Synthesis of nanocomposites based on strontium stannate

The process of thermolysis of double strontium-tin(IV) hydroxide obtained by precipitation from hydrochloric acid solutions by adding ammonia to pH=10 and the phase composition of its degradation products were studied by differential thermal analysis, X-ray phase analysis and scanning electron microscopy. It was shown that the main stages of dehydration are completed at about 350°C and as a result of thermolysis an X-ray amorphous product is formed, which at temperatures above 700°C transitions to the strontium stannate crystalline phase

Optimization of the obtaining temperature of powder composite material B

Boron carbide is characterized by a unique combination of low density (2.52 g/cm3), high hardness (up to 40 GPa), chemical inertness, the high melting point (2450 °C); for these reasons, the ceramics based on this compound have found application in a number of areas of state-of-the-art technologies. However, it is difficult to obtain dense B4C-based ceramics because of a low value of the self-diffusion coefficient, low plastic deformation of this compound, and high sliding resistance between its grains. The use of modifying additives of transition metal diborides appears to be a promising approach to improving the operational characteristics of B4C-based ceramics. They tend to activate the sintering process by means of activation energy reduction, which leads to a decrease in a grain size, an increase in density, strength, and fracture strength of sintered compositions. Zirconium diboride is often used for this purpose. The objective of the work is to study the changes occurring in the charge of boron carbide, zirconium dioxide and carbon when it is heated to determine the temperature of the complete reagents transformation into B4C –ZrB2 composite mixture

Synthesis of nanopowders by the glycine-nitrate method in the In-Dy-O system

We investigated the feasibility of synthesizing nanopowders containing indium and dysprosium oxides by the glycine-nitrate method. It was found that the glycine-nitrate method significantly reduces the content of the indium component in the resulting mixture of indium and dysprosium oxides. In this case, intensive absorption of carbon dioxide from the air by the formed particles induces formation of amorphous carbonaceous compounds, which decompose only under high-temperature treatment (900 °C). This prevents compaction of powders synthesized by the glycine-nitrate method. Comparison of the characteristics of powders containing indium oxides and dysprosium, synthesized by the glycine-nitrate method and by the method of co-precipitation of indium and dysprosium hydroxides from chloride solutions, showed the advantage of the co-precipitation method in the pressing of powders

Synthesis of BaSnO₃ as a Highly Dispersed Additive for the Preparation of Proton-Conducting Composites

The process of thermolysis of barium hydroxostannate BaSn(OH)6 as a precursor for preparing barium stannate BaSnO3 has been investigated using the method of differential thermal analysis. Thermal decomposition products of the precursor were characterized using X-ray diffraction, IR spectroscopy, low-temperature nitrogen adsorption, and scanning electron microscopy. It was shown that dehydration at nearly 270 °C resulted in the formation of an X-ray amorphous multiphase product, from which single-phase barium stannate crystallized at temperatures above 600 °C. The synthesized barium stannate was used as a functional additive to prepare composite proton electrolytes in the CsHSO4-BaSnO3 system. The structural and transport properties of the obtained system were investigated. It is shown that the highly conductive state of the salt is stabilized in a wide range of temperatures. High conductivity values of composite solid electrolytes in the medium temperature range create the possibility of their use as solid electrolyte membrane materials