Amorphous melt-spun ribbons of Didymium-Fe-Co-Nb-B alloys were prepared by the single-roller rapid-quenching method. The effects of the composition, wheel velocity, and heat treatment on the magnetic properties were investigated. Amorphous Didymium
9-Fe
76Co
8Nb
1B
6 ribbons prepared at a wheel velocity of 20 m/s were crystallized by heat treatment, and the optimum heat treatment condition was found to be 625°C for 5 min, in which case the value of (
BH)
max was 147.3 kJ/m
3. The temperature coefficients of
Br and
HcJ for ribbons of crystallized Didymium
9-Fe
76Co
8Nb
1B
6 alloy were α(
Br)= -0.087%/°C (reversible) and α(
HcJ)= -0.416%/°C (irreversible), respectively. The value of (
BH)
max for a compression molded Didymium
9-Fe
76Co
8-Nb
1B
6 isotropic bonded magnet prepared by using the ribbons annealed at 625°C for 5 min was 79.7 kJ/m
3.
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