阅读说明：本技术 一种钕铁硼磁体及其制备方法 (Neodymium-iron-boron magnet and preparation method thereof ) 是由 周高峰 鲍志林 于 2019-09-24 设计创作，主要内容包括：本发明涉及一种钕铁硼磁体及其制备方法,属于磁性材料技术领域。本发明钕铁硼磁体包括钕铁硼基体和基体表面的铜镝合金层；本发明铁硼磁体的制备方法包括如下步骤：对钕铁硼基体进行清洁处理；在清洁处理后的钕铁硼基体表面形成铜层,然后在铜层表面形成镝层,制成具有铜层和镝层的钕铁硼磁体半成品；对钕铁硼磁体半成品进行热处理,形成铜镝合金层；本发明的制备方法应用范围广,制得的钕铁硼磁体机械性能好、热稳定性高、矫顽力高。(The invention relates to a neodymium iron boron magnet and a preparation method thereof, and belongs to the technical field of magnetic materials. The neodymium iron boron magnet comprises a neodymium iron boron base body and a copper dysprosium alloy layer on the surface of the base body; the preparation method of the iron boron magnet comprises the following steps: cleaning the neodymium iron boron substrate; forming a copper layer on the surface of the cleaned neodymium iron boron substrate, and then forming a dysprosium layer on the surface of the copper layer to prepare a neodymium iron boron magnet semi-finished product with the copper layer and the dysprosium layer; carrying out heat treatment on the neodymium iron boron magnet semi-finished product to form a copper dysprosium alloy layer; the preparation method has wide application range, and the prepared neodymium iron boron magnet has good mechanical property, high thermal stability and high coercive force.)

1. The neodymium iron boron magnet is characterized by comprising a neodymium iron boron base body and a copper dysprosium alloy layer on the surface of the base body.

2. A method of manufacturing a neodymium iron boron magnet according to claim 1, characterized in that the method comprises the steps of:

s1, cleaning the neodymium iron boron substrate;

s2, forming a copper layer on the surface of the cleaned neodymium iron boron substrate, and then forming a dysprosium layer on the surface of the copper layer to prepare a neodymium iron boron magnet semi-finished product with the copper layer and the dysprosium layer;

s3, carrying out heat treatment on the neodymium iron boron magnet semi-finished product to form a copper dysprosium alloy layer.

3. The preparation method according to claim 2, wherein the cleaning treatment in step S1 includes sequentially performing water washing, alkali washing, hot water washing, acid washing, water washing, alcohol washing, deionized water washing on the neodymium iron boron substrate, and then drying.

4. The method according to claim 2, wherein the copper layer and the dysprosium layer in step S2 each have a thickness of 1-5 μm.

5. The method for preparing a copper-based alloy according to claim 2, wherein the copper layer and the dysprosium layer in step S2 are both formed by ionic liquid electrodeposition.

6. The method of claim 2 or 5, wherein the copper layer and the dysprosium layer are formed in step S2 by respectively dissolving a copper salt and a dysprosium salt in an ionic liquid to form a copper electrodeposition bath and a dysprosium electrodeposition bath, placing the cleaned NdFeB substrate in the copper electrodeposition bath for electrodeposition to form a copper layer, and then placing the NdFeB substrate with the copper layer in the dysprosium electrodeposition bath for electrodeposition to form the dysprosium layer.

7. The process according to claim 6, wherein the ionic liquid is urea-choline chloride.

8. The method according to claim 6, wherein the voltage of the electrodeposition treatment during the formation of the copper layer is 10 to 36V for 300 to 600s, and the voltage of the electrodeposition treatment during the formation of the dysprosium layer is 8 to 30V for 80 to 120 s.

9. The method according to claim 2, wherein the heat treatment in step S1 is performed in a vacuum environment at 800-900 ℃.

Technical Field

The invention belongs to the technical field of magnetic materials, and relates to a neodymium iron boron magnet and a preparation method thereof.

