Decomposition of FeSn intermetallic induced by mechanical milling

Abstract

Under mechanical milling (MM) in a planetary ball mill the FeSn intermetallic decomposes with formation of the Fe 5Sn 3 and FeSn 2 phases, which have the highest density among the phases of the Fe–Sn system. This process was investigated using conventional X-ray diffraction, DSC, magnetization and alternative current susceptibility measurements. If the amount of decomposition of FeSn is relatively small (<60%), the milled powder shows superparamagnetic behavior at room temperature. In this case, magnetization curves can be fitted by superposition of two Langevin functions. The particle sizes for the ferromagnetic Fe 5Sn 3 phase determined from the fitting parameters are in good agreement with the crystallite sizes determined from XRD data and remain approximately constant during MM. The decomposition of FeSn is attributed to the effects of local temperature and local pressure produced by ball collisions.