Nanocomposites and nanomaterials

Ferromagnetism of iron-copper nanocomposites
Revo S.L., Avramenko T.G., Ivanenko K.O., Naumenko S.M., Volkova T.V.
Physics of Metals and Ceramics Scientific Research Laboratory Faculty of Physics Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Street, 01601 Kyiv, Ukraine
E-mail: s_revo@i.ua

The magnetic characteristics of thin films in massive samples are considered and realized in present paper. Multilayer nanocomposite materials (MLNCM) from both iron and copper powders, and iron powders with multilayer carbon nanotubes were obtained in two ways. The first method is that a mixture of heterogeneous metal powders with the size of 4-100 microns was rolled, sintered and compressed with a total 99% reduction [1]. In a second method, the powders mixtures were previously treated in a planetary mill before sintering [2]. It is shown that the microstructure of the samples obtained is, as a rule, layered. Due to deformation, in particular, rolling, the thickness of the layers can be reduced to nanoscale. The properties of such massive materials, despite the possible heterogeneity of the continuity of the layers during rolling to nanoscale thicknesses and their fragmentation into nanoflakes, are similar in most properties of thin films. The relation between the microstructure, which is determined by the method of processing the powders mixture, the thickness of the layers/scales and the coercive force of the obtained materials, is established. It was determined that the change in the composition of the MLNCM and its layers thickness allows to obtain the bulk material by the first method with the value of the coercive force of 2.2 times higher than for iron-copper alloys of the corresponding concentration for compositions obtained by the second method. This excess can achieve 9.3 times. 

1.	Shpak А.P., Mayboroda V.P., Kunitskiy Yu.A., Revo S.L., Nano-composite materials and coatings (Kyiv, Publishing House "Academperiodika", 2004) (in Russian).
2.	Boshko O., Nakonechna O., Dashevskyi M., Ivanenko K., Belyavina N., Revo S., Effect of the carbon nanotubes on structure and magnetic properties of the Fe–Cu (4:1) composites // Advanced Powder Technology.-2016.-27 No4.-P.1101-1109.