The difference between sintered NdFeB and bonded NdFeB magnet
The difference between the two is mainly in the process, bonded NdFeB magnetic powder by adding binder made of bonding is actually injection molding, and sintering is vacuum through high temperature heating molding! The sintered Nd-Fe-B permanent magnets are made by powder metallurgy. The melted alloy is made into powder and pressed into compacted embryos in magnetic field. The compacted embryos are sintered in inert gas or vacuum to achieve densification. In order to improve the coercivity of magnets, aging heat treatment is usually needed.
Sintered NdFeB is a powder metallurgy process commonly known as NdFeB, the material itself is very hard, hardness about 560-580 Hv, but very brittle. Density of about 7.4-7.6 g/cubic centimeter with high demagnetization resistance, but the temperature stability is general, according to the performance level, the highest operating temperature between 80-250 degrees Celsius, if there is no plating or coating, the corrosion resistance of materials is very poor, very easy to oxidation. The resistivity of the material is about 160 microohm, the recovery permeability is about 1.05 microreo, the remanence temperature coefficient is between - 0.12 ~ - 0.1% / Celsius, and the intrinsic coercivity temperature coefficient is about - 0.6% / Celsius.
Bonded NdFeB magnets are made by mixing rapidly quenched NdFeB magnetic powder with binder through pressing 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, multi-polar orientation. Bonded NdFeB has high mechanical strength and can be molded at one time with other matching components.