Multifunctional advanced composite materials: from idea to market

Resume : UV-curing coatings are nowadays widely used due to their unique advantages. High-quality coatings can be obtained at short curing times and low temperatures so that thermal stress to the substrate is minimised. Photocured Cycloaliphatic-Epoxy Oligosiloxane (CEO) resin was reported to be used as encapsulation material for organic electronics. However, further reinforcement of CEO film properties is desired to achieve requested device lifetime. In this work we introduced Boehmite nanoparticles (BA) into CEO matrix in order to modify the film properties and study the main changes of the material behaviour with regard to its photocuring kinetics, thermal stability and glass transition. Particular interest was focused on the role of particle surface in nanocomposite properties. Hence, BA particles without (HP14) and with organic surface modifier (OS1) at different loadings (up to 10 wt%) were applied in this study. Morphology investigation with SEM operated in transmission mode showed good BA dispersion forming network-like structure. At the same time, distribution of particles differed for HP14 and OS1 as a result of different interaction in CEO-solvent-particles system. CEO structure obtained via non-hydrolytic sol-gel reaction was verified by 13C and 29Si NMR. In situ monitoring of film curing was performed using RT-IR spectroscopy. No significant modification of final convention degree with particle incorporation was observed in contrast to considerable decrease of curing efficiency reported previously for similar system by Esposito et al.,2008. Further, cured hybrid nanocomposite films were analysed by TGA and DSC, which revealed impact of surface modifier on film thermal properties.

Resume : Poly(lactic acid) based composites draw more and more attention as environmental concerns about petrochemical-based polymers grow because of their recyclability and depletion of resources. [1] Titanium dioxide reinforced PLA composites have been used mainly for food packaging and medical applications due to non-toxicity of TiO2 and enhanced bio-degradability of composites. However, to be able to fulfill the demand for their application in structural parts, mechanical properties of PLA has to be improved in terms of crystallinity, toughness and strength. [2] For this purpose, effects of TiO2 particles on mechanical properties of PLA has been investigated in depth with TiO2 particles used in various wt%. Melt-mixing with twin screw extruder and compression molding were used for compounding and shaping processes, respectively. Three different mechanical tests were carried out as tensile, flexural and fracture toughness tests in order to understand complete influence of TiO2 nanoparticles. Moreover, distribution of the particles and morphology of fracture surface were investigated for every specimen groups in two different magnication with scanning electron microscopy (SEM). According to the results of PLA reinforced with TiO2 nanoparticles, the effect of reinforcement content has been discussed and the optimum particle loading has been determined as 2 wt%. The improvements espescially in fracture toughness, GIC and flexural modulus have been found as 49% and 40% in relation to neat PLA. Keywords: Polylactide, Micro Titania, Nano Titania References: 1. Farah, S., Anderson, D., & Langer, R. (2016). Physical and mechanical proper-ties of PLA, and their functions in wide-spread applications — A comprehensive review. Advanced Drug Delivery Re-views, 107, 367-392. 2. Raquez, J., Habibi, Y., Murariu, M., & Dubois, P. (2013). Polylactide (PLA)-based nanocomposites. Progress In Pol-ymer Science, 38(10-11), 1504-1542.

Resume : A novel route to build the 3D structure of multi-walled carbon nanotubes (CNTs), Cu nanoparticle and graphene was studied for the thermally conductive composites. Poly(methyl methacrylate) (PMMA) beads were used as template to disperse the silane functionalized carbon nanotubes (sCNTs) following the electrostatic interaction method. The 3D structure results in a reduction of interfacial phonon scattering and leads to high thermal conductivity of CNTs/epoxy composites even at low content of filler. The thermal conductivity of epoxy composites increased from 0.19 W/mK of the neat epoxy to 0.96 W/mK at 1 wt% of sCNTs% and 49 wt% of PMMA beads. The scanning electron microscopy of the epoxy composites revealed a well dispersion of sCNTs at the interstitial space between PMMA beads in the epoxy matrix. It is speculated that the effective formation of the long-range phonon transfer of thermally conductive sCNTs was a main factor to reduce the interfacial phonon scattering and to improve thermal conductivity. The method developed in this work introduces a new approach of using non-conductive polymer beads as constituting element in conductive framework formation.

Resume : Polymer metal composites, because of their biphasic structure, show very interesting properties. These composites construct from a mixture of an insulating polymer and conductive micro/nano particle fillers. Here we would like to review some of the areas, we have investigated using these composites such as dielectrophoresis-based switch, magnetic based switch, interconnects and rotation sensor based on magnetic microrods. These conductive particles can move under the effect of electrical field according to dielectrophoresis effect and form conductive bridges. Another application for these CPMCs is to use ferromagnetic particles to benefit from the movement of these particles in both electric and magnetic fields. By applying this effect to form conductive tracks sequentially (between node 1 and 2 then node 2 and 3 and so on) enabled us to have a novel manner of forming interconnects in the distances of the range about 1 cm. By using a CPMC with high concentration of ferromagnetic microparticles as an inductor core, we could detect the rotation angle changes by detecting the inductance value. The mechanism of this rotation sensor is based on the rotation of the micro rods constructed from ferromagnetic particles in a constant magnetic field.

Resume : In the last decade, much research has focused on the implementation of carbonaceous nanofillers in Carbon Fiber Reinforced Polymer (CFRP) to improve its electrical conductivity and mechanical performance. Such highly conductive CFRPs are desirable functional materials for use, for instance, as modules to protect electronic parts from high-energy electromagnetic impulses in the aerospace, defense or automotive sectors. The incorporation of carbon nanofillers can be realized by various approaches which one of them includes the use of thermoplastic nonwoven fabrics which contain conductive nanofillers obtained mainly by immersing neat nonwovens in a filler solution. In this work, a novel type of thermoplastic nonwoven fabrics containing carbon nanotubes (CNTs) was obtained by the pressing method in laboratory conditions and in a half-industrial melt-blown process (developed by TMBK Partners). Both approaches start with thermoplastic pellets containing CNTs obtained by the extrusion method; this results in a well-dispersed nanofiller within the polymer matrix. In lab conditions, thin nanocomposite fibers are produced by extrusion and spinning and then pressed together to form the nonwoven. In the melt-blown process, pellets are melted and then blown to form short fibers that are deposited in the receiving system. These two types of nonwoven fabrics contain up to 7wt% CNTs in the first method and up to 3.5wt% CNT in the half-industrial technique; they differ in obtained areal weight and fiber thickness. Moreover, the production capacity of the melt-blown approach is 25 times higher; this could meet demand from the industrial sector. Thermoplastic nonwovens containing CNTs were interleaved in CFRP by prepreg and resin infusion manufacturing methods. In both cases, due to the high flexibility of the nonwovens used, they were easily implemented in the CFRP and fully impregnated with epoxy resin, as was confirmed by Scanning Electron Microscope (SEM). Generally, the presence of CNTs increased the electrical conductivity of the CFRP throughout the laminate thickness, but the level of improvement is strictly dependent on the type of nonwoven used, especially the amount of CNTs and the thickness of the fabrics. The latter has also an effect on the interlaminar fracture toughness of the laminates and should therefore be kept as low as possible. Furthermore, there is also a strong effect of the manufacturing technique and conditions of the CFRP on the behavior of the nonwovens and the state of CNT dispersion in the final composite panels. Only if the curing temperature is high enough are the thermoplastic nonwovens completely melted, thus forming the homogenous interlayers in the CFRP and creating the conductive pathways between the CNTs. In effect, the final composite panels were characterized by a significant improvement of electrical conductivity, especially in the case of laminates manufactured by resin transfer molding. The research leading to these results has received funding from the National Centre for Research and Development within grant no. DOB-1-3/1/PS/2014, and from the European Union Horizon 2020 Program under Grant Agreement n° 646307.

