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Hard magnetic nanocrystalline alloys of Fe–Fe2O3 system

“…The average crystallite size in the powders, determined from a X-ray-line broadening, decreased strongly after relatively short milling time to a constant value of /DS E10-20 nm (for a-Fe and FeO) [3,4]. At the same time, the average particle size in the milled powders, determined by scanning electron microscopy, was less than a micrometer.…”

“…[4,5] allows to assume that the amorphous phase is a solid solution of oxygen in iron. This result is in a good agreement with the X-ray data.…”

“…These materials are produced by various methods, in particular, by mechanochemical technique. We have previously showed that nanocrystalline hard magnetic Fe-O alloys could be produced by mechanochemical technique from a Fe 2 O 3 powder or a mixture of Fe and Fe 2 O 3 (Fe 2 O 3 +X%Fe where Xp50) [4,5]. The goal of the present work was to study the structure and magnetic properties of nanocrystalline Fe-O alloys in dependence on their composition.…”

“…According to X-ray and Mo¨ssbauer investigations, a low-temperature annealing of the milled powders led to a dissociation of FeO and the amorphous phase into aFe and a-Fe 3 O 4 [4,5]. The powders (except for the Fe powder) after the annealing contained only a-Fe and aFe 3 O 4 with the average crystallite size of 15-20 and 10-15 nm, respectively.…”

“…Therefore, production and investigation of new hard magnetic materials are urgent and important. Recently, considerable attention has been drawn to the investigation of nanocrystalline hard magnetic materials [1][2][3][4]. These materials are produced by various methods, in particular, by mechanochemical technique.…”