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Preparation method of high-binding-force and high-corrosion-resistance coating on surface of neodymium-iron-boron magnet

A NdFeB, bonding force technology, applied in jewelry and other directions, can solve the problems of poor bonding strength, poor bonding strength, environmental pollution, etc.

Active Publication Date: 2021-04-30
EARTH PANDA ADVANCE MAGNETIC MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the porosity of the Zn coating is relatively high, and the anti-corrosion performance is poor. In order to improve the corrosion resistance of the electroplated Zn coating, the Zn coating is usually subjected to passivation treatment to form a dense passivation film on the surface of the Zn coating. The use of chemical fluid will produce "three wastes", leading to environmental pollution problems
Moreover, the bonding strength between the Zn coating and the substrate is poor
[0004] Therefore, the higher porosity and poor bonding strength of the electroplated Zn coating on the surface of sintered NdFeB magnets need to be further improved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) A commercial sintered NdFeB magnet (state: unmagnetized, brand: 48SH) was selected for the test, and a sheet sample with a specification of 15×12×4mm (thickness 4mm is the direction of the c-axis). For pretreatment of the flake samples, NaOH solution with a concentration of 4wt% was used as the degreasing liquid, the temperature of the degreasing liquid was 55°C, and the degreasing time was 10 minutes; 3wt% HNO was used 3 The solution is pickled, and the pickling time is 30s.

[0023] (2) Electroplating a Zn coating on the surface of the pretreated magnet by electroplating. Wherein the prescription of Zn plating solution is: sodium hydroxide 90g / L, zinc oxide 8g / L, triethanolamine 15mL / L, brightener 0.1wt%; Wherein the prescription of brightener is: salicylaldehyde 30wt%, formaldehyde 20wt%, 8 wt% of benzylidene acetone, 6 wt% of 2.4-dichlorobenzaldehyde, and the balance is deionized water. The electroplating process parameters are as follows: the temperature of t...

Embodiment 2

[0030] (1) A commercial sintered NdFeB magnet (state: unmagnetized, brand: 48SH) was selected for the test, and a sheet sample with a specification of 15×12×4mm (thickness 4mm is the direction of the c-axis). For pretreatment of the flake samples, NaOH solution with a concentration of 5wt.% was used as the degreasing liquid, the temperature of the degreasing liquid was 60°C, and the degreasing time was 13 minutes; 4wt.% HNO was used 3 The solution is pickled, and the pickling time is 45s.

[0031] (2) Electroplating a Zn coating on the surface of the pretreated magnet by electroplating. The formulation of the electroplating Zn plating solution is: sodium hydroxide 110g / L, zinc oxide 10g / L, triethanolamine 25mL / L, brightener 0.2wt.%, wherein the brightener is salicylaldehyde 35wt%, formaldehyde 22.5wt%, benzylidene 10 wt% of acetone, 8 wt% of 2.4-dichlorobenzaldehyde, and the balance is deionized water. The parameters of the electroplating process are as follows: the temperat...

Embodiment 3

[0038] (1) A commercial sintered NdFeB magnet (state: unmagnetized, brand: 48SH) was selected for the test, and a sheet sample with a specification of 15×12×4mm (thickness 4mm is the direction of the c-axis). For pretreatment of the flake samples, NaOH solution with a concentration of 6wt.% was used as the degreasing liquid, the temperature of the degreasing liquid was 65°C, and the degreasing time was 16 minutes; 5 wt.% HNO 3 The solution is pickled, and the pickling time is 60s.

[0039] (2) Electroplating a Zn coating on the surface of the pretreated magnet by electroplating. The formula of electroplating Zn plating solution is: sodium hydroxide 130g / L, zinc oxide 12g / L, triethanolamine 35mL / L, brightener 0.3wt.%. Wherein the brightener is salicylaldehyde 40wt%, formaldehyde 25wt%, benzylidene acetone 12wt%, 2.4-dichlorobenzaldehyde 10wt%, and the balance is deionized water. The electroplating process parameters are as follows: the temperature of the electroplating soluti...

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Abstract

The invention discloses a preparation method of a high-binding-force and high-corrosion-resistance coating on the surface of a neodymium-iron-boron magnet. The preparation method comprises the following steps of electroplating a Zn plating layer, wherein the Zn plating layer is electroplated on the surface of a pretreated magnet through an electroplating method; conducting laser remelting treatment, wherein the Zn plating layer on the surface of the magnet is treated by adopting a laser remelting technology, so that the porosity of the Zn plating layer is 3-4%; and conducting heat treatment, wherein heat treatment is conducted on the Zn plating layer obtained after laser remelting treatment. According to the preparation method of the high-binding-force and high-corrosion-resistance coating on the surface of the neodymium-iron-boron magnet, the porosity of the Zn plating layer can be remarkably lowered, metallurgical bonding is formed between the Zn plating layer and the matrix, harmful impurities such as part of residual hydrogen ions in the magnet pretreatment process are effectively solved, and the problem of environmental pollution caused by passivating treatment after electroplating a Zn plating layer in the prior art is solved; and finally, the high-binding-force and high-corrosion-resistance Zn plating layer is prepared on the surface of the magnet.

Description

technical field [0001] The invention belongs to the field of magnetic material protection, and in particular relates to a preparation method of a coating with high binding force and high corrosion resistance on the surface of an NdFeB magnet. Background technique [0002] Sintered NdFeB magnets have excellent magnetic properties and high cost performance, and are widely used in many fields such as new energy vehicles, wind power generation, medical equipment, household appliances, and aerospace. Sintered NdFeB magnets belong to a multi-phase structure, and the potential difference between the phases is relatively large, especially the chemical activity of the grain boundary phase is the highest, and it is easy to corrode in a corrosive environment, resulting in the failure of the magnet due to corrosion. [0003] At present, the following two methods are mainly used to improve the corrosion resistance of magnets. One is the alloying method, adding trace amounts of Al, Cu, Zn...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/50C25D7/00C25D3/22C25D5/36
CPCC25D5/505C25D5/50C25D7/001C25D3/22C25D5/36
Inventor 曹玉杰吴玉程刘友好查善顺李磊黄秀莲刘家琴陈静武衣晓飞
Owner EARTH PANDA ADVANCE MAGNETIC MATERIAL