Synthesis, Magnetic and Moessbauer Studies of Mechanically Alloyed Fe_(0.63)Si_(0.37) a Alloys

摘要

Elemental powder mixtures of Fe and Si were mechanically alloyed with a ball-mill. Moessbauer spectroscopy and X-ray diffraction were used to characterise the microstructural changes of these mixtures which are induced by high-energy ball-milling. Moessbauer spectra are discussed in terms of two main spectral components (corresponding to FeSi alloy and α-Fe) and the time dependence of the alloy formation follows a Johnson-Mehl type law. Calorimetry measurements show that the formed alloy is stable up to 800℃ as no crystallisation or phase transformation peaks are observed. From X-ray diffraction, a crystallite size of 9 nm is obtained. Magnetic measurements at low temperature were carried out on the final alloy and the saturation magnetic moment at 4.2K is 0.44 μ_B/Fe.