Search

Using the method of the joint crystallization of solutions of nitrate salts with ultrasonic treatment, xerogels and highly dispersed mesoporous powders of the following composition are synthesized: (CeO2)1 – x(Nd2O3)x (x = 0.02; 0.05; 0.10), Gd1 – xSrxCo0.5O3 – δ (x = 0.1, 0.15, 0.2, 0, 25), Gd0.4Sr0.1Ni0.5O3 – δ, and Gd0.125La0.125Sr0.25Co0.5O3 – δ; and based on them, nanoceramic materials with a crystalline cubic structure of the fluorite type, as well as an orthorhombic and tetragonal structure of the perovskite type with CSR ~ 55–90 nm (1300°С), respectively, are obtained. The physicochemical properties of the resulting ceramics are studied; it is revealed that it has an open porosity of 7–11% for the composition (CeO2)1 – x(Nd2O3)x and 17–42% for materials with the Gd1 – xSrxCo0.5O3 – δ, Gd0.4Sr0.1Ni0.5O3 – δ, and Gd0.125La0.125Sr0.25Co0.5O3 – δ composition. Materials based on cerium oxide predominantly have the ionic (ion transport numbers ti = 0.71–0.89 in the range 300–700°С) type of electrical conductivity due to the formation of mobile oxygen vacancies in the heterovalent substitution of Ce4+ by Nd3+; and σ700°С = 0.31 × 10–2 S/cm Solid solutions based on nickelate and lanthanum cobaltite have mixed electron-ionic conductivity, σ700°С = 0.59 × 10–1 S/cm with transfer numbers te = 0.92–0.99 and ti = 0.08–0.01. The prospects for using the obtained ceramic materials as solid oxide electrolytes and electrodes for medium-temperature fuel cells (FCs) are shown. [ABSTRACT FROM AUTHOR]

This article describes the production of nanodisperse xerogel and powders (average CSR size of 9 nm) in the ZrO2–Y2O3–Al2O3 system by coprecipitation of hydroxides. A strong highly porous ceramic has been produced from the initial powder with the composition of [(ZrO2)0.97(Y2O3)0.03]0.8(Al2O3)0.2 with pore forming additives using patented solid phase sintering. Using Doppler sonography, the volume of blood flow in arteriolas and capillaries has been estimated 150 and 250 days after implantation of plates. Therefore, the microcirculatory Doppler sonography seems to be a promising intravital method of estimating blood flow in the zone of plates from biocompatible nonresorbable material and, probably, inside the plates. It has been found that the ceramic plates based on zirconium dioxide in the body of experimental animals do not result in a negative reaction of animal's body. The in vivo experimental results make it possible to state that the obtained bioceramic based on zirconium dioxide is a promising material for endoprosthetics. [ABSTRACT FROM AUTHOR]

By the joint crystallization of solutions of nitrate salts, fine powders of La1 – xSrxNiO3, La1 ‒xSrx-CoO3, and La1 –xSrxFe0.7Ni0.3O3 (x = 0.30 and 0.40) are synthesized. They have a specific pore volume of 0.018–0.035 cm3/g and a specific surface area of 15–31 m2/g. On their basis, ceramic nanomaterials of a given composition with CSR ~ 64–70 nm (1300°С) are obtained. The physicochemical properties of the obtained ceramic are studied; it is revealed that the ceramic is a solid solution with open porosity in a range of 17–30% and a high value of the relative density of 94%. In terms of their physicochemical properties (open porosity, density, coefficient of thermal expansion), the obtained ceramic materials are promising as solid oxide cathodes for intermediate-temperature fuel cells. [ABSTRACT FROM AUTHOR]

Mesoporous nanosized aerogels, xerogels, and powders in the ZrO2–Y2O3–CeO2 and ZrO2‒Y2O3–Al2O3 systems have been obtained by liquid-phase synthesis methods. The thermolysis, phase composition, and textural features of the synthesized materials have been studied. It has been found that the predominance of Lewis acid sites (LASs) on the surface of their particles indicates its lower hydroxylation and, as a consequence, a lower degree of agglomeration of the obtained materials. [ABSTRACT FROM AUTHOR]

Paint coatings based on a copolymer of vinyl chloride with vinyl acetate with an additive of epoxy-diane resin of six different compositions are developed. The coatings differ in the nature of fillers (anatase, rutile, and cobalt and lanthanum oxides) and the composition of soft biocidal additives of the atrane class (protatrane of salicylic acid and hydrometallatranes based on triethanolamine complexes with zinc(II) and copper(II) salts). The process of biofouling in the natural conditions of the White sea is studied. Fouling communities formed on the studied plates during 2.5 months of exposure to the sea is analyzed, depending on the composition of the coatings. The fouling is based on the attached forms: scyphistomas (polypoid stage) of jellyfish Aurelia aurita and Cyanea sp., mussels Mytilus edulis, and hydroid Obelia longissima. The efficiency of the same paint coating appear to differ towards different species of fouling organisms. [ABSTRACT FROM AUTHOR]

Abstract—: Xerogels in the ZrO2(Y2O3)-Al2O3 system are obtained by the coprecipitation method followed by a low-temperature treatment at -25°C for 24 h. The physicochemical properties of the powders of ZrO2(Y2O3)-xAl2O3 (х = 15, 20, and 25 mol %) compositions obtained by burning the xerogels are studied. It is shown that the introduction of 25 mol % of Al2O3 promotes the deceleration of the growth of the particles of the t-ZrO2(Y2O3) tetragonal solid solution. It is established that the obtained powders are characterized by high values of the degree of tetragonality (c/a = 1.438-1.436). [ABSTRACT FROM AUTHOR]