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Method of raising binding force of chemical coating on the surface of NdFeB permanent magnet

A surface chemical and permanent magnet technology, applied in the direction of liquid chemical plating, coating, metal material coating process, etc., can solve problems such as shedding, many pores, poor bonding between the coating and the magnet, and achieve excellent corrosion resistance. The effect of improving the process quality and strengthening the degreasing effect

Active Publication Date: 2008-10-22
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the limitation of the preparation process of NdFeB materials, there will be many defects such as uneven surface quality, many pores, loose and rough, etc. During the process of material processing and substrate pretreatment, it is easy to appear on the surface such as oil stains, residual liquid and other debris As a result, the resulting electroless coating is not firmly combined with the substrate, and the coating is prone to peeling and falling off. Therefore, it can be said that the problem of poor bonding between the coating and the magnet affects the promotion and application of the electroless plating technology in the NdFeB magnet anti-corrosion technology. biggest obstacle

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] (1) The magnet is subjected to ultrasonic alkaline degreasing. The formula of the degreasing liquid is: sodium hydroxide 12g / L, trisodium phosphate 50g / L, sodium carbonate 15g / L, sodium silicate 10g / L, surfactant 1.5 g / L, OP-10 emulsifier 1g / L, use acetic acid to adjust the pH value of the degreasing solution to pH=10; the degreasing temperature is 50°C, the ultrasonic frequency is 40kHz, the power is 100W, and the degreasing time is 10min. After degreasing the magnet, shake it in deionized water at 50°C for 5 minutes.

[0020] (2) Magnet pickling activation, the formula of activation solution: hydrochloric acid 5g / L, nitric acid 10g / L, surfactant 1.5g / L, corrosion inhibitor 1g / L, treatment at room temperature, time is 10s; magnet pickling Rinse with deionized water for 60s after activation, and immediately place it in the plating solution for plating.

[0021] (3) Ultrasonic pre-plating, the plating solution formula is: nickel sulfate 0.08mol / L, sodium hypophosphite 0...

Embodiment 2

[0024] (1) The magnet is subjected to ultrasonic alkaline degreasing. The formula of the degreasing liquid is: sodium hydroxide 10g / L, trisodium phosphate 70g / L, sodium carbonate 20g / L, sodium silicate 8g / L, surfactant 2g / L, OP-10 emulsifier 1.5g / L, use acetic acid to adjust the pH value of the degreasing solution to pH=9; the degreasing temperature is 70°C, the ultrasonic frequency is 40kHz, the power is 250W, and the degreasing time is 3min. After degreasing the magnet, shake it in deionized water at 70°C for 5 minutes.

[0025] (2) Magnet pickling activation, the formula of activation solution: hydrochloric acid 1g / L, nitric acid 15g / L, surfactant 2g / L, corrosion inhibitor 1.5g / L, treatment at room temperature, time is 60s; magnet pickling Rinse with deionized water for 60s after activation, and immediately place it in the plating solution for plating.

[0026] (3) Ultrasonic pre-plating, the plating solution formula is: nickel sulfate 0.12mol / L, sodium hypophosphite 0.40...

Embodiment 3

[0029] (1) The magnet is subjected to ultrasonic alkaline degreasing, and the formula of the degreasing liquid is: sodium hydroxide 15g / L, trisodium phosphate 60g / L, sodium carbonate 30g / L, sodium silicate 5g / L, surfactant 1g / L, OP-10 emulsifier 2g / L, use acetic acid to adjust the pH value of the degreasing solution to pH=9.5; the degreasing temperature is 65°C, the ultrasonic frequency is 40kHz, the power is 200W, and the degreasing time is 5min. After degreasing the magnet, shake it in deionized water at 65°C for 5 minutes.

[0030] (2) Magnet pickling activation, the formula of activation solution: hydrochloric acid 2g / L, nitric acid 12g / L, surfactant 1g / L, corrosion inhibitor 2g / L, treatment at room temperature, time is 40s; magnet pickling activation Afterwards, rinse with deionized water for 60s, and immediately place it in the plating solution for plating.

[0031] (3) Ultrasonic pre-plating, the plating solution formula is: nickel sulfate 0.10mol / L, sodium hypophosph...

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Abstract

The present invention provides method of raising binding force of chemical coating on the surface of NdFeB permanent magnet. The NdFeB permanent magnet is pre-coated in alkaline plating solution under ultrasonic action, and by means of the activation, cavitation and stirring of ultrasonic wave, one homogeneous and compact initial deposited layer is formed on the surface of the magnet, so as to raise the binding force of chemical nickel-base coating on the surface of the magnet obviously and reduce pores in the coating. The present invention also provides the technological process including deoiling and pickling to activate before plating, the ultrasonic pre-plating and the conventional chemical plating. The formed coating has high corrosion resistance, raised binding to the substrate and perfect protection on the NdFeB permanent magnet.

Description

technical field [0001] The invention relates to the field of surface treatment of materials, in particular to a method for improving the binding force of an electroless coating on the surface of an NdFeB permanent magnet. Background technique [0002] As the third-generation rare earth permanent magnet material, NdFeB magnets are widely used in industrial automation, computers, home appliances, communications and many other fields due to their excellent magnetic properties, good machining characteristics and relatively low price. However, the chemical stability of NdFeB material is poor, and it is prone to oxidation in the use environment, and severe electrochemical corrosion will occur under hot and humid conditions, which deteriorates the magnetic properties and greatly affects its service life. Therefore, the success of the protection of NdFeB materials is the key to whether the material can be popularized and applied. [0003] In the existing technology, the surface tre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C18/16C23C18/18C23C18/36
Inventor 严密罗伟吴磊应华根吴进明贺雪峰齐娜乔
Owner ZHEJIANG UNIV
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