Advanced Materials Research Vol. 1040

Abstract: The paper investigated the properties of the multilayer system: metal with polymer layer modified by radio frequency magnetron sputtering of a solid target made from hydroxyapatite. The material of the polymer layer is thermoplastic copolymer of tetrafluoroethylene with vinylidene fluoride. The roughness parameters of metal, polymer, and hybrid substrates are determined using atomic-force microscope. Calcium phosphate coatings increase the surfaces roughness of polymer and metal materials, thus presenting a stimulating factor for the attachment and proliferation of osteogenic cells. Wettability of the coatings was investigated by the “sit” drop method of the “Krüss Easy Drop” installation by measuring the effective contact angle. The hydrophobic polymer surface becomes hydrophilic after modification and the surface free energy increases.

Abstract: The paper investigated the modifying possibility of the biodegradable polymer materials surface (polylactic acid and polycaprolactone) in radio frequency discharge plasma, initiating hydroxyapatite solid target sputtering. It was demonstrated that discharge plasma treatment adjusts the surface properties of biodegradable polymers – surface free energy and the wetting angle. The disadvantage of biodegradable polymers, limiting their use in reconstructive medicine, is their hydrophobicity. The surface of biodegradable polymers becomes hydrophilic after modification.

Abstract: Particularities of the multilayered “Ti – Al₃Ti” composites structure formation were investigated. Spark plasma sintering of Ti and Al plates in cylindrical molds at the temperature of 830 ^оС and pressure of 3 kN during 5 minutes was found to be the most efficient technology of formation of materials with intermetallic layers. The regime described above allows fabricating material with high-quality intermetallic layers and with microhardness level up to 3800 MPa.

Abstract: At present the systems of layer-by-layer laser synthesis of three-dimensional articles are used to advance the introduction of new technologies and to reduce its costs. To produce articles in these systems a powder is applied and sintered layer-by-layer with a laser ray on the basis of a 3D CAD-model. The articles are produced in a particular range of laser action which is experimentally selected for each powder. The utilization of new powders, as well as selection of reasonable technological modes for producing articles of definite quality are vital tasks at present [1, 2].

Abstract: This paper studies the influence of a laser thermal effect on the material. It presents the research of the steel structure under laser irradiation. It explains and demonstrates the structure of steel 5140 after laser treatment. The research method, preparation for the research and material selection are described.

Abstract: The possibility of plasmodynamic synthesis in the carbon-nitrogen system when using melamine as a precursor is described in the paper. The system based on the capacitive energy storage, which allows simultaneously powering the two opposite-directed coaxial magnetoplasma accelerators, is developed. The effect of gaseous medium in the processing chamber of the system on the synthesis product is investigated by applying such techniques as X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). It is demonstrated that an increase in nitrogen pressure results in the structural and morphological changes in the synthesized sample, which might be caused by the increased carbon nitride yield and a great number of the appearing C-N bonds.

Abstract: Technology for manufacturing products by magnetic pulse compaction from oxide powders of the (ZrO₂ – Y₂O₃) – Al₂O₃ system is presented in the paper. Diagram of the magnetic-pulse press with its operating principle being based on Ampere's law is given. Physical and mechanical properties of the obtained compacts are determined. The main feature of the designed technology is the reduced sintering temperature (200 °С) and the acquired fine-grained structure of the products. Another significant advantage achieved by applying the technology is the possibility for manufacturing fine-grained structure ceramic products with high mechanical properties.

Abstract: Cyclic tension and alternating bending tests of 12Cr1MoV and 30CrMnSiNi2 steels specimens in as–supplied state and after surface irradiation by Zr⁺ ion beam have been carried out. Distinctions in formation of strain induced relief, as well as cracking pattern of modified surface layer are illustrated by methods of optical microscopy and interferential profilometry. Changes to occur in subsurface layer are characterized by means of nanoindentation and scanning electron microscopy of fracture surfaces. The description of differences of deformation behavior is carried out with use of the multiple cracking concepts.

Abstract: The article contains results of experimental studies, concerning the influence of sources with different spectra radiation on lettuce crop growth and development. The differential characteristic of the research is the use of RGBW light emitting diodes (LED) based modules. Prospects of LED based modules for radiation of plants are shown.

Abstract: The given work considers the influence of the power supply type (diode rectifier DR-306 and inverter Nebula-315) upon the chemical composition, microstructure, mechanical properties of weld joints and upon health characteristics of the manual arc welding process.It has been ascertained that the power supply type has a significant influence upon the weld joints properties and health characteristics of the manual arc welding process. Using a new generation inverter power supply allows less heat input into the weld bead, thus, decreasing silicium and manganese burning, improving impact resistance of weld joints under low (negative) temperature and reduces the risk of respiratory diseases for the workers.