Key Engineering Materials Vol. 822

Abstract: Supermacroporous three-dimensional matrices based on poly-D,L-lactide or polycaprolactone were fabricated by thermally induced phase separation method and 3D printing technique. The morphology and mechanical properties of the resulting matrices were studied with the use of optical and scanning electron microscopy and the uniaxial compression test, respectively. All matrices were characterized with supermacroporous structure suitable for cell penetration. A significant increase in Young's modulus and tensile strength was established for both polymer matrices prepared by 3D printing technique.

Abstract: The paper presents the results of research of compactability processes of thermally expanded graphite powders during rolling. The thermally expanded graphite powders can be used to obtain highly porous and high-density products having different geometric parameters. The rolling method is used to produce long-length products. Strips production of the thermally expanded graphite with a particular thickness, density and physical-mechanical properties can be achieved by controlling the rolling conditions. When implementing the rolling process it is necessary to use plates due to high adhesion of powder to the rolls of the rolling mill. The usage of plates has allowed to develop the technology for the production of single and multilayer strips and evaluate its effectiveness.

Abstract: In this work, p-type thermoelectric material was produced by hot extrusion of pre-synthesized in injection molding machine Bi_0.5Sb_1.5Te₃ solid solution. During the research radial distribution of the Seebeck coefficient was confirmed and described in material’s cross section using thermal measuring probe. Such nonuniformity of the Seebeck coefficient is correlated with the strain-stress state of extrudate specifically with the distribution of accumulated strain intensity, which was obtained by mathematical modeling of extrusion process using the software package DEFORM.

Abstract: In this paper, we report on obtaining dense samples of composites in the WC/ZrO₂(Y₂O₃) system with a nanoscale microstructure by the SPS method. A complete assessment of their properties, including cutting properties, was carried out. Microstructural characterization of the final samples was conducted using SEM.

Abstract: In this paper, the process of obtaining a spherical powder of titanium alloy of the “Grade 5” brand using inductively coupled argon-helium plasma has been studied. The structure of titanium alloy was studied before and after the spheroidization process. The results of particle size and X-ray fluorescent analysis were also obtained. As a result of the analysis of the structure, it was concluded that the crystallite sizes and microstress values change. Keywords: additive technology, plasmachemical synthesis, spheroidization, titanium alloy, grade 5.

Abstract: Synthesis of the Nb-Si in-situ composite was attempted by binder jetting additive manufacturing technology, using Nb powder and liquid Si during infiltration in furnace. The microstructures were examined with scanning electronic microscope, and the phase constituent were analyzed by X-ray diffraction. Furthermore, the effect of using prepared Nb-16Si (at.%) powder mixture as building powder for binder jetting and subsequent melting of internal silicon in furnace on synthesis of the in-situ composite also investigated. After infiltration, the sample mainly consisted of NbSi₂ and Si phases. With using of prepared Nb-16Si (at.%) powder and subsequent melting of internal silicon in furnace, microstructure consist of Nb_ss, Nb₃Si, NbSi₂ phases.

Abstract: Based on aerosol chemical deposition, a method was developed and the process of simultaneous formation of a composite with a carbon matrix and iron oxide nanoparticles incorporated therein was developed. As the source of carbon, o-xylene is proposed, source of nanoscale iron oxide - stabilized and unstabilized magnetic fluid based on benzoic acid in dimethylformamide solution, where benzoic acid is addition source of carbon. The proposed method makes it possible to obtain composite materials of various types with several directions of growth.

Abstract: The influence of the concentration of the initial solution on the size and composition of the particles obtained by the method of ultrasonic spray pyrolysis (USP) was investigated. An aqueous solution of Fe (NО₃)₃·9Н₂О, the concentration of which varied in the range of 0,0025–0,03 mol/l, was used as the starting material. As a result of the process, iron oxide particles were obtained, the average size of which varied from 123 to 292 nm. Based on FTIR and XRD, powders consist of several phases and have crystalline inclusions α-Fe₂O₃, β-Fe₂O₃, and γ-Fe₂O₃.

Abstract: The work investigates the characteristics of the porosity of inorganic salts: magnesium silicate and yttrium aluminum garnet (YAG). Using the example of nanocrystalline powders of magnesium silicate and yttrium aluminum garnet, the effect of synthesis parameters on the phase composition and porous characteristics of the obtained powders was studied. The average pore size of adsorbents was obtained: magnesium silicate - 48 nm; YAG, obtained by the standard Pechini method – 44 nm; YAG, obtained by the modified Pechini method – 37 nm; the industrial brand “magnesol” – 32 nm. The resulting materials can be attributed to mesoporous adsorbents.

Abstract: The authors have shown the effective use of synthesized epoxidized rubber seed oil as a modifier of epoxy compound materials. It was stated that at the content of epoxidized rubber seed oil of 10 weight parts for 100 weight parts of epoxy resin ED-20, hardness and wear have been increased by 34 and 21% correspondingly, while the frictional coefficient was being reduced by a factor of 1.5. Wollastonite has been synthesized on the base of rice husk and limestone. By means of the X-ray diffraction method, it was proven that the specimen of synthesized calcium silicate with the molar ratio СаСО₃:SiO₂ = 1.2:1 is characterized by the structure closest to the naturally occurring wollastonite.