A strong magnet is referred to as a neodymium magnet. Compared with ferrite magnets, Al-Ni-Co magnets, and Sm-Co magnets, Nd-Fe-B magnets can absorb 640 times the weight of their own.
Neodymium magnet is recognized as a high performance and cost-effective magnet product in the field of magnetic materials at present. Many high-tech fields have designated it to make various kinds of spare parts, such as national defense, military, electronic technology, medical devices, electrical machinery, and other fields. The more the magnet is used, the easier the problem will be found. The demagnetization phenomenon of Nd-Fe-B magnet in a high-temperature environment has attracted much attention.
The strong magnet can be magnetized and demagnetized because the magnet itself is or will bring some magnetism, so we can formulate a certain method of demagnetization according to the different use of the strong magnet.
1. High-temperature demagnetization method
The main operation of the high-temperature demagnetization method is to put rare earth magnets into the high-temperature furnace for heating. After high-temperature treatment, the magnetism of strong magnets will be removed. However, in the process of heating, the structure of the object inside the magnet will change dramatically because of the effect of high temperature. Therefore, this demagnetization method is generally used for discarded and recycled magnets.
2. Vibration demagnetization method
The operation of this method is very simple, that is, strong and intense vibration of the strong magnet. After the operation of vibration, the internal structure of the magnet has changed, thus changing the physical properties of the magnet. Generally speaking, this method has little effect, only a small amount of demagnetization can be used temporarily.
3. AC demagnetization of magnets
This method of demagnetization is that the magnet is put into space which can produce the AC magnetic field. After the interference of the AC magnetic field, the internal structure of the magnet will be disturbed, so that the demagnetization effect can be achieved. This method is a common method of demagnetization.
The three methods mentioned above are effective for demagnetization of high-strength magnets, but in general, we still prefer AC demagnetization method to high-temperature demagnetization method and vibration demagnetization method, which is the most widely used method in industrial production.