Перегляд за Автор "Fomina, L. P."
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Документ Functional Properties of Fe−Mo and Fe−Mo−W Galvanic Alloys(Springer, Heidelberg, Allemagne, 2016) Ved, M. V.; Sakhnenko, N. D.; Karakurkchi, G. V.; Yermolenko, I. Yu.; Fomina, L. P.The influence of the modes of electrodeposition on the morphology, topography, and structure of the galvanic alloys of iron with molybdenum and tungsten is discussed. It is shown that the increase in the corrosion resistance of Fe–Mo and Fe–Mo–W coatings in acid and neutral chloride-containing media is caused both by the elevation of their passivating ability caused by the process of alloying components and by the formation of globular surfaces with homogeneous chemical composition. The microhardnesses of Fe–Mo and Fe–Mo–W galvanic alloys prove to be 2–3 times higher than the microhardnesses of the substrates made of low-alloy steel, which can be explained by the formation of amorphous structures. The results of investigations and tribological tests show that it is reasonable to apply the coatings of double and triple iron alloys in order to reduce wear in friction couples and to increase the corrosion resistance and mechanical strength of the surfaces, which makes them promising for the repair and restoration technologies.Документ Galvanic ternary Fe−Co−W coatings: structure, composition and magnetic properties(Науково-технологічний комплекс "Інститут монокристалів", 2018) Yermolenko, I. Yu.; Ved, M. V.; Sakhnenko, N. D.; Fomina, L. P.; Shipkova, I. G.Principles of Fe–Co–W alloys electrodeposition from complex Fe (III) based citrate electrolytes are discussed. The effect of both current density and pulse on/off time on the quality, composition and surface morphology of the electrolytic alloys were determined. The application of pulsed electrolysis provides increasing ungsten content up to 13 at.%, at current efficiency of 70-75 %. Globular surface of Fe–Co–W coatings is caused by refractory metals incorporation, and crystalline and amorphous parts of structure are visualized by X-ray spectroscopy, including inter-metallic phases Co₇W₆, Fe₇W₆ along with α-Fe and Fe₃C. The coherent-scattering region size of the amorphous part is 2-8 nm. Magnetic characteristics of amorphous Fe–Co–W coatings were measured in dependence of deposition ime. The conclusion was made that the content of magnetic phase in upper layers of coating is greater than in the bottom ones due to decreasing W atom concentration.Документ Galvanochemical formation of functional coatings by the cobalt-tungsten-zirconium alloys(Institute for Single Crystals, 2020) Nenastina, T. A.; Ved, M. V.; Sakhnenko, N. D.; Proskurina, V. O.; Fomina, L. P.The functional properties of ternary Co-W-Zr(ZrO₂) alloys obtained in a pulsed mode from pyrophosphate-citrate electrolytes are discussed. The obtained coatings are characterized by a uniformly developed surface without cracks and a sufficiently high and reproducible microhardness. It was determined that the size of the globules on the alloy surface decreases with increasing of the current density to 10 A/dm². It was found that increase of temperature favorably affects the current efficiency of the alloy and the microhardness of the Co-W-Zr(ZrO₂) coating. The modes of electrosynthesis of the coatings by cobalt-tungsten-zirconium alloys are substantiated, an their influence on the functional properties of the alloy and current efficiency is investigated.Документ Optimization for the range of analytical line intensity measurement in energy-dispersion X-ray fluorescent analysis(Национальный научный центр "Харьковский физико-технический институт", 2015) Mamaluy, A. A.; Mikhailov, A. I.; Fomina, L. P.Optimization for the range of measuring the analytical line integral intensity and background signal has been proposed using the criterion of the detection limit for the case of energy-dispersion analysis. By the example of a standard of 1 % Co solution in boron acid, it was shown, that the optimal measurement range was by a factor 1.5 higher than the analytical line full width at its half-maximum.Документ X-Ray Fluorescence Determination of Trace Gold in an Ion-Exchange Resin(Pleiades Publishing, Ltd., 2014) Mikhailov, I. F.; Baturin, A. A.; Mikhailov, A. I.; Fomina, L. P.The use of portable X ray optics with a secondary radiator in the determination of trace gold in an ion exchange resin within the mass fraction range of 1–50 ppm is described. It is shown that the secondary radiator design with primary radiation filtering allows one to determine trace gold in an ion exchange resin when the mass fraction of gold is lower than 1 ppm.