SUMMARYThe melt-spun ribbons of Pr-Fe-Co-V-W-Si-B system alloys were prepared by single roller rapid-quenching method. The effects of composition, surface velocity, and heat treatment on the magnetic properties were investigated. The P 9 sFe 71 Co 8 V 0.5 W 0.5 Si 0.5 B 10.5 alloy ribbons prepared at a surface velocity of 12.5 m/s were crystallized by heat treatment, and the optimum heat-treatment condition was found to be at 575 °C for 3 min, for which the magnetic properties were (BH)