Resume : Polylactide (PLA) is an aliphatic polyester and can be produced from renewable sources such as corn and starch. It is an significant biopolymer used especially for biomedical and food packaging applications due to its inherent biodegradable and compostable na-ture. Polyhedral Oligomeric Silsesquioxanes (POSS) are nanosized cage structures that are generally represented by (RSiO1.5)8, and can be easily incorporated into thermoplastics or thermosetting polymers. This study basically investigates effects of using four different POSS structure on the mechanical behavior of PLA matrix nanocomposites. The first POSS structure used have isobutyl groups at eight corners (POSS), the second one has aminopropyl group at one corner (ap-POSS), the third one has propanediol group at one corner (pd-POSS), while the fourth one have silane groups at eight corners (os-POSS). PLA matrix nanocomposites having 1 wt% of each POSS structure were prepared by melt-mixing method in a laboratory scale twin-screw extruder. Specimens for testing and analysis were shaped in required dimensions by using a laboratory scale compression molder. Three different mechanical tests were carried out as tensile, flexural and fracture toughness tests. In addition, fracture surface morphology and distribution of the POSS nanoparticles in the matrix were investigated under scanning electron microscopy (SEM). It was generally observed that use of different POSS structures improved mechanical properties of PLA matrix with different levels. For instance, use of POSS, ap-POSS, pd-POSS and os-POSS structures increased GIC fracture toughness of PLA by 42%, 20%, 9% and 39%, respectively. Keywords: Polylactide, POSS nanoparticles, Mechanical properties, Nanocomposites

Resume : New reinforcement material for structural polymer based composites had been proposed in the kind of weft knitted fabrics containing high strength carbon fibers produced from PAN precursors. Matrixes for polymer based composites had been produced from epoxy binder with the hardener of anhydride type. One of the advantages of weft-knitted fabrics to be used for the reinforcement of polymer based composites is the possibility of production of the materials with wide range of physical and mechanical properties. For the optimal realization of the properties of high strength fibers several samples had been produced by hot pressing with various schemes of reinforcement arrangement: 1D unidirected arrangement of reinforcements and 2D - two-dimensionally reinforced polymer based composites. Physical and mechanical properties ( tension strength and elastic modulus according to ASTM D3039/D3039M-140 had been determined for polymer based composites reinforced by Tenax-J/EHTA 40F13 and УКН 5000 carbon fibers. Experimental results had shown essential anisotropy of polymer based composites reinforced by weft-knitted fabrics. Obtained level of mechanical properties for 1D and 2D composites taking into account the arrangement of high strength carbon fibers ensures the opportunity of the most rational variant of reinforcement scheme when the most part of high strength fibers are situated in the direction of applying of mechanical loadings during their service conditions. Experiments had been performed within the join pilot activity of AERO-UA project (grant agreement No.724034)

Resume : Weft-knitted fabrics produced from high strength carbon fibers synthesized from PAN precursors are the perspective materials for creation of polyfunctional composites for structural and other types of applications. Experimental study of electrical resistivity of such kind fabrics had been performed by 4-electrode method. The results of experiments showed that electrical conductivity of the fabrics in the direction of loop rows due to the properties of weft yarn is essentially higher than corresponding value in the direction of loop columns and may reach 1,6 Ohm. Shielding properties of the samples from fabrics and polymer based composites had been determined by means of waveguide measuring cell for the frequency interval 26-20 GGz. Reflection and attenuation coefficients had been measured, absorption coefficient for electromagnetic radiation had been calculated. Shielding properties almost had not been varied during changing the directions relatively loop rows. However the values of the reflection and absorption coefficients had been changed in essential manner. the mean value of absorption coefficient is about 17 %-19 %. Properties anisotropy had been revealed relatively the direction of weft yarn in fabric. Studies of composites reinforced by weft-knitted carbon fabrics had shown the influence of polymer matrix on the absorption properties of composite. If the shielding coefficients for weft knitted fabrics and composites reinforced by weft-knitted fabrics had been equal each other the absorption coefficient for carbon plastics is higher than corresponding value for weft-knitted fabrics and equal 23 %-25 %. So the structure of reinforcement fabrics containing high strength carbon fibers from PAN precursors allows to realize necessary complex of composite properties such as strength, electrical conductivity, shielding properties with the ability of electromagnetic radiation absorption. Experiments had been performed within the join pilot activity of AERO-UA project (grant agreement No.724034)

Resume : Stabilized zirconium dioxide is the material which can be used in solid oxide fuel cells, high-temperature electrochemical devises, separating membranes e.g. Stereolithography (SL) is the most promising additive manufacturing technique to fabricate complex zirconia parts via photopolymerization of a curable system consisting of sensitive monomer/oligomer resin and ceramic fillers. Most publications regarding SL of ceramics fully describe resin compositions and/or processing conditions but they rarely reveal the effect of the nature of ceramic dispersion on the SL process. The aim of the present work was to explore relationship between the properties of stabilized zirconia powders and behavior of UV-curable slurries in photopolymerization reaction. ZrO2 powders stabilized with 4 and 8 mol.% of Y2O3 with different particles size distribution, tap density and specific surface area were synthesized by co-precipitation method from aqueous solutions of zirconium oxychloride, yttrium nitrate and ammonia. The slurries consisting of 1,6 hexanediol diacrylate, photoinitiator, ceramic fillers and dispersants (Triton X-100 and BYK 969) were prepared for SL process. It was shown that the nature of ceramic dispersion has a crucial role in the fabrication of 3D objects. Viscosity and curing behavior of the suspensions strictly depends on the fillers concentration, density of the powders and yttria content in ZrO2.

