Comparison of microstructure and magnetic properties of the SmCo₄B-based ribbons melt-spun at different speeds

The SmCo4B-based ribbons were melt-spun at 35 m/s and 40 m/s, respectively, and annealed at 800 C-degrees for 30 min. The dependence of the annealed ribbons' microstructure and magnetic properties on melt-spinning speed sensitivity was studied. The results show that the as-spun ribbons comprise an amorphous matrix and Sm-Co-B nanograins. For SmCo4B-based ribbons, the critical cooling rate to obtain an amorphous matrix is 35-40 m/s. Compared to the annealed ribbons melt-spun at 40 m/s, the formation of the uniform platelet-shaped grains in the annealed ribbons prepared at 35 m/s helps to improve coercivity but decreases the remanence and saturation magnetization. These results provide a reference for a comprehensive understanding of the relationship between the microstructure and magnetic properties of SmCo4B-based magnets.