Background

The neodymium iron boron magnet has high saturation magnetic flux, coercive force, magnetic energy product and good machining characteristics, and is widely applied to a plurality of basic industrial and high-precision technical fields of acoustics, aviation, electronics, automation, biology, communication and the like. However, the ndfeb magnet still has some defects in the using process, which affects the expansion of the application field. The neodymium iron boron magnet has poor mechanical property, is extremely fragile, has high unfilled corner rate, and cannot be applied to working environments with higher requirements on toughness. The neodymium-iron-boron magnet has poor heat resistance, and is easy to demagnetize in a thermal environment, so that the service performance and the service life of the neodymium-iron-boron magnet are influenced. In addition, although the coercivity of the existing neodymium iron boron magnet is higher than that of other magnets, the requirement for the coercivity of the magnet in the prior art is higher and higher, and the coercivity of the neodymium iron boron magnet is still to be further improved.

Disclosure of Invention

The invention aims to provide a neodymium iron boron magnet with good toughness, good mechanical property, high thermal stability and high coercive force aiming at the problems in the prior art.

The purpose of the invention can be realized by the following technical scheme:

a neodymium iron boron magnet comprises a neodymium iron boron base body and a copper dysprosium alloy layer on the surface of the base body.

According to the invention, the copper-dysprosium alloy layer is formed on the surface of the neodymium iron boron base body, so that the mechanical property of the neodymium iron boron magnet can be effectively improved, the high-temperature demagnetization rate of the neodymium iron boron magnet is reduced, and the intrinsic coercive force of the neodymium iron boron magnet can be improved.

The invention also aims to provide a preparation method of the neodymium iron boron magnet, the preparation method has wide application range, and the prepared neodymium iron boron magnet has good toughness, good mechanical property, high thermal stability and high coercive force.

The preparation method of the neodymium iron boron magnet comprises the following steps:

s1, cleaning the neodymium iron boron substrate;

s2, forming a copper layer on the surface of the cleaned neodymium iron boron substrate, and then forming a dysprosium layer on the surface of the copper layer to prepare a neodymium iron boron magnet semi-finished product with the copper layer and the dysprosium layer;

s3, carrying out heat treatment on the neodymium iron boron magnet semi-finished product to form a copper dysprosium alloy layer.

According to the invention, the copper layer is formed on the surface of the neodymium iron boron substrate, then the dysprosium layer is formed on the surface of the copper layer, then the surface permeation effect is generated under the heat treatment effect, and the copper-dysprosium alloy layer is formed on the surface of the neodymium iron boron substrate, so that the mechanical property and the magnetic property of the neodymium iron boron magnet are improved, meanwhile, copper and dysprosium elements in the copper-dysprosium alloy layer can also partially infiltrate into the neodymium iron boron substrate, the bonding property of the copper-dysprosium alloy layer and the neodymium iron boron substrate is improved, and the mechanical property and the magnetic property of the neodymium. Because the neodymium-iron-boron matrix is active and easy to corrode in the air environment, the copper layer is formed firstly, the neodymium-iron-boron matrix can be protected, and the matrix is prevented from further corroding in the treatment process. And the bonding performance of the copper layer and the matrix is better than that of the dysprosium layer and the matrix, so that the flatness of the copper layer and the dysprosium layer can be improved, and the bonding with the matrix has no delamination and bubble phenomena, thereby further improving the overall performance of the alloy layer.

Preferably, the cleaning treatment in step S1 includes sequentially performing water washing, alkali washing, hot water washing, acid washing, water washing, alcohol washing, deionized water washing on the neodymium iron boron substrate, and then drying.

The invention can remove oil stain and oxide film of the neodymium-iron-boron matrix through cleaning treatment to obtain a clean and bright neodymium-iron-boron matrix surface, thereby facilitating the formation of a copper layer.

Preferably, the thickness of the copper layer and the thickness of the dysprosium layer are both 1-5 μm.

