Friends with a little knowledge of magnets all know that NdFeB magnets are recognized as high-performance and cost-effective magnets in the field of magnetic materials. Many high-tech fields are designated to use them to make all kinds of spare parts, such as national defense and military, electronic technology, medical equipment, electrical machinery and other fields. The more it is used, the easier it is to find out the problem. Among them, the demagnetization phenomenon of NdFeB strong 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 general magnet can produce a magnetic field is that the electrons carried by the substance itself rotate around the atom in a certain direction, thus generating a certain magnetic force, and then having an impact on the surrounding affairs. However, there are certain temperature restrictions for electrons to rotate around the atom in the given direction. Different magnetic materials can bear different temperatures. In the case of too high temperature, electrons will deviate from the original orbit, causing chaos. At this time, the local magnetic field of the magnetic material will be disturbed, resulting in demagnetization.
And the temperature resistance of NdFeB magnet is about 2 Baidu, that is to say, if it exceeds 2 Baidu, demagnetization will occur. If the temperature is higher, demagnetization will be more serious.
Is magnet degaussing permanent or temporary at high temperature?
The Curie temperature of NdFeB is 320 ℃ - 380 ℃, but in fact, the molecular structure of NdFeB has been changed when it is heated. If the Curie temperature can not reach the theoretical value, the magnetic force will fade. The temperature resistance of NdFeB in my experiment is 100 degrees. When it is heated to about 100 degrees, the magnetic force begins to decrease, but the speed cannot be opened. After 150 degrees, the magnetic force drops obviously and rapidly. After keeping 150 degrees for 20 minutes, the magnetic force basically goes out. After demagnetizing, the demagnetized NdFeB can only reach about 50% of the original. And the surface appears black oxidation phenomenon.
The most effective solutions for demagnetization of NdFeB magnet at high temperature
I. do not put the NdFeB magnet product in the too high temperature, especially pay attention to its critical temperature, i.e. Er Baidu. Adjust its working environment temperature timely to minimize demagnetization.
Second, starting from technology, improve the performance of products using NdFeB magnets, so that they can have a more temperature structure and are not easily affected by the environment.
3. You can also choose the high coercive force material with the same magnetic energy product. If not, you have to sacrifice a little magnetic energy product to find the higher coercive force material with a little lower magnetic energy product. If not, you can choose to use SmCo. As for reversible demagnetization, you have to choose SmCo.
PS: each kind of material has different characteristics, so choosing the right one is economic. When designing, you should consider it carefully, otherwise you will lose!