Resume : In recent years, ionic polymer metal composites (IPMCs) have attracted so much attention, because of their valuable properties such as built-in sensing, actuation capabilities, light weight, mechanical flexibility, resilience, and easy processing. Electroless plating is the conventional approach for fabrication of electrodes in IPMCs, but this process is less controllable, time-consuming and needs expensive metal salts such as [Pt(NH3)4)Cl2]. In this work, we have proposed a new method for electrode formation of IPMC using inkjet-printing technique. We have modified a regular desktop printer, and it was used to print silver nano-particle ink (NovaCentrix Metalon) on Nafion membrane. The sheet resistance of the fabricated electrodes by multi-pass of printing is lower than 5Ω/Square, which is smaller than electrodes formed by the conventional electroless plating. In this approach we can control the thickness of electrodes and the layout of the patterned electrode without photolithography. The advantages of the proposed technique include low-investment cost, low temperature and fast process, low material wastage, and non-contact patterning.

Resume : Nowdays, highly competitive market puts forward great demands to increase efficiency and reduce costs in the manufacturing sector. Computer simulation modelling is widely used as a successful tool for design and analysis of the finished product. Distinguished feature of the most common technologies of modern materials science – is the use as a primary feedstock, materials in a granular state. It's not only well-known processes of powder metallurgy, but also powder coating, nanotechnology, etc. Creation of new materials from powders with predetermined properties put forward new demands for research and solving of technological tasks. Filling processes, despite its simplicity, depends on particle size distribution of charge, physical and mechanical characteristics of powders, filling method of a volume, dimensions of product and other. Investigation of filling process is possible by several ways: by a natural experiment, computer simulation modelling and etc. Analysis of the modern state of modelling studies in powder metallurgy indicates on a clear trend in description of properties of physical processes on the basis of models of random packing of particles. The series of computer-simulation models of particle packing for monodispersed and polydispersed case of filling powders developed in Lutsk NTU (Ukraine) are presented in this work. Peculiarities of developed software and the areas of practical using of obtained results had been described.

Resume : A non-labeled portable plasmonic biosensor-based device was developed to enable the ultra-sensitive and selective detection of Salmonella typhimurium in pork meat samples. Specifically, a plasmonic sensor applying the self-assembly of the gold nanoparticles (AuNPs) of 20 nm, was used to conduct high-density deposition on a transparent substrate in order to achieve a regulated diameter of AuNP monolayers, which produced longitudinal wavelength extinction shifts through the localized surface plasmon resonance (LSPR) signal. The developed aptamers conjugated the LSPR sensing chips revealed an ultra-sensitive limit of detection (LOD) for S. typhimurium as ~104 cfu/mL in pure culture under the optimal assay conditions with a total analysis time of 30-35 min. The LSPR sensing chips when applied on artificially contaminated pork meat samples, the detection range of S. typhimurium in the spiked pork meat samples was also observed in pure cultures as 1×104 cfu/mL. The developed method could detect S. typhimurium in spiked pork meat samples without a pre-enrichment step. Additionally, the LSPR sensing chips developed against S. typhimurium did not show any susceptibility to any effect of the food matrix or background contaminant microflora. These findings confirm that the developed gold nanoparticle-aptamer-based LSPR sensing chips may have practical applications for the sensitive detection of S. typhimurium in food samples.

Resume : Development of a rapid and sensitive method for infectious disease diagnosis is highly important to prevent the further spread of disease and to enable effective clinical treatment. Herein, an ultrasensitive colorimetric approach combining the advantage of immunomagnetic nanobeads and the enzyme mimic activity of gold nanoparticles has been developed. Two kinds of amplification processes are used to enhance the detection sensitivity. The increased surface area and the magnetic properties enable the magnetic nanobead to catch a large number of antibodies and target viruses, thus very small amounts of the virus can be easily detected. And the signal amplification of naonzyme causing the enhancing of the optical signal. This approach could avoid complicate instruments and allowed detecting Influenza virus only by naked eyes as well as microplate reader. In addition, we introduced a novel practical approach to develop a robust sensing system, named magnetoplasmonic ELISA (magplas-ELISA), which collects and concentrates target antigen, and amplifies signal simultaneously. Gold nanoparticles (Au NPs) were decorated with the magnetic nanoparticles (MNPs) based on its ease of synthesis and bio-compatibility. It can replace peroxidase in colorimetric biosensor owing to its outstanding peroxidase-like activity. Our choice of MNP-Au NP has a triple function which is a capture probe, magnetic concentrator and signal amplifier in this system. Triple-functional- magnetoplasmonic NPs described here provides direct monitoring of biomarker in a clinical sample as urine and serum.

Resume : Ideal electronic sensory system model is a biological skin, in a variety of neural mechanoreceptors for the ionic mechanotransduction that sense to various external stimuli such as pressure, shear, torsion vibration, and temperature. Among several functions of receptors, sensors detecting and discriminating external mechanical forces are a principal component in the development of electronic tactile systems that can mimic the multifunctional properties of the human skin. Here, we demonstrate a pyramid-plug structure for highly sensitive tactile sensor that enables to detect pressure, shear and torsion. The device is composed of pyramid-patterned ionic gel inspired by neural mechanoreceptor and engraved electrode. Based on pyramid-plug structure, the deformation mechanism is different for the type of external mechanical loadings. The sensor provided the high sensitivities of 1.93 kPa-1, 29.88 N-1, and 3.39 N·cm-1 and detection range to a wide range of tactile daily activity. Moreover, it is noted that this tactile sensor could be worked by each of two transduction methods (capacitive and piezoresistive). We show that the tactile sensor can be used to monitor the change in electrical signals ranging from human breathing to an arbitrary multiplex human touching.

Resume : The desire to restore the quality of life to transtibial amputees in Nigeria has been on the front burner in recent years. In this study, a home-grown nanocomposite (NC) material (multi-walled carbon nanotube reinforced natural rubber) and multiflex dynamic response 2 foot (a common foreign foot prosthetics in Nigeria) were investigated with a view to comparing their water absorption capacity, thermal stability, wear resistance and morphological properties. The inherent challenge of ensuring uniform distribution of multi-walled carbon nanotube (MWCNT) in the host matrix was addressed by the use of sodium dodecylbenzene sulfonate (C18H29NaO3S). The CNT was synthesised via catalytic chemical vapour deposition (CCVD) technique and the NC was produced using an electrically heated hydraulic press. While the initial decomposition temperatures (Tonset) of the materials show that the newly developed NC with 260.01 oC is more thermally stable than M. DR2 foot with the temperature of 238.17 oC, incorporation of MWCNTs into the unfilled NR matrix shows a significant change in Tonset. MWCNT loading was found to influence the moisture content of the reinforced matrix by about 7% with the NC being 35% more thermally stable than M. DR2 foot. SEM/EDS micrographs indicated complete embedment of MWCNTs in NR matrix thereby making it more suitable than M. DR2 foot which was inundated with cavities. While it takes both NR/MWCNT and DR2 foot 120 days to attain saturation point in water, the former is 93% more dimensionally stable than the latter and also demonstrated better resistance to wear than the latter. It can, therefore, be concluded from the foregoing that the home-grown material is to be preferred to its foreign counterpart for anthropomorphic prosthetic foot application.

