Magnetic Properties of Melt-Spun Pr(Nd)-Fe-Co-Nb-Cu-Si-B System Ribbons and Their Bonded Magnets

摘要

Melt-spun ribbons of Pr-Fe-Co-Nb-Cu-Si-B system alloys were prepared by a single roller rapid-quenching method. The effects of composition, wheel velocity, and heat treatment on their magnetic properties were investigated. The optimum preparation conditions of compounds were as follows: composition Pr{sub}9Fe{sub}68.5Co{sub}10Nb{sub}1Cu{sub}0.5-Si{sub}0.5B{sub}10.5; wheel velocity 12.5 m/s; heat treatment 625℃ for 5 min. The magnetic properties obtained were (BH){sub}(max) = 121.8 kJ/m{sup}3, J{sub}r = 0.90 T, H{sub}(cJ) = 898.7 kA/m, and H{sub}(cB) = 509.0 kA/m. The temperature coefficients of Jr and HcJ of the ribbons of Pr{sub}9Fe{sub}68.5Co{sub}10Nb{sub}1Cu{sub}0.5Si{sub}0.5B{sub}10.5 alloy were a(J{sub}r){sub}(ave) = -0.034%/℃ and a(H{sub}(cJ)){sub}(ave) = -0.290%/℃, respectively. The value of (BH)max for isotropic Pr{sub}9Fe{sub}68.5Co{sub}10Nb{sub}1Cu{sub}0.5Si{sub}0.5B{sub}10.5 bonded magnets prepared by using ribbons annealed at 625℃for 5 min was 84.4 kJ/m{sup}3. The irreversible loss of the bonded magnets was -2.74% at 125℃.