V.V. Zyryanov

• Prof.
• Russian Academy of Sciences

We have studied the effect of surface modification with noble metals on the morphology of δ-Bi2O3/Ag-based nanocermets as potential materials for medium-temperature oxygen membranes. Gold has been found to have a strong effect on silver recrystallization on the surface of the composites. The observed changes in morphology are due to the effect of t...

Size fractions of shungite rock modified by heat treatment in argon at 1400°C have been characterized by X-ray diffraction; scanning electron microscopy in combination with energy dispersive X-ray microanalysis; transmission electron microscopy; optical microscopy; and IR, Raman, and Mössbauer spectroscopies. The material consists largely of a mixt...

We have tested a number of approaches to producing oxygen-selective planar multilayer membranes with mixed conductivity of functional layers on metallic gauze as a key component of a porous support. The results demonstrate that the shrinkage mismatch can be considerably reduced via pressure sintering. The conditions for firing metallic gauzes and a...

The solid electrolyte Zr0.88Sc0.12Y0.02O1.93 for reduced-temperature SOFCs has been characterized by Rietveld X-ray powder diffraction analysis and conductivity measurements in the temperature range 295–970 K. Gas-tight nanostructured ceramic composites consisting of cubic, rhombohedral, and monoclinic phases have been produced by reaction sinterin...

Six samples of magnetospheres, recovered by magnetic separation from fly ashes, collected from power plants with high temperature boilers in the former USSR, were investigated by combination of instrumental techniques. The phase and chemical compositions, morphology and microstructure of magnetospheres have been studied by optical microscopy, scann...

IntroductionSupportSelection of Ceramics with High Oxygen MobilitySynthesis of Ceramics with Required Ts and a High Oxygen PermeabilityCombination of Compatible Materials and OperationsDesign of Catalyst for Selective Reforming of Methane to SyngasConclusion References

The nanocrystalline samples of 10wt%Scandia stabilized Zirconia (10ScSZ) and 1wt%Ceria doped ScSZ (1Ce10ScSZ) prepared via co-precipitation route were characterized and compared to commercially available samples regarding their transport properties and electrical conductivity. The results of oxygen isotope experiments show that for Zr-based electro...

Two series of Sc-stabilized zirconia nanostructured ceramic composites were prepared from mechanochemical origin nanopowders. The first series was obtained by reaction sintering, and the second one by conventional sintering of ceramic powders prepared mechanical activation route. Ceramic samples were studied by complex impedance method and characte...

Magnetic spheres of various origins, isolated from fly ashes of the main Russian thermal coals, have been studied by electron microscopy, optical microscopy, X-ray diffraction, and Mössbauer spectroscopy. The magnetic spheres differ in morphology and have the form of multilevel core-shell nanocomposites, with a hematite or spinel Fe-rich core and a...

Studies of mechanochemical powders and sintered ceramics in scandia stabilized zirconia system have been carried out by means of XRD technique, Raman spectroscopy and SIMS. Nanostructured single phase ceramics of Zr0.88Sc0.1Ce0.01Y0.01O1.955 composition with the room-temperature rhombohedral structure caused by ordering of oxygen vacancies possesse...

X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Mössbauer spectroscopy have been used to investigate the structural phase transformations of SrCo0.5Fe0.5O3 − δ-based mixed-oxide nanocomposites containing fine iron oxide particles. The nanocomposites have been prepared using sol-gel and mechanochemical processe...

The development of multilayer mixed conducting oxide membranes on macroporous dead-end tubular composite glass/ceramic substrates is presented. Sol modification of glass/ceramic substrate enhances the performance of catalytic membrane reactor (CMR) with reduced thickness of ceramic layers. The shrinkage misfit between support and ceramic layers can...

The structure of the Zr0.88 Sc0.1Ce0.01Y0.01O1.955 solid solution, a candidate for the use as a solid electrolyte in fuel cells with a low temperature, has been investigated using x-ray powder diffraction and Raman spectroscopy. Single-phase ceramic materials have been produced from powders prepared by the mechanochemical synthesis from ZrO2 nanopr...

A novel low-cost, effective, and environmentally friendly method is proposed for depositing porous or dense coatings from a charged aerosol (a gas-dust plasma) onto different planar substrates. The generation of dense aerosols from charged aggregates consisting of nanoparticles and their deposition are performed using devices of the electromassclas...

We describe glass-ceramic materials produced using several kaolins for the fabrication of inert porous supports by a casting process. Optimizing the slurry composition and preparing quality slurries, we obtained a support material which had an open porosity of ≃34% after firing at 1380°C. Modification of the support material fired at 850–950°C thro...

Devices used to carry out mechanochemical transformations are described. The key views of the threshold mechanism of ultrafast mechanochemical synthesis in oxide systems with oxide melting points up to 3000 K in energy intensive mills are presented. Data on structural studies of complex oxides obtained by mechanochemical synthesis are analysed. The...

The development of multilayer mixed conducting oxide membranes on porous dead‐end tubular mineral‐based glass‐ceramic supports is presented. Nanopowders of compatible complex perovskites and fluorites as membrane materials were obtained by mechanochemical synthesis. The deposition of oxide ceramic porous and dense layers was carried out by casting...

Zirconia-and scandia-based complex solid solutions predominantly with a monoclinic structure are prepared by mechanochemical synthesis. The dense ceramic materials, which, for the most part, have a cubic structure with grain sizes of 250–400 nm and possess good mechanical properties, are produced by sintering submicron fractions of the powders unde...

Nanocomposites consisting of phases with fluorite (doped CeO2) and perovskite (LaMnO3, GdMnO3) structures are synthesized using the method of ester polymeric precursors (the Pechini method) and two sources of rare-earth elements (Ln), such as pure cerium and gadolinium salts or a commercial mixture of rare-earth carbonates containing La, Ce, Pr, Nd...

