FE-AL2O3 NANOCOMPOSITES PREPARED BY HIGH-ENERGY BALL-MILLING

Nanocomposites of alpha-Fe and alpha-Al2O3, prepared by high-energy ba ll milling, exhibit coercivities which are enhanced by about two order s of magnitude with respect to the bulk value. The degree of enhanceme nt depends on the volume fraction (x(upsilon)) of Fe, with a maximum f or x(upsilon) almost-equal-to 0.25. The effect is ascribed to the prod uction of single-domain magnetic grains. Mossbauer spectroscopy reveal s the presence of iron oxide phases which could not be seen by x-ray a nd electron diffraction measurements.