Nanostructured coatings based on amorphous carbon and gold nanoparticles obtained by the pulsed vacuum-arc method

Nanostructured coatings based on diamond-like carbon and gold-doped carbon with a thickness of 100-300 nm were obtained by a pulsed vacuum-arc method on silicon substrates. The structure of the coatingswas studied by high-resolution transmission electron microscopy, the elemental composition was studied by X-ray microanalysi

СОСТАВ И СВОЙСТВА ПОВЕРХНОСТНЫХ СЛОЕВ, ФОРМИРУЕМЫХ ИОННО-АССИСТИРУЕМЫМ ОСАЖДЕНИЕМ КАТАЛИТИЧЕСКИХ МЕТАЛЛОВ ИЗ ПЛАЗМЫ ВАКУУМНОГО ДУГОВОГО РАЗРЯДА НА УГЛЕРОДНЫЕ ПОДЛОЖКИ

Surface layers were prepared by ion beam-assisted deposition (IBAD) of platinum and rare earth metals (Ce, Yb) on the carbon-based Toray Carbon Fiber Paper TGP-H-060 T catalyst support in effort to produce electrocatalysts for direct methanol and ethanol oxidation fuel cells (DMFC, DEFC) with polymer electrolyte membrane. The layer formation in the IBAD mode, by means of the metal deposition and the mixing of a precipitating layer with the substrate by accelerated (U = 10 kV) ions of the same metal, was carried out. In this process, a neutral fraction of metal vapor and ionized plasma of vacuum pulsed electric arc was used. The study of morphology and composition of the layers was performed by scanning electron microscopy and electron probe microanalysis, X-ray fluorescence analysis and Rutherford backscattering spectrometry. Properties of the prepared electrocatalysts were investigated by cyclic voltammetry. It was established that the prepared electrocatalysts show their activity in the processes of electrochemical methanol and ethanol oxidation. Поверхностные слои сформированы ионноассистируемым осаждением (IBAD) платины и редкоземельных металлов (Ce, Yb) на носитель Toray Carbon Fiber Paper TGP-H-060 Т с целью получения электрокатализаторов для топливных элементов прямого окисления метанола и этанола с полимерным мембранным электролитом. Формирование слоев проведено в режиме IBAD, при котором осаждение металла и перемешивание осаждаемого слоя с атомами поверхности подложки ускоренными (U = 10 кВ) ионами того же металла осуществляются соответственно из нейтральной фракции пара и плазмы вакуумного дугового разряда импульсного электродугового ионного источника. Исследование морфологии и состава слоев проведено методами сканирующей электронной микроскопии и электронно-зондового микроанализа, рентгеновского флуоресцентного анализа и спектрометрии резерфордовского обратного рассеяния. Свойства электрокатализаторов исследовались методом циклической вольтамперометрии. Получаемые электрокатализаторы проявляют активность в процессах окисления метанола и этанола.

Properties of carbon coatings obtained by pulsed high power methods of vacuum-arc and magnetron sputtering

Investigation results of the structure, mechanical, tribological and adhesion characteristics of carbon coatings obtained by two different methods: high-power impulse magnetron sputtering and pulsed cathodic arc deposition are presente

The local crystallization in nanoscale diamond-like carbon films during annealing

The local crystallization during annealing at 600° C in nanoscale diamond-like carbon coatings films grown by pulsed vacuum-arc deposition method was observed using modern techniques of high-resolution transmission electron microscopy. The crystallites formed by annealing have a face-centred cubic crystal structure and grow in the direction [011] as a normal to the film surface. The number and size of the crystallites depend on the initial values of the intrinsic stresses before annealing, which in turn depend on the conditions of film growth. The sizes of crystallites are 10 nm for films with initial compressive stresses of 3 GPa and 17 nm for films with initial compres- sive stresses of 12 GPa. Areas of local crystallization arising during annealing have a structure dif- ferent from the graphit

Galvanic corrosion resistance of aluminum and its alloy in galvanic couples with steels with metallic coatings

