Magnetic Properties of SmFe3-Type Sm–Zr–Fe–Co–Ti Melt-Spun Ribbons

The magnetic properties and structures of (Sm,Zr)5(Fe,Co)17−xTix (x = 0–2.0) melt-spun ribbons were investigated in the as-quenched condition and after annealing. The as-quenched (Sm,Zr)5(Fe,Co)17−xTix (x = 0–0.5) specimens consisted of the Sm5Fe17-type and SmFe3-type phases, while the as-quenched (Sm,Zr)5(Fe,Co)17−xTix (x = 1.0–2.0) specimens contained the SmFe3-type phase. These specimens showed low coercivity regardless of the Ti content. Heat treatment of the melt-spun ribbons resulted in a drastic increase in coercivity. The maximum coercivity of 1.11 MAm−1 was achieved in the (Sm,Zr)5(Fe,Co)15.5Ti1.5 specimen annealed at 1073 K. Microstructural studies revealed that the annealed specimen consisted mainly of the SmFe3-type phase. The achieved high coercivity of the annealed specimen was therefore attributed to the existence of the SmFe3-type phase.