Effect of annealing on the structure and magnetic properties of SmCo5-based ribbons with 3 wt% Al-Cu-Fe addition

Al-Cu-Fe alloying addition can simultaneously improve the coercivity and magnetization of the as-spun SmCo5-based ribbons, the annealing process can further improve the hard-magnetic properties of ribbons. In this paper, SmCo5+3 wt% Al82.8Cu17Fe0.2 ribbons melt-spun at 40 m/s were annealed at 500 – 700 °C for 30 min. It is found the annealing improves the crystallinity of the grains, changes the phase composition and microstructure, especially the distribution of Sm(Co, M)7 phase. By doping 3% Al82.8Cu17Fe0.2 alloy and annealing at 600 °C for 30 min, the SmCo5-based ribbons obtain ultra-high coercivity of 26.83.3 kOe. The reason for the maximum coercivity at 600 °C can be attributed to the high content of Sm(Co, M)5 grains, improved crystallinity of the grains, and the refinement of the grains.