Magnetic and structural properties of the nanostructured Fe1-xSix system with x=0.1, 0.2 and 0.3, mechanical alloyed and sintered

The magnetic and structural properties of the nanostructured system Fe1-xSix with x = 0.1, 0.2 and 0.3 were studied by X-Ray diffraction (XRD), SEM, and Mossbauer Spectrometry (MS). The samples were prepared by compacting and sintering at two temperatures, 900 and 1000 degrees C, from powders obtained by means of two procedures: by elemental mixing of Fe and Si powders and by mechanical alloying (MA). For samples obtained from mixed powders and sintered at 900 and 1000 degrees C, XRD and MS show the presence of pure iron and silicon, indicating that these conditions do not favor alloying, except for the sample with 30 at.% and 1000 degrees C, for which, besides of iron and silicon patterns, the DO3 and FeSi phases are also evidenced. The grain sizes are approximately ranged from 24 to 40 ran for the pure iron and 43 to 90 nm for the pure silicon. For the mechanical alloyed powders, the as milled samples with 10 and 20 at.% Si consist of a bcc structure and for 30 at.% of FeSi and DO3 phases. The grain sizes are 14, 12 and 7 nm for 10, 20 and 30 at.% Si, respectively, showing that the fragility increases with silicon content and for the as sintered sample with 10 at.% Si BCC grain size is now approximately 15 nm. It is worthy to note that when sintering, the DO3, FeSi and Fe5Si3 phases are developed, while in the 30 at.% Si as sintered mixed elemental powder, only an incipient alloy is obtained.