Formation of Pyramidal Shaped Single Crystal Diamonds in Chemical Vapor Deposition

P. G. Kopylov, A. N. Obraztsov, M. A. Dolganov, and S. S. Abramchuk

Physics Faculty, Moscow State University, Moscow, 119899 Russia

Received March 12, 2009

Abstract — The work demonstrates the possibility of obtaining material containing micron-size diamond single crystals with a regular pyramidal shape surrounded by a low-order diamond fraction by plasma-enhanced deposition (CVD). To study the morphology of these films, the selective oxidation technique followed by an analysis of its results by electron microscopy and Raman spectroscopy is applied. We propose a model that describes the formation of these films. The possibilities to use the materials of this type are also discussed.

PACS numbers: 81.05.Vw, 52.77.Dq

Topology of Nanometric Graphite Films

A. V. Tyurnina*, D. V. Serov, and A. N. Obraztsov

Physical Faculty, Lomonosov Moscow State University, Moscow, 119992 Russia

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Received on March 12, 2009

Abstract — This work submits the results of a study in which the combinational scattering (CS) spectroscopy and electronic and optical microscopy of nanometric single-crystal graphite films obtained by precipitating in gas phase were used. It is shown the graphite material samples synthesized in this manner are fine, highly streamlined films that grow alongside of the substrate surface. The films feature a fairly smooth surface and thicknesses of 100–1 atomic layers. The study of the topologic properties of the material, such as the formation of folds along the entire surface and the occurrence of waveform ripples on some surface areas, showed that they may appear due to large differences in the carbon film and nickel substrate thermal expansion factors. The film thickness was assessed for the observed parameters of the periodic structures and the results comply with data obtained using other techniques. In some areas of the material in study, the graphene layers spontaneously split and form bubbles. The results of the CS analysis of various bubbles on studied film surfaces are evidence that, similar to the film itself, the walls of bubbles are composed of different numbers of graphite layers. It is shown that transparent bubbles in which meshlike topology is observed are formed with a single atomic layer.

PACS numbers: 81.16.Rf

ESTM Study of Nanostructure and Surface Energetic Properties of Individual Chromium and Nickel

Yu. M. Stryuchkova and E. V. Kasatkin

Karpov Institute of Physical Chemistry, Vorontsovo pole 10, Moscow, 105064 Russia

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Received July 29, 2008

Abstract — Individual chromium and nickel in air and at interfaces to 0.01 N HCl and 0.1 N H₂SO₄ solutions are studied with the use of electrochemical scanning tunneling microscopy (ESTM) and electrochemical scanning tunneling spectroscopy (ESTS) at the controlled potentials of the specimen and tip. The potential range of chromium specimens was 0.1 to 0.9 V in 0.01 N HCl and 0.3 to 1.1 V in 0.1 N H₂SO₄; the potential range of nickel was –0.01 to 0.64 V in 0.01 N HCl and 0.184 to 0.834 V (N.H.E.) in 0.1 N H₂SO₄. At the controlled potential, the surfaces in the studied acid solutions are smoother than in air. The potential of the specimen affects the electrophysical properties, which determine the electron tunneling transfer, more noticeably than the nanorelief of the metals. The obtained changes in the I_t,dZ spectra dependence on the distance in air on a field of 1 nm² at a step of 0.04 nm enabled us to estimate the effective barrier of tunneling K_ef between neighbor atoms, which is in good agreement with the known dependence of K_ef on the work function.

Effect of the Composition of Water-Acetone Solvent and Benzhydrazine Structure on Their Efficiency During Cadmium Electrodeposition from Perchlorate Media

V. V. Kuznetsov, L. M. Skibina, R. R. Khalikov, and M. A. Yakusheva

South Federal University, ul. Zorge 7, Rostov-on-Don, 344090 Russia

Chemistry Department, Electrochemistry Subdepartment

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Received June 28, 2007

Abstract — The feasibility of controlling the degree of retardation of a cathodic process by changing the ratio of the components in the liquid phase and nature of electron shifts in additive molecule (benzhydrazine) is discussed. The minimum electrode reaction rate is observed in a range of water structure stabilization under conditions of the predominant adsorption of organic molecules. The highest efficiency are achieved using an addiive with an electron-donating substituent in the molecule. The highest rate of the electroreduction of Cd²⁺ and the lowest efficiency of the additives are registered in the region of the loosening of the structure of the mixed solvent, causing selective ion solvation to become possible, which results in an abrupt increase in the adsorption activity of ClO₄^– anions on the cathode and is the main reason for the ’ effect during the electroreduction of metal ions.

PACS numbers: 81.15.Pq

Certain Characteristics of Nickel-Containing and Copper-Containing OxidePhosphate Layers on Titanium

V. S. Rudnev^a, M. S. Vasil’eva^b, A. Yu. Ustinov^a, and P. M. Nedozorov^a

^a Institute of Chemistry, Far East Division, Russian Academy of Sciences,
pr. Stoletiya Vladivostoka 159, Vladivostok, 690022 Russia

^b Institute of Chemistry and Applied Ecology, Far East State University, ul. Sukhanova 8, Vladivostok, 690095 Russia

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Received January 28, 2008

Abstract — The oxide–phosphate layers on titanium are formed by plasma–electrolytic oxidation in aqueous electrolytes with polyphosphate complexes of Ni(II) and Cu(II). The obtained coatings are investigated by Xray photoelectron spectroscopy and X-ray spectral analysis. A nonuniform distribution of elements over the thickness of coatings is established; they are characterized by an insignificant titanium content on the surface, concentrated copper in the surface layer, and the presence of carbon. It is shown that the obtained compositions film/Ti manifest a certain catalytic activity in the oxidation of CO to CO₂.

