Two types of hydroxyapatite powders different origin (biogenic and synthetic) were coated by graphene oxide using LPCVD method and studied by SEM, XRD, FTIR, BET and DLS. Biogenic and synthetic hydroxyapatites remained phase-pure after LPCVD modification, showing no secondary phases formation. The adsorption capacity for methylene blue increased by 50% for coated hydroxyapatites, despite the thinness of the layer and the decrease in specific surface area of powders. Moreover, graphene oxide allows to keep moderately negative zeta potential of both modified hydroxyapatites during 6 months in comparison to pure powders that could promising influence on bone regeneration.

Highly porous bioceramics (porosity equal to 93–94 %) based on biogenic hydroxyapatite and sodiumborosilicate glass (40wt% of glass) was prepared by foam replication method at 700 °C and coated by graphene oxide using CVD method. Obtained bioceramics samples were studied by SEM, XRD and Raman spectroscopy. Phase composition, morphology, skeleton density, porosity and compression strength were evaluated. It was shown that biogenic hydroxyapatite in highly-porous bioceramics composition is stable and keeps hydroxyapatite phase without secondary phase formation after sintering with sodiumborosilicate glass as well as after application of CVD method for graphene oxide coating. Formation of graphene oxide for coated bioceramics was confirmed by XRD, SEM and Raman spectroscopy. Significant effect of graphene oxide coating on the porosity and skeleton density was not detected due to thin layer and low content of graphene oxide, but it allows 30 % increasing the compression strength of highly porous bioceramics.

The object of research in this work was the coating of oxygraphene on a silicon single crystal substrate. In the work, the LPСVD (Low Pressure Chemical Vapor Deposition) method of deposition from the gas phase at low pressure is used to obtain graphene-like coatings on heat-resistant materials. A feature of the proposed LPCVD method in comparison with the classical method of deposition from the gas phase CVD (Chemical Vapor Deposition) by the method of catalytic decomposition of carbon-containing gas followed by the deposition of a graphene-like coating on a copper template is the use of a higher partial gas pressure, which leads to the deposition of graphene-like waste not only on the surface of the copper template-catalyst, but also in the entire volume of the reaction chamber and the materials introduced into it. A monocrystalline silicon template was used as a model for coating. The resulting coatings of different thicknesses were examined by scanning electron microscopy, Raman spectroscopy, and density was assessed by helium pycnometry. Based on the analysis of the results obtained using the method of scanning electron microscopy, the possibility of varying the thickness of the oxygraphene coating was shown. In addition, the formation of oxygraphene on a silicon single crystal substrate was confirmed by the Raman spectroscopy method, namely the presence of characteristic peaks in the spectra of the studied materials. Using the helium pycnometry method, a decrease in the density of the coated material from 2.25 g/cm3 to 2.08 g/cm3 was found. It was established that the greater the coating thickness, the lower the density. The general analysis showed that the developed LPСVD technology allows obtaining an oxygraphene coating on materials of any shape, porosity, size and resistant to temperatures above 600 °С in order to functionalize their surface and improve and improve their properties.

Today bone tissue engineering is one of the most used technologies for treat bones injure. Materials containing hydroxyapatite and graphene have received much attention recently. The aim of this study was preparation of biogenic hydroxyapatite bioceramics modified by graphene-like structures investigation effect of graphene on the structure and properties of material. Biogenic hydroxyapatite bioceramics modified by graphene-like structures were successfully prepared by chemical vapor deposition (CVD) method. Subsequently, microstructure, composition, specific surface area, skeleton density, resorption rate in physiological solution and cytotoxicity were evaluated. XRD, IR spectroscopy, micro-Raman spectroscopy and SEM proved graphene oxide’s formation on biogenic hydroxyapatite as well as on silica single crystal for comparison. Although the coating of graphene-like structures on biogenic hydroxyapatite bioceramics reduces the specific surface area, it allows to 4 times increase resorption rate of biogenic hydroxyapatite bioceramics in physiological solution and does not affect the overall assessment of the cytotoxicity. MTT assay established non-cytotoxic effect and indicated a high potential of biogenic hydroxyapatite bioceramics modified by graphene-like structures using CVD method for medical application.

In the present work magnetite nanopowders were synthesized by chemical precipitation using FeCl 3 ·6H 2 O and FeCl 2 ·4H 2 O (80 °C, maintaining 5 min–1 h) and decomposition of FeC 2 O 4 (470 °C, in hydrocarbon and nitrogen media maintaining 2 h) and investigated by X-ray diffraction analysis, IR spectroscopy and Scanning electron microscopy. Specific surface area and magnetic properties (specific saturation magnetization and coercive force) were also evaluated. It was shown that the time of synthesis did not influence on the phase composition and nanopowder with specific surface area equal to 141 m 2 /g could be prepared using chemical precipitation method for 5 min. Thermal decomposition method was found to allow obtaining of nanopowders with the higher degree crystallinity. It was established that increasing time of chemical precipitation causes decreasing the specific saturation magnetization from to 62 down to 53.5 emu/g and coercive force from 18.1 down to 3.0 Oe. Thermal decomposition method significantly improve magnetic properties and allow to obtain magnetite nanopowder with the specific saturation magnetization 135 emu/g.

