Method for diffusing multi-element heavy rare earth on sintered neodymium-iron-boron magnet grain boundary

A technology of grain boundary diffusion and heavy rare earth, applied in the direction of magnetic objects, magnetic materials, electrical components, etc., can solve the problems of high manufacturing cost, inability to adjust at will, increase the manufacturing cost of NdFeB magnets, etc., and meet the requirements of reducing the target material. The effect of avoiding cost increases

Active Publication Date: 2021-08-27
INST OF MECHANICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are many problems in the manufacture and application of multi-element heavy rare earth alloy targets
First of all, each enterprise has different requirements for the ratio of elements in the multi-element heavy rare earth alloy target, the target cannot be mass-produced, and the manufacturing cost is high, even higher than the price of pure heavy rare earth target, which further increases the manufacturing cost of NdFeB magnets
Secondly, limited by the high brittleness of the multi-element heavy rare earth alloy target, the ratio of each element in the target can only be adjusted within a certain range
In addition, one target only corresponds to one element ratio, once the target is formed, it cannot be adjusted at will

Method used

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  • Method for diffusing multi-element heavy rare earth on sintered neodymium-iron-boron magnet grain boundary
  • Method for diffusing multi-element heavy rare earth on sintered neodymium-iron-boron magnet grain boundary
  • Method for diffusing multi-element heavy rare earth on sintered neodymium-iron-boron magnet grain boundary

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] In this embodiment, the sintered NdFeB magnet #1 whose brand is 52N is used, and its size is 25mm*25mm*3mm. Dy is selected as the heavy rare earth element target, and Al is selected as the low melting point element target. The heavy rare earth Dy coating and the low melting point Al coating were sequentially deposited on the surface of 25mm*25mm by magnetron sputtering, followed by vacuum heat treatment.

[0058] The specific process is as follows:

[0059] The first step is to clean the surface of the sintered NdFeB magnet. The surface of the NdFeB magnet was ground, ultrasonically cleaned and dried in sequence; then the NdFeB magnet was placed on the workpiece frame of the coating preparation device, and the vacuum cavity was pumped to 5×10 by the vacuum obtaining system. -3 Pa. The Ar gas is introduced into the vacuum chamber and the Ar gas flow rate is adjusted so that the vacuum degree reaches 2Pa. Use a bias power supply to negatively bias the workpiece holder...

Embodiment 2

[0073] In this embodiment, the sintered NdFeB magnet #4 whose brand is 52N is used, and its size is 25mm*25mm*3mm. Dy is selected as the heavy rare earth element target, and Al is selected as the low melting point element target. Magnetron sputtering is used to sequentially deposit heavy rare earth Dy coating / low melting point Al coating on its 25mm*25mm surface, followed by vacuum heat treatment.

[0074] The specific process is as follows:

[0075] The first step: cleaning the surface of the sintered NdFeB magnet. Exactly the same as the first step in Example 1.

[0076] The second step: heavy rare earth Dy coating deposition. Exactly the same as the second step in Example 1

[0077] The third step: low melting point Al coating deposition. It is exactly the same as the third step in Example 1, except that the deposition time is 4 minutes, and the thickness of the Dy coating is about 1.2 μm.

[0078] The fourth step: exactly the same as the fourth step in Example 1.

...

Embodiment 3

[0089] In this embodiment, the sintered NdFeB magnet #6 whose brand is 52N is used, and its size is 25mm*25mm*3mm. Dy is selected as the heavy rare earth element target, and Al is selected as the low melting point element target. Magnetron sputtering is used to sequentially deposit heavy rare earth Dy coating / low melting point Al coating / heavy rare earth Dy coating / low melting point Al coating on the surface of 25mm*25mm, followed by vacuum heat treatment.

[0090] The specific process is as follows:

[0091] The first step: cleaning the surface of the sintered NdFeB magnet. Exactly the same as the first step in Example 1.

[0092] The second step: heavy rare earth Dy coating deposition. Adjust the Ar gas flow rate so that the air pressure in the vacuum chamber is 0.7 Pa. Turn on the Dy target magnetron magnetron sputtering source, and load the negative bias voltage on the NdFeB magnet to complete the deposition of the Dy coating on the surface of the NdFeB magnet. Among ...

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Abstract

The invention belongs to the technical field of sintered neodymium-iron-boron magnet surface engineering, and aims to provide a method for diffusing multi-element heavy rare earth on a sintered neodymium-iron-boron magnet grain boundary in order to solve the problems in manufacturing and application of a multi-element heavy rare earth alloy target material in the prior art. Firstly, multiple coatings are prepared on the surface of a sintered NdFeB magnet through the magnetron sputtering technology, the first coating is a heavy rare earth coating such as Dy or Tb, and the second coating is a low-melting-point coating such as Al. And subsequent coating is performed, and the first coating and the second coating are repeated according to the requirements of a grain boundary diffusion process. After the coating is prepared, a magnet is put into a vacuum diffusion furnace, and gradient temperature heating is conducted on the magnet. A multi-element heavy rare earth alloy coating is formed on the surface of the NdFeB magnet through first-stage vacuum heat treatment, and synergistic diffusion of low-melting-point elements and heavy rare earth elements in grain boundaries of the sintered NdFeB magnet is achieved through second-stage vacuum heat treatment. And finally, tempering treatment is carried out, so that the coercive force of the sintered NdFeB magnet is improved.

Description

technical field [0001] The invention belongs to the technical field of surface engineering of sintered NdFeB magnets, and in particular relates to a method for diffusing multi-element heavy rare earths in grain boundaries of sintered NdFeB magnets. Background technique [0002] As a new generation of rare earth permanent magnet materials, sintered neodymium iron boron (NdFeB) magnets have been widely used in electronic devices, rare earth permanent magnet motors and other fields due to their ultra-high magnetic properties. In recent years, the increasingly serious environmental pollution problem has pushed the new energy automobile industry into a stage of rapid development, which has greatly stimulated the demand for NdFeB magnets, the core component of rare earth permanent magnet motors. However, the working environment temperature of motors in new energy vehicles is often as high as 150 °C, while NdFeB magnets have low coercive force and poor temperature stability, and ma...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02H01F1/057
CPCH01F41/0293H01F1/0577Y02E10/72
Inventor 夏原许亿李光
Owner INST OF MECHANICS - CHINESE ACAD OF SCI
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