Moessbauer study of mechanically alloyed Fe57Cr31Co12

Nanostructured powders of Fe57Cr31Co12 were prepared by mechanical alloying from elemental Fe, Cr and Co powders, using a planetary ball mill type Fritsch Pulverisette 7. The powders were characterized by X-ray diffraction and 57Fe Moessbauer spectrometry. A detailed analysis of the diffraction patterns reveals a decrease of the crystalline grain size as a function of milling time. For the first hours of milling, Moessbauer spectra are composed of a magnetic contribution and a single line. The paramagnetic component, whose relative area increases with milling time, can be attributed to paramagnetic Cr-rich clusters. The results are compared to those obtained on the same alloy prepared by conventional melting technique. (orig.)