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Method for electrodepositing Al protective plated layer on surface of NdFeB magnet by using ionic liquid

An ionic liquid and electrodeposition technology, applied in the field of material surface coating protection, can solve problems such as complex process, inability to deposit aluminum coating, poor coating adhesion, etc., and achieve simple process and operation, easy promotion and implementation, and environmentally friendly Effect

Active Publication Date: 2012-11-07
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Electroplating and electroless plating have the advantages of low cost and uniform coating, but this process is generally carried out in aqueous solution. NdFeB is a material that is very sensitive to aqueous solution. When electroplating in aqueous solution, the plating solution easily penetrates into the NdFeB matrix and electroplating Hydrogen will be evolved during the process, resulting in poor adhesion of the coating and a decrease in corrosion resistance
[0004] Al protective coating is a coating with excellent corrosion resistance. Al protective coating is generally obtained by hot-dip plating and physical vapor deposition (PVD), but these two methods have the disadvantages of complex process and high cost.
Since aluminum is a relatively active metal, its potential is as low as -1.67V, so general aqueous solution electroplating cannot deposit aluminum coatings.

Method used

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  • Method for electrodepositing Al protective plated layer on surface of NdFeB magnet by using ionic liquid
  • Method for electrodepositing Al protective plated layer on surface of NdFeB magnet by using ionic liquid
  • Method for electrodepositing Al protective plated layer on surface of NdFeB magnet by using ionic liquid

Examples

Experimental program
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Effect test

Embodiment 1

[0031] (1) Preparation of ionic liquid

[0032] Weigh BMIC (1-butyl-3-methylimidazole chloride) and aluminum chloride anhydrous according to the molar ratio of 1:2, add aluminum chloride anhydrous slowly in BMIC several times, and constantly Stir continuously, and the rate of adding aluminum chloride should be as slow as possible, otherwise the ionic liquid will be overheated and decomposed due to the exothermic reaction, and white smoke will be emitted. After the aluminum chloride is added, the mixed ionic liquid is magnetically stirred for about 24 hours to ensure that the aluminum chloride is completely dissolved, and finally a pale yellow transparent ionic liquid is obtained. A piece of aluminum wire is put into the prepared ionic liquid, which is used to refine the ionic liquid to replace the trace impurity heavy metal ions in it, and it can be used for electrodeposition after about 24 hours of treatment. The configuration of the ionic liquid and the subsequent electrode...

Embodiment 2

[0039] The steps in this embodiment are basically the same as in Example 1, except that in step (3), before electrodeposition, 20% toluene additive of ionic liquid volume is added in the plating solution, and the plating solution is stirred for a period of time to ensure that The two are mixed evenly.

[0040] Compared with Example 1 of the coating obtained, the microscopic appearance of the coating becomes more compact, and the crystal grains of the coating become smaller, as attached figure 2 shown. The corrosion resistance of the coating is also improved compared to Example 1, and the salt spray test time has reached 240 hours.

Embodiment 3

[0042] The steps in this example are basically the same as in Example 1, except that in step (1), 1-ethyl-3-methylimidazole chloride (EMIC) is used instead of BMIC in Example 1. Compared with the ionic liquid in Example 1, the conductivity of this ionic liquid is reduced, and the voltage under the same current is increased during electrodeposition. The appearance and corrosion resistance of the Al protective coating obtained by electrodeposition are reduced relative to Example 1, and the salt spray test time is 120 hours

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Abstract

The invention discloses a method for electrodepositing an Al protective plated layer on the surface of an NdFeB magnet by using ionic liquid. According to the method, disubstituted imidazolium chloride-aluminium chloride type ionic liquid is used as a plating solution, and a certain quantity of aromatic organic additive is added into the plating solution. By using the method, a silvery white bright and compact aluminum plated layer can be obtained on an NdFeB matrix, and an electromechanical experiment and a salt mist test show that the Al protective plated layer obviously improves the corrosion resistance of the NdFeB matrix. Moreover, the ionic liquid is incombustible and unvaporized, so that the ionic liquid can be repeatedly used, cannot generate electroplating wastewater, and is environment-friendly.

Description

technical field [0001] The invention belongs to the field of material surface coating protection, and in particular relates to a method for electrodepositing an Al protective coating on the surface of a NdFeB permanent magnet material by utilizing an ionic liquid. Background technique [0002] Since the invention of the NdFeB permanent magnet in the 1980s, it has been widely used in the energy, automobile, home appliance and computer industries due to its good magnetic properties and abundant resource reserves. Because the surface of NdFeB permanent magnet is loose and microporous, and its grain boundary is enriched with very active rare earth element neodymium, the corrosion resistance of NdFeB is very poor, and it must be protected by a certain coating before use. [0003] At present, the commonly used protection methods for the surface of NdFeB permanent magnets are electroplating or electroless metal coatings. Commonly used metal coatings include Ni, Zn, Cu, Ni-Cu and Ni...

Claims

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Application Information

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IPC IPC(8): C25D3/44
Inventor 宋振纶汪少杰郑必长冒守栋杨丽景
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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