THE EFFECT OF FE CONTENT ON THE TEMPERATURE-DEPENDENT MAGNETIC-PROPERTIES OF SM(CO,FE,CU,ZR)(Z) AND SMCO5 SINTERED MAGNETS AT 450-DEGREES-C

The magnetic properties of SmCo5, Sm(Co-bal.Fe-0.21 Cu0.06Zr0.03)(7.6) , Sm(CobalFe0.25Cu0.06Zr0.03)(7.6), Sm(CobalFe0.28Cu0.06Zr0.03)(7.6), sintered magnets have been measured up to 350, 400 and 450 degrees C, For a fined temperature range, the irreversible loss of Sm(Co,Fe,Cu,Zr )(z) magnets has been found to increase with increasing Fe content, De spite the high B-r obtained at 25 degrees C, a magnet must have a low. irreversible loss of induction to retain a high magnetization after t hermal cycling. Compromising the B-r of 11.3 kG obtained at 25 degrees C and the irreversible loss of 1.9% after thermal cycling to 450 degr ees C, a magnet with the composition of the Sm(Co-bal.Fe0.21Cu0.06 Zr- 0.03)(7.6) was found to exhibit the highest retained magnetization amo ng the magnets studied. This magnet also exhibited the highest H-ci (2 .8 kOe) and BHmax (6.7 MGOe) at 450 degrees C among all magnets studie d. The reversible temperature coefficients of induction of Sm(Co,Fe,Cu ,Zr)(z) sintered magnets were found to be about - 0.03 to -0.04%/degre es C, while those of SmCo5 magnet were about - 0.05%/degrees C.