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To expand the number of possible precursors of carbon nanoparticles, i.e., low-layer graphenes and nanoscrolls, binary and ternary graphite nitrate cointercalation compounds (GNCCs) with formic and acetic acid esters have been synthesized. X-ray powder diffraction data have demonstrated that the obtained GNCCs are stage II and IV intercalation compounds. It has been shown that the use of ethyl formate or an ethyl acetate/butyl acetate mixture as organic cointercalants leads to an increase in the height of the layer filled with intercalants as compared with graphite nitrate. Dispersions of carbon nanoparticles (low-layer graphenes and nanoscrolls) were obtained by sonication-assisted liquid-phase exfoliation of studied GNCCs in ethanol. The morphology of the obtained nanoparticles has been studied by transmission electron microscopy. more...

Путем расслоения терморасширенного графита в этиловом и трет-бутиловом спиртах под действием ультразвука получены дисперсии малослойных графеновых наночастиц. Исходный терморасширенный графит получен термической обработкой в ударном режиме нагрева тройного соединения соинтеркалирования нитрата графита с уксусной и муравьиной кислотами. Проведено исследование структурных характеристик соинтеркалата нитрата графита и терморасширенного графита методом рентгенофазового анализа. Микроструктура и морфология полученных графеновых частиц исследованы методом просвечивающей электронной микроскопии. Dispersions of graphene nanoparticles were obtained by liquid phase exfoliation of thermally expanded graphite in ethanol as well as tert-butanol via sonication. Initial thermally expanded graphite was obtained by heat treatment in the shock mode of ternary graphite nitrate intercalation compound with formic and acetic acids. Investigation of the graphite nitrate intercalation compound and thermally expanded graphite structural characteristics by X-ray diffraction analysis has been carried out. The microstructure and morphology of the obtained graphene particles were studied by transmission electron microscopy. more...

Triple graphite nitrate cointercalation compounds (GNCCs) with acetic acid were synthesized, characterized by powder XRD and SEM methods, and used as a source of the thermally expanded graphite (TEG). Structural reorganization of graphite nitrate-acetate and triple GNCCs with acetic acid as a result of their exposition in air is discussed on the base of powder XRD data. Dispersions of carbon nanoparticles were prepared by liquid phase exfoliation of TEGs obtained from the GNCCs. It was demonstrated by TEM method that using of the studied TEGs as a source of carbon nanoparticles favours formation of few-layered graphene. more...

The reaction between succinic anhydride and 2-aminothiazole was carried out in polar organic solvents (acetone, 1,4-dioxane, isopropanol) and in a mechanochemical reactor. By of X-ray phase analysis, IR, 1H, 13C NMR spectroscopy it was found that in both techniques of carrying out the reaction, the only product was succinamide. It was shown that the process efficiency in the mechanochemical reaction conditions is higher in comparison with the traditional solution’s synthesis. The solid-phase interaction development was proceeded during 45 days after load removed, it was especially intense in the first 10 days. more...

Hafnium diboride films have been obtained by the method of nonreactive hf magnetron sputtering in an argon atmosphere. It has been shown that the determining role in the processes of the formation of the structure of these films belongs to the size effect. The coatings with a highly pronounced texture were characterized by a clearly pronounced anisotropy of the sizes of coherent domains (the axial ratio of the crystal lattice c/a≈ 1.1, which is close to the tabulated value) and by high residual compressive macrostresses ∼8 GPa. As the degree of texture decreased, there formed structures with axial ratios c/a ≈ 1.05–1.07; simultaneously, there occurred a decrease in the sizes of coherent domains and a reduction of residual macrostresses. Upon the formation of amorphous cluster films with a grain size of ∼5 nm, close-packed structures with a structure close to cubic were formed. more...

Nanostructured tantalum boride films have been synthesized using the method of nonreactive radio-frequency sputtering of TaB2 target. The effect of sputtering regimes on the phase formation, structure, and the state of stress of the samples produced has been studied. The thickness of films was determined by multibeam interferometry and X-ray diffraction methods; the structure and phase composition of films were studied by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy; and the chemical composition was determined by the secondary ion mass spectrometry. The change in the sputtering regimes affected the phase formation and the structure of the synthesized films and led to changes in their substructural parameters, namely, subgrain sizes, microdeformations of the crystal lattice, and the degree of texture and the level of macrostresses. Both textured stressed and nontextured stressless nanostructured films of tantalum borides have been obtained. more...

The structure, as well as the phase and elemental compositions, of tantalum diboride-based nanostructured films deposited by rf magnetron sputtering under various conditions are studied by X-ray diffraction, electron microscopy, and secondary ion mass spectrometry. The physicomechanical properties of the films (hardness, as well as elastic and plastic properties) are determined. The maximum hardness and elastic modulus of the synthesized films are 42 are 240 GPa, respectively. The grain size is found to influence the physicomechanical and electrical properties of the films. more...

Transmission electron microscopy and X-ray radiography are used to show that pressing of α-aluminum oxide powders at pressures up to 2.0 GPa is accompanied by crushing of particles and the appearance of dislocations with a density of about 1011 cm−2. Sintering of these powders at temperatures up to 1550°C reduces the dislocation density 2–4-fold. When the compacts reach a critical density (about 62%) the shrinkage in sintering of nonsintered powders is shown to be independent of the compact density and the pore size. The increase in the sintering rate with increase in the hydrostatic pressure to 0.6 GPa is shown to be caused mainly by an increase in the compact density and at still higher pressures by the mechanical activation of the powders. more...