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

Sintered NdFeB magnet surface corrosion-resistant composite coating and preparation method thereof

A composite coating and corrosion-resistant technology, which is applied in coatings, anti-corrosion coatings, magnetic objects, etc., can solve the problems of limited improvement in the corrosion resistance of magnets, achieve uniform and controllable coating thickness, extend service life, and improve The effect of coating corrosion resistance

Inactive Publication Date: 2022-02-01
HEFEI UNIV OF TECH +1
View PDF6 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The alloying method generally improves the corrosion resistance of the magnet at the expense of the performance of the magnet, and the range of improvement in the corrosion resistance of the magnet is limited

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

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Sintered NdFeB magnet surface corrosion-resistant composite coating and preparation method thereof
  • Sintered NdFeB magnet surface corrosion-resistant composite coating and preparation method thereof
  • Sintered NdFeB magnet surface corrosion-resistant composite coating and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A preparation method of a corrosion-resistant composite coating on the surface of a sintered NdFeB magnet, comprising the following steps:

[0029] (1) Preparation of Co-BDC nanosheets;

[0030] 32ml of N,N-dimethylformamide was added to 2ml of ethanol and 2ml of water, mixed to form solution A, 125.9mg of terephthalic acid was dissolved in solution A to form solution B, and 180.2mg of cobalt chloride hexahydrate was dissolved. In solution B, to form solution C, 0.8 ml of triethylamine was rapidly added to solution C, magnetically stirred for 5 min, and then the solution C was continuously sonicated for 8 h, and the product was centrifuged, washed with ethanol, and dried in an oven. Dry to obtain Co-BDC nanosheets;

[0031] (2) Pretreatment of sintered NdFeB magnets;

[0032] First, the sintered NdFeB magnets were pickled in 3 wt% nitric acid solution for 20 s; then, the magnets were sonicated in deionized water and ethanol in sequence for 60 s, and finally, the magne...

Embodiment 2

[0048] The preparation method of this example is the same as that of Example 1, except that the dispersion concentration of Co-BDC nanosheets in the composite coating is 25 g / L.

[0049] After soaking the sintered NdFeB magnet with the composite coating on the surface prepared in Example 2 in 3.5wt% NaCl solution for 5 days, the corrosion-resistant composite coating on the surface of the sintered NdFeB magnet was obtained according to the above steps. Impedance (|Z|0.01Hz) is 1.19×10 8 Ω cm -2 , which was four orders of magnitude higher than that of control group 1. After immersion for 30 days, the electrochemical polarization curve test shows that the corrosion potential is -0.382V, and the self-corrosion current density is 7.639×10 -9 A cm -2 , which was four orders of magnitude lower than that of control group 1.

Embodiment 3

[0051] The preparation method of this example is the same as that of Example 1, except that the dispersion concentration of Co-BDC nanosheets in the composite coating is 75 g / L.

[0052] After soaking the sintered NdFeB magnet with the composite coating on the surface prepared in Example 3 in 3.5wt% NaCl solution for 5 days, the corrosion-resistant composite coating on the surface of the sintered NdFeB magnet was obtained according to the above steps. Impedance (|Z|0.01Hz) is 8.92×10 7 Ω cm -2 , which was three orders of magnitude higher than that of control group 1. After soaking for 30 days, the electrochemical polarization curve test shows that the corrosion potential is -0.677V, and the self-corrosion current density is 8.772×10 -7 A cm -2 , which was two orders of magnitude lower than that of control group 1.

[0053] figure 1 This is a FESEM photo of the Co-BDC nanosheet in the present invention. The thickness of the nanosheet is relatively thin, the surface is rela...

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
concentrationaaaaaaaaaa
corrosion potentialaaaaaaaaaa
corrosion potentialaaaaaaaaaa
Login to View More

Abstract

The invention provides a sintered NdFeB magnet surface corrosion-resistant coating and a preparation method thereof. The method mainly comprises the following steps of Co-BDC nanosheet preparation, magnet surface pretreatment, composite coating preparation and high-temperature curing. According to the prepared composite coating, the Co-BDC nanosheets serve as reinforcing materials, the porosity between a magnet and a corrosive medium is reduced by changing the adding amount of the Co-BDC nanosheets, the compactness of the coating is improved, and therefore the corrosion resistance of the coating is effectively improved. Therefore, the corrosion-resistant coating does not influence the inherent performance of the magnet, is uniform and controllable in thickness, and can provide a longer corrosion protection effect for the sintered NdFeB magnet.

Description

technical field [0001] The invention relates to the field of surface protection of magnetic materials, in particular to a corrosion-resistant composite coating on the surface of a sintered NdFeB magnet and a preparation method thereof. Background technique [0002] Compared with other permanent magnet materials, sintered NdFeB magnet has outstanding magnetic properties. It has extremely high magnetic energy product, coercive force and energy density. It is called "Magnetic King", and its mechanical properties are good and easy to process. These excellent properties make sintered NdFeB permanent magnets widely used in modern industry and electronic technology. The more common ones are permanent magnet motors, speakers, magnetic separators, computer disk drives, and magnetic resonance imaging equipment. However, the surface of the sintered NdFeB magnet prepared by powder metallurgy process is loose and porous, and it has a multi-phase structure, and the potential difference be...

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
Patent Type & Authority Applications(China)
IPC IPC(8): C09D163/00C09D5/08C09D7/61C23C26/00H01F1/057H01F41/02
CPCC09D163/00C09D5/08C09D7/61C23C26/00H01F1/057H01F41/02C08K2201/011C08K5/098
Inventor 崔接武张金华吴玉程张鹏杰余东波曹玉杰徐光青孙威李炳山
Owner HEFEI UNIV OF TECH
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