Magnetic hardening of Pr-Fe-Co-B alloys by rapid quenching

We have investigated the magnetic properties of liquid-quenched Pr/sub 15/ (Fe/sub 1-//sub x/ Co/sub x/ )/sub 77/ B8 over the whole range of Co concentrations. The coercivity H/sub ci/ and the remanence J/sub r/ depend on the Co content in the same way as in Nd/sub 15/ (Fe/sub 1-//sub x/ Co/sub x/ )/sub 77/ B8 . For the ternary Pr-Co-B a high H/sub ci/ , as large as 15.2 kA/cm, has been obtained. In Co-rich alloys the temperature dependence of H/sub ci/ and J/sub r/ is limited by the spin reorientation at temperatures well below the Curie point. Except for Pr/sub 15/ Co/sub 77/ B8 , annealing of overquenched ribbons leads to substantially lower coercivities. The possible microstructural origin of the magnetic hardening is discussed