STRUCTURE OF MASSIVE MATERIAL PREPARED FROM ULTRAFINE IRON

Ultrafine Fe powder was prepared by plasma recondensation method and s ubjected to cold compaction. Structural and magnetic investigations of ultrafine Fe particles and the compacted massive material were carrie d out by Mossbauer spectroscopy and X-ray diffraction. They revealed t hat the Fe particles ave surrounded by an Fe oxide layer composed of u ltrafine Fe3O4 and / or gamma-Fe2O3 grains. At room temperature the ox ide components are superparamagnetic and show a very broad Mossbauer a bsorption spectrum superimposed on that of alpha-Fe. The area of the b road subspectrum is found to be changing as a result of compaction pro cess and annealing. If may be caused by microstructured changes and th eir correlation with magnetic properties.