Effect of La on Phase Formation, Microstructure, and Magnetic Properties of ThMn₁₂‐Type SmFe₁₁Ti Melt‐Spun Ribbons

The effect of La on the phase formation, microstructure, and magnetic properties of SmFe 11 Ti melt‐spun ribbons is investigated by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The XRD and TEM results show that Sm 1− x La x Fe 11 Ti ( x = 0–0.4) and SmLa y Fe 11 Ti ( y = 0.1–0.4) melt‐spun ribbons are composed of the 1:12 main phase with a ThMn 12 ‐type structure, α‐Fe phase, Fe 2 Ti, and α‐La phase. It is concluded that the substitution of Sm by La is unfavorable to the formation of the 1:12 main phase, while the α‐La phase coexists primarily with the 1:12 main phase and does not exist as a grain boundary phase in Sm 1− x La x Fe 11 Ti and SmLa y Fe 11 Ti melt‐spun ribbons. The VSM magnetic measurements indicate that SmLa 0.2 Fe 11 Ti melt‐spun ribbon exhibits better magnetic properties ( H cj = 4.56 kOe, B r = 6.26 kGs, M s = 9.15 kGs, (BH) max = 5.54 MGOe) after annealing at 1073 K for 30 min. The inhibition formation of α‐Fe phase and Fe 2 Ti and the homogeneous microstructure with the refined grains in SmLa 0.2 Fe 11 Ti ribbon can be the main reason for the excellent magnetic properties.