Magnetite powder (FeO·Fe2O3 or Fe3O4) is obtained by the chemical precipitation method, using FeCl3·6H2O and FeCl2·4H2O as a starting materials in the presence of hydrazine N2H4 at a temperature of 80 °C. X-ray diffraction analysis, infrared spectroscopy, and scanning electron microscopy are used for the study of the phase composition and morphology of the synthesized powder. Its specific surface area and magnetic properties such as, in particular, the specific saturation magnetization, coercive force and residual induction are investigated. It is established that the composition of the synthesized powder is represented by magnetite as the main phase with a small admixture of hematite. It is shown that the particles of the obtained magnetite have sizes of 33-84 nm and tend to the agglomeration. The prepared powder has superparamagnetic properties (specific magnetization — 35 A · m2/kg, coercive force — 0.24 kA/m, residual induction — 0.009 T) and is promising for the biocomposite creation.

Highly-porous bioceramic scaffolds based on biogenic hydroxyapatite with addition of 40 wt.% of glass (wt.%: 45.7 SiO 2 , 28.2 B 2 O 3 , 26.1 Na 2 O) were prepared by foam replication method at 700  С followed by coating of chitosan dissolved in 1% acetic acid solution and drying at 50  С. Bioceramic samples were studied by XRD, IR spectroscopy and SEM. Phase composition, morphology, skeleton density, porosity, compression strength and in vitro tests were evaluated. The results show that, during sintering, the biogenic hydroxyapatite in bioceramic composition is stable and keeps hydroxyapatite phase without secondary phase formation. Chitosan coating shows twofold increase in the compression strength in comparison with pure bioceramics. Moreover, chitosan coating significantly influences on the structure of highly-porous bioceramic scaffolds and dissolution rate in saline. Thus, balanced porosity and dissolution rate make the prepared materials promising for bone marrow stromal cell loading, drug delivery and bone tissue

The object of research is transparent conductive coating based on fluorine doped tin oxide deposited on silica float glass by the pyrolytic method. However, both in the manufacturing process of such a coating and in the process of its operation, degradation of its electrically conductive properties is observed. This may be due to changes in the structure of the coating under the influence of certain technological and operational factors, namely: process temperature, holding time, gas environment during the application and operation of a transparent electrically conductive coating. Studies have confirmed a significant increase in electrical conductivity. They also found a slight decrease in the transmittance of transparent oxide-tin films obtained with the introduction of ammonium fluoride as a dopant during the pyrolysis of 1M alcohol solutions of Sn2+ and Sn4+chlorides and are widely used as precursors for the content of such coatings. So, with a ratio of Sn4+/F=10 in working solutions, a minimum of specific surface resistance was fixed at 32 Ohm/m2. At the same time, a decrease in the value of the averaged transmittance in the optical wavelength range of 0.2-6.0 μm by 51 %, and in its visible part (0.4-0.8 μm) by 11 %. It is shown that thermal degradation of the coating is a significant factor in increasing the resistance values both in the technological process and during operational impacts. The results obtained indicate that reheating to temperatures above 450 °C leads to the appearance of the phenomenon of thermal degradation of the electrically conductive properties of the coating. So, during a 1-hour exposure at a temperature of 550 °C, the increase in specific surface resistance increases by 2 times and is fixed at 68 Ohm/m2 after complete cooling. Repeated heating cycles with the indicated parameters lead to a significantly lesser effect, which may indicate stabilization of the processes that occur during thermal destruction of the electrically conductive coating.

Effect of fluorine introduction into composition of high-porous glass ceramics based on biogenic hydroxyapatite and glass of the SiO2-CaO-Na2O system on structure and properties of the material obtained via doubling the polymer matrix structure has been studied. It is established that during sintering of samples from high-porous glass ceramics at 900 degrees C a partial decomposition and/ or interaction of hydroxyapatite with the glass phase occur, that results in forming the multiphase ceramics containing renanite, calcium silicophosphate, calcium pyrophosphate, pectolite and hydroxyapatite. In addition, in the case of fluorine introduction, fluorapatite is formed and sample strength increases by 30 % along with slight decrease in solubility in vitro.

Highly porous biomaterials with a structure close to that of cancellous bone have been prepared using biogenic hydroxyapatite and glass of the SiO2-Na2O-CaO system by a replication of the polymer template structure. It has been established that during sintering of the samples the hydroxyapatite decomposes, which involves the formation of glass-ceramics containing phases of renanit NaCaPO4, calcium phosphate silicate Ca5(PO4)2SiO4, calcium pyrophosphate Ca2P2O7 and impurities of hydroxyapatite Ca5(PO4)3(OH). Structural characteristics and mechanical properties of the obtained materials are promising for the replacement of defective cancellous bone.