DdFeB magnet surface composite metal protection layer and preparing method thereof

A metal protective layer and surface composite technology, applied in the field of metal surface treatment, can solve the problems of low corrosion resistance, low hardness of the protective layer, high brittleness of the protective layer, etc., and achieve the effect of preventing cracking

Active Publication Date: 2018-03-30
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The object of the present invention is to provide a kind of NdFeB magnet surface composite metal protective layer and preparation method thereof, solve the problem that the hardness of the protective layer is low and the corrosion resistance is not high when plating Al alone, and the protective layer when plating amorphous Al-Mn alloy alone brittle problem

Method used

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  • DdFeB magnet surface composite metal protection layer and preparing method thereof
  • DdFeB magnet surface composite metal protection layer and preparing method thereof
  • DdFeB magnet surface composite metal protection layer and preparing method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Step 1) Pre-processing

[0041] Soak NdFeB in degreasing agent to remove oil, then soak in 3% dilute nitric acid to remove rust, then wash with water, alcohol and then dry. Thereafter, the NdFeB was placed in an argon-protected glove box, and the AlCl with a molar ratio of 2.0 3 -Anode activation in EMIC ionic liquid, the anode is NdFeB, the cathode is Al, and the current density is 20mA / cm 2 , the time is 10min.

[0042] Step 2) Ionic Liquid Aluminum Plating

[0043] AlCl at a molar ratio of 2.0 3 - Galvanostatic Al plating in EMIC ionic liquids. The pretreated NdFeB is used as the cathode, the pure Al is used as the anode, the bath temperature is 25°C, and the current density is 10mA / cm 2 , the plating time is 50min, and the coating thickness is 10μm.

[0044] Step 3) Ionic Liquid Plating Amorphous Al-Mn Alloy

[0045] in AlCl 3 / EMIC molar ratio is 2.0, MnCl 2 Concentration of 0.20M MnCl 2 -AlCl 3 -EMIC ionic liquids for galvanostatic plating of amorphous ...

Embodiment 2

[0050] Step 1) is the same as in Example 1.

[0051] In step 2), the plating time is 25min, and the others are the same as in Example 1.

[0052] Step 3) in, plating time is 60min, other is the same as embodiment 1.

[0053] Step 4) is the same as in Example 1.

[0054] Result: if image 3 As shown, the Al coating is 5 μm, the Al-Mn alloy coating is 5 μm, and the Mn content in the alloy layer is 15.0 at.%, which is in the range of amorphous composition (as shown in Table 1). The bonding strength of the coating is greater than 20MPa, the sample has no rust after 1000h neutral salt spray test, and the thermal attenuation of magnetic properties is less than 1%.

Embodiment 3

[0056] Step 1) is the same as in Example 1.

[0057] In step 2), the bath temperature is 50°C, and the current density is 50mA / cm 2 , the plating time is 2min, and others are the same as in Example 1.

[0058] In step 3), MnCl 2 The concentration is 0.15M, the bath temperature is 50°C, and the current density is 9mA / cm 2 , the plating time is 24min, other with embodiment 1.

[0059] Step 4) is the same as in Example 1.

[0060] Result: if Figure 4 As shown, the Al coating is 2 μm, the Al-Mn alloy coating is 3 μm, and the Mn content in the alloy layer is 14.1 at.%, which is in the range of amorphous composition (as shown in Table 1). The bonding strength of the coating is greater than 20MPa, the sample has no rust after 500h neutral salt spray test, and the thermal attenuation of magnetic properties is less than 1%.

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Abstract

The invention discloses a DdFeB magnet surface composite metal protection layer and a preparing method thereof. By means of the method, after pretreatment, ionic liquid aluminum plating, ionic liquidamorphous Al-Mn alloy plating and aftertreatment are conducted in sequence, then the composite metal protection layer with the total thickness ranging from 5 microns to 20 microns is obtained, whereinthe outer layer of the composite metal protection layer is an amorphous Al-Mn alloy plating layer, and the inner layer of the composite metal protection layer is an Al plating layer. The flexible Alplating layer serves as the transition layer of bristle NdFeB and the amorphous Al-Mn alloy plating layer, cracking of the Al-Mn alloy plating layer can be prevented, and colliding damage of NdFeB corners can be prevented. The amorphous Al-Mn alloy plating layer serves as the outer layer so that the scratching and abrasion resisting performance of the plating layer can be improved. The corrosion potential of the amorphous Al-Mn alloy plating layer is lower than that of the Al plating layer and a NdFeB base body, and therefore sacrificial anode type protection can be formed on NdFeB through theabove protection plating layer, and therefore good corrosion resisting performance is achieved.

Description

technical field [0001] The invention relates to a metal surface treatment method, in particular to a composite metal protective layer on the surface of a NdFeB magnet and a preparation method thereof. Background technique [0002] Neodymium-iron-boron (NdFeB) permanent magnet material has excellent magnetic properties and is widely used in audio-visual, instrumentation, communication, motor, national defense and military industries and other fields. Since NdFeB contains active rare earth Nd and is composed of multi-phase structure, the potential of each phase is different, so it is very easy to corrode in the use environment. Preparing a protective layer on the surface of NdFeB is the most effective anti-corrosion method. [0003] At present, the most commonly used method in the NdFeB industry is electroplating, and its coating materials include Zn, Ni, Cu, and Ni-Cu-Ni. There is also the technology of electroless plating to prepare Ni-P coating. Among them, Zn is an anod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D3/56C25D3/54C25D7/00
CPCC25D3/54C25D3/56C25D7/001
Inventor 凌国平方旭峰
Owner ZHEJIANG UNIV
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