Effects of annealing and magnetic field on the structure and magnetic properties of Fe-Cr-Co alloy-doped Sm(Co_(0.9)Cu_(0.1))_5 ribbons

摘要

Sm(Co_(0.9)Cu_(0.1))_5 ribbons doped by Fe-Cr-Co alloy were prepared by melt-spinning at 40 m/s and annealing at 450°C for 15 min. The annealing and magnetic field have different effects on the structure and magnetic properties of the ribbons. The solute-partitioned structures consisting of Co-rich SmCo_5- and (Sm, Cu, Fe, Cr)-rich CeCo_5-type phases formed in each of the three ribbons. The as-spun ribbons show the SmCo_5- and CeCo_5-type phases in two distribution modes and high magnetic properties of H_c = 24.6 kOe, M_r = 45.4 emu/g and M_s = 61.5 emu/g. Annealing increases the content of SmCo_5-type phase and enlarges the componential differences between the two Sm(Co, M)_5 phases, eventually leading to an increase in H_c and a decrease in Mr. MHT plays a vital role in promoting doping atoms to occupy the 2c sites, narrowing the differences in content and composition between the two Sm(Co, M)_5 phases, and forming a nearly equiaxed and uniform two-phase structure, which not only inhibits the negative effect of annealing on Mr but also increases H_c to 30.1 kOe and M_s to 63.0 emu/g.