P. A. Arkhipov

Simulation of the electric field in an electrolytic cell with a liquid metal anode

The influence of the temperature and the level of liquid metal electrodes on the direct current distribution over the surface of the liquid metal anode and the electrolyte KCl-PbCl2 volume in a cylindrical electrolytic cell is studied by simulating the electric field.

Thermodynamic characteristics of the Pb-Bi alloys in the KCl-PbCl2 melt

The thermodynamic properties of the Pb-Bi alloys containing from 1.5 to 95 mol % Pb are investigated in a molten mixture of potassium and lead chlorides in a temperature range of 723–873 K by measuring the equilibrium values of the electromotive force. The partial and integral thermodynamic characteristics of the system are calculated, and its small negative deviations from ideality are established.

Estimation of the activity of lead in the binary Pb-Sb and Pb-Bi systems

The activity of lead in its alloys with bismuth and antimony is estimated by the least squares method and interval analysis. The interval method of processing the experimental results is shown to calculate the reliable ranges of the estimated parameters in the dependences of thermodynamic functions and the actual level of the total measurement errors.

Raman spectra and conductivity of PbO–PbCl 2 –CsCl melts

The structure and the conductivity of homogeneous CsCl–PbCl2–PbO melts with different compositions are studied. The Raman spectra (RS) of the chloride and oxide–chloride melts containing lead oxide have been measured. It is found that the CsCl (71.3 mol %)–PbCl2 (28.7 mol %) system with the addition of 12 mol % PbO and the CsCl (18.3 mol %)–PbCl2 (81.7 mol %) system with the addition of 18 mol % PbO contain Pb3O2Cl+ oxide–chloride groups. The temperature dependences of the electrical conductivity are measured in the PbCl2–CsCl chloride melts containing 28.7 and 81.7 mol % lead chloride and in homogeneous molten mixtures CsCl (71.3 mol %)–PbCl2 (28.7 mol %) with the addition of 12 mol % PbO and the CsCl (18.3 mol %)–PbCl2 (81.7 mol %) with the addition of 18 mol % PbO. Significant degradation of the ion conductive properties of the PbO–PbCl2–CsCl oxide–chloride melts as compared to those of the PbCl2–CsCl chloride electrolytes has been revealed. It is shown that the decrease in the electrical conductivity of the PbCl2–CsCl oxide–chloride melts as lead oxide is added is due to the presence of Pb3O2Cl+ oxide–chloride groups.

Electrical conductance, density, and the liquidus temperature of the KCl–PbCl2 equimolar mixture with lead oxide additives

The influence of the PbO additive (up to 8.1 mol %) on the physicochemical properties of the KCl–PbCl2 molten system is investigated. The primary crystallization temperatures of selected electrolyte compositions are determined. The temperature and PbO-content dependences of the conductance of electrolytes in cells with parallel electrodes are found by the impedance measurement method. The temperature dependence of density of the KCl–PbCl2 equimolar melt containing up to 8.1 mol % lead oxide is measured by the Archimedean method, and the molar volumes are calculated. It is shown that the concentration dependence of the molar volume has an extreme form.

Influence of the electrolyte composition on the current distribution in an electrolytic cell with liquid-metal electrodes

The article discusses the influence of the molten electrolyte composition on the direct current distribution in a cylindrical electrolytic cell over the surface of a liquid-metal anode and in the volume of a KCl-PbCl2 electrolyte. Electric field plotting is applied. The distributions of the bulk current density are graphically illustrated, and the electrical conductivities of the melts are estimated.

Dissolution rate of lead(II) oxide in an equimolar KCl-PbCl2 melt

Dissolution rates (W) of lead(II) oxide in a KCl-PbCl2 equimolar melt are determined experimentally using the gravimetric method at T = 773, 823, and 873 K. It is shown that, as the temperature increases from 773 to 873 K, the initial magnitude of W increases from 23.9 to 45.6 mg/(cm2 min) with a conventional roughness coefficient of 10. Then the values of W for all temperatures are leveled, being close to zero after 25 min, which indicates the diffusion mode of the process in natural convection conditions. The activation energy of the interaction between PbO and the KCl-PbCl2 melt was 37.370 ± 0.118 kJ/mol. The limiting concentration of PbO in the equimolar KCl-PbCl2 melt was determined, being 9.1, 10.6, and 13.5 wt % at T = 773, 823, and 873 K, respectively.

