In the present work, high-energy milling under two different atmospheres wa
s applied to the ErFe2 intermetallic compound and to the chemical elemental
powders of Er and Fe with ErFe2 stoichiometric composition. Sample A is th
e compound milled under Ar, sample B the compound milled under N-2 and samp
le C the elemental powders milled under N-2 atmosphere. X-ray diffraction (
XRD) and Mossbauer spectroscopy (MS) results of the samples A and B show a
segregation process with increase of the milling time. Under N-2 atmosphere
, the initial compound was nearly dissociated with 50 h of milling, while w
ith Ar atmosphere the segregation process was completed with 100 h of milli
ng. From the analysis of the XRD and MS results, it was possible to observe
the appearance of other phases at intermediate milling times, in both samp
les A and B. One phase was associated with an amorphous ErFe2 alloy with a
magnetic ordering temperature, obtained by AC magnetic susceptibility, at a
bout 190 K, a second phase was attributed to nanocrystallites of alpha-Fe a
nd a third one associated with an fee Er high-pressure phase stabilized by
N atoms. In the case of sample B, for milling times longer than 400 h, XRD
and MS results indicate the presence of an Fe-Er-N disordered alloy, with m
agnetic ordering temperature above room temperature. The XRD and MS results
of sample C show the formation of an ErFe2 amorphous phase, with about 87%
of MS relative area in this phase at 68 h of milling.