Estudo experimental do sistema binário samário ferro

Abstract

Intermetallics compounds of rare-earth and 3D transition metal have attracted great interest in recent decades. This interest occurs because these types of materials have magnetic properties which make them strong candidates for building high-performance permanent magnets. There are several compounds that can be formed from the combination of rare earth elements in 3d transition metals. The samarium iron binary system was studied experimentally in this work. The sample used in this study were alloys prepared by arc fusion, with the following concentrations: Sm30Fe70, Sm40Fe60, Sm50Fe50, Sm70Fe30 and Sm80Fe20. They were then investigated by X-ray diffraction, metallography, thermomagnetic analysis and magnetometry. Three intermediatescompounds were observed: Sm2Fe17, SmFe3 and SmFe2 . Their lattices constant and Curie temperatures have been determined. The magnetic properties of the first three samples (Sm30Fe70, Sm40Fe60 and Sm50Fe50) were consistent with the ratio and magnetic characteristics of the present intermetallic compounds. However for the Sm70Fe30 and Sm80Fe20 samples, the study indicates a possible formation of metastable phases. There was also a dependence on the magnetic properties of the alloys with the samarium concentration.