Structure of ndfeb _ ndfeb strong magnet manufacturers
Ndfeb is Nd2Fel4B compounds as the base phase (
Referred to as '2 -
The rare earth permanent magnetic alloys.
Nd2Fel4B compounds belong to tetragonal crystal system and crystal structure as shown in figure, space group of P42 / MNM, rare earth neodymium atom occupies f and g crystal, crystal boron occupy g, iron c, e, j1, j2, k1 and k2 six kinds of crystal.
It has a high saturation magnetization, its & mu;
61 t, the theoretical maximum magnetic energy product [
Theory = 516 kj/m3;
And there is a lot of magnetocrystalline anisotropy field, HA≥
5840 ka/m, which is the main source of high coercive force, the Curie temperature Tc = 312 ℃.
Therefore, it has very excellent permanent magnetic properties.
In nd-fe-b alloy Nd2Fel4B accounted for more than 90% of the total volume, the other is rich phase, rich boron phase and neodymium metal neodymium oxide as Nd2O3, etc.
Also known as the third generation of rare earth permanent magnet nd-fe-b alloy alloy.
The ndfeb alloy microstructure is mainly composed of three phase.
Is the main phase Nd2Fel4B, it is the main source of permanent magnet performance, grain assumes the polygon, generally accounted for more than 90% of the total volume;
The other is rich and rich neodymium boron is equal.
In sintered magnets, rich boron phase exist in isolated block or granular, rich neodymium phase along the grain boundary and grain boundary corner office on thin layer the main phase grain encirclement.
In addition, in the corner office on some oxide (
Such as Nd2O3)
- - - - - -
Fe and empty.
Sintered magnets, magnetic hardening is thought to be determined by the nucleation of anti magnetic domain.
In fast hardening type magnet, although phase and sintering of the same, but the grain fine, about 10 ~ 100 nm, there is no oxide and empty.
The rapid quenching magnet magnetic hardening is believed to have originated from grain boundary of domain wall pinning.
Weakness is: (ndfeb alloy
Low Curie temperature, temperature stability is bad, can only be used within 80 ℃.
Ndfeb alloy oxidation and easily be corrosion environment.