Effects of Solution Treated Temperature on the Structural and Magnetic Properties of Iron-Rich ${\rm Sm}({\rm CoFeCuZr})_{\rm Z}$ Sintered Magnet

The effects of solution-treatment temperature on the phase constitution, microstructure and magnetic properties of Sm(Co bal. Fe 0.35 Cu 0.06 Zr 0.018 ) 7.8 were investigated systematically. The formation of Sm 2 Co 7 around the Sm 2 O 3 was confirmed and the volume fraction of Sm 2 Co 7 increases with decreasing solution-treatment temperature. An area without cellular structure was observed around the Sm 2 Co 7 phase in aged specimens solution treated at 1403 K. Thus, it was found that precipitation of Sm 2 Co 7 phase prevents the formation of cellular structure during aging treatment. The coercivity of those magnets was less than 600 kA/m. On the other hand, the obvious formation of cellular structure was confirmed in the case of solution treatment at 1423 K and these magnets showed high coercivity of more than 1000 kA/m. The magnetic properties of M r = 1.22 T and H cJ = 1011 kA/m have been obtained for Sm(Co bal. Fe 0.35 Cu 0.06 Zr 0.018 )7.8 by solution treatment at 1423 K.