Nanocomposites comprised of fluorite-like (Gd- or Pr-doped ceria) and perovskite-like (LaMnO3+δ) phases were prepared using a polymerized precursor (Pechini) route. Genesis of the structure of composites with annealing temperature has been studied by X-ray diffraction, Transmission Electron Microscopy and EXAFS. Up to 1300 °C, particle sizes of bot...

The sintering behavior of mechanochemically prepared 0.9Pb(Zn1/3Nb2/3)O3-0.1ABO3 (ABO3 = BaBiO3, BaMnO3, BaTiO3) powders is studied. PbO and Bi2O3 are shown to volatilize at relatively low temperatures owing to partial reduction of these oxides during the mechanochemical synthesis. Dense (97% of theoretical density) ceramics are obtained under mild...

In this paper we show that mechanochemical approach allows fast synthesis of individual phases with fluorite and perovskite structures and preparation of dual-phase nanocomposites with mixed ionic–electronic conductivity. Binary oxides obtained by mechanosynthesis are frequently metastable compounds which decompose at moderate temperatures before s...

Nanopowders of LaGaO3- and LaMnO3-based complex perovskites (P) and ceria-based fluorites (F) were prepared by mechanosynthesis. Compatible nanocomposites F + P and P + P with mixed ion and electron conducting (MIEC) properties were prepared and sintered at moderate temperatures up to dense ceramics. The obtained materials were studied by means of...

Crystalline mechanochemical synthesis products in the Bi2O3–GeO2 system are studied by x-ray diffraction. The results indicate the formation of sillenite (Bi12GeO20), eulytite (Bi4Ge3O12), and Aurivillius (Bi2GeO5) phases. The Aurivillius phase is shown to be in mechanochemical equilibrium with the sillenite phase in the 2Bi2O3 + GeO2 system and wi...

A mechanism of superfast mechanosynthesis reaction for oxide systems is proposed on the base of a dynamics study. The threshold effect and linear dependence of the chemical response on the effective temperature of the reaction zone are established. Major factors are determined: molecular mass of reagents, enthalpy and difference of reagents in Mohs...

Metastable BIMEVOX solid solutions with the -Bi2VO5.5 - x structure (Aurivillius phases) and nominal compositions Bi2M0.1V0.9O5.5 - x (M = V, Zn, Sc, Sb, In) and Bi1.8Pb0.2VO5.4 - x are prepared for the first time by mechanochemical synthesis. Structural studies of these materials reveal high vacancy concentrations and substitutional disordering. S...

Metastable solid solutions of complex oxides with fluorite and perovskite structures are obtained by mechanosynthesis. Dense ceramics on the base of these metastable phases was obtained by thermal sintering of nanopowders due to kinetic stabilization. Different degrees of a chemical interaction (interdiffusion) are observed during sintering of "per...

Nanosized powders of conductive complex fluorites based on δ-Bi2O3 and perovskites based on LnMnO3, SrFeO3, LnGaO3 have been obtained by mechanochemical synthesis. Complex doping was used for kinetic stabilization of the metastable phases, which provides dense ceramics prepared by the standard sintering procedure. Some perovskites and especially fl...

Polymerized precursor route [M.P. Pechini, US Patent 3, 330 (1967) 697] was applied for synthesis of dispersed ceria-based solid solutions Ce1−xMex3+O3−y (Me3+= Sm3+ or Bi3+, x up to 0.5). The surface properties of those samples were modified by supporting Pt. Their bulk and surface structural features were characterized by using XRD, TEM, EXAFS, X...

Metastable fluorite solid solutions with the nominal composition Bi1.6Mo0.4O3 – x (M = Ca, Ca0.5Sr0.5, In, Y, La) are prepared by mechanochemical synthesis, and their structure is studied by x-ray diffraction. The oxygen ion conductivity of dense samples prepared by hot pressing is measured in air.

Mobility and reactivity of the surface and bulk oxygen of perovskite-like mixed oxides including lanthanum manganite (I) and ferrite (II) systems modified by Ca (I,II) and fluorine (I), as well as some Co, Fe-containing complex perovskites were considered. Combination of thermal analysis data, oxygen isotope exchange, O2 TPD, reduction by CO, H2 an...

The phase composition of crystalline mechanochemical synthesis products in the CaO–Sb2O3–Bi2O3 system was determined. Of the known phases in this system, only three could be prepared mechanochemically: Ca2Sb2O5, CaSb2O4, and CaBiO2.5 (fcc). A new metastable phase, "-Bi2O3, with an orthorhombic structure close to that of the high-temperature, fluori...

The mechanochemical reactions induced in 2CdO(HgO) + Sb2O5(Sb2O3) oxide mixtures by high-energy ball milling were studied by x-ray diffraction. New pyrochlore and fluorite phases were found to be formed at a high rate. Using thermal analysis, the temperature ranges of the structural and chemical transformations in the reaction products were determi...

The products of mechanochemical synthesis in the Pb–V–O system were characterized by x-ray diffraction and magnetic resonance spectroscopy techniques. The mechanical processing was found to yield only new crystalline compounds, Pb2.67V1.33O5.96and Pb3.5V4.5O14.75. Structural analysis of these phases revealed a low atomic density, mixed-valent state...

The mechanochemical processes, including mechanochemical synthesis of mixed-valence lead oxides, in mixtures of PbO, Pb3O4, and PbO2were studied by x-ray diffraction. The results demonstrate that the reduction of Pb4+is accompanied by the formation of Pb2O3, Pb3O4, and possibly PbO1.37. Phases of variable composition close in structure to minium, P...