Magnetic powder is a short form of magnetic powder, is composed of a large number of neodymium iron boron base material particles and the gap between the particles formed by the aggregate. Powder body is between the solid and colloid material. Solid materials below 0.1um called colloids, the size of lmm above called dense or solid.
Neodymium iron boron magnets powder particles in the body between many small pores and the coupling surface is very small, the surface atoms can not form a strong bond between the powder body does not have the same shape as a dense body, and showed similar to the liquid fluidity. There is no macroscopic pore in the dense body, which is connected by the atomic bond force.
Rare earth magnet alloy preparation process commonly used by powder metallurgy. This method produces alloy ingots. NdFeB magnet powder is divided into coarse powder, medium and fine three kinds of technology, milling requirements of particle size of 3 ~ 5um. Rare earth magnet metal easy oxidation, for example, generate Smz 03, Nd2 03, these oxide fine powder in the air at high temperature will spontaneous combustion, magnetic interaction, the powder becomes secondary powder particles, that is, a number of powder particles in the powder Van der Waals force between the London force and the magnetic force of the reunion of small particles under the group, so rare earth permanent magnet alloy powder in the main air flow poor, for the next process a magnetic field orientation caused some difficulties.