STRUCTURAL AND MAGNETIC-PROPERTIES OF MECHANICALLY ALLOYED FE81SI9B6NB3CU1 POWDERS

Nanocrystalline powders of Fe81Si9B6Nb3Cu1 composition have been synth esised by high-energy ball milling and characterised by means of X-ray and neutron diffraction, Mossbauer spectroscopy and magnetic tests. T he diffraction and Mossbauer measurements point out the progressive fo rmation of a bcc alpha-Fe(Si, Nb, Cu, B) disordered solid solution wit h average particle size in the nanometre range. In addition, for the s pecimens mechanically treated for prolonged times, the Mossbauer spect ra show an ultrafine non-stoichiometric Fe3+xSi1-x crystalline phase. The coercive field of the powder after long milling time is higher tha n that of the partially crystallized metallic glass of similar composi tion. The annealing at 973 K in inert atmosphere of the samples mechan ically alloyed for long times mainly produces the Fe3Si crystalline ph ase and small amounts of borides and Fe-Nb aggregates.