Abstract:Nd10Fe81Co3B ribbons were prepared by melt-spinning method at different melt-spinning speeds, and the effects of melt-spinning speeds on the microstructure and magnetic properties of Nd10Fe81Co3B ribbons were studied. The results show that the content of amorphous phase is increased with increasing the melt-spinning speed. After annealed at 800 °C for 10 min, the ribbons melt-spun at 15 m/s speeds are consisted of Nd2(Fe,Co)14B and Fe7Co3. The medium grain size of Nd2(Fe,Co)14B is greater than 50 nm, however that of Fe7Co3 size is smaller than 25 nm. Inter-grains exchange coupling interaction is weakened; there are high content of amorphous phase in the ribbons melt-spun at 50 m/s, which makes the remanence reduce, and the coercivity didn’t obviously reduce. The ribbons melt-spun at 50 m/s had a optimum crystallization, and the inter-grains exchange coupling interaction acted well. Their magnetic properties are Hc=249 928 A/m, Mr=84.3 A·m2/kg. Furthermore, Curie temperature of the ribbons with different melt-spinning speeds are basically same, it’s about 630 K.