High performance Sm-Co powders obtained by crystallization from ball milled amorphous state

Abstract Isotropic Sm-Co nanoparticle powders with high coercivity were prepared by high-energy ball milling followed by optimal annealing at different temperatures. The covercivity increased monotonically with increasing of the annealing temperature and a highest coercivity of 31.2 kOe was obtained. The sample with an optimal energy product of 17.0 MGOe still had a coercivity of 18.2 kOe. The evolution of phase, particle size, mechanism of coercivity and other related magnetic properties were analyzed. The excellent performance is attributed to nanoscale size grains below 15 nm and good exchange coupling between nanoparticles.