Preparation method and product of a corrosion-resistant coating on the surface of a rare earth permanent magnet material

A rare-earth permanent magnet and corrosion-resistant technology, which is applied in the manufacture of permanent magnets, inductors/transformers/magnets, and coatings. It can solve the problems of chemical corrosion of the substrate, weakened protection of the substrate, and insufficient density of the nickel coating to reduce corrosion. , It is beneficial to the maintenance of the plating solution and the effect of protecting it from corrosion

Active Publication Date: 2022-01-11
ZHEJIANG UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In order to solve the current rare earth permanent magnet materials (such as sintered NdFeB magnets, all-metal SmFeN magnets and sintered SmCo magnets, etc.) , after the coating is corroded, the protective ability of the substrate is greatly weakened, and the present invention utilizes sodium glutamate and copper ions (Cu 2+ ) produces different forms of complexation products in different pH solutions, providing electrodeposition in alkaline solutions to generate copper pre-plating layers, and further depositing glutamic acid with self-corrosion repair characteristics in acidic solutions on this basis- Copper plating, so as to achieve the purpose of improving the corrosion resistance of rare earth permanent magnet materials

Method used

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  • Preparation method and product of a corrosion-resistant coating on the surface of a rare earth permanent magnet material
  • Preparation method and product of a corrosion-resistant coating on the surface of a rare earth permanent magnet material
  • Preparation method and product of a corrosion-resistant coating on the surface of a rare earth permanent magnet material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A method for preparing a corrosion-resistant coating on the surface of a rare earth permanent magnet material is carried out according to the following steps:

[0027] (1) The equipped cyanide-free alkaline copper plating solution, the other components of the plating solution are: 102g L -1 Sodium glutamate, 32g·L - 1 CuSO 4 ·5H 2 O, the rest is water, use KOH, H 2 SO 4 Adjust the pH of the solution to 8.

[0028] (2) The acid sodium glutamate-copper ion solution equipped, its plating solution is composed of sodium glutamate 102g L -1 , 32g·L -1 CuSO 4 The rest is water, with KOH, H 2 SO 4 Adjust the pH of the solution to 3.

[0029] (3) Sonicate the prepared acidic sodium glutamate-copper ion solution for 10 minutes, then put it into a magnetic stirrer and stir for about 4 hours at a speed of 800 rad / min.

[0030] (4) Use a sample of sintered NdFeB (size 10mm×10mm×h1mm) with a brand name of 35SH, and place the chamfered sample in a 12g·L -1 NaOH, 12g·L -1...

Embodiment 2

[0038] A method for improving the corrosion resistance of sintered NdFeB magnets is carried out according to the following steps:

[0039] (1) The cyanide-free alkaline copper plating solution equipped consists of: 102g L -1 Sodium glutamate, 32g·L -1 CuSO 4 ·5H 2 O, the rest is water, use KOH or H 2 SO 4 Adjust the pH of the solution to 8.

[0040] (2) The sodium glutamate-copper ion-nano-alumina solution equipped, its plating solution is composed of sodium glutamate 102g L -1 , 32g·L -1 CuSO 4 , nano-alumina, the rest is water, with KOH or H 2 SO 4 The pH of the solution was adjusted to 3, and three groups of experiments were set up, and the alumina contents were respectively 5g / L, 10g / L, and 15g / L.

[0041] (3) After adjusting the pH of the prepared acidic sodium glutamate-copper ion-nano-alumina solution, it was ultrasonicated for 10 minutes, then placed in a magnetic stirrer and stirred for about 2 hours at a speed of 1000 rad / min.

[0042] (4) Use a sample of ...

Embodiment 3

[0046] The surface of the sintered NdFeB magnet is pre-plated with copper in an alkaline cyanide-free copper plating solution, and then copper-plated in a glutamic acid copper plating solution. Except that nano-alumina is not added to the glutamic acid copper plating solution, all other steps and processes are consistent with Implementation 2.

[0047] The sintered NdFeB samples coated with two layers of coatings in Example 2 and Example 3 were washed and dried for surface morphology observation respectively (see image 3 ) and cross-sectional morphology observation (see Figure 4 ), observation of surface film morphology after corrosion (see Figure 5 ), contact angle test (see Figure 6) and electrochemical performance analysis (see Figure 7), and comparative analysis.

[0048] like image 3 As shown, with the increase of alumina content in the bath, the surface becomes smoother without obvious gaps.

[0049] Figure 4 The cross-sectional topography shows that alkaline c...

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Abstract

The invention discloses a method for preparing a corrosion-resistant coating on the surface of a rare earth permanent magnet material. The method comprises the steps of first putting the sample into an alkaline sodium glutamate-copper ion plating solution to obtain a pre-plating sample with a certain thickness, and then placing the pre-plating sample The plated sample is put into the electroplating solution of acidic sodium glutamate-copper ion, and the corrosion-resistant coating is obtained by electroplating under the action of magnetic stirring. The method can avoid the chemical corrosion of the substrate caused by the contact of the substrate with the acid solution through the alkaline copper plating solution of sodium glutamate earlier, and then carry out composite co-deposition in the acidic sodium glutamate-copper ion plating solution under magnetic stirring, containing The particles of glutamate group enter the coating to make the coating have the characteristics of self-corrosion and repairing.

Description

technical field [0001] The invention relates to the technical field of surface protection treatment of rare earth permanent magnet materials, in particular to electroplating a copper coating on the surface of a sintered NdFeB magnet in a sodium glutamate-copper ion alkaline plating solution, and then depositing glutamine in an acidic electroplating solution Acid-copper coating, forming a coating with self-corrosion characteristics, can improve the corrosion resistance of rare earth permanent magnet materials, especially sintered NdFeB. Background technique [0002] Rare earth permanent magnet materials, such as sintered NdFeB magnets, all-metal SmFeN magnets, and sintered SmCo magnets, have excellent comprehensive magnetic properties and are widely used in high-tech fields such as computer hard disks, electric vehicles, and nuclear magnetic resonance. However, due to the high activity of rare earth elements and the characteristics of the structure, rare earth permanent magne...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25D5/10C25D3/38C25D15/00C25D7/00H01F41/02
CPCC25D5/10C25D3/38C25D15/00C25D7/001H01F41/026
Inventor 郑精武张栓乔梁车声雷蔡伟李涓李旺昌应耀余靓刘友好衣晓飞陈静武黄秀莲
Owner ZHEJIANG UNIV OF TECH
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