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NdFeB Permanent Magnet Surface Treatment Technology

Nov. 12, 2019

At present, electroplating is often used to provide a protective layer on the surface of NdFeB. High-quality plating is a guarantee of high quality and long life of NdFeB permanent magnets. It can be seen that the new permanent magnet material NdFeB is closely related to the surface treatment industry. So what is the NdFeB permanent magnet surface treatment technology? Magnetic Chamfer Strip Supplier will come to tell you.


Cylinder Neodymium Magnet


Cylinder Neodymium Magnet


Permanent magnet material is a new type of magnetic material, also known as hard magnetic material. The neodymium-iron-boron permanent magnet material is the third-generation rare earth permanent magnet material. In addition, there is Precast Concrete Magnet. Its application can greatly reduce the volume and quality of the whole machine. For example, the application on magnetic disks can miniaturize disk drives. And better performance. Among audio devices, neodymium iron boron is widely used in miniature speakers, headphones and speakers of high-end cars, which greatly improves the fidelity of the sound and the signal-to-noise ratio. In addition, it can also be applied to DC motors and nuclear magnetic resonance imaging, especially on magnetic levitation trains. Not only the number is large, but also high-speed transportation, safety and reliability, and low noise.


In summary, neodymium-iron-boron is a high-tech new material, and the processing methods of neodymium-iron-boron permanent magnets include sintering and bonding, and the maximum output is sintering. The sintered neodymium-iron-boron is produced by powder metallurgy. The surface is loose and porous, and the grain boundary has a negative potential of the neodymium-rich phase, so the corrosion resistance is extremely poor. The corroded permanent magnet will greatly affect its magnetic properties and service life.


NdFeB magnets are extremely susceptible to oxidation and corrosion. Therefore, strict anticorrosive treatment must be performed before use. This should be the main purpose of NdFeB surface treatment. In addition, NdFeB surface treatment has the following purposes:


(1) Remove loose magnetic particles on the surface of the magnet through surface treatment, so as not to affect the magnetic function or damage the magnetic system, and achieve the purpose of smooth surface; 

(2) the surface protective coating can make the magnet (especially the edge) be assembled or work During the process, the magnetic particles are prevented from falling off.

NdFeB can be directly coated on the substrate using organic coating technology, that is, substrate-painting. However, the main problems of this solution are poor coating adhesion and low corrosion resistance, because the NdFeB matrix cannot provide the good surface conditions required to obtain a high-quality coating. Technologies such as neodymium iron boron phosphating-painting, neodymium iron boron phosphating-passivation-painting can be used. However, the coating-coating technology, such as dark nickel-cathode electrophoresis, zinc-cathode electrophoresis, bright nickel-cathode electrophoresis, etc., can provide a better surface state for organic coatings and have better corrosion resistance. Studies have shown that after NdFeB electroplating, zinc phosphating treatment is performed before painting, namely NdFeB electroplating-phosphating-painting. This composite coating scheme can obtain better paint film adhesion and corrosion resistance.


The above is the surface treatment technology of neodymium iron boron permanent magnet introduced by the supplier of Cylinder Neodymium Magnet. Hope to help everyone.

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