Resume : The possibility of application of carbon and aluminum-oxide nanofilms coatings on copper, covar, and niobium as barriers limiting the spreading soldering materials tin, lead, silver, germanium, copper and nickel was investigated. It is determined that carbon films onto copper and alumina films onto the covar and niobium are suitable as barriers to the prevention of spreading of molten germanium, silver and solder Cu-Ag; the alumina films as screens for preventing the spreading of molten copper over the covar and nickel in niobium are unsuitable. It can be argued that the screening film on the interphase surface, which does not dissolve in solid and liquid metals, will be stable for thermodynamically equilibrium systems (the chemical potentials of the components in the solid and liquid phases are the same). In such systems there are no chemical transformations, processes of transport and exchange of matter between the solid and liquid phases. In nonequilibrium systems, interfacial films can be destroyed as a result of the interaction between the solid and liquid phases (dissolution, formation of intermetallic compounds), which is accompanied by volumetric changes, film peeling and the establishment of a contact between the solid and liquid phases, at which such interaction begins mainly locally in defects. Carbon and alumina films 50 – 100 nm thickness were recommended for practical application of copper brazing using tin, silver and copper-silver solders; as well as aluminum-oxide films of the same thickness on the covar – for brazing by silver and copper-silver solders and also these films up to 200 nm thickness onto niobium – for brazing by silver, copper-silver and copper solders.

Resume : Brazed metal-quartz products are widely used in modern technique. They are used in cryogenics, microwave technology, electronics, space technology and many other industries. One of the important and promising areas is the creation of brazed quartz-aluminum scintillation chambers used in geological equipment, mainly using the gamma-ray logging method. Such chambers should be operated under extreme conditions, including simultaneous impact of abrupt temperature changes from -50 °C to +250 °C (up to 1000 thermal cycles), mechanical action and shock loads while maintaining high chamber tightness and no stresses in the optical element made of quartz glass. Aluminum alloys AD1 and AMn were used to develop the technology for manufacturing such products. As a solder a plastic metallic alloy of lead and indium was selected, which included up to 5% (mass) fine-dispersed titanium powder. The optimal design of quartz glass connection with an aluminum frame is the female jointing in which the solder is placed in the annular gap between the end face of the quartz glass and the metal frame. The brazing was carried out in a vacuum no worse than 2 x 10-3 Pa for 30 min at a temperature of 620 °C. Experienced samples of brazed quartz-aluminum scintillation chambers were produced and tested. These samples were capable withstand without disturbing the vacuum density of the chamber, and in the absence of mechanical stresses in quartz optical element, the action of 1000 thermocycles in the -50 °C - +250 °C mode with simultaneous vibration and shock loads including mechanical single shocks with an acceleration of 100g with a duration of impact of 11 ms.

Resume : Ceramics generally have excellent heat resistance, the fracture behavior has not yet been sufficiently understood. This is because many ceramics are heterogeneous materials. We have focused on the several refractory compounds in the CaO-Al2O3 quasibinary system, consisting of common elements on the earth. Since they have relatively high melting points, they can be used not only as cement and concrete materials but also as high-temperature refractories. The objective is to evaluate the mechanical properties of calcium aluminate-based compounds used in these materials. Alumina and calcium carbonate powders were weighed as raw materials so that the molar ratio of Ca: Al = 1:6 (or less), and were wet-ball milled with ZrO2 balls in ethanol for 2 h. The mixed slurries were dried by vacuum drying and dried in an oven at 80 ° C overnight to remove residual ethanol. The dried powders were granulated by passing through a 150-mesh (< 100 micrometer) sieve to obtain the mixed powders. Uniaxial pressing was carried out twice to obtain rectangular bar samples under 15 MPa, for 1 min. The samples were sintered with the ramp rate of 5 ° C/min and kept at 1,600 ° C. for 3 h. Some the sintered samples were pulverized, for the XRD measurement, and a single phase of CaAl12O19 (CA-6) was identified. The microstructure was investigated by SEM observation and their particle sizes were analyzed. Mechanical properties were evaluated by three point bending test and micro Vickers hardness measurement.

Resume : Marine lanterns are installed on light buoys for safe navigation of ships. Marine lanterns used oil in the beginning of 1900 and the light bulb in the 1950s. Since 2003, the LED marine lantern has been developed. However, only ordinary bulbs are replaced with LEDs, but the installation and configuration remain the same. Fresnel lenses of a marine lantern play a role to transmit light horizontally for transmitting light in parallel. The lenses are difficult to design and require high cost. Therefore, we developed a novel optical design which replaces conventional lens to a reflector of marine lantern. Illumination optics design program (LightTools) was used for simulation the light distribution according to the LED-200hi standard for marine lantern. In the simulation, we used 13 W XHP35 model from Cree. The luminous flux of the LED chip was calculated by Cree product Characterization Tool. The LED chips with 13 W was calculated as 797 cd in the simulation that satisfied the average horizontal brightness of the LED-200hi standard. As a result, the power consumption of the Simulated LED module using 13 W LED chip in was 68.7% lower than 30 W of LED-200hi standard. Acknowledge This research was conducted under the Pukyong National University Research Park(PKURP) for Industry-Academic Convergence R&D support program, which is funded by the Busan Metropolitan City, Korea

Resume : Currently, the a mount of coal waste is increasing by the increase in electric power consumption. Therefore, we focused that the coal waste can be applied to new format through the production of porous foam. By using the coal waste as foaming agent, a porous foam are fabricated to apply in the construction materials. Compression strength of the porous foam using coal waste was 11.2 Mpa, and far-infrared emissivity and emission power of the porous foam using coal waste were confirmed 0.918 and 354 W/(m2·µm), respectively. The deodorization rate of NH3 of the porous foam using coal waste was 87.8%. The porous foam using coal waste was satisfied the standard of emission of environmentally hazardous substances. As a result. We confirmed that the porous foam using coal waste had various functionalities, and it could be applied in various field. Acknowledge This research was conducted under the Pukyong National University Research Park(PKURP) for Industry-Academic Convergence R&D support program, which is funded by the Busan Metropolitan City, Korea

