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, Despite 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 thermal 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 degrees 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 among 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 studied. 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%/degrees C, while those of SmCo5 magnet were about - 0.05%/degrees C.