When the thickness of the copper layer and the dysprosium layer is too low, the improvement effect on the neodymium iron boron magnet is not obvious, and when the thickness is too high, the enhancement effect on the improvement effect on the neodymium iron boron magnet is not obvious, so that the material waste is caused.

Preferably, the copper layer and the dysprosium layer are both formed in step S2 by ionic liquid electrodeposition.

Preferably, in step S2, the copper layer and the dysprosium layer are formed by dissolving a copper salt and a dysprosium salt in an ionic liquid to form a copper electrodeposition solution and a dysprosium electrodeposition solution, respectively, placing the neodymium iron boron substrate in the copper electrodeposition solution to perform electrodeposition to form a copper layer, and then placing the neodymium iron boron substrate with the copper layer in the dysprosium electrodeposition solution to perform electrodeposition to form a dysprosium layer.

Preferably, the copper salt is copper sulfate or copper chloride, and the dysprosium salt is dysprosium chloride.

Preferably, the copper electrodeposition solution contains copper salt in a concentration of 5 to 15 wt%, and the dysprosium electrodeposition solution contains dysprosium salt in a concentration of 5 to 15 wt%.

Preferably, the ionic liquid is urea-choline chloride.

Preferably, the voltage of the electrodeposition treatment during the copper layer formation is 10-36V and the time is 300-600 s, and the voltage of the electrodeposition treatment during the dysprosium layer formation is 8-30V and the time is 80-120 s.

According to the invention, the copper layer and the dysprosium layer are formed on the surface of the neodymium iron boron substrate by adopting an ionic liquid electrodeposition mode, so that the hydrogen evolution phenomenon of traditional solution electrodeposition can be avoided, the substrate can not be damaged, the coating has no defects of layering, foaming, hydrogen embrittlement and the like, and meanwhile, the ionic liquid is non-volatile and non-combustible, and has strong dissolving capacity and a wide electrochemical window. Because dysprosium element is difficult to electrodeposit on a substrate, and an electrodeposited dysprosium layer is difficult to obtain a good coating effect, a copper layer is firstly electrodeposited, and then the dysprosium layer is electrodeposited on the basis of the copper layer, so that a good coating is obtained, the coating is flat and has no layering or bubbling, and the problems of nonuniformity, unevenness and the like of a copper-dysprosium alloy layer and a permeable layer due to the problems of unevenness, layering, bubbling and the like of the coating are avoided during further heating treatment.

According to the invention, the urea-choline chloride is preferably used as the ionic liquid for dissolving the copper salt and the dysprosium salt, the copper salt and the dysprosium salt can obtain a better dissolving effect, the viscosity of the obtained electrodeposition liquid is proper, and the microstructure of the coating can be improved and the coating is prevented from being loose and porous by matching with proper electrodeposition voltage and time, so that the dense, uniform and good-binding-force coating is obtained. The copper layer and the dysprosium layer are selected from the same ionic liquid, so that the bonding performance of the copper layer and the dysprosium layer can be improved.

Preferably, the heat treatment in step S1 is performed in a vacuum environment at 800-900 ℃.

The invention is preferably carried out under the vacuum condition, and can further ensure that the neodymium iron boron magnet does not react with the environmental medium and cannot corrode under the condition that the combination of the substrate and the plating layer is not particularly tight.

Compared with the prior art, the invention has the following beneficial effects: a copper layer and a dysprosium layer are formed on the neodymium iron boron substrate by adopting an ionic liquid electrodeposition method, and a copper-dysprosium alloy layer is formed through heat treatment, so that the mechanical property and the intrinsic coercive force of the neodymium iron boron magnet are effectively improved; the method has the advantages that the copper layer is deposited firstly, then the dysprosium layer is deposited, the quality of the copper-dysprosium alloy layer and the bonding performance of the copper-dysprosium alloy layer and the neodymium-iron-boron matrix can be effectively guaranteed, and the neodymium-iron-boron matrix can be guaranteed not to be corroded as much as possible.

Detailed Description

The following are specific examples of the present invention and further describe the technical solutions of the present invention, but the present invention is not limited to these examples.