Resume : Microgels have served as microcarriers for cells and drugs as they provide fast diffusion and injectable suspension. In a typical procedure of microgel production, water-in-oil emulsion drops containing gel precursors are formed and the precursors are then crosslinked by chemical reactions. However, the reactions are sometimes not biocompatible due to toxicity of small precursor molecules or use of harmful reaction triggers. In this work, we propose a highly biocompatible method for fabricating microgels using complexation of graphene oxide (GO) nanosheets and polyvinyl alcohol (PVA). With a microfluidic device, we prepared water-in-oil-water double-emulsion drops. The inner drops contain GO and PVA without any small molecules. The GO and PVA at low concentration are randomly dispersed. When the double-emulsion drops were subjected to high osmotic pressure, water was selectively pumped out, leading to gradual concentration. During the concentration, GO formed a nematic liquid crystalline phase and crosslinked PVA to form a homogeneous hydrogel through complexation caused by hydrogen bonds between PVA and GO. The microgels suspended in water are stable, which is attributed to the formation of ordered GO enabling the uniform gelation of PVA. This microfluidic strategy does not use any toxic components or harmful stimuli, potentially providing a useful means to create microgels containing cells and delicate protein molecules.

Resume : Thermally conductive composite films containing anisotropic boron nitride (h-BN) species mixed with spherical aluminum nitride (AlN) or aluminum oxide (Al2O3) particles in polyimide matrix have been developed. The plate-shaped h-BN species in the obtained hybrid films were aligned along the through-plane direction the confirmed mobility resulting from the presence of the AlN or Al2O3 components as well as high anisotropy. The highest in-plane thermal conductivity was obtained for the films containing hybrid fillers. Still, the highest through-plane thermal conductivity was the composites containing only the h-BN fillers owing to the high anisotropy and the intrinsic high thermal conductivity of h-BN, which lead to thermal diffusion pathways by particle aggregation. A composite model based on two-population approach was developed for the first time to consider two different ceramic conducting fillers.

Resume : Cu as a metal material is used for IC lead frames and heat exchangers and has high electrical conductivity and high thermal conductivity. In addition, Cu has diversified applications, as a component of precision instruments, building materials, and other accessories. Cu has a face-centered cubic crystal structure, and is usually a bulk body. Recent studies have reported that nanoparticles can be produced using electrolytic reduction. In a previous study, we showed that a Cu dendrite structure could be fabricated on a Zn/Al alloy substrate using supersaturated copper sulfate solution (presented at the 2017 E-MRS Fall Meeting). In this presentation, Zn derived from the substrate penetrated the Cu dendrite structure as an impurity. Therefore, the structure was dendritic with Cu/Zn alloy. This time, in the Cu deposition process on the Zn/Al substrate with supersaturated copper sulfate solution, an additional Cu electrode was placed on top of the Zn/Al substrate. This successfully eliminated Zn from the Cu dendrite by utilizing the electric field effect of the additional electrode. As a result, we succeeded in depositing Cu dendrite crystals with purity exceeding 98%. By SEM observation of the growth process and surface element distribution analysis by EDS, we confirmed the following formation mechanism. In the early stage of Cu deposition, Zn is prevented from being mixed into the Cu crystal by the electric field effect of the upper additional electrode; simultaneously, the three-dimensional growth of Cu is suppressed, and two-dimensional planar growth occurs instead. An almost perfect two-dimensional Cu dendritic structure was confirmed. In the middle stage of growth, we confirmed the vertical growth of the Cu dendrite on the Al site. In the later stage of growth, three-dimensional growth of Cu dendrites was confirmed on the upper additional electrode surface. Thus, it was possible to control Cu crystal formation and longitudinal growth. In addition, the Cu dendrite crystal showed lateral strength due to the two-dimensional growth surface constructed in the early stage of growth, making it possible to form a Cu thin film which can be handled with tweezers.

Resume : Metal atoms are known to exhibit properties different from the bulk by miniaturization. Examples of converting gold into nanoparticles, constructing a sensor material, and using it as a chemical reaction promoter exist. Further, metal fine particles of Au or Ag are attracting attention as intermetallic bonding materials and low resistance materials for fine wiring. However, Au and Ag are cost prohibitive. Meanwhile, Cu has high thermal and electrical conductivity. Further, the problem concerning the high material cost of Au and Ag is not declaration. Therefore, studies on the fabrication of Cu microparticles have also been conducted. Although it is known that microparticles are difficult to obtain in solution, Cu microparticles are primarily prepared using the electrolytic reduction method. In our previous studies, we have succeeded in fabricating three-dimensional tree-structured Cu crystals (Cu dendrite crystals). We herein report that this Cu dendritic crystal was pulverized in solution using ultrasonic waves to produce fine particles of diameter 1 μm to 10 μm. As this Cu microparticle was produced by pulverization, it was confirmed in a fracture state rather than a particle. As the Cu dendrite crystal used had a purity level of 98%, almost pure Cu microparticles were obtained. This Cu microparticle was blended with inkjet printer ink and successfully formed a conductive line on a nonconductive film. This experimental procedure is much simpler than the method of forming Cu nanoparticles, and has been used for printed electronics. We also found that by controlling the surface oxidation level of the Cu microparticles, printed matter having a resistance element function can be formed. Although this oxidation level control is difficult to form with nanoparticles, the abovementioned method is extremely simple. This demonstrated the possibility of multi-functionalizing printer ink containing microparticles.

Resume : In this study, the dielectric paste was fabricated using polystyrene-block-polyisoprene-block-polystyrene (SIS) as polymer matrix and barium titanate (BT) as dielectric filler in order to produce organic-inorganic composite for 3D inkjet printing applications. Since a high loading of filler is required to realize a high dielectric properties, the surface of inorganic filler was modified with two different phosphonic acids having functional groups resembling the groups contained in the block copolymer for higher compatibility of fillers with the polymer matrix. With the incorporation of 80 wt% BT in SIS, the dielectric constant was increased to about 3 times higher than that of bare SIS and the surface modification of fillers resulted in suppressed dielectric loss and improved dispersion of them. The dispersion of the fillers in the polymer matrix was investigated by 3D scanning microscope images of each composite films. The rheology of the paste was optimized through fine tuning of total solid content, and consequently, the potential as 3D printable paste was demonstrated through layer by layer printed structure.

