Magnetic behavior and phase composition of CeDidymium-Fe-B sintered magnets with additions of Si, Co and Dy2O3

The influence of Si, Co and Dy₂O₃ on the magnetic properties of CeDidymium-Fe-B inexpensive sintered magnets is investigated. The CeDidymium (CeDidym) synthesized for this study has the composition of 40Ce-50Nd-10Pr in wt.%. Two series of alloys having the composition of CeDidym_16.5Fe₇₇ B_6.5 and CeDidym_16.5Fe_73-y Co_ySi₄B_6.5, where 0⩽x⩽8 and 0⩽y⩽30, are prepared. It is found that the intrinsic coercivity _iJ_c and the Curie temperature T_c are increased from 5.1 kOe and 261°C for x=0 to 7.2 kOe and 286°C for x=8, respectively. The addition of 10 at.% of Co causes a substantial increase in T_c from 275°C to 350°C. The intrinsic coercivity of the (Si, Co)-containing magnets is further improved by Dy ₂O₃ addition. The magnetic properties of the sintered magnets made from the CeDidym_16.5Fe₆₃Co ₁₀Si₄B powder blended with 3 wt.% Dy₂O ₃ are B_r=10.9 kG, _iH_c=9.2 kOe, (BH)_max=28.2 MGOe and T_c=350°C