O. Yu. Goncharov

Effect of the burning temperature on the phase composition, photovoltaic response, and electrical properties of Ag/Pd resistive films

Silver-palladium (Ag/Pd) films were grown by thick-film technology using a resistive paste consisting of Pd, Ag2O, and glass on ceramic substrates at burning temperatures of 878, 1013, and 1113 K. The effect of the burning temperature and Pd content in the initial paste on the phase composition, resistivity, photovoltaic properties of films, free carrier concentration, and mobility was studied. It was found that the films grown at a burning temperature of 878 K have the greatest factor of conversion of the pulsed laser power to the photovoltaic signal, which depends on the direction of the incident radiation wave vector. Using X-ray diffraction, X-ray photoelectron spectroscopy, and thermodynamic modeling, it was shown that the AgPd alloy and PdO oxide are the main components of the Ag/Pd film with photovoltaic properties.

High-temperature oxidation of Fe-Cr alloys in air

The scales formed on the Fe-Cr (19, 29.5, and 46.8 at % Cr) and Fe70Cr15B15 alloys in the initial stages of oxidation in air at 1470 K have been analyzed using depth profiling. The results demonstrate that the Cr/(Fe + Cr) ratio in the scales on the Fe-Cr alloys is close to 30 at %, independent of the bulk chromium concentration. The top scale layers on the Fe-Cr alloys consist predominantly of M2O3 (M = Cr, Fe) solid solutions and CrO2, the intermediate layers are composed of (Fe, Cr)3O4 and FeO, and the internal oxidation and nitridation layers consist of chromium oxides and nitrides. The top scale layers on the oxidized Fe70Cr15B15 alloy contain, in addition, boron oxides, and the internal nitridation product is BN instead of chromium nitrides.

Effects of temperature and gas phase impurities on the composition of Co-B alloy surface layers

Layers formed on the surfaces of Co-B melts in vacuum and in a helium atmosphere with oxygen and carbon contamination are purified. It is established that films containing B2O3 and CoO oxides form on the melt surfaces, leading to abnormalities in the temperature dependences of viscosity. It is shown that increasing the boron content in the Co100−xBx alloys lowers the temperature of oxide disappearance. Raising the oxygen content stabilizes oxides, while carbon impurities block their formation.

Specific features of the structure of sol-gel silicate films doped with Mn and Pt

Sol-gel silicate films undoped and doped with Mn and Pt are investigated by X-ray photoelectron spectroscopy and atomic-force microscopy. The effect of the annealing atmosphere on the composition and structure of doped silicate films is discussed.

Thermodynamic analysis of Ta chemical vapor deposition via the reduction of tantalum halides with cadmium and zinc

This paper presents thermodynamic analysis of the gas-phase reduction of tantalum chlorides, bromides, and iodides by zinc and cadmium. We consider in detail the reduction process and optimize low-temperature tantalum deposition parameters.

The estimation of structural component contents in lead silicate glasses

The contents of structural components in lead silicate glasses were determined by the X-ray electron spectroscopy and thermodynamic analysis methods. Lead silicate glasses were described as solid solutions of lead and silicon oxides and lead silicates. The thermodynamic properties of metastable lead silicates were estimated. Thermal treatment in an inert or oxidizing atmosphere led to identical glass structures. High-lead glasses are based on metastable lead-oxygen structures containing 3–7 lead atoms. Such structures are absent in crystalline silicates.

Analysis of the formation of Al2O3 + Fe nanocomposites

The formation of Al2O3 + Fe nanocomposites (in the range 0–20 wt % Fe) in the course of three sequential processes, such as dispersion, compaction, and sintering at a temperature of 1573 K, is investigated. It is revealed that the sintering is accompanied by the formation of the spinel phase at interfaces. It is demonstrated that the composition of the sintered samples corresponds to an equilibrium composition at a temperature of approximately 1073 K and that the spinel phase serves as a barrier layer preventing oxidation of iron

Evaluation of the parameters of cation distribution in Y3A5−zBz O12 solid solutions

AbstracCrystal chemical models are proposed for describing the regularities in the distributions of ions and point defects in solid solutions of yttrium aluminum, yttrium gallium, and yttrium iron garnets. The concentration dependences of the distributions of ions and point defects in solid solutions are evaluated in terms of multidimensional nonlinear optimization.

Features of polytherms of the viscosity of Fe–B melts

It is established that the formation of a viscous film on the surface of a melt is possible during the viscosimetry of Fe–B melts under normal conditions. It is noted that the film has a considerable effect on the results from measurements and can lead to the appearance of additional features on polyterms. Thermodynamic analysis of the composition of surface layers shows that a viscous film contains mainly boron oxide B2O3. It is concluded that the evaporation of B2O3 from the surface of the alloy produces additional anomalies on the polytherm of viscosity.

Tantalum chemical vapor deposition on substrates from various materials

Tantalum coatings have been produced for the first time by hydrogen-free chemical vapor deposition through reduction of tantalum pentabromide with cadmium vapor, which allowed the deposition temperature to be substantially reduced (by more than 200 K). The coatings consisted of α- and/or β-Ta, depending on the substrate material.