Structure and permanent magnetic properties of SmFex (x=3–8) melt spun ribbons during heat treatment

Compounds with the composition SmFex (x=3–8) were prepared by melt spun method at a velocity of 40 m/s and subsequent annealing at temperature between 600–1000 °C. The crystal structures of the as-quenched and as annealed powders were investigated by XRD methods with following Rietveld analysis. The glass forming ability could be enhanced by the increase of Sm content to x≤5. Metastable Sm5Fe17-type structure existed when 3≤x≤5 and temperature was lower than 800 °C. SmFe2-type structure could be stable up to 1000 °C when x>3 and temperature was under 800 °C. The content of SmFe2-type decreased with the increase of x value and increased with temperature lower than 800 °C, from which SmFe2-type started to bring the transition to SmFe3-type. As for Sm5Fe17-type compounds with x=3.4, the highest coercivity of 33.6 kOe could be obtained under a velocity of 30 m/s and heat treated under 700 °C×1 h.

Graphical AbstractObserved and calculated patterns of SmFex (x=5) under 40 m/s with RWP=10.32% and s=1.7088, (1), (2), (3), (4), (5) and (6) referring to the difference, calculated Sm2Fe17-type, calculated SmFe2-type, calculated amorphous, observed and calculated pattern respectivelyFigure optionsDownload as PowerPoint slide