Structural transformations in heat resistant coatings containing rare earth elements

Degradation of two-layered coatings and ZhS6U alloy microstructure were studied during long-term processes of high temperature annealing and creeping. It was shown that yttrium and zirconium oxides are promising as protective coatings for heat resistant nickel based alloy

Surface layer composition of titania produced by various methods: the change of layer state under illumination

The comparative analysis of experimental data over titanium dioxide powders prepared by various ways under ambient air is carried out. The results over TiO2 prepared by high-temperature heating of anatase, produced by burning of titanium micro particles and grinding of rutile crystal are used for that comparison. Water and carbon dioxide were the main products released from the surface of the titania powders. It was found that under UV irradiation absorbed by titania, in absent oxygen, water effectively reacts with lattice oxygen of titanium dioxide

Aluminium oxide-hydroxides obtained by hydrothermal synthesis: influence of thermal treatment on phase composition and textural characteristics

Aluminium oxide-hydroxides obtained by means of the hydrothermal synthesis of aluminium nanopowder are of great interest in terms of the potential supports for heterogeneous catalysts due its high specific surface area (200...300 m2/g) and pore size of 4...17 nm. In this work the influence of thermal treatment (150...1300 °C) on structural and phase composition, specific surface area and porosity of aluminium oxide-hydroxides has been investigated. Nanostructured γ-Al2O3 (T=400 °C) was found to have the specific surface area of 328 m2/g and average pore size of ~9 nm. The thermal treatment of aluminium oxide- hydroxides at the temperature of higher and lower than 400 °C has caused the reduction of specific surface area and overall pore volume

The preparation of the Ti-Al alloys based on intermetallic phases

This article deals with a method of obtaining materials in the Ti-Al system. Research was carried out in accordance with the phase diagram of the system state. It was established, that both single-phase and multiphase systems, containing finely dispersed intermetallic compositions of phases Ti3Al, TiAl and TiAl3, are formed. Additionally, it was found that the pure finely dispersed (coherent-scattering region (CSR) up to 100 nm) intermetallic compound TiAl3 is formed at molar ratio of Ti:Al = 1:3. Experimentally proved the possibility of produce the complex composition of alloys and intermetallic compounds and products based on them

Structural transformations in heat resistant coatings containing rare earth elements

Degradation of two-layered coatings and ZhS6U alloy microstructure were studied during long-term processes of high temperature annealing and creeping. It was shown that yttrium and zirconium oxides are promising as protective coatings for heat resistant nickel based alloy

Influence of the catalyst preparation on properties of chromium-magnesium catalysts for freon 125 synthesis

The effect of the chromium-magnesium precursor preparation techniques on physicochemical properties (BET surface area, total pore volume, mean pore diameter) and catalysts activity in the gas-phase hydrofluorination of perchloroethylene to pentafluoroethane (Freon 125) was studied. Kinetics of the catalytic reactions was studied for the most active catalyst. Based on the experimental data, the pathway of perchloroethylene fluorination with HF was suggested

Influence of the catalyst preparation on properties of chromium-magnesium catalysts for freon 125 synthesis

The effect of the chromium-magnesium precursor preparation techniques on physicochemical properties (BET surface area, total pore volume, mean pore diameter) and catalysts activity in the gas-phase hydrofluorination of perchloroethylene to pentafluoroethane (Freon 125) was studied. Kinetics of the catalytic reactions was studied for the most active catalyst. Based on the experimental data, the pathway of perchloroethylene fluorination with HF was suggested

Characterization of electroexplosive zinc nanopowders in aqueous suspensions

Zn and ZnO nanosized powders are increasingly in demand of materials engineering, power systems and biotechnology. Meanwhile, elaboration, production and application of nanopowders have created the conditions for nanoparticles release into the environment. The lack of physicochemical information about nanoparticles behaviour in liquid environment does not allow to give deep interpretation of toxic effects of nanoparticles and elaborate new techniques for testing of nanomaterials. This study is primarily focused on the characterization of nanopowder composition, shape and dispersity of electroexplosive zinc nanopowder in aqueous suspensions based on simple physiological solutions of phosphate buffering saline, glucose solution, and distilled water. With the help of SEM images, X-ray analysis, and visualization it was revealed that on the surface of sphere-like Zn nanoparticles formed insoluble oxide-hydroxide compounds with strongly developed structure. The method of laser diffraction was used to give a description of the aggregation status of nanoparticles and its evolution on the time-scale.</jats:p