Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Surface treatment method for corrosion-resistant sintered NdFeB magnet

A surface treatment and sintered magnet technology, which is applied in the manufacture of permanent magnets, inductors/transformers/magnets, electrical components, etc., can solve the problems of magnetic performance damage and limited gain, and achieve long service life, low equipment requirements, and process flow short effect

Active Publication Date: 2019-08-16
江西永磁磁浮科技有限责任公司
View PDF12 Cites 3 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The addition of elements can reduce the potential difference between the main phase and the rare earth-rich phase, and improve the corrosion resistance of the magnet, but the increase is limited, and it will cause certain damage to the magnetic properties

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) Cut the sintered NdFeB magnet into a cylinder of φ20*15mm as required.

[0027] (2) Prepare degreasing liquid in the ultrasonic degreasing tank according to the ratio of 50 g degreasing spirit per liter of water, and heat up to 50 o C heat preservation treatment, then put the cut magnetic block into the ultrasonic degreasing tank, turn on the ultrasonic device to degrease for 3 minutes, and then perform secondary water washing, each washing time is 5-15 s.

[0028] (3) Put the prepared nitric acid solution with a concentration of 3% into the pickling tank, then put the magnet, and shake it for cleaning. The pickling time is 10-20 s. The pickled magnet needs to be taken out quickly for secondary water washing , each washing time is 5-15 s, followed by ultrasonic shock treatment, after the complete peeling off of the oxide skin on the surface of the magnet is observed, it is taken out and dried at a temperature of 40 o C, the drying time is 20 min.

[0029] (4) Fix ...

Embodiment 2

[0040]Using the ultrasonic impact effect of the sphere on the magnet, the grain refinement of the surface layer of the NdFeB magnet is realized. As shown in Example 1, a magnet sample with refined surface grains was prepared by impacting a sphere at high frequency. The difference is that the material of the sphere and the diameter of the sphere used in step (4) have changed. The magnetic properties of magnets produced by ultrasonic impact of spheres with different diameters and types are shown in Table 3. The electrochemical workstation was used to measure the electrochemical corrosion potential and current density of the magnet under the ultrasonic impact of cemented carbide balls with different diameters, as shown in Table 4.

[0041] Table 3 Magnetic properties of magnets produced by ultrasonic impact of spheres with different diameters and types

[0042] sample Br / kGs Hcj / kOe (BH)max / MGOe 1mm carbide ball (10min) 14 16.8 47.59 3mm carbide ...

Embodiment 3

[0047] Using the ultrasonic impact effect of the sphere on the magnet, the grain refinement of the surface layer of the NdFeB magnet is realized. As shown in Example 1, a magnet sample with refined surface grains was prepared by impacting a sphere at high frequency. The difference lies in: Step (5) is not ventilated or ventilated with different types of inert gas, such as nitrogen and argon. The magnetic properties of the prepared samples under different atmospheres are shown in Table 5. The electrochemical workstation was used to measure the changes of the electrochemical corrosion potential and current density of the magnet surface under ultrasonic impact in different atmospheres, as shown in Table 6.

[0048] Table 5 Magnetic properties of magnets prepared by ultrasonic impact in different atmospheres

[0049] sample Br / kGs Hcj / kOe (BH)max / MGOe Ar protection (10min) 14 16.8 47.59 CO2 protection (10min) 13.98 16.54 47.27 N2 protectio...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
Diameteraaaaaaaaaa
Login to View More

Abstract

The invention relates to a surface treatment method for a corrosion-resistant sintered NdFeB magnet. The method is applicable to sintered NdFeB magnets of various compositions. The method comprises NdFeB magnet pre-stage surface pretreatment, a magnet surface grain refinement process, atmosphere protection measures during the refining process and a subsequent ultralow-temperature de-stressing process. The method realizes the effective control of the surface grains of the magnet by the high and low frequency composite impact on the magnet by a hard alloy sphere, and improves the corrosion resistance of the magnet on the basis of ensuring the original magnetic performance. Compared with other methods of improving corrosion resistance measures, the method avoids the influence of other elements added on the magnetic properties of the magnet and reduces costs. The method is simple in process, low in equipment requirements, and beneficial to the batch processing of the magnet surface layer,and has a very wide application value.

Description

technical field [0001] The invention belongs to the technical field of rare earth permanent magnet materials, and in particular relates to a simple and practicable batch magnet surface treatment method for improving the corrosion resistance of the magnet surface. Background technique [0002] NdFeB permanent magnets are known as the "Magnetic King" due to their excellent magnetic properties, and are widely used in aerospace, wind power generation, energy-saving home appliances, electronic appliances, and new energy vehicles. And with the continuous improvement of manufacturing technology and the improvement of people's awareness of environmental protection, it has attracted the attention of the market in the three major fields of energy conservation and environmental protection, new energy, and new energy vehicles, and has become an indispensable material in daily work and life. Its consumption is 10 per year. The rapid growth rate of ~20% shows a good development prospect. ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): H01F41/02C21D7/06C21D1/30C23G1/08
CPCH01F41/026C21D7/06C21D1/30C23G1/085
Inventor 杨牧南卢耀军钟淑伟杨斌
Owner 江西永磁磁浮科技有限责任公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com