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Tuesday 17 January, 2023 | RSS Feed

Factors of Demagnetization of Strong Magnet

by AOMag | post a comment

All magnets have the possibility of demagnetization, even powerful magnets can't avoid demagnetization or degaussing. Only by better understanding the reason of demagnetization can we better use and preserve magnets.

Most magnetic materials can be magnetized to saturation in the same direction, which is called "magnetization direction" (orientation direction).Magnets without orientation (also called isotropic magnets) are much weaker than oriented magnets (also called anisotropic magnets).The temperature resistance of strong magnets is below 80 degrees. Just put the strong magnet on the fire for a few minutes, and then put it next to the iron block after cooling. It is found that it has lost its magnetism and can no longer be sucked.
The reason is that the strong magnet is magnetic because the iron atoms in the strong magnet are arranged regularly. After it is heated, the original arrangement of iron atoms is out of order, thus losing its original magnetism.

Strong magnet generally refers to neodymium magnet, which is mainly composed of rare earth Pr, Nd and common element iron. At present, this material is widely used in the market, but it often happens that the China magnets often encounters the weakening or disappearance of magnetic force during use. We summarize the reasons for degaussing the magnet as follows:

1.Magnets are demagnetized or demagnetized after injection molding. The minimum temperature resistance of NdFeB N series is 80℃, and sometimes injection molding is basically above 120℃. Therefore, short-term injection of 2 seconds to 3 seconds may cause some demagnetization imagination.
2. Magnets are demagnetized after hot pressing. Glass fiber plates are often used for hot pressing, and the temperature is above 150℃.
3. Magnets are demagnetized after baking in the oven.
4. The magnetic material contains too many impurities, which leads to weak magnetism.
5.Impact leads to the resultant demagnetization of magnets, such as high-frequency impact, so be especially careful during transportation.
6.The material contains metal, which leads to the pulverization of magnets.
7.The high magnetic field environment makes the magnet force disappear or the N/S pole change.

To sum up, the above demagnetization (demagnetization) reasons are basically these four points: high temperature demagnetization, material itself problem demagnetization, high frequency impact demagnetization and high magnetic field demagnetization.Therefore, we should pay attention to the temperature of the environment in the process of using the magnet, not higher than the temperature that the magnet itself can withstand, and do not collide with the magnet during use.

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