Realization of large coercivity in MnAl permanent-magnet alloys by introducing nanoprecipitates

[Display omitted] •Nanoprecipitates are formed through combining Tb dopant and rapid solidification.•The evolution of nanoprecipitates in Tb-doped MnAl ribbons are clarified.•Improved coercivity is realized due to the pinning effect of nanoparticles. Acquisition of large coercivity remains as a key issue in MnAl permanent-magnet alloys. In this work, we successfully introduce rhombohedral nanoprecipitates with the size of ∼20 nm into L10 MnAl alloys via doping 0.2 at.% Tb and melt spinning technology. The motion of magnetic domain walls can be more effectively pinned by the dispersive nanoprecipitates. This results in an improved coercivity of 5.43 kOe in Tb-0.2 at.% powders which is 22% larger than that of the binary powder without significant degrading in saturation magnetization and magnetocrystalline anisotropy. This work may provide a new method to improve the coercivity in MnAl permanent magnets.