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1.
The Forming Conditions and Structure Characteristics of the Nickel Molybdenum Boron Chemico-Catalytic Coatings A. B. Drovosekov, M. V. Ivanov, V. M. Krutskikh, E. N. Loubnin, and Yu. M. Polukarov Institute of Physical Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia e-mail:
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Received September 27, 2004 Abstract — The effect of the components of chemico-catalytic reduction solutions on the formation rate, composition, and structure characteristics of Ni–Mo–B-alloy coatings is studied. The chemical state of elements and the composition of the surface and bulk layers of the coating containing 11 to 22 wt % of molybdenum and 1.0wt % of boron are studied using XPS combined with layer-by-layer profile analysis. The alloys have crys-talline nanostructure stable at temperatures of up to 500°C. Molybdenum is incorporated into the coatings pref-erably in its completely reduced form, as a supersaturated solid solution in the nickel matrix. Yet at the same time, the deposits absorb a substantial amount of the absorbed intermediate products of the molybdate reduction to Mo(IV).
23/09/2008 | 1049 Hits | Print
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2.
Pulsed Deposition of Silver from Polyligand Electrolytes A. V. Balmasov*, A. V. Sonin*, A. K. Krivtsov*, and S. A. Lilin** * Ivanovo State University of Chemistry and Technology, pr. Engel’sa 7, Ivanovo, 153460 Russia e-mail:
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, (0932)32-73-94 ** Institute of Chemistry of Solutions, Russian Academy of Sciences,
ul. Akademicheskaya 1, Ivanovo, 153045 Russia e-mail:
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, (0932)35-18-51 Received August 19, 2004 Abstract — The effect of electric conditions on the cathodic deposition of silver from pyrophosphase-ammonium electrolytes is studied. A pulse-current mode is shown to enhance cathodic polarization. This effect increases with an increase in the relative pulse duration. The advantages of nonsteady-state electrolysis for the improvement of the uniformity and structure of silver deposits formed on the inner surface of a cylindrical cathode are demonstrated.
23/09/2008 | 1067 Hits | Print
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3.
Electrodeposition of Copper-Containing Polymer Coatings from Sulfate Electrolytes Containing N-Methylpyrrolidone V. V. Kuznetsov*, L. M. Skibina*, E. F. Kuznetsova*, I. N. Loskutnikova**, and A. I. Sokolenko** * Department of Chemistry, Rostov State University, ul. Zorge 7, Rostov-on-Don, 344090 Russia e-mail:
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** Don State Technical University, Russia Received November 23, 2004 Abstract — In sulfate electrolytes for copper plating, N-methylpyrrolidone (MP) was found to form stable 2 : 1 complexes with the metal. The nature of electroactive species at the copper cathode depends on the MP concentration. In a concentration range from 10–4 to 10–2 mol/l, the electrode reaction involves complexes of discharging metal ions with adsorbed MP molecules, the complexes being formed in the surface layer. At higher MP concentrations, a slow chemical step associated with dissociation of complex species in the bulk of the solution precedes ion discharge. The inhibitive effect of MP on copper electrodeposition is due to adsorbed MP molecules at the electrode; the adsorption value determines the efficiency of the additive and the wear resistance of the coating.
23/09/2008 | 1085 Hits | Print
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4.
Inhibition Effect of Thallium Cations on Aluminum Corrosion in Hydrochloride Solutions V. V. Bartenev* and O. I. Barteneva** * Rostov State University, ul. Zorge 7, Rostov-on-Don, 344090 Russia e-mail:
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** Research Institute of Physical and Organic Chemistry,
pr. Stachki 194/2, Rostov-on-Don, 344090 Russia Received February 25, 2004 Abstract — The effect of contact thallium deposition on the corrosion rate of aluminum in hydrochloride solutions is studied. When a fraction of “metal” depolarization of aluminum corrosion is insignificant, the corrosion rate depends on the aluminum surface coverage with thallium deposit and the time. Partial inhibition coefficients, which are associated with the variations in the free-corrosion potential (K E) and in the fraction of aluminum surface area occupied by thallium deposit (Ks), are calculated. The variations of partial inhibition coefficients Ks and KE with the variations of thallium iodide concentration and the corrosion test time are analyzed.
23/09/2008 | 1085 Hits | Print
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5.
Study of Organic Derivatives of the VIa Group Elements as Steel Acid Corrosion Inhibitors I. N. Chernyad’ev, A. B. Shein, and A. N. Nedugov Perm’ State University, ul. Bukireva 15, Perm’, 614990 Russia e-mail:
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; Tel. (3422)396349 Received October 27, 2004 Abstract — Effects of derivatives of (4-dimethylaminophenyl) disulfide, diselenide, and ditelluride, as well as bis(4-dimethylaminophenyl)thio- and bis(4-dimethylaminophenyl)selenodimethyl ether on an   3 steel free corrosion and on partial electrode processes in sulfuric and hydrochloric acid solutions are studied by gravimetric and voltammetric methods. It is shown that the protective action of the studied substances becomes more pronounced when passing from the initial compounds to their di-iodmethylates; in a sequence of similarly structured compounds, the protective action changes when passing from sulfur to selenium and tellurium derivatives.
23/09/2008 | 1119 Hits | Print
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6.
