Application of the shock compaction technique for consolidation of hard magnetic powders

A shock compaction technique has been successfully applied for the consolid ation of hard magnetic powders without appreciable changes in the phase str ucture and grain size. Pr-Fe-B and Sm-Fe-N materials, prepared with the app lication of melt spinning and mechanical alloying, respectively, were shock compacted with a shock wave speed of 1200 m/s and a pressure of 4.4 GPa. W e found that the coercivity of high RE containing material, for which the m agnetic hardness is controlled by good magnetic separation of magnetic grai ns by a RE-rich paramagnetic phase, decreases slightly, by similar to 5 %, due to the closer proximity of the crystallites in a dense material. For lo w RE, exchange coupled materials, the densification does not change the coe rcivity. (C) 1998 American Institute of Physics.