Step-by-step powder composite mechanosynthesis for functional nanoceramics

To study the possibility of Fe2O3 mechanochemical reduction by preliminary mechanically alloyed Fe+20%Al compound their powder mixture was subjected to high-energy ball-milling in Ar atmosphere, with the milling time varying between 2 and 12 minutes. The milled samples obtained at various times of milling were characterized by X-ray diffraction and Moessbauer spectroscopy. As a result gradual α-Fe2O3 reduction via formation of intermediate Fe-Al-O oxides was observed. The presence of the intermediate Fe2AlO4 spinel phases stable over long milling time is stated. Mechanocomposite Fe+20%Al transformation to α-Fe(Al) solid solutions which evolve peculiarly with the milling time, was observed also. The kinetics of α-Fe2O3 reduction process was analyzed in comparison with the same processes in the systems: α-Fe2O3 + Al and α-Fe2O3 + Al + Fe.