MAGNETIC-BEHAVIOR AND PHASE-COMPOSITION OF CEDIDYMIUM-FE-B SINTERED MAGNETS WITH ADDITIONS OF SI, CO AND DY2O3

The influences of Si, Co and Dy2O3 on the magnetic properties of CeDid ymium-Fe-B inexpensive sintered magnets were investigated. The CeDidym ium (CeDidym) synthesized for this study had the composition of 40Ce-5 ONd-10Pr in wt%. Two series of alloys having the composition of CeDidy ml6.5Fe77-xSixB6.5 and CeDidym16.5Fe73-yCoySi4B6.5, where 0 less-than- or-equal-to x less-than-or-equal-to 8 and 0 less-than-or-equal-to y le ss-than-or-equal-to 30, have been prepared. It is found that the intri nsic coercivity H-i(c) and the Curie temperature T(c) were increased f rom 5.1 kOe and 261-degrees-C for x = 0 to 7.2 kOe and 286-degrees-C f or x = 8 respectively. The addition of 10 at% of Co causes a substanti al increases in T(c) from 275-degrees-C to 350-degrees-C. The intrinsi c coercivity of the (Si, Co)-containing magnets was further improved b y Dy2O3 addition. The magnetic properties of the sintered magnets made from the CeDidym16.5Fe63Co10Si4B6.5 powder blended with 3 weight perc ent Dy2O3 are B, = 10.9 kG, H-i(c) = 9.2 kOe, (BH)max = 28.2 MGOe and T(c) = 350-degrees-C.