Zinc-based composite coating for improving corrosion resistance of neodymium-iron-boron magnet

A composite coating, corrosion-resistant technology, applied in coatings, devices for coating liquids on surfaces, anti-corrosion coatings, etc. Excellent weather resistance and chemical stability, small impact, improved corrosion resistance

Inactive Publication Date: 2012-09-05
BAOTOU RES INST OF RARE EARTHS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to improve the corrosion resistance of the surface of NdFeB magnets, to solve the problem that the electroplating of NdFeB magnets with Zn, Ni, Ni-Cu-Ni, Ni-P and epoxy plating is too thick to affect the performance of the magnets. The corner effect is obvious (especially for large-size magnets), the bonding force of the coating is not enough, the corrosion

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0025] Example 1:

[0026] This embodiment is a sintered neodymium iron boron magnet for a motor, the size is 56*25*4mm. The specific coating steps are as follows:

[0027] 1) Pre-coating chamfering: manual chamfering to R=0.3mm; soaking in a special alkaline degreasing agent at 40~50℃, degreasing for about 10 minutes, drying; shot blasting and rust removal in a shot blasting machine, Ultrasonic cleaning.

[0028] 2) The zinc-based composite mother liquor (mainly composed of CrO 3 , Polypropanol, Polyethylene Glycol, Acrylic) and base material (mainly composed of flake aluminum powder and zinc powder) are thoroughly mixed at 20°C and continuously stirred to prevent base material from settling; spray the treated magnet with a spray gun , The spray gun pressure is 0.4MPa, the angle is 60°; the spray filter system is activated to ensure that the solution is trapped in the pool of the rotating chamber, and the leveling time is controlled for about 1 hour.

[0029] 3) After leveling, put...

Example Embodiment

[0034] Example 2:

[0035] The size of the sintered NdFeB magnet in this implementation is 4*4*2mm. The specific coating steps are as follows:

[0036] 1) The magnet is rolled and chamfered in a chamfering machine equipped with abrasives to R=0.1mm; soaked in an alkaline degreasing liquid at 40~50℃ for about 15 minutes, and dried; carried out in a shot blasting machine Shot blasting rust removal, ultrasonic cleaning.

[0037] 2) Mix the chromium-free zinc-based composite coating solution at 20℃ and stir continuously to prevent the base material from settling; put the treated magnet into the zinc-aluminum composite tank solution for dipping for three minutes, and then spin dry, generally 200 rpm, remove the excess droplets.

[0038] 3) Put the magnet into a curing oven and bake and solidify, and heat up with the oven, and keep it at about 60°C for about 10 minutes. After that, the furnace will be heated to 300°C for 40 minutes. After power failure, the furnace door will be opened an...

Example Embodiment

[0043] Example 3:

[0044] The size of the sintered NdFeB magnet in this implementation is 60*50*26mm. The specific coating steps are as follows:

[0045] 1) Roll the magnet in a chamfering machine equipped with abrasives and chamfer it to R=0.5mm; soak it in an alkaline degreasing liquid at 40~50℃ to degrease for about 20 minutes, then dry it; proceed in a shot blasting machine Shot blasting to remove rust, ultrasonic cleaning after cooling.

[0046] 2) The zinc-based composite mother liquor (mainly composed of CrO 3 , Polypropanol, Polyethylene Glycol, Acrylic) and base material (mainly composed of flake aluminum powder and zinc powder) are thoroughly mixed at 20°C and continuously stirred to prevent base material from settling; spray the treated magnet with a spray gun , The spray gun pressure is 0.4MPa, the angle is 60°; the spray filter system is activated to ensure that the solution is trapped in the pool of the rotating chamber, and the leveling time is controlled for about ...

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Abstract

The invention relates to a zinc-based composite coating for improving corrosion resistance of a neodymium-iron-boron magnet. The zinc-based composite coating is characterized by comprising a zinc-based coating and a reinforced protective coating, wherein the zinc-based coating consists of the following components by mass percent: 65%-95% of flake zinc powder, 1%-30% of flake aluminum powder and 0%-5% of amorphous composite chromic salt compound, the molecular formula of the amorphous composite chromic salt compound is nCrO3.mCr2O3, and n and m are natural numbers; and the reinforced protective coating is one of a wear-resisting organic silicone resin coating, a polytetrafluoroethylene coating and an epoxy resin coating. The zinc-based composite coating provided by the invention has the advantages that the coating is uniform and compact in structure and good in substrate bonding property, is not easy to peel or fall off, is less in magnetic property influence, uniform in thickness, low in porosity and extremely strong in corrosion resistance, is extremely compact and has no corner effect and no hydrogen embrittlement; and the process is environment-friendly.

Description

Technical field: [0001] The invention relates to the field of surface anticorrosion of NdFeB magnets, in particular to a zinc-based composite coating for improving the anticorrosion performance of NdFeB magnets, which functions to improve the surface corrosion resistance of NdFeB magnets. technical background: [0002] NdFeB magnets are a new generation of permanent magnet materials with the highest magnetic performance, the most widely used and the fastest development that have been produced industrially. One of the most important functional materials in the technical field. At present, my country has developed into the world's largest producer of NdFeB magnets. In 2008, the output of sintered NdFeB magnets in my country has accounted for about 80% of the total output of sintered NdFeB magnets in the world, with a total output value of 14-20 billion yuan, driving the output value of related applications to more than 100 billion yuan. [0003] NdFeB magnets generally work ...

Claims

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Application Information

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IPC IPC(8): C09D5/38C09D5/10B05D7/14H01F41/02
Inventor 陈蓓新邢正茂
Owner BAOTOU RES INST OF RARE EARTHS
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