Modified Means for Corrosion Protection of Aluminum Alloys. 1. Estimates of Effectiveness of R-3b and EP-060tsb Compositions A. A. Gerasimenko and T. E. Yampol’skaya Institute of Physical Chemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow, 117071 Russia Received January 25, 2001 Abstract — Accelerated corrosion and outdoor climatic (Cuba) testing of standard and newly developed agents and systems designed for the purpose of preventing the development of exfoliation and microbiological corrosion types on metal samples and structural parts were carried out. Recommendations on using most effective agents are given, which include procedures of aluminum alloy surface treatment involving the removal of corrosion products.
23/09/2008 | 1088 Hits | Print
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7.
Solid-Phase Diffusion at a Galvanostatic Anodic Dissolution of Zn Ag and Cu Au Alloy O. A. Kozaderov, E. V. Bobrinskaya, T. V. Kartashova, and A. V. Vvedenskii Voronezh State University, Universitetskaya pl. 1, Voronezh, 394006 Russia Received August 17, 2004 Abstract — The ionization stages of copper and zinc at a galvanostatic anodic dissolution of Zn–Ag and Cu–Au alloys in acidic chloride environment are found to be electrochemically nonequilibrium. Selective dissolution of the alloys is limited by the transient mutual diffusion of components within a nonequilibrium surface layer. In terms of diverse theoretical models of the solid-phase mass transfer, the effects of the electrode surface microroughness, the apparent shift of the alloy–electrolyte interface boundary, and the relaxation of the vacancy subsystem are analyzed. The parameters of the diffusion layer, namely, its thickness, diffusivities, mutual diffusivities, and the over-equilibrium vacancy concentration were found. The latter characteristic is determined by the dissolution rate of the electrochemically negative alloy component, and, hence, the diffusivities and the Sand parameter of the diffusion kinetics substantially increase with an increase in the current density.
23/09/2008 | 1125 Hits | Print
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8.
Electrochemical Dissolution of Silver Sulfide in Aqueous Acetate Alkaline Media at Cathodic Potentials G. V. Makarov, I. G. Soboleva, and A. G. Makarov Lipetsk State Technical University, ul. Moskovskaya 30, Lipetsk, 398600 Russia e-mail:
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Received January 27, 2004 Abstract — Cathodic dissolution of silver sulfide in acetate media containing no silver ions in a pH range from 8.32 to 13.02 is studied by voltammetric technique. The partial reaction orders in hydroxyl, acetate, and hydrogen ions are –0.88, –0.13, and 0.01, respectively, while the overall reaction order is –0.1. A kinetic equation and a scheme of cathodic reduction of  -Ag2S are proposed. The presence of silver in solid products of electrolysis is confirmed by XRD analysis. The presence of sulfur in the aqueous medium is revealed by x-ray fluorescence analysis.
23/09/2008 | 1126 Hits | Print
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9.
Structural-Phase Composition and Corrosion Behavior of Finely Dispersed Fe C Powders in Neutral Media S. F. Lomayeva*, B. B. Bokhonov**, A. V. Syugaev*,E. P. Elsukov*, and S. M. Reshetnikov*** * Physicotechnical Institute, Ural Division, Russian Academy of Sciences,
ul. Kirova 132, Izhevsk, 426000 Russia e-mail:
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** Institute of Solid-State Chemistry and Mineral Processing, Siberian Division,
Russian Academy of Sciences, ul. Kutateladze 18, Novosibirsk, 630128 Russia e-mail:
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*** Udmurt State University, ul. Universitetskaya 1, Izhevsk, 426034 Russia e-mail:
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Received August 16, 2004 Abstract — Effects of the structural-phase state and the structure of the surface layer on the corrosion behavior of mechanically activated finely dispersed Fe–C powders were studied. The powders prepared by mechanical milling of iron in graphite or heptane were mixtures of phases (nanocrystalline -Fe + amorphous Fe–C phase (AP), -Fe + Fe3C, and -Fe + graphite) in different ratios. Corrosion tests were carried out in a model medium (0.85% NaCl) at 37°C. The oxide surface layer of powders containing a high content of AP was found to exhibit protective properties. The corrosion behavior of the powders is insensitive to such changes in the structuralphase state as the formation of carbides, graphite encapsulation, grain size alterations, and hydrogenation.
23/09/2008 | 1055 Hits | Print
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10.
Diagrams of Chemical and Electrochemical Stability of Thermal-Diffusion Zinc Coatings A. G. Tyurin* and R. G. Galin** * Chelyabinsk State University, ul. Br. Kashirinykh 129, Chelyabinsk, 454021 Russia e-mail:
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** OOO Vika-Gal Research-and-Production Plant,
ul. Molodogvardeitsev 7, Chelyabinsk, 454138 Russia e-mail:
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Received April 26, 2004 Abstract — Cutsets are calculated for the Zn–Fe–O system phase diagram at 700 and 298 K and the Zn–Fe–H2O system potential–pH diagram at 298 K, 1 atm (air), and ai = 10–6 mol/l with zinc excess ( >  ) or deficiency ( <  ) in the alloy surface layer of the Zn–Fe alloy. Thermodynamics of corrosion–electro-chemical behavior of different phases in thermal-diffusion zinc coatings are discussed.
23/09/2008 | 1075 Hits | Print
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