Advanced Materials Research Vol. 1085

Abstract: The paper is dedicated to the research of calcium-phosphate coatings formed on the surface of the polymer layers (copolymer tetrafluoroethylene with vinylidene fluoride) by pulsed laser deposition. The calcium-phosphate coatings were formed using two different by composition targets. The morphology of the obtained coatings was analyzed by Scanning Electron Microscopy, the elemental composition was analyzed by Energy Dispersive Analysis, and the chemical composition was analyzed by Fourier Transform Infrared Spectroscopy.

Abstract: Zn and ZnO nanosized powders are increasingly in demand of materials engineering, power systems and biotechnology. Meanwhile, elaboration, production and application of nanopowders have created the conditions for nanoparticles release into the environment. The lack of physicochemical information about nanoparticles behaviour in liquid environment does not allow to give deep interpretation of toxic effects of nanoparticles and elaborate new techniques for testing of nanomaterials. This study is primarily focused on the characterization of nanopowder composition, shape and dispersity of electroexplosive zinc nanopowder in aqueous suspensions based on simple physiological solutions of phosphate buffering saline, glucose solution, and distilled water. With the help of SEM images, X-ray analysis, and visualization it was revealed that on the surface of sphere-like Zn nanoparticles formed insoluble oxide-hydroxide compounds with strongly developed structure. The method of laser diffraction was used to give a description of the aggregation status of nanoparticles and its evolution on the time-scale.

Abstract: Modification of a titanium surface layer with yttrium using the combined technique of electroexplosive doping and the subsequent irradiation by a high-intensity electron beam is carried out. The studies on the structure, the element and the phase composition, mechanical and tribological properties of the doped layer are carried out. Formation of a multiphase submicron-nanocrystalline eutectic is revealed. A multifold increase in the microhardness, a decrease in the friction coefficient and the wear rate of the modified layer is established.

Abstract: The equilibrium and dynamics of sorption of Co²⁺ and Cu²⁺ ions have been investigated on highly cross-linked carboxyl cation exchangers of gel (KB-125P) and macroreticular (KB-2E-10) structure from solutions with an ionic strength of 0.1 and 1. It has been established that there is a weak effect of salt background concentration on selectivity of ion sorption in static conditions. In dynamic conditions with increased levels of background electrolytes, there is a decrease in the degree of ion exchanger layer KB-2E-10, which indicates a decrease in the selectivity of sorption. For the cation exchanger KB-125P, on the contrary, there is an increase in the degree of the layer use. It has been concluded that the gel structure of the sorbent KB-125P provides selective sorption of Co²⁺ and Cu²⁺ ions from solutions with high salt background. Coloring of cation exchangers layer KB-125P and KB-2E-10 in the absorption of Cu²⁺ and Co²⁺ makes it possible to create effective indicator tubes on their basis.

Abstract: Synthesis of glyoxylic acid was carried out by oxidation of glyoxal aqueous solutions by nitric acid. Glyoxylic acid and oxalic acid (as a by-product) were isolated from technological mixtures in the form of their calcium salts in a strictly defined region of pH. Previously, model calcium salts were synthesized from the commercial acids as reference objects.The results of infrared spectroscopy and complexometric titration of precipitates of calcium salts of glyoxylic and oxalic acids, isolated in various pH regions, allow one to construct reliable research strategies of complex mixtures, such as obtained from the oxidation products of aqueous solutions of glyoxal.

Abstract: The Al₂O₃/SiO₂ materials prepared by impregnation of mesoporous silica with water solution of Al(NO₃)₃·9H₂O were suggested to be used as supports for catalyst of high-temperature catalytic reactions. It was shown that the distribution of Al₂O₃ component inside wide pores of silica (10-50 nm) occurs with the formation of Al₂O₃ layer in case of low loading and porous layer or particles, if Al₂O₃ loading increases. Thus, materials with bimodal pore size distribution were obtained. The Cr-containing catalysts were prepared on the basis of these supports and tested in the process of isobutane dehydrogenation at 540 °C. It was observed that the activity of the obtained Cr/Al₂O₃/SiO₂ materials was comparable with the one for Cr/Al₂O₃ catalyst. Thus, the suggested Al₂O₃/SiO₂ materials with unique porous structure are promising to be used as supports for catalysts for high-temperature reactions.

Abstract: The interaction of components in modifying mixtures with the elements of Fe-Mn-С alloys hyperfine structure is investigated. Comprehensive study of the modified material microstructure is conducted. The substructure of Fe-Mn-С alloys is shown to undergo significant changes. The produced castings are characterized with enhanced physical-and-chemical and technological properties

Abstract: Normal 0 false false false RU X-NONE X-NONE The combination of methods of voltammetry, Raman spectroscopy, and X-ray reflectometry for the first time has been applied for the more comprehensive investigation of interfacial boundaries of GaAs, i.e. determination of phase distribution and thickness of the phase layers. The conditions for the formation of elemental arsenic on a GaAs surface in the process of selective dissolution are discussed. The stability of interfacial boundaries in air has also been studied. The investigations have shown that air storage lead to the oxidation of formed As⁰ and reorganization of GaAs interfacial boundary accompanied by the formation of Ga₂O₃ and As⁰ as a result of a reaction between As₂O₃ and GaAs. The results on interfacial boundaries composition were found to be correlated with the theoretical data. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Обычная таблица"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;}

Abstract: TiO₂ and F-TiO₂ powders were prepared by hydrolysis of titanium tetraisopropoxide with reversed mixing of different hydrolytic reagents. The typeof the hydrolytic agentstronglyinfluences particle size, morphology and phase composition ofpowder.It was found, that the amount of injected water is significantly affects on BET surface area and particle size ofbare TiO₂.The presence offluorinemakes the samplemore porous and preventsanatase to rutile phase transformation under prolonged heat treatment, also particle formed are bigger in comparison with un-doped TiO₂.

Abstract: Sorption selectivity of a number of REE ions (Pr³⁺, Nd³⁺, Sm³⁺, Yb³⁺) was studied with the help of the KB-2E macroreticular carboxylic cation exchanger with a different content of a crosslinking agent. Selectivity was weakly dependent on the degree of crosslinking of the cation exchanger and concentration of the sorbed metal ion, which could be explained by the macroreticular structure of the cation exchanger. An increase in sorption selectivity of heavier REEs (Yb³⁺) correlated with a decrease in their crystallographic radius. It was concluded that a coordinate link of REE ions and oxygen donor atoms - a part of the cation exchanger - had been formed.