Four main factors affecting demagnetization (demagnetization) of NdFeB magnets
Strong magnet generally refers to neodymium iron boron magnet, mainly composed of rare earth PR nd and common element iron alloy. At present, this material is widely used in the market, but strong magnet often meets the situation of magnetic weakening or disappearing in the process of use. We summarize the reasons for magnet demagnetization as follows:
1: Demagnetization or demagnetization of magnets after injection. The minimum temperature resistance of NdFeB n series is 80 ℃, while sometimes the injection temperature is above 120 ℃. Therefore, injection in a short time of 2 seconds to 3 seconds may cause partial demagnetization.
2: After the magnet is hot pressed, the magnetic field is demagnetized, and the glass fiber plate is often used for hot pressing, and the temperature is above 150 ℃.
3: The magnet demagnetizes after oven baking.
4: Too much impurity in the magnet material leads to weak magnetism. This is the common result of most small and cheap buyers. Because the price of goods than three, choose the manufacturers with low price. Clearly, the customer’s requirements are N35 brand. As a result, the defective manufacturers with ultra low quotation use n28 and N33 materials. The customer should not expect to detect it. If the quantity reaches 30K, can we use flux meter to measure it slowly? (demagnetization occurs in 6 months in short, and demagnetization occurs in two months soon). It is really important for a reliable and stable supplier. How could you make it with N35 without that price? And some merchants magnets are used for packaging, anyway, it can be absorbed, and material waste is garbage.
5: The impact causes the magnetic demagnetization, such as high frequency impact, etc. special care should be taken during transportation.
6: The material contains metal which causes the powder of magnet.
7: The magnetic force of the magnet itself disappears or the n/s pole changes (demagnetizer of charger) in high magnetic field environment.
The above reasons are 90% of the reasons for demagnetization (demagnetization) are summarized. There are 4 points: high temperature demagnetization, demagnetization of materials themselves, high frequency impact demagnetization and high magnetic field demagnetization.
Post time: Apr-02-2021