Numerical research of materials crystal lattice parameters based on rare-earth metals

Geometrical parameters (coordinates and angles) of CeO2 crystal lattice by molecular dynamics method are calculated. Calculated parameters of crystal lattice are applied for definition the energy band structure via Hartree-Fock method in an approximation to CO LCAO (crystal orbitals as linear combination of atomic orbitals) and using the model of cyclic cluster. Calculated minimum energy band p-d is within the value range of experimental data. Valence band maximum is 4.2 while minimum energy band p-d width is 2.8 eV Quantum-chemical calculations are accelerated by Schwarz inequality and direct inversion method in iterative subspace. The obtained mathematical model is implemented into software package for calculating material properties

Data visualization tools for materials properties research

In work presented the results of research the algorithms of experimental data visualization, which obtain in the simulation of materials. The algorithms study was carried out on the example of the complete cycle for calculating the properties of an ideal diamond crystal. The calculation of crystal lattice properties was carried out using a software package for materials simulation. The obtained experimental data were analyzed using program REM_Viewer in which have been realized the algorithms of data visualization

Effect of preparation conditions on physic-chemical properties of tin-doped nanocrystalline indium oxide

In this paper the results of investigation of phase formation and change of concentration of free electrons (Ne) in indium tin oxide system during heat treatment of coprecipitated hydroxides of indium and tin from nitric and hydrochloric solutions and also, for comparison melts of salts nitrates by an alkaline reactant (NH4OH) are considered.The performed investigation allowed to set the optimal condition of preparation of polycrystalline tin-doped indium oxide with maximal electron concentration

The influence of scandium on the composition and structure of the Ti-Al alloy obtained by "Hydride Technology"

In this study the influence of scandium on the structural and phase state of the Ti-Al alloy obtained by the method of “Hydride Technology” (HT). The Rietveld method has allowed for determining the content of basic phases of the 49at.%Ti-49at.%Al-2at.%Sc system. By means of the methods of transmission electron microscopy (TEM) and X-ray spectral microanalysis, it has been established that scandium additives into the Ti-Al system result in the change of the quantitative content of phases in local regions of the structure. The Ti2Al5 phase has been found, and Ti2Al has been absent. In the morphology of substructures Ti-Al and Ti-Al-Sc there are lamellar structures or lamellae; the peculiarities of the distribution, fraction and size of which are influenced by scandium additives. The average width of Al-rich lamellae has been 0.85 U+03BCm, which is four times greater than that for the Ti-Al system (0.21 U+03BCm). For Ti-rich lamellae of the sample of the Ti-Al-Sc alloy, the average width of the lamellae has been 0.54 U+03BCm, and for Ti-Al it has been 0.34 U+03BCm. Based on the obtained data, a scheme of the distribution of phases in the composition of the Ti-Al-Sc alloy in the lamellar structures has been proposed. It has been established that in the Ti-Al-Sc system there is growth of the near-surface strength relative to Ti-Al. In this way, the microhardness of the Ti-Al-Sc alloy has amounted to 1.7 GPa, that is of the Ti-Al alloy which is 1.2 GPa

Prospects of photocatalysis in diesel fraction purification

The photocatalysis process is widely used for removal of toxic chemical compounds from water and air. Oxides, sulfides of semiconductor materials are used as catalysts in photochemical processes, one of which is titanium dioxide. The manufacturing of an effective catalyst – nanotubes of titanium dioxide and the study of its physicochemical characteristics are considered in this paper. The behavior of titanium dioxide with various structures in the course of removing sulfur-containing organic compounds from diesel oil fractions is investigated. It is found out that titanium dioxide nanotubes (NT) are the most efficient catalysts for the photooxidation. Photocatalytic treatment of diesel fractions allows efficient and simple purification of oil products from unwanted components

Corrosion resistance of neodymium and dysprosium hydrides

This paper describes the methods of obtaining hydrides of rare earth elements such as dysprosium and neodymium. The properties and corrosion resistance of these elements are investigated. A synthesis method of monophasic dysprosium and neodymium dihydrides is presented. Synthesized dihydrides are agglomerates with an average size of 3-50 µm and are formed by crystalline grains of a nanometer size. BET specific surface area, morphology, elemental analyses and composition of samples have been studied. Corrosion stability in aqueous solutions of hydrochloric acid and sodium hydroxide were studied. It was determined that both hydrides undergo hydrolysis in acid and alkaline mediums. Neodymium hydride is more stable to corrosion than dysprosium hydride, which is proved by its longer exposure to aggressive medium to hydrides. The formation of insoluble /poorly soluble products of corrosion can make a significant contribution to the process of powder dissolution

Rare earth elements materials production from apatite ores

The paper deals with the study of processing apatite ores with nitric acid and extraction of the rare earth elements. The rare earth elements can be successfully separated and recovered by extraction from the nitrate- phosphate solution, being an tributyl phosphate as extraction agent. The developed scheme of the processing apatite concentrate provides obtaining rare earth concentrates with high qualitative characteristics

The structural and phase state of the TiAl system alloyed with rare-earth metals of the controlled composition synthesized by the "hydride technology"

The structural state and the quantitative phase analysis of the TiAl system, alloyed with rareeart

A mechanism for creating an inversion of populations of energy levels

The possibility of the Gadolinium nuclei energy levels population inversion under neutron bombardment is theoretically shown. In the process two isotopes of gadolinium take part. Light isotope Gd155 capturing neutron transforms to heavy isotope Gd156 at that heavy nucleus is in an excited metastable state. The population inversion is investigating during several tens of second when the neutron flux intensity is 1013 cm-2 · s-1

Effect of preparation conditions on physic-chemical properties of tin-doped nanocrystalline indium oxide

In this paper the results of investigation of phase formation and change of concentration of free electrons (Ne) in indium tin oxide system during heat treatment of coprecipitated hydroxides of indium and tin from nitric and hydrochloric solutions and also, for comparison melts of salts nitrates by an alkaline reactant (NH4OH) are considered.The performed investigation allowed to set the optimal condition of preparation of polycrystalline tin-doped indium oxide with maximal electron concentration