National University of Science and Technology «MISIS»:

E. A. Skryleva

N. Yu. Tabachkova

K. D. Scherbachev

M. I. Voronova

The effect of magnetic field treatment on the structure and chemical composition of reduced iron powders has been studied. The methods of transmission electron microscopy, X−ray diffraction and X−ray photoelectron spectroscopy have been used, and corrosion rate has been measured. We show that the processing of powders in an installation having an alternating magnetic field of 0.1 T and a frequency of 21 Hz does not result in any changes to the structure and phase composition. Reduced iron powder particles are spherical; the average diameter is of 2−3 microns, the particles being covered with an amorphous shell. Surface chemical composition studies have shown the shell to be a layer of natural ferric oxide/hydroxide forming in air. A method has been developed for determining the thickness of the oxide shell covering the spherical particles based on the relation of photoelectron lines intensities of the zero−valent and oxidized iron. We show that the shell thickness in magnetic field treated specimens is by 10−20% less than that in untreated powder. Corrosion rate measurements in a corrosive environment have shown that magnetic treatment significantly reduces the oxidation rate of the powders: the more the processing time, the lower the corrosion rate.

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