Influence of Fe Content on Magnetic Properties of High Temperature Rare Earth Permanent Magnets Sm(CobalFexCu0.1Zr0.03)7.5(x=0.09–0.21)

The influence of Fe content on magnetic properties of high temperature rare earth permanent magnets Sm(CobalFexCu0.1Zr0.03)7.5 (x=0.09–0.21), prepared by the conventional powder metallurgy method, has been studied. The results show that: with increasing of Fe content, Br and (BH)max increased, whose optimum value reached to 0.96 T and 176.7 kJ/m3 while x=0.21; Hci increased first, but then decreased with further increasing of Fe content; the optimum value of Hci reached to 2276.6 kA/m while x=0.15. The temperature stability of the magnet with x=0.15, prepared by optimum process, has been proved to be excellent, and the B-H demagnetization curve kept a straight line at 500 °C; the intrinsic coercivity coefficient β was −0.16%/°C, and the maximum operating temperature was up to 533 °C.