Phase and microstructure of TbCu7-type SmFe melt-spun powders

The SmxZr0.3Fe9.1–xCo0.6 (x=0.8, 0.9, 1.0) powders were prepared by melt-spun method with different quenching velocities. The phase and microstructure were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Th2Zn17-type structure of the as-cast state changed to TbCu7-type after quenching to a rotating molybdenum roll under certain velocity, and the formation of TbCu7-type phase was strictly depending on the Sm content and roll speed. The SEM morphology showed that the Fe-rich zone was typically fish-bone structure and TEM diffraction pattern indicated the nano-scale crystal size with TbCu7-structure when x=0.9, and FCC type γ-Fe on the basis of α-Fe formed in the non-equilibrium solidification could be detected by selected area electron diffraction (SAED) indexing in the x=0.8 samples.