Process through the adoption of effective measures to improve the density of NdFeB magnets is to improve the corrosion resistance of magnets itself
Can be the key. Higher density of the magnets have a high corrosion resistance. In the magnet exposed to the air in the supermarket
When NdFeB sintered magnets of different densities absorb different amounts of hydrogen, absorb the higher density magnets
A smaller number of hydrogen, while the low density of magnets to absorb a large amount of hydrogen. The results clearly show that
Hydrogen corrosion of NdFeB magnets play a key role.
Some of the new process can effectively increase the density of magnets:

(1), the use of rapid quenching HDDR powder and sintered powder production
Body, since these powders is very small grains, can be dispersed evenly distributed during sintering in NdFeB around so that the complete separation, so that excess liquid can be reduced not only guarantee the volume fraction of NdFeB to increase, and to make sintered density and coercivity is improved;

(2), film casting process using Nd-rich phase of this process can be diffuse sub -distributed in NdFeB around, resulting in the best distribution of liquid phase during sintering, which improve the density of sintered magnets have lee;

(3), wet-forming process, its process as follows: the use of mineral oil as solvent, the slurry in the magnetic field to suppress forming. After 100 degrees -300 degrees, filtered to suppress the oil, and then vacuum sintering.