Electrical Conductivity Of Oxide Research Articles

Thermal Expansion and Conductivity of Sm0.9Ca1.1Fe1 – yCoyO4 – δ Solid Solutions

Complex oxides Sm0.9Ca1.1Fe1 − yCoyO4 − δ (y = 0, 0.7) are synthesized in air at 1100°С using the glycerol-nitrate technique. The temperature dependences of the total electrical conductivity, Seebeck coefficient, and thermal expansion of the compositions Sm0.9Ca1.1Fe1 − yCoyO4 − δ (y = 0, 0.7) are studied in the 25–1100°C temperature range and at $${{P}_{{{{{\text{O}}}_{2}}}}} = 0.21$$ atm. The average TEC values are calculated over linear sections of the ΔL/L = f(T) dependences. It is shown that the considered samples possess semiconductor-type conductivity. An increase in the concentration of cobalt raises the total electrical conductivity of Sm0.9Ca1.1Fe1 − yCoyO4 − δ. The activation energy of conductivity is calculated from the dependences of the total electrical conductivity of oxides in Arrhenius coordinates. It is found that the temperature dependence of the Seebeck coefficient for Sm0.9Ca1.1FeO4 − δ has positive values in the range of 25–1100°C, testifying to the predominance of hole conductivity.

Oxygen isotope exchange and electrical conductivity of CaZr1–x Sc x O3–x/2

The effect of scandium content in CaZr1–xScxO3–x/2 on electrical conductivity and oxygen exchange kinetics was investigated. The electrical conductivity was studied by means of impedance spectroscopy depending on temperature (700–850 °С) and oxygen partial pressure (2.1 · 104 > pO2 > 10–15 Pa). The oxygen exchange kinetics was studied using the isotope exchange method with gas phase equilibration in the temperature range of 700–850 °С and oxygen pressures of 0.13–6.7 kPa. The oxygen tracer diffusion coefficient, the oxygen heterogeneous exchange rate, and the electrical conductivity of oxides with the growing scandium content were found to increase. It was assumed that the electronic defects play an important role in the oxygen surface exchange.

Fundamental relation between the main parameters of the thermally activated transport phenomena in complex oxide melts

The relation between the activation energy and the preexponential factor in the Arrhenius equation that describes the viscosity and electrical conductivity of oxide (slag) melts is systematically analyzed over wide composition and temperature ranges for the first time. When deriving this relation, we do not use any model concepts and assumptions concerning the structure of slag melts or the character of electric charge transfer in them. The fundamental applicability of the Meyer-Neldel rule for this relation is shown and grounded. The application of this algorithm in practice can give information on the structure of experimental data, nonobvious correlations, and possible relations of a higher order and can quantitatively predict the behavior of parameters, including the range outside experimentally determined data.

Mechanism and Microstructure of Oxide Fluxes for Gas Tungsten Arc Welding of Magnesium Alloy

Five single oxide fluxes—MgO, CaO, TiO2, MnO2, and Cr2O3—were used to investigate the effect of active flux on the depth/width ratio in AZ31B magnesium alloy. The microstructure and mechanical property of the tungsten inert gas (TIG) welding seam were studied. The oxygen content in the weld seam and the arc images during the TIG welding process were analyzed. A series of emission spectroscopy of weld arc for TIG welding for magnesium with and without flux were developed. The results showed that for the five single oxide fluxes, all can increase the weld penetration effectively and grain size in the weld seam of alternating current tungsten inert gas (ACTIG) welding of the Mg alloy. The oxygen content of the welds made without flux is not very different from those produced with oxide fluxes not considering trapped oxide. However, welds that have the best penetration have a relatively higher oxygen content among those produced with flux. It was found that the arc images with the oxide fluxes were only the enlarged form of the arc images without flux; the arc constriction was not observed. The detection of arc spectroscopy showed that the metal elements in the oxides exist as the neutral atom or the first cation in the weld arc. This finding would influence the arc properties. When TIG simulation was carried out on a plate with flux applied only on one side, the arc image video showed an asymmetric arc, which deviated toward the flux free side. The thermal stability, the dissociation energy, and the electrical conductivity of oxide should be considered when studying the mechanism for increased TIG flux weld penetration.

Electrical conduction and mass transfer in crystalline oxides

The electrical conductivity of oxides is closely related to the reducibility or oxidizability of their metals. The experimental results of the authors and reported data are used to explain the behavior of the electrical conductivity of solid oxides and its relation to mass transfer with allowance for the ionic structure of these oxides.

Flicker noise spectroscopy – a new method of studying non-stationary effects in electrical conductivity of oxides

This work shows the possibilities of the application of a new phenomenological approach known as flicker noise spectroscopy (FNS) in studying the non-equilibrium effects in d.c. and a.c. electrical conductivities of oxides (local phase transitions under the influence of high electric fields and local heating effects, generation of space charges, memory effects, pre-breakdown instabilities, influence of environment, etc.).The FNS method is very informative in describing dynamic effects, which assist the electrical current flow through thin (20–60 nm) oxide films formed at the Si surface by its electrochemical oxidation. Polarity of the voltage applied to the structure and polarization history (whether the voltage increases or decreases) essentially influence the electrical noise, first of all, a degree of dynamic memory in a sequence of individual bursts contribute to the noise signal.

Correlation between the electrical conductivity of oxides and their adhesion to an OZZhR ferrous melt

A comparison between the adhesion and electrophysical characteristics of oxides may be useful in predicting the interaction between the latter and a metal. The experimental and calculated data for these characteristices taken both from our own studies and from the published literature [i] are given in Table i. The values of the limiting wetting angle and the electrical conductivity of oxides are given for temperatures of 1700-1800~ at which the region of intrinsic conductivity is reached. The published data which is lacking for the electrical conductivity of oxides at this temperature were obtained by extrapolation using the activation energy [I].

Correlation between the composition profile and electrical conductivity of the thermal and anodic oxides of InSb

The differences between the electrical conductivity of thermal and anodic oxides of InSb have been reported previously. In this paper these differences are correlated with the chemical compositional profiles of the two oxides. The anodic oxide is shown to be an indium oxide containing a large concentration of Sb, while the thermal oxide contains a relatively low concentration of Sb, but has an Sb-rich layer between the indium oxide and the InSb. By postformation annealing of the anodic oxide or application of a large electric field to the thermal oxide, the oxide compositions are changed. These changes are accompanied by a corresponding change in the electrical conductivity of the oxide. From these data and the changes in the Auger line shape for In, it appears that Sb–In bonding in the oxide is related to the change of conductivity.