NdFeB magnets are never demagnetized under normal circumstances, so they are called permanent magnets. After 100 years of production and molding, it may only demagnetize 2 percent -3 percent , which is equivalent to permanent magnetization for 3C products, where NdFeB magnets are widely used in motors and speakers. Namun, NdFeB magnets can not be permanent magnetized under extreme condition, below we summarize the situation that NdFeB magnets will demagnetize and demagnetize.
1. Tinggi suhu demagnetisasi.
The working magnetic force of NdFeB magnet is 60-200 degree Celsius, according to the working temperature, it can be divided into N,M,H,SH,UH and other grades, after the corresponding working temperature, the NdFeB magnet will be demagnetized. When the magnet is in the environment less than the working temperature but close to the maximum working temperature, the magnetic force of NdFeB magnet may also decrease about 2 percent -5 percent , but the magnetic force can be recovered accordingly after the environment cools down. If the working temperature is exceeded, the magnetic force will be irreversibly faded. That is, even after the environment cools down, the magnetic force still cannot be recovered. As the temperature rises, the magnetic force fading speed will be further accelerated. In other words, once the environment exceeds the maximum working temperature, the NdFeB magnet will be demagnetized immediately, but it will be demagnetized at a certain speed. When the NdFeB magnet is completely demagnetized (no magnetism) at a certain temperature for a sufficient time, we call it the Curie temperature of NdFeB magnet, which is around 320-380 degrees Celsius.
2.Demagnetisasi oleh dampak
We will emphasize with our customers when we are docking them that we should take the NdFeB magnets lightly, put them together and assemble them together and so on to take a mat and handle them carefully. The reason is not only that NdFeB magnets are brittle and fragile, the high magnetic force is easy to hurt people, but also NdFeB magnets will demagnetize when they are hit serius. Even if the NdFeB magnet is not broken, but due to the serious impact to bring the magnet internal molecular arrangement error, its magnetic force will be reduced in different degrees.
The above two points are the common demagnetization causes of NdFeB magnets, and the essence is that these factors lead to the disorder of the magnetic molecule structure inside the NdFeB magnets, which leads to the weaking of the magnetic force in the macroscope.