Resume : Tantalum carbide (TaC) has excellent high temperature hardness, strength, and the highest melting point among commercially available carbides. In addition to these advantages, TaC has been used as an additive in the cemented carbide (WC-Co) industry for the purpose of preventing grain refinement and erosion. In this study, TaC was fabricated by using Self-propagating High-temperature Synthesis method. After the synthesis, the shape of the microstructure did not change by changing the green density. Significant change was shows in size distributions of TaC. When the compaction pressure and green density were higher than 3.5 Mpa and 51% respectively, single phase tantalum carbide samples without unreacted Ta and C were achieved. The combustion temperature was up to 2,200℃, and at that time relatively low vapor pressure such as Ga, Mn, In, and Ba were volatilized resulting in the increase in purity of TaC up to 99.32%. TaC was fabricated by Self-propagating High-temperature Synthesis (shortly SHS) method using recycled scrap materials available in domestics. SHS offers high process efficiency and faster production rate. Furthermore, SHS process could design that feed stock does not contact with other structural components like a crucible and requires no additional heat after ignition. Up to now, SHS regards as suitable processes to manufacture these kinds of ceramic tool materials. In addition, to fabricate TaC powder, by changing the wire from Ni-Cr to W we were able to achieve the ignition without the need of an external ignitor. No paper in this regards has been published to the best of our knowledge. Used materials in this experiments is that purity of Ta raw material was 98% with an average particle size of 31㎛. Carbon powders had an average particle size of 6㎛ and plate like shape. The green density of feedstock was selected as the variable parameter of this study.

Resume : A possibility of cemented carbide wastes usage as a reinforcement filler for aluminum alloy-based composites manufacture has been investigated. Interphase interaction of high-modulus carbides powders with aluminum-based melts has been studied by synchronous thermal analysis technique. The wettability of silicon carbide single crystal and cemented carbides by liquid aluminum-based alloys have been measured using the sessile drop method. The regularities of vacuum infiltration of dispersed particles by aluminum-based melts have been studied. It is established that the infiltration process practically does not depend on the type of the particles material, but is affected by their dispersion. Increasing the vacuum to 20 kPa leads to a sharp increase in the infiltration depth, and its further increasing practically does not affect this process. The infiltration rate dependences on the temperatures of the mold and the melt, the soaking time and the dispersion of the filler have been established. A special technological diagram has been designed for optimal operating modes choice for cast billets production using the infiltration method. A technique have been elaborated for aluminum alloys-based composite materials cast billets production with a high content (about 60 vol.%) of high-modulus carbide disperse particles. An alloying method have been devised for cemented carbide and silicon carbide dispersed particles introduction into the aluminum-based melts (1-5 wt.%).

Resume : Smart window is a functional device that can freely adjust the transmittance of sunlight transmitting from the outside. In recent years, as the interest in the environment has increased rapidly, the importance of efficient energy use such as smart window has emerged, which is expected to be widely available in the near future. One of the types of smart windows, polymer dispersed liquid crystal (PDLC) refers to a form in which liquid crystal is dispersed in polymer matrix between two films having a transparent electrode.[1] A smart window currently used is made by attaching a PDLC film made on glass using a UV adhesive. In this study, we have studied how to make a smart window by directly coating polymer and liquid crystal mixture on glass without forming PDLC films separately. While attaching PDLC film on a glass is time consuming and not cost-effective, this direct coating technique can be applied for a large smart window as building materials. In order to coat PDLC directly on glass, the viscosity of the PDLC mixture was adjusted by adding glass beads to the mixture. It was confirmed that the optical properties of our samples such as transmittance and response time were commercially applicable. Reference [1] David Coates. “Polymer-dispersed Liquid Crystals.” J. MATER. CHEM., 5(12), 2063-2072 (1995)

Resume : This paper presents the results of mechanical tests at a uniaxial tension of a nanocomposite obtained as a result precipitation hardening in the process of ageing of quenched ferromagnetic Fe-27.2% Ni-17.4% Co-5.2% Ti (wt%) alloy having the martensitic, austenitic or mixed structure of matrix after cooling and/or applied stress. To obtain the nanocomposite, the alloy samples were subjected to a preliminary thermomechanical treatment (TMT), which consisted of multiple drawing operations, followed by quenching in water from 1373 K and ageing at 923 K for 5, 10, 20 minutes. As a result of such TMT, a sufficiently high level of superelastic deformation and shape memory effect were achieved. It was experimentally established that the preliminary TMT, consisting of drawing with compression degree 7.4÷22.5%, followed by quenching and aging at 923 K for 5÷10 minutes, favours the deformation of the nanocomposite along the channels of phase and twinning plasticity in the range of testing temperature Ms

Resume : As electronic devices become more miniaturized and integrated, studies on high thermal conductivity and low dielectric properties packaging materials become more important. In this study, we made a boron nitride/polyimide (BN/PI) porous composites using high internal phase emulsion (HIPE) method. The composites can be contained a large amount of the uniformly dispersed filler without the additional modification of filler through HIPE method. And then, we fabricated porous films by pressing the composites to reduce free volume of composite and increase the connection of BN. The free volume in pressed BN/PI porous composite films allows lower dielectric properties than BN/PI composite films using the conventional mixing method. Also, this films have sufficient thermal conductivity because of uniformly and densely dispersed the filler in polymer matrix. The free volume of films can be controlled by temperature conditions when the composite was pressed. As pressed above Tg, the free volume in composite films decreases. Accordingly, thermal conductivity and dielectric constant of the composite films increased. These results show the potential of our composite films as a packaging material for microelectronic devices.

Resume : In the industrial part, polyvinyl chloride (PVC) are daily made for packaging, films, covers, bags and containers. The PVC have several attractive proprieties for use as corrosion protection coatings that include good mechani-cal characteristics, as well as chemical resistance to acidic, alkali, and oxidative environments [1]. The low cost of PVC promotes the wide facile application of this polymer in industrial processes [2, 3]. On the other hand, it also has some disadvantages such as detects and bursts on the coating surface in the highly acidic conditions for long working time. To solve these problems, inorganic filers are involved in the PVC sol for increasing the durability of coating films. But the even distribution of inorganic filers in the highly viscous polymer sol is not easy to achieve. Therefore we need the improving method for dispersing the inorganic particles in the polymer matrix with chemical bonding. In this sturdy, we tried to modify the surface of inorganic particles before mixing with PVC and plasticizer for making the better flowability particles and bonding with PVC. For surface modification of inorganic particles, we used silane coupling agent which has some group react with PVC resin. The PVC coating film with the surface modified inorganic particles showed the enhanced chemical and physical properties, because the inorganic particles were evenly dispersed and increased the adhesion with PVC matrix. References [1] Polyaniline/polyvinyl chloride blended coatings for the corrosion protection of carbon steel, Progress in Organic Coatings 106 (2017) 50–59 [2] Preparation ofporous super-hydrophobic and super-oleophilic polyvinyl chloride surfacewith corrosion resistance property, Appl. Surf. Sci. 258 (2011) 1008–1013 [3] Superhydrophobic, nanotextured polyvinyl chloride films fordelaying Pseudomonas aeruginosa attachment to intubation tubes andmedical plastics, Acta Biomater. 8 (2012) 1881–1890

