Microstructure evolution of Pr-doped SmCo4B-based ribbons with improved magnetization

Abstract

Searching for high-performance permanent magnets is always challenging for modern technological applications. The novel SmCo4B phase has a higher anisotropy field than SmCo5, and this paper disclosed the effect of Pr addition on the phase transformation, microstructure evolution, and magnetism of the multi-element doped Sm1−xPrxCo3.04Fe0.9Cu0.06B ribbons. The results show that Pr addition decreases the amorphous forming ability of the as-spun ribbons. After annealing, Pr addition promotes the growth of strip-like Sm-Co-B grains, and 8 at% Pr addition increases the saturation magnetization and remanence of the Sm-Co-B ribbons by 96.2% and 48.0%, respectively. Pr addition weakens the anisotropy field of the Sm-Co-B phase, resulting in a gradual decrease in coercivity. We revealed the transformation mechanism of strip-like grains during melt-spinning and annealing, found the relationship between phase content, dislocation density, strain, and grain size, and proposed the corresponding microstructure evolution models.