Main factors of the demagnetization (degaussing) for NdFeB magnets
Strong magnets generally refer to neodymium-iron-boron magnets, which are mainly composed of rare earth niobium and alloys of common elemental iron.
Currently, neodymium magnets are widely used in the market, but strong magnets often encounter magnetic weakening or even disappearance during using. It is often the case that we summarize the following reasons for magnet demagnetization:
1: Magnetic injection mold retreat magnetic or degaussing, neodymium iron boron N series of the max temperature is 80°C, and sometimes the basic injection is above 120°C, so a short 2 seconds to 3 seconds of injection molding, may cause partial demagnetization phenomenon.
2: The magnet is demagnetized after hot pressing, and glass fiber board is often used for hot pressing, and the temperature is above 150°C.
3: The magnet is demagnetized after oven baking.
4: Magnet material contains too much impurities and causes weak magnetic field. This is the common result of most greedy and cheap buyers. Because the price on the goods than the three, pick the manufacturers with low prices. Obviously, the customer's request is to use the N35 brand. The result is that the manufacturer with the ultra-low quoted price uses the N28 and N33 materials. Customers should not expect to be able to detect it. If the quantity reaches 30K, do you measure it slowly with a magnetic flux meter? (Reverse demagnetization occurs in 6 months and demagnetization occurs in 2 months.) A reliable and stable supplier is really important. How could the price of the N35 material be used for you without that price? And some merchant magnets are used for packaging. Anyway, they can suck it. Material garbage is garbage.
5: Impact causes magnetic demagnetization of the magnet, such as high-frequency impact, and care must be taken during transportation.
6: The material contains metal antimony that causes the magnet to be powdered.
7: High magnetism environment The test magnet itself loses magnet force or the N/S pole changes (magnetizing machine demagnetizer).
Summing up the above demagnetization (degaussing) causes the basic 90% which has 4 points, high temperature demagnetization, demagnetization of the material itself, high frequency impact demagnetization, high magnetic field demagnetization