Resume : Simple and lithium-doped biological-origin hydroxyapatite layers were synthesized by Pulsed Laser Deposition technique onto medical grade Ti substrates. The effect of lithium addition on the biocompatible and antimicrobial properties of the coatings was assesed using three cell lines (MG63 osteosarcoma, new initiated dermal fibroblast and immortalized keratinocyte HaCaT), and two microbial species, known to be involved in the etiology of medical devices biofilm-associated infections, respectively (i.e., Staphylococcus aureus and Candida albicans). Our findings suggest that the synthesized lithium-doped coatings exhibited an excellent biocompatibility on human osteosarcoma and skin cells, correlated with a long-lasting anti-staphylococcal and –fungal biofilm activity. Along with the low fabrication costs from sustainable resources, these biological-derived materials demonstrate their promising potential for future prospective solutions – viable alternatives to commercially available biomimetic HA implants – for the fabrication of a new generation of implant coatings. Acknowledgements: This work was supported by a grant of Ministery of Research and Innovation, CNCS - UEFISCDI, project number PN-III-P1-1.1-PD-2016-1568, within PNCDI III. LD and VC acknowledge with thanks the partial support of Core Programme 3N/2018.

Resume : Au plating has been used in some of the ornaments from ancient times. In recent years, it has been used as a surface material of electronic parts from several feature such as excellent corrosion resistance, low contact resistance, superiority compared with other metals at soldering and excellent conductivity. Au plating is generally formed using a cyanide electroplating bath. Cyanide is an environmentally hazardous substance, which is industrially undesirable. For this reason, formation of Au plating using a non-cyanized substance gradually spreads. However, when Au plating was formed on Zn / Al alloy by this method, remarkable deterioration of plating luster had been confirmed. In our previous studies, it was found that when Au plating was performed on Zn / Al alloy, ZnO was formed simultaneously during gold plating construction. Then ZnO builds whisker crystals from the bottom of Au plating thin film and breaks Au plating from backside. We has reported that this is the cause of metallic luster disappearance. In this study, we will report that the formation timing of ZnO can be controlled by the amount of input current density at forming Au plating. When the input current density is 2.0 A/m2 or less, ZnO whisker crystal structure develops moderately backside of the Au plating surface. Therefore, it turned out that more than 72 hours is necessary for the disappearance of the metallic luster. However, when the input current density was 2.0 A/m2 or more, ZnO whiskers grew simultaneously with the Au plating construction, ZnO mixed during Au plating, and the metallic luster disappearance was completed in about 12 hours. As a result, it was found that the growth of ZnO whisker crystals were controlled by the input current density of Au plating, and the metallic luster disappearance time of Au plating could be controlled.

Resume : Today highly-porous bioceramics is one of the most promising materials for replacement of defective cancellous bone tissue in surgery. Highly porous glass-ceramics based on biogenic hydroxyapatite with addition of 40 wt.% of glass (SiO2-B2O3-Na2O, SiO2-CaO-Na2O and SiO2-CaO-Na2O with fluorine addition glasses) have been prepared by foam replica method at sintering temperature 950 °С. The composition of prepared samples was controlled by XRD (X’Pert PRO (PANalytical)), IR spectroscopy (FCM 1202 (Infraspectr)) and energy-dispersive X-ray fluorescent element analysis (Expert 3L (INAM)). The structure was examined by SEM using Zeiss Ultra Plus (Carl Zeiss Meditec AG) microscope. The total porosity of the samples was calculated using the skeleton density values measured by helium pycnometer AccuPyc II 1340 (Micromeritics). Open porosity measurement of the samples was performed in ethanol using the Archimedes principle. It was established the significant influence of type of glass on the phase composition of highly-porous glass ceramics. Using of SiO2-B2O3-Na2O glass allows keeping the phase of hydroxyapatite during the sintering. At the same time SiO2-CaO-Na2O glass (without and with flourine addition) leads to partial decomposition and/or interaction of biogenic hydroxyapatite with the glass phase that results in forming multiphase ceramics. All prepared samples are characterized by a permeable structure with porosity of 85-95 %. Using of SiO2-B2O3-Na2O glass reduces the porosity of bioceramics due to the viscosity properties of the glass and features of liquid-phase sintering of ceramics in the presence of this glass system. Moreover, the structure of the samples is characterized by vitrification of surface and pore walls which are associated with the lower viscosity of SiO2-B2O3-Na2O glass in comparison with SiO2-CaO-Na2O glass (without and with flourine addition). The publication contains the results of studies conducted by Grant for monthly visits of Ukrainian scientists to Poland according to the Protocol to the Agreement on Scientific Cooperation between the National Academy of Sciences of Ukraine and Polish Academy of Sciences

Resume : The development of composite materials in the “intermetallics – refractory compounds” systems is one of the actual and promising trends in creation of novel materials aimed at operating under abrasive and corrosion wear conditions and aggressive environment, such as sea water. Corrosion and hydro-abrasive resistance in 3% NaCl water solution of initial NiAl and NiTi intermetallic compounds and developed NiAl (NiTi) – 15(30)wt.% CrB2 bulk composite materials and coatings from them were studied. Silicon carbide (90–125 and 180-500 microns) was used as an abrasive material. Stainless steel was used as a control sample. Composites microstructures after hydro-abrasive tests were studied using SEM analysis. Topography of composite materials surfaces were investigated after 20, 40, 80 and 160 hours of the tests using Optical profilometer Micron-alpha. It was shown that the surfaces structure of the developed NiTi-30wt.% CrB2 composite materials is characterized by the absence of areas of material destruction. These materials also have minimum intensity of wear compared with steel and initial intermetallics.

Resume : An investigation of phase formation upon interaction between boron carbide and aluminium in vacuum has been done up to temperature of 1400 C. Thermodynamic calculations show that the interaction between B4C and aluminium melt is low. At the same time, using gaseous aluminum drastically changes the situation: the system becomes reactive, interaction goes with significant heat release and decrease of internal energy. Investigations were done by variation of aluminium content: from the maximum representing full B4C decomposition and AlB12 and Al4C3 formation, to the minimum – when some boron carbide is found in the reaction products. Phase availability, content, and lattice parameters were determined using XRD. It was determined, that binary compounds do not form in practice during the interaction, possibly because of entropic factors. Optimal interval of aluminium concentrations to produce a composite product of 85% AlB12C2 and 15% Al8B4C7 was determined. Ceramic samples were compacted by hot pressing at temperatures below 1900 C. It was established that Al8B4C7 facilitates the activation of sintering of icosahedral AlB12C2. Samples were polished, and microstructure and Vickers hardness of the materials were studied.

