ИСТИНА

Carbon nanotubes (CNTs) have been intensively studied because of their remarkable electronic, mechanical properties and unique one-dimensional (1D) structures. Due to their nanosize features, extraordinary mechanical strength and thermal stability, carbon nanotubes have been considered as ideal candidates to substitute for the conventional ligating components in multifunctional composite steels. Up to now one of the main approaches to improve mechanical properties of the final composites as well as dispersive properties of carbon materials in coatings is decoration of CNTs by metals or metal oxides. Also such materials are applicable in industrial catalysis and electronic industry. There are some ways to prepare coated CNT, like chemical vapor deposition (CVD), sol-gel method or impregnation by metal precursors with its further decomposition. Present work deals with supercritical fluid technique (SCF) application for this reason. In recent years, supercritical fluids have been widely utilized in material science because of low viscosity, high diffusivity, near zero surface tension, and strong solvent power for many of small molecules. The flexibility of SCFs, in terms of tunable solvation strength and access to high operating temperatures and pressures, enables the synthesis of a variety of nanostructured metal and other materials. A fluid media, water and n-hexane were used, since their critical parameters and low cost. As a source of metal Cu(NO3)2*3H2O and (NH4)10[H2W12O42] *4H2O we used. The condition of one-step synthesis CNT-composites was changed from 320 – 450oC, 8 – 30MPa and 0.5 – 67 hours. CNT-composite materials with Cu and WO3 nanoparticles, obtained in supercritical solvents, have been characterized by XRD, SEM and HRTEM. It was found, that their size, morphology and type of particles immobilization on CNTs depends on all the variable parameters - reaction time, temperature and pressure. It was shown that the increase of time and temperature led to decreasing of size Cu and WO3 particles without CNT coating. So, we can widely change a sizes of composites by changing of condition of supercritical fluids.