Effect of Si on the magnetic properties of the Fe70Al30 alloy

(Fe70Al30)(100-x)S-x (x = 0, 5, 10 and 20) alloys were obtained by mechanical milling for durations of 12, 24 and 36 h. They were studied by X-ray diffraction (XRD), Mossbauer spectrometry and magnetic measurements at room temperature. The XRD experiments show that all the samples have the Fe-BCC phase and for x = 20 an additional Fe0.34Si0.66 phase appears. The obtained Mossbauer spectra show a decreasing broad magnetic component and increasing broad paramagnetic component when the Si concentration increases. The spectra were fitted by using a hyperfine field distribution and a quadrupolar splitting distribution, respectively. The broad spectra show the disordered character of the samples. When the milling time increases the mean HF increases. These results suggest that Si acts as magnetic dilutor and that the milling time increases the magnetism. All the samples present magnetic hysteresis cycles in which the coercive field decreases with the Si increase, improving in this way the semi-soft character of the alloy. (c) 2006 Elsevier B.V. All rights reserved.