Effect of amorphous evolution on structure and absorption properties of FeSiCr alloy powders

The master alloys of Fe87.5-xSi13.5Crx (x = 0, 4, 8, 12 at%) were prepared in vacuum induction melting furnace. Corresponding powder samples were obtained by 60 h ball milling of the crushed master alloys, and studied by morphological, microstructural, electromagnetic and microwave absorption tests in the frequency range from 0.5 to 18 GHz. The powders were characterized by a particle size less than 1 mu m and a grain size less than 100 nm. In the cases of x >= 8, Fe3Si phase with D03-type structure was observed, and the powders became amorphous completely. A crystallization temperature of 685 K was found for x = 8. Coercivity force and saturation magnetization of the powders decreased with the increasing of Cr content. As an electromagnetic wave absorbing material, the minimum reflectivity was - 15.5 dB at 8.5 GHz and the absorption band was broad for x = 8 powders. (c) 2013 Elsevier B.V. All rights reserved.