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Several Effective Solutions for Demagnetization of Nd-Fe-B Magnets at High Temperature

Friends with a little knowledge of magnets know that Nd-Fe-B magnets are recognized as high performance and cost-effective magnets in the field of magnetic materials. Many high-tech fields have designated them to make various kinds of spare parts, such as national defense, military, electronic technology, medical devices, electrical machinery and electrical appliances. The more the magnet is used, the easier the problem will be found. The demagnetization phenomenon of Nd-Fe-B magnet in high temperature environment has attracted much attention.
 
Why does NdFeB demagnetize at high temperature?
The demagnetization of NdFeB in high temperature environment is determined by its physical structure. The reason why a magnet can generate a magnetic field is that the electrons carried by the material itself rotate around the atom in a certain direction, thus producing a certain magnetic field force, and then affecting the related affairs around it. However, the rotation of electrons around atoms in a given direction is also limited by certain temperature conditions. Different magnetic materials can withstand different temperatures. In the case of excessive high temperature, electrons will deviate from the original orbit, resulting in confusion. At this time, the magnetic field of the magnetic material will be disturbed, thus the phenomenon of demagnetization will occur.
 
And ndfeb magnet temperature tolerance is about two baidu, that is, more than two baidu will appear demagnetization, if the temperature is higher, demagnetization phenomenon is more serious.
 
Is permanent or temporary magnet degaussing at high temperature?
The Curie temperature of Nd-Fe-B is 320-380 C, but in fact the molecular structure of Nd-Fe-B has changed when heated, and the magnetic force will fade if the theoretical Curie temperature is not reached. The temperature resistance of Nd-Fe-B in my experiment is 100 degrees. When heated to about 100 degrees, the magnetic force begins to decrease, but the speed is not high. After 150 degrees, the magnetic force decreases rapidly, and keeps 150 degrees for 20 minutes, the magnetic force basically fades. The NdFeB with retrograde magnetism can only reach about 50% of the original after demagnetization. Moreover, the surface appears black and oxidized.
 
Ndfeb magnet high temperature demagnetization of the most effective several solutions
First, do not put Nd-Fe-B magnet products in excessive temperature, especially pay attention to its critical temperature, that is, Baidu, timely adjust its working environment temperature, can minimize the occurrence of demagnetization phenomenon.
 
Secondly, from the technical point of view, we should improve the performance of Nd-Fe-B magnets so that they can have a more temperature structure and are not susceptible to environmental impact.
 
Three. You can also choose high coercivity materials with the same magnetic energy product. If not, you can sacrifice a little magnetic energy product and find a higher coercivity material with a lower magnetic energy product. If not, you can choose to use samarium cobalt. As for reversible demagnetization, you can only choose samarium cobalt.

PS: Each material has its own characteristics, so choosing the right one is economical. When designing, we should consider it thoroughly, otherwise it will bring losses.

This article belongs to the magnet industry news column. Link to the column: http://www.couragemagnet.com/news/hyxw/

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