MAGNETIC-PROPERTIES OF MELT-SPUN CE-DIDYMIUM-FE-CO-B SYSTEM ALLOYS AND THEIR BONDED MAGNETS

Experiments were carried out to investigate the magnetic properties of melt-spun Nd-Ce-Fe-Co-B alloys, Ce-Didymium-Fe-Co-B alloys and their bonded magnets. Magnetic properties of the melt-spun Nd-Ce-Fe-Co-B system alloys were deteriorated with the increase of Ce content. A maximum energy product of 134.6 kJ/m3 was obtained for (Nd0.9Ce0.1)11Fe72Co8B9 ribbon prepared at the substrate surface velocity (Vs) of 17.1 m/s. This value was 93.3% of that for Nd11Fe72Co8B9 ribbon (Vs = 17.1 m/s). A maximum energy product of 139.8 kj/m3 Was obtained for 26 mass%R-65.4 mass%Fe-7 mass%Co-1.6 mass%B(R = Ce-Didymium) alloy ribbons prepared at Vs = 17.1 m/s. Using the 26 mass%R-65.4 mass%Fe-7 mass%Co-1.6 mass%B ribbons prepared at Vs = 20.7 m/s, the effect of annealing on the magnetic properties were examined, and the optimum annealing condition was found to be at 650-degrees-C for 20 min. Its corresponding value of (BH)max was 135.7 kJ/m3. From the TEM observation, the particle size of these crystallized ribbons was 20-30 nm. A maximum energy product of 90.5 kJ/m3 was achieved with the 26 mass%R-65.4 mass%Fe-7 mass%Co-1.6 mass%B bonded magnets made from the optimally prepared ribbons.