Thermodynamic Calculation of Flade Potential of Fe, Ni, and Cr Taking into Account Surface Energy

Yu. Ya. Andreev

Moscow Institute of Steel and Alloys, State Technological University, Leninskii pr. 4, Moscow, 119049 Russia

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Received May 20, 2009

Abstract — A method for the thermodynamic estimation of the active–passive transition potential of metals (Flade potential) in sulfuric acid (pH 0) is proposed. This theoretical calculation of the Flade potential () differs from the conventional one in that the Gibbs formation energy of the metal oxide on the surface is a sum of the Gibbs formation energy of the oxide < 0 and the surface Gibbs energy of the metal> 0. The technique of estimation used is based on the concept of the auto-adsorption of metal atoms (A) in the superficial layer and obeys the Gibbs adsorption equation = G_AA. The estimated Flade potentials of Ni, Cr, and Fe agree with the known experimental data.

PACS numbers: 82.45.Bb

Sorption of Water by Polyacrylic Acid

A. A. Borisevich, A. E. Chalyh, G. S. Kulagina, and V. K. Gerasimov

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,

Leninskii pr. 31, Moscow, 117071 Russia

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Received March 20, 2009

Abstract — The interaction of polyacrylic acid with water is reported. Water, which is consumed by polyacrylic acid in a wide range of humidities is found to exist in two states, i.e., statistically dissolved in the matrix (Flory-Huggins mode) and in cluster form. No retention due to the sorption on active sites according to Langmuir’s mode is detected.

Synthesis of Functionally Substituted Metalloporphyrin Receptor and Study of Their Supramolecular Properties

Yu. P. Yashchuk, V. S. Tyurin, and I. P. Beletskaya

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia

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Received April 01, 2009

Abstract — The ways of supramolecular self-assembly of metalloporphyrins containing peripheral ligand groups with metal cations and exobidentate ligands are studied.

Interaction of Stilbenes with TiO₂ Studied by Fourier IR Spectroscopy

K. E. Polunin, N. P. Sokolova, A. M. Gorbunov, R. A. Bulgakova, and I. A. Polunina

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
31 Leninskii pr., Moscow, 119991, Russia

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Received February 29, 2008

PACS numbers: 68.43.-h

PVC Materials with Sorption-Active Surfaceof Ethanol Cyclam Nanofilms

A. Yu. Tsivadze, A. Ya. Fridman, A. M. Voloshchuk, E. M. Morozova, N. P. Sokolova,
G. A. Petukhova, I. I. Bardyshev, A. M. Gorbunov, A. V. Dorokhov, I. Ya. Polyakova,
O. P. Shapokhina, and I. V. Solov’eva

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, building 4, Moscow, 119991 Russia

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Received November 26, 2008

Abstract — Materials with sorption-active nanofilms based on PVC materials with surface layers modified into ethanol cyclam nanofilms were obtained, based on which new functional materials with given properties can be developed. The properties and molecular structure of ethanol cyclam nanofilms with different sorption-active surfaces were studied using physicochemical research methods.

Hyperfine Structure and Electrochemical Behavior of FeCrNi Alloys

O. V. Kasparova^a and Yu. V. Baldokhin^b

^a Karpov Institute of Physical Chemistry, Vorontsovo Pole 10, Moscow, 105064 Russia

^b Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, Moscow, 119991 Russia

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Received June 10, 2008

Abstract — With the use of nuclear -resonance Mössbauer spectroscopy, the hyperfine structure of quenched (1100C, 1 h, water) Fe~20% Cr–(9.6, 40.8, 70.7)% Ni alloys is studied. With the Normos program package, the isomer (chemical) shift (mm/s) of the singlet and doublet signals, the half-width (mm/s) of the singlet and doublet spectral components, the area part S (%) of the components in the general spectra, and the probability distribution function of hyperfine magnetic fields P(H_eff) are calculated. The effect of nickel on the electron density distribution around ⁵⁷Fe nuclei is discovered. Novel data on the presence of ferromagnetic phases, their nuclei and clusters in Fe–19.6% Cr–9.6% Ni are obtained. The data of Mössbauer spectroscopy are compared to the anodic polarization curves recorded in a 1 N H₂SO₄ solution with the aim to clarify the relation between the electronic structure and electrochemical behavior of alloys

PACS numbers: 76.80.+y; 82.45.Bb

Transformation of Metal-Oxide Nanostructures in the Process of Afteroxidation of Iron Reactively Evaporated in Oxygen Atmosphere

