Magnetic Properties of Rapidly Quenched Pr-Co Ribbons

The tendency of Pr-Co system materials toward oxidation, together with conventional powder metallurgy techniques, has led to high oxygen contents in PrCo5 sintered magnets, accompanied by low coercivities and the formation of a Pr2Co17 phase. The single-roller quenching method was used to form Pr-Co ribbons, and it was found that at 17.3 at% Pr and a roller speed of 37.7 m/s, a single PrCo5 phase was obtained, with coercivities twice those of sintered magnets, but less than 1/10 the oxygen content. In addition, the magnetic properties of such samples were highly stable, showing no significant deterioration over a period of 30 months.