Structure and magnetic properties of Sm(Co0.74Fe0.1Cu0.12Zr0.04)8 melt-spun nanostructured alloys

Melt-spun ribbons with a composition of Sm (Co0.74Fe0.1Cu0.12Zr0.04)8 were prepared with a wheel speed of 40 m/s, followed by vacuum heat treatment in the temperature range of 650-850 °C, for different durations. X-ray powder diffraction (XRD) results showed that the main phase is of TbCu7-type for both, as-spun and annealed ribbons, except a small amount of α-Fe(Co). The intrinsic coercivity values iHc = 6.9 kOe for the sample heat treated at 700 °C for 35 min. When the annealing time is increased more than 30 min, the coercivity decreases and a third phase appears. The microstructure of the ribbon samples was characterised by using scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDAX). Detailed results for the microstructure in Sm(Co0.74Fe0.1Cu0.12Zr0.04)8 melt-spun ribbons and the correlation between the magnetic properties and the grains size are presented.