Thermodynamic characteristics of Pb-Sb alloys

Thermodynamic properties of Pb-Sb alloys containing 20–95 mol % Pb are investigated by the method of measurement of equilibrium emf values in the range T = 723–873 K in a molten mixture of potassium and lead chlorides. The partial and integral thermodynamic characteristics of the system are calculated, and small negative deviations from ideality are revealed. The extremum of integral functions of mixing lies in the region of 0.55 mole fraction of Pb. The system could not be treated as a regular solution since the excess entropy introduces a considerable contribution to deviation from ideality, while the excess Gibbs energy differs considerably from the heat of mixing.

EFFECT OF CRYSTALLIZATION CONDITIONS ON STRUCTURE AND MODIFYING ABILITY OF Al–Sc ALLOYS

The study covers the impact of thermo-time processing and cooling rate of molten metal on the crystallization regularities, structure, properties and modifying ability of Al–Sc alloys. The Al–Sc alloys obtained by electrolysis in the KF–NaF–AlF 3 –Sc 2 O 3 melts at 820–850 °C were used as an initial charge for casting. It was found that changes in overheat values and casting temperatures make it possible to vary the shape, number and size of crystals in a wide range. The modifying effect of the cast and fast-quenched master alloys and alloy produced by electrolysis was tested on Al–4,5%Cu alloys. The greatest refinement of the Al–4,5%Cu–0,4%Sc alloy structure was obtained with the fast-quenched master alloy.

Электродные процессы при электрорафинировании свинца в расплаве KCl-PbCl 2 -PbO П. С. Першин, А. А. Бурич, Ю. Р. Халимуллина, П. А. Архипов, Ю. П. Зайков

The corrosion of Hastelloy S, Hastelloy X, Haynes 230, Hastelloy N, Hastelloy G35 and Hastelloy C2000 alloys was studied in KCl–AlCl 3 melts at 550 ° С . The rates and the mechanisms of corrosion of the studied materials were determined. The processes taking place during the interaction between alloys and chloroaluminate melts were investigated.The mode and conditions of thermal sensitization in the temperature range 648-698K lead selenide films deposited from ethylendiamine acetate system were determined. The effect of heat treatment on the morphology and properties of photosensitive chemically deposited films of PbSe was showed. It is concluded that the results obtained by hydrochemical synthesis of nanostructed highly sensitive to infrared range radiation layer of lead selenide provide performance on the level of best foreign analogues.The present work was focused on the studies of crystal structure, oxygen nonstoichiometry, thermal expansion of SmBaCo 2−x Cu x O 6- δ and SmBaFe 2−x Cu x O 6- δ . Values of the oxygen content in complex oxides SmBaCo 2‑ x Cu x О 6‑ δ were determined over a wide temperature range in air using high temperature thermogravimetry and iodometric titration. Also, chemical stability with respect to Ce 0.8 Sm 0.2 O 1.9 and Zr 0.85 Y 0.15 O 1.93 two common solid electrolyte materials used for SOFCs was evaluated.The influence of PbO addition on current efficiency during the electrorefinement of lead in the KCl-PbCl 2 -PbO melt was investigated. It was shown that with PbO concentration in the KCl-PbCl 2 eqiumolar mixture increasing, the current efficiency of lead decreases. Electrode processes mechanism is proposed.Polycrystalline BaМe 1-x Y x O 3-δ (Me=Co, Fe) samples were synthesized by a conventional route and glycerol–nitrate technique. According XRD patterns of single phase solid solutions BaCo1-xYxO3-δ (0.1≤x≤0.4) and BaFe 0.9-y Y 0.1 Co y O 3-δ (0.05≤y≤0.15) were indexed using Pm3m space group. The unit cell parameters were refined using Rietveld full-profile analysis. Oxygen nonstoichiometry of these solid solutions was measured by means of thermogravimetric technique within the temperature range 298–1273 K in air.