surface, easy falling of surface coating layer, high equipment cost, etc. , to achieve the effect of preventing mutual adhesion, easy industrial mass production, and reducing material cost

Active Publication Date: 2021-01-29
宁波金鸡强磁股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the grain boundary diffusion methods announced in the field of NdFeB mainly include sputtering method, evaporation method, electrophoresis method, surface coating method and dipping method, but the methods of mass production in the industrial field are mainly sputtering method and coating method. The sputtering method has the disadvantages of expensive equipment, harsh operating environment, and low output per unit time, while the coating method is simple to operate and has loose environmental requirements, which is suitable for mass production
The preparation of Dy / Tb-containing fluoride or heavy rare earth simple substance published by Japan's Shin-Etsu Chemical Co., Ltd. is prepared as a slurry and coated on the surface of the magnet, as well as the slurry coating method published by Yantai Zhenghai and Earth Bear Co., Ltd., all of which have surface coating layers that are easy to fall off. , After the diffusion is completed, the content of oxygen and carbon will increase in the magnet, and after the diffusion is completed, the magnets are easy to stick, the surface of the magnet is uneven, and the defects on the surface of the magnet need to be machined to clean

Method used

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Examples

Experimental program
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Effect test

preparation example Construction

[0037] In an example of the present invention, the preparation method of a high-coercivity NdFeB magnet comprises the following steps: after the surface treatment of the sintered NdFeB magnet, the organic slurry is coated, and the organic slurry is composed of the following Composition by weight percentage: elemental metal powder is 30%-70%, thermoplastic resin powder is 5-10%, accelerator is 3-5%, and the rest is organic solvent. After drying, aging treatment is carried out to obtain the desired magnet.

[0038] The raw materials of sintered NdFeB magnets include neodymium, iron, boron and other trace elements, or other rare earth elements except neodymium. The preparation process mainly includes smelting, hydrogen breaking, powder making, molding, sintering and other treatments. The surface treatment of sintered NdFeB magnets includes degreasing, pickling, drying and other steps to remove oil and impurities on the surface of the magnet and improve the adhesion of the slurry....

Embodiment 1

[0041] Cut the 38H sintered NdFeB magnet into 50mm*50mm*6mm squares (denoted as 38H matrix sample), after degreasing, pickling, and drying, the prepared organic slurry is evenly coated on the On the substrate sample, the thickness of the coating is 20 μm, which is kept at 100°C for 10 minutes, followed by primary aging treatment at 880°C for 12 hours, and secondary aging treatment at 520°C for 4 hours after cooling to obtain the desired magnet.

[0042] The proportion of components in the organic slurry is 60% of terbium elemental (Tb) powder, 8% of polyvinyl butyral powder, 2% of cobalt isooctanoate, 2% of N,N-dimethylaniline, and the rest is for analysis Pure acetone. During the preparation process of the organic slurry, the oxygen content is controlled below 100ppm.

Embodiment 2

[0044] Cut the 38H sintered NdFeB magnet into 50mm*50mm*6mm squares (denoted as 38H matrix sample), after degreasing, pickling, and drying, the prepared organic slurry is evenly coated on the On the substrate sample, the thickness of the coating is 20 μm, which is kept at 100°C for 10 minutes, followed by primary aging treatment at 880°C for 12 hours, and secondary aging treatment at 520°C for 4 hours after cooling to obtain the desired magnet.

[0045] The proportion of components in the organic slurry is 60% of terbium elemental (Tb) powder, 8% of polyvinyl butyral powder, 4% of cobalt isooctanoate, and the rest is analytically pure acetone. During the preparation process of the organic slurry, the oxygen content is controlled below 100ppm.

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Abstract

The invention belongs to the technical field of rare-earth permanent magnets and particularly relates to organic slurry coated to a neodymium-iron-boron magnet and a preparation method of the high-coercivity neodymium-iron-boron magnet. The organic slurry is composed of the following components in percentage by weight: 30%-70% of elemental metal powder, 5-10% of thermoplastic resin powder, 5-10% of thermoplastic resin powder, 3-5% of accelerant and the balance of organic solvent. The preparation method comprises the steps that after being subjected to surface treatment, the sintered neodymium-iron-boron magnet is coated with the organic slurry, and aging treatment is carried out after drying so as to obtain a required magnet.

Description

technical field [0001] The invention belongs to the technical field of rare earth permanent magnets, and in particular relates to an organic slurry coated on an NdFeB magnet and a preparation method of a high coercivity NdFeB magnet. Background technique [0002] Rare-earth permanent NdFeB magnets are the third generation of magnets. Because of their high performance, they are widely used in new energy vehicles, air-conditioning compressors, various motors, and acoustic devices. At the same time, in recent years, the country has vigorously advocated and supported the development of new energy vehicles, and sintered NdFeB magnets, as the main components of permanent magnet motors, have a huge market demand. Since the internal temperature of Nd-Fe-B sintered magnets is about 300°C, the application temperature of some products using this magnet will exceed this temperature. Once the temperature rises above the specified temperature, the problem of demagnetization due to heat wi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057H01F41/02
Inventor 张勇蔡岭文沈是茂胡元虎
Owner 宁波金鸡强磁股份有限公司