How to distinguish between two kinds of magnets, bonded NdFeB and sintered NdFeB
Time:06/06/2019
Neodymium magnet can be called neodymium iron boron magnet. It is a general name for strong magnet. Its chemical formula is Nd2Fe14B. It is an artificial permanent magnet and is the permanent magnet with the strongest magnetic force so far. The material grade of NdFeB magnets is N35-N52; the shape can be processed into different shapes according to specific requirements, such as round, square, perforated, magnetic tile, magnetic bar, convex or trapezoidal.
So how do you distinguish between bonded NdFeB and sintered NdFeB? In fact, these two kinds of magnets belong to NdFeB. The distinction between the two magnets is based on their production process. The bonded NdFeB is actually formed by injection molding, and the sintered NdFeB magnet is formed by evacuation and then heating at a high temperature.
The bonded NdFeB magnets are formed by injection molding and therefore contain a binder, wherein the density is generally only 80% of the theoretical value. The sintered NdFeB magnet is heated at a high temperature by a complicated process. Therefore, the magnetic Nb-bonded boron is attenuated by about 30% with respect to the sintered NdFeB.
The sintered NdFeB magnet is an anisotropic magnet produced by a powder sintering method. Generally, only blanks can be produced by sintering, and then mechanically processed (such as wire cutting, slicing, grinding, etc.) to become magnets of various shapes. Sintered NdFeB is a hard and hard material that is difficult to process. It has large loss during processing, high cost, poor dimensional accuracy, poor corrosion resistance, and surface treatment. But the advantage is that the performance is higher, and now it has achieved more than 50M.
In combination, the magnetic properties of the bonded NdFeB magnets are only about 5% of the sintering. At present, the magnetic energy product of the sintered NdFeB magnet can reach more than 50M, and the bonded magnet is generally below 10M, and the best is only 12M. The performance of the magnetic powder used for bonding the magnet is generally 15M, and it is only 10.5M after the bonded magnet. Therefore, the sintered NdFeB is generally used in a wider range than the bonded NdFeB.
