What is the difference between sintered magnet and bonded magnet of NdFeB magnet?
NdFeB magnets can be divided into two types: bonded NdFeB and sintered NdFeB. The difference between the two is mainly in the process. Bonding NdFeB is made by adding NdFeB magnetic powder to the binder. Bonding is actually injection molding, while sintering is vacuumed and heated at high temperature! The sintered NdFeB permanent magnet material adopts powder metallurgy technology. The smelted alloy is made into powder and pressed in a magnetic field to form a compact. The compact is sintered in an inert gas or vacuum to achieve densification, in order to improve the coercivity of the magnet , Usually requires aging heat treatment.
Sintered NdFeB This is a powder metallurgy process
Generally called NdFeB, the material itself is very hard, the hardness is about 560-580Hv, but it is quite brittle. The density is about 7.4-7.6 g/cm3, with high resistance to demagnetization, but the temperature stability is general. Depending on the performance level, the maximum working temperature is between 80-250 degrees Celsius. If there is no electroplating or coating, the material's corrosion resistance is very good. Poor, easily oxidized. The resistivity of the material is about 160 micro ohm centimeters, the recoil permeability is about 1.05 μreo, and the temperature coefficient of remanence is between -0.12~-0.1%/degree Celsius.
The temperature coefficient of intrinsic coercivity is about -0.6%/degree Celsius.
The price of bonded NdFeB is relatively cheap. On the one hand, there are less materials and fewer processes. The current process technology of sintering NdFeB is too poor, and the process of bonding NdFeB is simple, so the price is very different; bonded NdFeB magnets It is a magnet made of quick-quenched NdFeB magnetic powder and a binder through "compression molding" or "injection molding". Bonded magnets have high dimensional accuracy, can be made into magnetic components with relatively complex shapes, and have the characteristics of one-time molding and multi-pole orientation. The bonded neodymium iron boron has high mechanical strength and can be formed with other supporting components at one time during forming.
