DIE-UPSET PRCO5-TYPE MAGNETS FROM MELT-SPUN RIBBONS

We used consolidation (hot pressing) and deformation (die upsetting) techniques to produce magnetically anisotropic permanent magnets from melt-spun PryCo100-y-xCx alloys. The primary phase in these magnets (16 less-than-or-equal-to y less-than-or-equal-to 24 at. %) was the hexagonal PrCo5 phase. The greatest alignment was obtained for low-carbon compositions (0 less-than-or-equal-to x less-than-or-equal-to 2 at. %); in particular, Pr18Co81C produced a remanence of approximately 8.7 kG and an energy product of 16.9 MG Oe. The addition of 1 at % carbon enhanced the coercivity (H(cl) almost-equal-to 5.9 kOe) by nearly 80% compared to the carbon-free composition (H(cl) almost-equal-to 3.3 kOe). Higher carbon levels (x greater-than-or-equal-to 4 at. %) resulted in even larger coercivities (H(cl) greater-than-or-equal-to 10 kOe) but were accompanied by significantly lower remanences (B(r) almost-equal-to 6 kG).