S. M. Kuz’min

Effect of anodic potential on process of formation of polyporphyrin film in solutions of tetrakis(p-aminophenyl)porphin in dichloromethane

The electrode impedance spectroscopy technique was used to study the process of formation of a conducting polyporphyrin film on a Pt electrode from a 10−3 M solution of tetrakis(p-aminophenyl)porphin in dichloromethane. An equivalent circuit is suggested for simulation of interface impedance in a wide range of working electrode potentials. It is shown that regions with a different mechanism of film formation are observed at an increase in potential from 0.0 to +1.0 V. The kinetics of film formation are studied at the potentials of +0.40, +0.60, and +0.80 V. It is found that good agreement is observed between the model and experimental data when the growing film is simulated using a Warburg element with a finite diffusion length. Conductivity and the diffusion coefficient of charge carriers in it are estimated on the basis of the suggested model for a film obtained at the potential of +0.40 V. It is shown that conductivity of a polyporphyrin film grows by more than an order of magnitude at an increase in deposition potential from +0.40 to +0.80 V.

Modification of polyester fibrous materials with surface barrier discharge for making them more hydrophilic

The possibility of using surface barrier discharge for the surface modification of polyester fabrics with the aim of making them more hydrophilic was studied. The action of surface-barrier discharge leads to the formation of hydrophilic oxygen-containing groups on the surface of polyester fabrics owing to weak degradation of poly(ethylene terephthalate) macromolecules, and the thread surface becomes rougher on the nanolevel. This leads to a considerable decrease in the contact angle and to an increase in the wettability of the polyester fabric, i.e., the fabric becomes considerably more hydrophilic. Modification of the polyether fabric with surface barrier discharge does not cause appreciable decrease in the strength and breaking elongation of the material.

On the motion of charged particles in an alternating nonuniform electric field

The equations of motion for a charged particle in an electric field featuring a stationary and an oscillating component are considered for the case where the force of friction is linear in the particle velocity. The averaging of these equations over the period of field oscillations is legitimate under some specific conditions. The most general expression for an additional stationary force acting on the particle under these conditions is derived, and the limiting values of this force are found. Applications of the results obtained in the present study are considered. Such applications include the use of pulsed currents in the electrochemical dimensional treatment of materials.

Effect of pulsed polarization parameters on the nickel shaping

Electrochemical shaping of nickel under pulsed polarization with various pulse shapes and repetition frequencies was studied. The effect of parameters of the pulsed dimensional electrochemical machining on the process of anodic dissolution of the metal was examined.

A new composite polypropylene material with improved physicochemical and consumer properties

A new composite material, polypropylene threads fi lled with nanosized copper powder, was prepared. The material exhibits decreased electrical resistivity.

Morphological and dimensional properties of ultradispersed powders produced by the electrochemical method from electrolyte solutions

Ultradispersed copper-bearing powders have been produced by the method of electrochemical cathode reduction from water-isopropanol solutions of copper dichloride. The dimensional and morphological properties of the obtained compounds have been studied using the procedure of atomic-power microscopy. It is shown that the introduction of isopropyl alcohol additions into the aqueous electrolyte composition causes a change of both the dimensional and qualitative features of the powders. The isopropyl alcohol admixture shifts the ratio between the components entering into the composition of the copper-bearing powders towards a greater content of copper oxide (I).

Effect of Surfactants on Electrodeposition of the Sn–Ni Alloy from Oxalate Solutions

The effects of surfactants on the electrolytic deposition of tin–nickel alloys from oxalate–ammonium electrolytes were determined. The adsorption of the nonionic surfactant at the interface decreases the rate of charge transfer across the interface. As a result, the electrochemical stage of the electroreduction of metals slows down, and the alloy is deposited in the form of shiny finely crystalline coatings. The range of optimum surfactant concentrations in the oxalate–ammonium electrolyte was determined based on the simulation of the interface impedance obtained during the alloy deposition and the electron microscopy studies of the obtained coatings.

Influence of pulse recurrence frequency on the accuracy of electrochemical machining of nickel, copper, and steel

The influence of pulse recurrence frequency on the accuracy of electrochemical machining of steel 08KP, nickel H1, and copper M1 is shown. Variation of the pulse recurrence frequency leads to similar changes in the tool electrode copying accuracy. This allows us to extend the scope of application of the pulsed mode of electrochemical machining. The correlation between the surface passivity and the effects of the pulse mode is demonstrated. A possible explanation of the observed effects using the existing theoretical background regarding the motion of charged particles in nonstationary inhomogeneous electric fields is discussed.

Effect of the structure of the electrode|solution interface on the electrocrystallization of high-dispersity copper compounds

Impedance spectroscopy was used to study properties of the Cu|H2O + i-C3H7OH + CuSO4 interface. It was shown that, at isopropanol concentrations of 0.04–0.06 mol fraction, the structural transformation in the near-electrode space decelerates the transport in the diffusion layer, which promotes synthesis of nanosize copper-containing powders. The qualitative composition and size characteristics of the powders obtained under the suggested conditions were analyzed.

Electrochemical processes on the copper electrode in water-ethanol solutions of copper sulfate

The system Cu/H2O-C2H5OH-CuSO4 was studied in a wide range of organic component concentrations by the impedance spectroscopy method. In the studied range of ethanol concentrations the diffusion of ions to an electrode is the limiting stage of the electrode process. An increase in the ethanol concentration results in a decrease in the double electrical layer capacity, which is caused by a change in the double electrical layer structure at the electrode-solution boundary.