PACS numbers: 82.45.Cc

Catalytic Properties of Ni-, Cu-Containing Oxide Film/Aluminum Alloy Composition

I. V. Lukiyanchuk, L. M. Tyrina, and V. S. Rudnev

Chemistry Institute, Far-East Branch, Russian Academy of Sciences,
pr. 100-letiya Vladivostoka, 159, Vladivostok, 690022 Russia

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Received on March 06, 2008

Abstract — Copper and nickel oxide compounds containing layers were formed using the plasma electrolytic oxidation technique on aluminum and its alloys. It was studied how the aluminum alloy compound impacted on the Ni-, Cu-containing oxide film/aluminum alloy combinations catalytic activity in a CO oxidation reaction.

Magnetoelectrical Effect in Layered Composites PbZr_0.53Ti_0.47O₃Mn_0.4Zn_0.6Fe₂O₄

S. A. Gridnev, Yu. E. Kalinin, A. V. Kalgin, and E. S. Grigor’ev

Voronezh State Technical University, Voronezh, 394026 Russia

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Received

Abstract — The magnetoelectric (ME) effect in two- and three-layered composites made up of polarized ceramic plates of lead zirconate-titanate PbZr_0.53Ti_0.47O₃ (PZT) and manganese-zinc ferrite Mn_0.4Zn_0.6Fe₂O₄ (MZF) has been studied. Dependences of the transverse ME voltage coefficient (₃₁) on the magnetostrictive layer thickness and the magnetic field intensity and frequency have been established. The mechanical coupling coefficient of the composite plates has been estimated. Results obtained for two-layered PZT–MZF structures have been analyzed using the method of efficient medium parameters.

PACS numbers: 77.84.Lf, 75.80.tq

CobaltMolybdenumPhosphorus Alloys: Electroplating and Corrosion Properties

V. Kublanovsky^a, O. Bersirova^a, Yu. Yapontseva^a, H. Cesiulis^b, and E. Podlaha-Murphy^c

^a Vernadskii Institute of General and Inorganic Chemistry, Ukrainian National Academy of Sciences,
pr. Akad. Palladin 32/34, Kiev-142, 03680, Ukraine

^b Vilnius University, Naugarduko 24, Vilnius, LT-03325 Lithuania

^c Northeastern University, Boston, MA, 021156 United States

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Received June 25, 2008

Abstract — The relation between the composition, morphology, and corrosion resistance of the electrolytic oMoP coatings plated at various current densities from citrate baths containing ammonia or hydrazine and various amounts of sodium hypophosphite is studied. Phosphorus was included in the coatings as a result of the electrochemical reduction of hypophosphite ions. Ternary Co–Mo–P alloys containing up to 26 at % Mo and p to 3 at % P were electroplated. Coatings of the highest quality were obtained from a bath containing hydrazine admixture at a temperature of 50°C. Corrosion resistance of CoMoP coatings increases with an increase in the Mo content and a certain decrease in the phosphorus amount in the deposit. The best protective properties were demonstrated by coatings obtained at higher concentrations of sodium hypophosphite and high deposition current densities when CoMoP alloys containing 23 2 at % Mo and up to 1.5 at % P were formed.

Contact Corrosion of Metals in Aqueous and Aqueous Organic Environments: III. Corrosion of Metals Aqueous Glycol Solutions with High Water Contents

V. N. Esenin and L. I. Denisovich

Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul. Vavilova 28, Moscow, 119991 Russia

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Received November 2, 2006

Abstract — The corrosion behavior of aluminum, steel, and cast iron as either individual metal specimens or as parts of contact aluminum–steel, aluminum–cast iron, steel–cast iron, and aluminum–steel–cast iron systems in aqueous glycol solutions containing 5–50 vol % water is studied. In all systems, aluminum is found to act as a cathode with respect to steel and cast iron and, in contrast to them, is not corroded under the effect of electrolytes. With an increase in the water content in the ethylene glycol solution from 70 to 95%, the corrosion behavior of the metals becomes similar to that in water.

PACS numbers: 82.45.Bb

Features of Wetting with Water of Anodic  PlasmaElectrochemical Coatings on Aluminum and Titanium

V. S. Rudnev, A. E. Lysenko, and A. Yu. Ustinov

Institute of Chemistry, Far East Division, Russian Academy of Sciences,
pr. Stoletiya Vladivostoka 159, Vladivostok, 690022 Russia

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Received February 4, 2008

Abstract — Wetting with distilled water of coatings formed in orthophosphate–borate aqueous electrolyte is investigated. For an aluminum alloy, the wetting angle of freshly prepared films with water is ~20°. After annealing in air at temperatures higher than 300°C, the films become hydrophilic and water spreads over their surface. With time of storage in air and after sequential operations of wetting in water–drying in air, the wetting angle increases, reaching the values of ~70–80°. The composition of the film bulk (X-ray spectral analysis) and surface (X-ray photoelectron spectroscopy) during their wetting and limited wetting with water is presented. The possible causes of the observed phenomena are discussed.

PACS numbers: 82.45.Cc