Structural and magnetic investigation of Co-rich Sm–Co unidirectionally solidified alloys

Abstract

Sm(Co, Fe, Cu, Zr)z alloys, with various degrees of crystallographic and magnetic texture, were synthesized by a route based on floating zone melting and unidirectional solidification. The phase composition, the microstructure and magnetisation curves of these materials were investigated by scanning electron microscopy, X-ray diffraction and magnetisation measurements. The trials undertaken by systematically varying the process parameters (heating power, floating zone velocity) allowed us to determine for each particular start composition the solidification regimes which yield materials with 1:5- and/or 2:17-type phases, free of Co metal precipitates, as well as with the crystallographic c-axis, easy magnetisation direction, respectively, oriented parallel or perpendicular to the temperature gradient main direction. The effect of solutionizing and ageing treatments on the microstructure and magnetic properties of the textured alloys was also investigated.