Solid State Phenomena Vol. 245

Abstract: We develop the method for determining the Mueller matrix elements using standard photometric ellipsometer. Small ellipsometer design changes give an opportunity to completely determine all elements of the Mueller matrix. It is shown how the values of Mueller matrix elements can be obtained from the measurements at different azimuthal positions of optical units.

Abstract: In this paper discusses and demonstrates the possibility of modeling materials with amorphous and nanocrystalline structure using random close packing of atoms and nanoclusters models. Concordance structure of the real models alloys was evaluated by the radial distribution function obtained as a result of calculations, and in its modeled structures estimation. Modeling structure of the amorphous matrix and the spatial distribution of nanoclusters in two-component amorphous alloys with composition Fe₈₀B₂₀ carried out by Ishikawa method. For modeling structure multicomponent amorphous metal alloys we developed correlation-spectral model of the amorphous matrix and nanoclusters. At modeling passing electron wave through the sample used a layered approach, and for the "visualization" imaging we modeled optical schemes of high-resolution electron microscopes.

Abstract: Here we report about study the novel class of nanocomposite for optical control devices. It was observed that nanocomposite based on cadmium sulfide quantum dots in silica matrix can change its optical properties under irradiation of UV-light. These changes are expressed as increasing of optical absorbance coefficient and not only decreasing of luminescence intensity but in some cases red-shifting of maximum. Dependence of quantum dot optical properties upon the kind of matrix and polarization degree of modifying radiation was obtained.

Abstract: Formation of GaSb by means of solid phase epitaxy of amorphous Ga:Sb (1:1) layer on Si (001) substrate at 500 °C has been studied. At amorphous layer thickness of 16 nm, a continuous nanocrystalline layer of GaSb was formed. Decreasing of amorphous layer thickness up to 0.8 nm resulted in formation of separated GaSb nanocrystallites (NCs), which had a mean lateral size of 30–80 nm and mean height of 2–3 nm, while their concentration reached 3×10⁹ cm^-2. Atomic force microscopy and low energy electron diffraction data showed that GaSb NCs could be fully embedded into silicon lattice by deposition of 25-nm-thick silicon layer at 650 °C. Nevertheless, on a surface of the silicon layer, some holes have been formed because of NCs moving toward to the surface. The holes formation can be almost completely suppressed by deposition of additional 25-nm-thick silicon layer at 500 °C – so-called “stop-layer”.

Abstract: The mesoporous CaMoO₄ microcrystals have been prepared by precipitation in an aqueous solution. The scheelite-type structure in space group I4₁/a has been verified by the XRD analysis of the final powder product. The CaMoO₄ powder is composed of the almost size-uniform erythrocyte-like microspheroids with a diameter of ~5 μm. Every particle is formed by plate-like crystals with the characteristic thickness at a few-nanometer level and a diameter of ~1-2 μm.

Abstract: The way of self-healing coating formation at the surface of magnesium alloys by means of plasma electrolytic oxidation method (PEO) with subsequent filling of the obtained layer with inhibitor has been suggested. The electrochemical properties of such coatings have been described in details. The obtained experimental results indicate that the protective properties of the samples with inhibitor-containing coating were increased (I_C = 8.6×10^–8 A/cm²) in comparison with the samples without coating (5.3×10^–5 A/cm²) and the base coating obtained by plasma electrolytic oxidation method (PEO) (3.4×10^–7 A/cm²). The local scanning electrochemical methods of surface investigation, notably Scanning Vibrating Electrode Technique (SVET) and Scanning Ion-Selective Electrode Technique (SIET) were used for determining the kinetics and mechanism of the self-healing process. The treatment by the solution containing 8-hydroxyquinoline, which inhibits the corrosion process, enables one to increase the protective properties of the composite coating in 30 times in the corrosion-active environment in comparison with the base PEO-coating and avert the intensive destruction of the material.

Abstract: Investigation results of the composite coatings obtained on MA8 magnesium alloy by plasma electrolytic oxidation (PEO) and post-treated by electrophoretic deposition of superdispersed polytetrafluoroethylene (SPTFE) are presented. Comprehensive research of electrochemical and mechanical properties of the obtained polymer-containing coatings on the magnesium alloy has been performed. It has been established that composite coatings to decrease the corrosion current density by three orders of magnitude (down to I_c = 2.0×10^-10 A/cm²) and the wear by two orders of magnitude (down to 1.2×10^-6 mm³/(N·m)), as compared to the basic PEO-coating.

Abstract: Surface modification of magnesium alloys by plasma electrolytic oxidation (PEO) and subsequent treatment with suspension of superdispersed polytetrafluoroethylene and tetrafluoroethylene telomeric solution are presented. Electrochemical, mechanical properties and wettability of obtained composite coatings were investigated. The polymer-containing coatings decrease the corrosion current and wear by orders of magnitude as compared to unprotected magnesium alloy and base PEO-coatings.

Abstract: The prospects of an original method of pulsed high-voltage discharge in synthesis of nanostructured FeOF–FeF₃ composite anode for Li-ion battery has been demonstrated. Scanning electron microscopy investigation shows as-synthesized FeOF–FeF₃ consists of nanocrystallites ranging in sizes from 10 to 300 nm. Galvanostatic discharge–charge cycling of the Li/FeOF–FeF₃ half-cell at current density of 10 mA g^–1 in the range from 3.0 to 0.005 V yields 210 mAh g^–1 after 10 cycles. The electrochemical reaction mechanism within the Li/FeOF–FeF₃ has been investigated by the cyclic voltammetry method.

Abstract: The developed methods of formation and results of the study of the hydrophobic layers on aluminum alloy, previously subjected to plasma electrolytic oxidation (PEO) and additional treatment (either in ethanol solution or under UV-radiation in the presence of ozone plasma) with subsequent deposition of the hydrophobic agent (methoxy-{3-[(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluoroctyl) oxy] propyl}-silane solution in decane) have been described. It was found, that the formed composite layers possess a hydrophobicity (contact angle higher 157o) and high anticorrosion properties (the impedance modulus, |Z|_{f = 0.01 Hz}, ranges from 9.2·10⁹ to 4.0·10¹⁰ Оhm·cm² depending on the treatment procedure).