We generally use remanence, coercive force, and maximum magnetic energy product to measure the magnetic properties of neodymium magnets.
1. Remanence (Br)
After the neodymium magnet is magnetized to saturation in an external magnetic field, the remaining magnetic induction intensity when the external magnetic field is reduced to zero is called remanence. The unit is usually millitesla (mT) or kilogauss (kGs), 1 Tesla = 10,000 Gauss.
2. Coercive force (Hcb)
Coercive force refers to the reverse magnetic field strength required to reduce the remanence (Br) to zero after the neodymium magnet is saturated. The unit is ampere per meter (A/m) or oersted (Oe), and the conversion relationship is 1A/m= (4π/1000) Oe.
3. Maximum Energy Product (BH) max
The maximum energy product (BH) max indicates the magnetic energy density established by the magnet in the space between its two poles. It is the maximum value of the product of B and H (unit: kJ/m³ or GOe), which directly indicates the performance level of the magnet.
Factors affecting the magnetic properties of neodymium magnets
1. Raw material composition
Neodymium magnets are magnetic materials made of rare earth metal neodymium, pure iron and boron through powder metallurgy. Other elements can also be added to the ternary Nd-Fe-B material to further enhance the magnetic properties of neodymium magnets.
2. External environment
Temperature: Neodymium magnets have strict restrictions on operating temperature. If the ambient temperature exceeds this limit, the magnets may demagnetize. When the temperature exceeds the Curie temperature, the demagnetization of the magnets will be irreversible.
Humidity: Neodymium magnets are made by powder metallurgy, with large internal structure gaps and high iron content, which are prone to rust. Therefore, neodymium magnets are usually coated with anti-corrosion coatings. The drier the environment, the longer the magnetic properties of neodymium magnets will last.
