Abstract
In melt-spun ribbons of (Pr, Dy)15(Fe, Co,)77(B, C)8 alloys prepared by the single roller method, the effects of C substitution for B, Co for Fe and Dy for Pr in Pr15Fe77B8 alloy, substrate surface velocity and subsequent annealing on the magnetic properties were studied, and their bonded magnets were made of the optimum-quenched ribbons. The maximum energy product of 98.3 kJ/m3 was obtained for Pr15Fe77B8 ribbon prepared at a substrate surface velocity of 11.8 m/s. In (Pr, Dy)15(Fe, Co)77(B, C)8 ribbons, we confirmed that the best maximum energy product of 96.4 kJ/m3 was obtained for (Pr0.95Dy0.05)15(Fe0.9Co0.1)77(B0.5C0.5)8 alloy which contains Dy and Co to improve the temperature dependence of Br and HCB. X-ray diffraction patterns from samples with the highest coercivity showed a mixture of an amorphous and a fine crystalline phase. The best magnetic properties obtained in these bonded magnets of (Pr0.95Dy0.05)15(Fe0.9Co0.1)77( B0.5C0.5)8 alloy were (BH)max=64.9 kJ/m3, HCJ=1400 kA/m, HCB=419 kA/m, and Br=0.62 T. It was known that the temperature dependence of Br and HCB for (Pr, Dy) -(Fe, Coi)-(B, C) bonded magnets was superior to those of Pr-Fe-B bonded magnets.