China permanent magnet manufacturer:

Can iron boron magnets demagnetize?

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NdFeB magnet is a permanent magnet, that is to say, it still keeps its own magnetic characteristics when the external magnetic field is withdrawn.
There are two main factors that affect its magnetism.

First: environment

NdFeB magnets contain rare earth metal neodymium, which is easily oxidized.
Therefore, it is necessary to electroplate the magnet and make the coating according to the environment.
The best coating is Ni Cu Ni, which is three layers: Ni Cu Ni. The coating is 5-5-5 μM.
The coating can be thickened and the salt spray test can be carried out in particularly harsh environment. 24-48-72 hours salt spray test can be done respectively.

Second: working temperature

The corresponding brand has corresponding working temperature.
For example, NM grade NdFeB, whose working temperature is within 100 ℃, will begin to demagnetize when it exceeds the working temperature. When its working temperature reaches 340 ℃, it will completely lose its magnetism.
When the corresponding material is used, it will not demagnetize when it does not reach the upper limit of working temperature.
NdFeB magnets may demagnetize under the following conditions:

  • 1. The maximum working temperature of NdFeB magnets of different grades is different, 80-220 ° C, and demagnetization will occur when the temperature exceeds.
  • 2. Neodymium iron boron belongs to rare earth permanent magnet, in which the rare earth metal neodymium is relatively active and easy to be oxidized. Therefore, the surface of neodymium iron boron magnet generally needs to be electroplated for anti-corrosion treatment. Due to the different environment and the passage of time, once the electroplated coating is damaged, the neodymium iron boron magnet is easy to be oxidized and demagnetized.
  • 3. Demagnetization may also occur when the magnet is impacted.
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