The aim of this work is comparison of corrosion resistance of aluminum and its alloy D16 to galvanic corrosion in couples with carbon steel A284 and stainless steel type 321, on the surface of which various metallic coatings were deposited. Zinc, cad mium and aluminum used as the metal coatings on the steel. Coatings deposited by electroplating and vacuum ion-beam assisted deposition. Study of galvanic coupling of deposited coatings with aluminum and its alloy carried out by electrochemical methods in a 3% NaCl solution. Zinc and cadmium coatings on steel, formed by both methods, have electrochemical characteristics of deposited metals. Zinc coatings in galvanic couples with aluminum and its alloy are anodes and aluminum coatings are cathodes. Compromise potentials of cadmium coatings approximately coincide with those for aluminum and its alloy. Current density of the galvanic corrosion of aluminum and its alloy in galvanic couples with steel with-out coatings was ~10{–2}mA/cm{2}, and in galvanic couples with aluminum coatings on steel – ~10{–3}mA/cm{2}. Corrosion current density of zinc in coatings was 2 ⋅ 10{–2}mA/cm{2}, and cadmium – 6 ⋅ 10{-3} mA/cm{2}. Best galvanic compatibility with aluminum and its alloy D16 in 3% NaCl have cadmium coatings

Galvanic corrosion resistance of aluminum and its alloy in galvanic couples with steels with metallic coatings

The aim of this work is comparison of corrosion resistance of aluminum and its alloy D16 to galvanic corrosion in couples with carbon steel A284 and stainless steel type 321, on the surface of which various metallic coatings were deposited. Zinc, cad mium and aluminum used as the metal coatings on the steel. Coatings deposited by electroplating and vacuum ion-beam assisted deposition. Study of galvanic coupling of deposited coatings with aluminum and its alloy carried out by electrochemical methods in a 3% NaCl solution. Zinc and cadmium coatings on steel, formed by both methods, have electrochemical characteristics of deposited metals. Zinc coatings in galvanic couples with aluminum and its alloy are anodes and aluminum coatings are cathodes. Compromise potentials of cadmium coatings approximately coincide with those for aluminum and its alloy. Current density of the galvanic corrosion of aluminum and its alloy in galvanic couples with steel with-out coatings was ~10{–2}mA/cm{2}, and in galvanic couples with aluminum coatings on steel – ~10{–3}mA/cm{2}. Corrosion current density of zinc in coatings was 2 ⋅ 10{–2}mA/cm{2}, and cadmium – 6 ⋅ 10{-3} mA/cm{2}. Best galvanic compatibility with aluminum and its alloy D16 in 3% NaCl have cadmium coatings

Composition of Surface Layers Prepared by Ion Beam Assisted Deposition of Catalytic Metals from Pulsed Arc-Discharge Plasma onto Carbon Paper Substrates

The layers were prepared by ion beam assisted deposition of iridium and platinum onto AVCarb® Carbon Fiber Paper P50 electrocatalyst supports for the production of diffusion layers of the membrane-electrode assemblies of low temperature fuel cells with polymer electrolyte membrane. Formation of the layers in the ion beam assisted deposition mode, by means of the deposition of metal and mixing of precipitating layer with the substrate by the accelerated (U=10 kV) ions of the same metal, was performed. In this process neutral fraction of metal vapour and ionized plasma of vacuum pulsed electric arc discharge were used. The investigations of morphology and composition of layers were carried out by the scanning electron microscopy, energy dispersive X-ray microanalysis, wave dispersive X-ray fluorescence analysis, and the Rutherford backscattering spectrometry methods. It was established that the obtained catalytic layers contain atoms of the deposited metals and substrate material as well as impurity oxygen atoms. The surfaces contain also metal inclusions of several micrometer size which arise from the precipitation of deposited metal droplets from the arc discharge of an ion source. The content of iridium and platinum atoms in the layers is ≈2×10¹⁶ cm¯²; the concentration of the deposited metals equals about several atomic percent

Composition of Surface Layers Prepared by Ion Beam Assisted Deposition of Catalytic Metals from Pulsed Arc-Discharge Plasma onto Carbon Paper Substrates

Целью данной работы является изучение состава и морфологии поверхностных слоев, создаваемых ионным пучком вспомогательного осаждения каталитических металлов (иридия и платины) на подложки электрокатализатора копировальной бумаг

Composition and Microstructure of Surface Layers Produced by Ion Beam Assisted Deposition of Metals from a Pulsed Arc-Discharge Plasma onto Aluminum Substrates

Ion beam assisted deposition of alloying metals (Zn, Cd, Zr, Cr) onto pure aluminum and aluminum alloy substrates from the plasma of a pulsed arc discharge for the purpose of materials corrosion stability was carried out. The Rutherford backscattering spectrometry, electron backscatter diffraction, scanning electron microscopy, and electron probe microanalysis methods were applied to investigate composition and microstructure of the prepared layers. It was found that the obtained layers are characterized by amorphous atomic structure and contain the atoms of deposited metal, substrate material components, as well as impurities of oxygen and carbon; their thickness was measured to be ≈ 30-100 nm