Nanocrystallization in amorphous Fe<inf>40</inf>Ni<inf>40</inf>(Si+B)<inf>19</inf>Mo<inf>1-2</inf>ribbons

Abstract

Cut Fe40Ni40(Si+B)19Mo1-2ribbons were annealed for 2 h at various temperatures between 350°C and 600°C. XRD and Mossbauer effect spectroscopy (ME) measurements were then performed on all of the ribbons. The magnetic properties of several ribbons were measured using a vibrating sample magnetometer (VSM). A differential thermal analysis scan (over the range 20-800°C) of the as-cast ribbon showed two phase transitions; the first at 454°C and the second at 525°C. Both the XRD and ME spectra of the as cast, the 350°C and 400°C annealed ribbons showed that they were amorphous. The ME spectra of the 450°C, 475°C and 500°C annealed ribbons showed that these ribbons contained α-Fe, α-Fe(Si) and t-Fe2B nanocrystallites. For the ribbons annealed above 550°C, crystallites of t-Fe2B, t-Fe3B, t-Fe5SiB2and FCC-FeNi appeared, with the α-Fe and α-Fe(Si) crystallites disappearing. The sextets of all of the Fe compounds appeared in the ME spectra of the 525°C annealed ribbon. The VSM measurements supported the picture of a two-stage phase transitions; amorphous phase→a nanocrystalline phase (Fe-containing nanocrystallites in an amorphous matrix) at 454°C and then a second transition, the nanocrystalline phase→a disordered alloy containing Fe-B and Fe-Ni crystallites at 525°C. © 2004 Elsevier B.V. All rights reserved.