Sputtering targets made of an Si-Ti-Co alloy

The effect of the cooling rate on the microstructure and the micromechanical properties of a resistance air-cast Si-23% Ti-10% Co alloy and on the residual stresses in magnetron sputtering targets made of it is studied. The choice of a proper temperature schedule of melting the alloy and the optimum cooling rate of the alloy melt are shown to result in a homogeneous fine-grained structure of the alloy, high strength characteristics of the targets, and a low level of residual thermal stresses in them.     

Extraction of antimony and niobium with tributyl phosphate from fluoride-ammonium solutions

The purification of niobium from antimony impurity via extraction with tributyl phosphate from solutions of the HF + NH₄F mixture has been studied. It has been established that at an HF + NH₄F content equal to 7–16 mol/L and an NH₄F concentration of 30% in the mixture, Sb extraction hardly changes (70–80% for one stage), and Nb coextraction abruptly decreases to values of less than 0.5%.     

On the acceleration of clusters in a linear resonance accelerator for controlled thermonuclear fusion: Estimation of losses in the acceleration

The restrictions on the mean cluster-beam current due to cluster-cluster collisions during acceleration in a linear accelerator are considered. The relationship between the total number of accelerated atoms in the accelerated beam and the average number of atoms per cluster was obtained. This relationship allows for optimization of the intense accelerated-particle beam generation in a linear accelerator.     

Strongly enhanced current densities in superconducting coated conductors of YBa2Cu3O7-x + BaZrO3

There are numerous potential applications for superconducting tapes based on YBa(2)Cu(3)O(7-x) (YBCO) films coated onto metallic substrates. A long-established goal of more than 15 years has been to understand the magnetic-flux pinning mechanisms that allow films to maintain high current densities out to high magnetic fields. In fact, films carry one to two orders of magnitude higher current densities than any other form of the material. For this reason, the idea of further improving pinning has received little attention. Now that commercialization of YBCO-tape conductors is much closer, an important goal for both better performance and lower fabrication costs is to achieve enhanced pinning in a practical way. In this work, we demonstrate a simple and industrially scaleable route that yields a 1.5-5-fold improvement in the in-magnetic-field current densities of conductors that are already of high quality.     

Synthesis of a nanocomposite based on polyethylene and modified vermiculite

A composite of polyethylene and vermiculite, a natural aluminosilicate, has been prepared by treating vermiculite with a concentrated polyethylene solution in xylene. Varying the concentration of the polyethylene solution, we obtained materials with various compositions, which were then modified by heat treatment and chemical means (by HCl solution, followed by precipitation of metal ions). We have determined the elemental composition of the composite materials, obtained their IR spectra and X-ray diffraction patterns, and evaluated their surface properties and sorption capacity for organic dyes and oil products. The chemical modification of the composite materials increases their dye sorption capacity, which correlates with the observed changes in their specific surface area and specific pore volume.     

Sorption of U(VI) onto TiO<Subscript>2</Subscript>/ZrO<Subscript>2</Subscript>/SiO<Subscript>2</Subscript> Mesoporous Materials from Sulfate Solutions

New nanostructured mesoporous materials of the composition TiO₂/ZrO₂/SiO₂ were prepared by the template sol–gel method using a siloxane–acrylate emulsion as a template. The morphology and structure of these materials and their ability to take up U(VI) were studied. The influence of various factors (ZrO₂ content, pH of solution) on the sorption properties was studied. The suggested materials allow efficient sorption of U(VI) from sulfate solutions with low U(VI) concentrations and can be used in final purification processes.     

Extraction of tantalum, niobium, and antimony fluorides

This report deals with the effects of the HF and H₂SO₄ concentrations and the organic-to-aqueous phase ratio V _org: V _aq on the distribution of Ta, Nb, and Sb in their extraction with tributyl phosphate and n-octanol from model solutions that are similar in composition to those obtained in columbite-tantalite processing. The recovery of these elements decreases in the order Ta ? Sb ≥ Nb. Process conditions for efficient separation of Ta from Nb and Sb have been found.     

Phase formation during the carbothermic reduction of eudialyte concentrate

The phase transformations of eudialyte concentrate during the carbothermic reduction in the temperature range 25–2000°C are studied by thermodynamic simulation, differential thermal analysis, and X-ray diffraction. As the temperature increases to 1500°C, the following phases are found to form sequentially: iron and manganese carbides, free iron, niobium carbide, iron silicides, silicon and titanium carbides, and free silicon. Strontium, yttrium, and uranium in the temperature range under study are not reduced and are retained in an oxide form, and insignificant reduction of zirconium oxides with the formation of carbide ZrC is possible only at temperatures above 1500°C.