Permanent-magnet properties of Sm-Ce-Co-Fe-Cu alloys with compositions between 1-5 and 2-17

This paper describes magnetic and metallographic properties of rare-earth-cobalt alloys of (Sm, Ce) (Co, Fe, Cu)z(5 \lsim z \lsim 8.5). Some alloy compositions exhibit anomalously large coercive forces and have excellent potential for permanent-magnet application. The composition Sm0.75Ce0.25(Co0.81Fe0.04Cu0.15)7.2shows a maximum energy product of 20.2 MG Oe, which is the highest among the compositions studied. Most alloys exist in the CaCu5-type crystal structure although some show a few of very weak superlattice lines characteristic of hexagonal Th2Ni17. When aged at about 960°C, the alloys show another phase in addition to the aforementioned structures.