Densification mechanism and its effect on the magnetic properties of Nd-Fe-B bonded magnets through the new high-energy compaction method

[Display omitted] •Isotropic NdFeB magnets were successfully prepared by high-energy compaction method.•The density was significantly increased (6.9 g/cm3) by high pressure in short period.•The optimal binder content (1.0 wt%) & pressure (3 GPa) was found for Nd-Fe-B magnets.•The remanence (6.635 kG) of Nd-Fe-B magnets are significantly improved. Gas-atomized Nd-Fe-B magnetic powders were subjected to magnetic pulse compaction, which is very high-energy compaction method, can be densified in a short time with various binder contents at different compaction pressures. The powders were rapidly forced together with in an abbreviated period, and formed a well-packed dense sample with full density during the magnetic pulse compaction process. The influence of density on the magnetic properties of the Nd-Fe- B magnet was investigated. The relative density increased with pressure and highest density of 6.9 g/cm3 was achieved at a consolidation pressure of 3 GPa. The optimized binder content and pressure were found to be 1 wt% and 3 GPa, respectively, for achieving the highest density. The remanence and maximum energy product of the Nd-Fe-B magnets gradually increased with increasing density. The significant improvement in density can effectively offers high remanence of 6.635 kG and maximum energy product of 8.5 MGOe.