Kateryna Ivanenko

Structure and Strength of Iron-Copper-Carbon Nanotube Nanocomposites

Nanocomposite materials of the Fe-Cu system with/without small addition of carbon nanotubes have been synthesized by mechanochemical activation of elemental Fe and Cu powders in a high-energy planetary ball mill and have been examined by the X-ray diffraction method, SEM and the thermopower methods; the tensile strength of the materials obtained has been estimated. The metastable (Fe, Cu) supersaturated solid solution is formed in the Fe-Cu nanocomposites during milling process. The coherent scattering block size of the materials obtained is decreased with increase of milling time. The duration of mechanochemical activation affects the physical properties of nanocomposites studied. Addition of a small amount of nanotubes into Fe-Cu charge results in a significant increase of strength of the Fe-Cu (4:1) + CNT nanocomposite materials (NCMs) obtained.

Thermal analysis of polyethylene + X% carbon nanotubes

The aim of this research is to study the influence of the multi-walled carbon nanotubes (MWCNTs) on the thermomechanical and structural properties of high-density polyethylene. Several, complementary experimental techniques were used, namely, dilatometry, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Raman spectroscopy, and infrared (IR) spectroscopy. Dilatometry data showed that nanocomposites exhibit anisotropic behavior, and intensity of the anisotropy depends on the MWCNT concentration. The shapes of the dilatometric curves of the nanocomposites under study differ significantly for the radial and longitudinal directions of the samples. DSC results show that MWCNTs weekly influence calorimetry data, while Raman spectra show that the ID/IG ratio decreases when MWCNT concentration increases. The IR spectra demonstrate improvement of the crystallinity of the samples as the content in MWCNTs rises.

Luminescence of the Alkali-Metals Nitrites Incorporated into Cellulose Matrix

Surface morphology and photoluminescence (PL) properties of both microcrystalline cellulose (MCC), microcrystalline powders of the alkali metals nitrites MNO2 (M = Na. K, Cs) (MCN) and two-component composite materials based on the MCC and MCN have been studied and characterized by means of optical microscopy and luminescence spectroscopy.

Surface modification and creation of nano-objects for nanoelectronics

The practical use of a scanning tunneling microscope for modifying the sample surface and for creation of nano-objects on the sample surface is shown. The possibility of modification of the sample surface by tunneling current was shown. Nano-objects on the surface of the experimental samples were created using contact and non-contact modification of surface. This may also enable preparation of the surface for subsequent applications in which it is necessary to reduce the average irregularities of the surface.

Structure Features, Strength, and Microhardness of Nanocomposites Obtained from Fe, Cu, and Carbon Nanotubes

The effect of the treatment mode on the structure and mechanical properties such as strength and hardness of the nanocomposite materials (NCMs) synthesized from Fe, Cu, and carbon nanotubes (CNTs) has been studied. A comparison of the characteristics of nanocomposites obtained by two different methods, namely, by mechanochemical activation in a planetary ball mill and without milling, has been provided. It has been shown that materials obtained without pretreatment of their components in a ball mill do not demonstrate any advanced mechanical properties and their components are not dissolved. But a number of metastable solid solutions are formed in NCMs after mechanochemical treatment of Fe, Cu, and CNT powder mixture in a ball mill. Moreover, it is shown that several phases were forming at the different stages of the milling process of Fe and CNT powders, namely, α-(Fe,C) and γ-(Fe,C) supersaturated solid solutions along with the Fe3-x C and the Fe7C3 carbide phases. These phases mainly determine the properties of material. Thus, it was found that mechanical milling allows to obtain NCMs with higher characteristics than without such processing. So, the tensile strength σB of NCMs obtained from Fe and Cu powders reaches 1800 MPa, whereas this value in a case of NCMs obtained without milling of components is 1200 MPa. The microhardness of Fe-CNT nanocomposites reaches 10 GPa compared to 5 GPa for Fe-C NCMs. The criteria of the powder mixture treatment for nanocomposites synthesized to ensure uniform distribution of the components, CNT agglomerate dispersing, predicted changes in morphology, phase composition of the powders, and characteristics of the NCMs obtained have been optimized.

Spectroscopy of the alkali-metal nitrite and nitrate incorporated into cellulose host matrix

Morphology and photoluminescence (PL) properties for microcrystalline cellulose (MCC), microcrystalline nitrite, MNO₂, or nitrate, MNO₃, (MCN) powders of common formulae MNO_n (n = 2, 3) (M = Na. K, Cs) and two-component materials composed of MCC and MCN have been studied and characterized.