V. A. Kotenev, D. N. Tyurin, A. Yu. Tsivadze, M. R. Kiselev,  V. V. Vysotskii, and V. I. Zolotarevskii

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, 119991 Moscow, Russia

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Received July 10, 2008

Abstract — The methods of atomic force microscopy combined with the digital processing of images were used to study the change in the morphology of nanostructured metal-oxide coatings obtained by reactive evaporation at 10⁶ torr in the atmosphere of oxygen and further low-temperature iron afteroxidation in an air atmosphere at different temperatures. It is shown that a nanostructured layer with a unimodal distribution according to the  size and degree of nonsphericity of the particle is formed in the case of sputtering. Using the sample detection methods, it is shown that a unimodal distribution is transformed into a bimodal distribution at an increase in the reoxidation temperature from 50 to 200°C, after which it becomes a trimodal distribution, which proves that the building blocks of a nanostructured layer are nanoparticles and four- and 16-particle surface nanoparticle conglomerates. This structure can explain the functional properties of these coatings, which are of practical importance.

PACS numbers: 81.07.Bc

Surface Structure of Multicomponent Oxide Coatings on Titanium

V. S. Rudnev^a, I. V. Lukiyanchuk^a, L. M. Tyrina^a, S. Wybornova^b, T. Staedler^b, and M. S. Vasil’eva^c

^a Institute of Chemistry, Far East Branch, Russian Academy of Sciences,
pr. 100 let Vladivostoka 159, Vladivostok, 690022 Russia

^b Institute of Materials Engineering Chair of Surface and Materials, Technology University, Paul-Bonatz Str. 9–11, Siegen,
57076 Germany

^c Far East State University, ul. Oktyabr’skaya 27, Vladivostok, 690091 Russia

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Received July 9, 2008

Abstract — Data on the surface structure of Cu–Ni containing oxide films formed on titanium under the effect of electric spark and arc discharges are considered at the scale of tens to hundreds nanometers. The surface sites of films around electric discharge channels are perforated with pores of diameters around 10 nm. Spheroids with diameters of tens to hundreds of nanometers, which chiefly elements contain involved in the electrolyte components including heightened amounts of copper and carbon, are distributed over the surface. Furthermore, agglomerates formed by planar particles with sizes of tens to hundreds of nanometers of irregular geometric shapes are also present on the surface. Elemental compositions of the film surface and planar agglomerates coincide. The particles are supposedly the products of the electric-discharge erosion of the film material.

Formation of Silver Nanoparticles in Solutions of Carboxymethylcellulose

A. V. Guselnikova, V. V. Visotskiy, O. Ya. Uryupina, and V. I. Roldugin

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
31 Leninskii pr., Moscow, 119991 Russia

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Received 19.03.2009

Abstract — An investigation is reported on the relation between the size and potential for silver nanoparticles prepared in aqueous solution of carboxymethylcellulose to pH of the solution by virtue of dynamic light dissipation. The changes in the size distribution for nanoparticles and their potential were monitored over time. The size of particles was found to degrease linearly with increasing pH; a similar effect was created by the maturation of colloidal solution. The potential of the maturation process tended to take an identical value for all hydrosol samples studied. A procedure is proposed for the numerical calculation of the relative concentration of nanoparticles that is applicable for the investigation of samples with various types of distribution for particle sizes. The degree of reduction for silver ions was found to depend significantly on the quantity of AgNO₃ presented and the ration between the precursor and the reducing agent.

Electroplating of Catalytically Active Nickel Coatings from Baths of Various Anionic Compositions

O. V. Dolgikh^a, N. V. Sotskaya^a, Vu Thi Duyen^a, E. A. Kotlyarova^a, and B. L. Agapov^a,b

^a Voronezh State University, Universitetskaya pl. 1, Voronezh, 394006 Russia

^b Voronezh State Technological Academy, pr. Revolyutsii 19, Voronezh, 394017 Russia

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Received November 6, 2008

Abstract — The effect of the nature of bath anions (Cl, and CH₃COO) on the characteristics of the electrochemical plating of nickel coatings, namely, parameters of the cathodic polarization curves, bath stability, and current efficiency, as well as the composition and morphology of deposits and their catalytic activity in the anodic oxidation of hypophosphite ions and cathodic evolution of hydrogen, is studied. The anionic composition of the baths is found to substantially affect not only the kinetics of the deposit growth, but also the properties of the deposit. The differences observed are determined by the complex-forming and buffering properties of the anions.

PACS numbers: 81.15.Pg