Resume : It is well known that copper is an essential trace element that is vital to the health of all living organisms. Due to the antibacterial activity Cu widely used for preparation of materials for filling osseous defects. In the present work four types of biogenic hydroxyapatite/glass composites (BHA/glass=50/50 wt.%) were prepared by two-stage sintering. Starting powders of BHA and glass-forming components of sodiumborosilicate glass were mixed with addition of Cu powder (0, 0.5, 1 and 2 wt.%) followed by primary sintering at 1100°C for 1 h. Then obtained composites were crushed, formed cylindrical samples (pressure 100 MPa) and sintered at final sintering at 750°C for 1 h. Obtained samples were investigated by XRD (Ultima IV (Rigaku)), IR spectroscopy (FCM 1202 (Infraspectr)) and energy-dispersive X-ray fluorescent element analysis (Expert 3L (INAM)), SEM (REM 106 I (Selmi)). The total porosity of the samples was calculated using the skeleton density values measured by helium pycnometer AccuPyc II 1340 (Micromeritics). Open porosity measurement of the samples was performed in ethanol using the Archimedes principle and compression strength using CeramTest Systhem. Experiments in vitro (evaluation of solubility) were carried out in saline at 36-37°C for 2 days. It was established the significant influence of copper on the structure and properties of BHA/glass composites. Using of copper decreases the porosity from 16 to 11% and increases the compression strength in 1.6 times (from 130 to 210 MPa). Moreover, copper leads to changes of phase composition and structure of material and reduces the solubility in saline. The publication contains the results of studies conducted by Grant for monthly visits of Ukrainian scientists to Poland according to the Protocol to the Agreement on Scientific Cooperation between the National Academy of Sciences of Ukraine and Polish Academy of Sciences

Resume : At present, there is a great interest in hybrid metal-oxide composites activated with organic dyes to produce multifunctional materials with improved properties for different environmental and energy applications. We studied powder titanium dioxide (TiO2) composites with organic phenothiazine (PTZ, C12H9NS). High-purity single-phase anatase and rutile TiO2 particles were synthesized by thermal hydrolysis followed by calcination at 300 C, and then mixed and ground with a small (~5 wt.%) admixture of granular PTZ (98%, Fluka) at room temperature. It was found that PTZ/TiO2 powder changes its color from white to dark blue. The samples were characterized by XRD, FTIR, Raman, UV-vis absorption and PL spectroscopy. According to XRD, PTZ-doped TiO2 has a good nanocrystalline structure (crystallite size ~10 nm, specific surface area ~240 m2/g) without any phase changes compared to pure TiO2. FTIR spectra showed the formation of PTZ+• and Ti3+ ions as well as extra oxygen vacancies (VO) in the TiO2 matrix, which caused by PTZ. UV-vis spectra showed an increase in absorption in the visible region (> 400 nm), a red shift in the absorption edge, and a narrowing of the band gap by 0.24 and 0.49 eV for direct and indirect electronic transitions compared to pure TiO2. These effects are evidently due to the increased number of intrinsic defects associated with interstitial Ti3+ ions and [VO–Ti3+] vacancies. PL spectra confirmed that the excitonic PL emission in PTZ/TiO2 is inhibited compared to pure TiO2 due to the nonradiative recombination of charge carriers. The distinction between the PTZ-doped rutile and anatase TiO2 properties is discussed. Support of the Polish-Ukrainian Scientific Cooperation Program 2018 is gratefully acknowledged.

Resume : The polycrystalline samples of YBa2Cu3O7-x High-Temperature Superconductor (HTS), also called „YBCO-123”, were prepared by mixing copper (II) oxide (CuO), barium carbonate (BaCO3) and yttrium (III) oxide (Y2O3) powders and followed by a heat treatment at high temperatures (900 ̊C - 950 ̊C) in flowing oxygen [1]. The polycrystalline samples of YBCO-Fe composites were prepared by grinding the mixture of single phased YBCO-123 and small amount of iron (1% and 3% wt.), followed over by a heat treatment [2]. The results of structural (XRD, EDX, Raman), magnetic (AC and DC magnetic susceptibility, EPR) and magneto-transport studies on produced composites will be presented. [1] Peczkowski P., Kowalik M., Zachariasz P., Jastrzebski C., Jaegermann Z., Szterner P., Woch W. M., Szczytko J., Synthesis and Physicochemical Properties of Nd-, Sm-,Eu- Based Cuprate High-Temperature Superconductors, Phys. Stat. Soli. A, 2018. [2] Pomorski K. Prokopow P., Perspective on basic architectures and properties of unconventional and Field Induced Josephson junction devices, Inter. J. Microelec. Comp. Sci., 2013.

Resume : Currently, the cost of recycling waste coffee powder is increasing as the domestic coffee market grows. Therefore, a most efficient way needed to recycle waste coffee powder. In this context, our studies focused on production of ceramic foams using waste coffee. The ceramic foam has many pores and advantageous to thermal transfer by structural features. By utilizing the advantage of thermal transfer, a heat-sink was developed using the synthesized ceramic foam from waste coffee. A universal testing machine was used to measure the compressive strength. The compressive strength of ceramic foam using waste coffee was about 3.384 MPa. The temperature of LED(light emitting diodes) PCB(printed circuit board) after protecting with the synthesized ceramic foam was about 53.6 °C, and the performance of the aluminum heat-sink was confirmed to be 99.8%. As a result, The synthesized ceramic foam facilitates the manufacturing process with higher durability of LED PCB, which results in the cost-effective material. Therefore, waste coffee based ceramic foams are readily available to replace the existing aluminum heat-sink. Acknowledgement This paper was supported by R&BD program for reginal outstanding researchers, startups and innovative firms.

Resume : As study objects, zirconium, titanium, vanadium, chromium, molybdenum, and tungsten borides and carbides nanopowders were used, as well as silicon carbide, obtained by plasmochemical and high-temperature electrochemical synthesis. In both groups of compounds, the corrosion resistance of the materials is comparable and is primarily due to the acidity of the electrolyte. In acidic electrolytes (pH = 2.0 ÷ 3.0), nanopowders dissolve rapidly. Nanopowders of metal-like carbides have a higher corrosion resistance. For all materials, there was corrosion resistance decrease with increasing temperature and specific surface growth during dissolution, which is 2000 ÷ 10000 m2/kg with the particles shape preservation. This indicates the layered nature of the process. The only exception is the silicon carbide nanopowder, which dissolution degree throughout the studied range of pH and temperature values did not exceed 7 ÷ 10%. According to calculations based on the results obtained, in electrolytes with pH = 2.5, the time for which half of the initial disperse material dissolves was 32 ÷ 49 h for borides and 68 ÷ 88 h for carbides; in electrolytes with pH = 3.0, this time was 92 ÷ 112 h and 138 ÷ 167 h, respectively, and in electrolytes with pH = 5.0, it was practically unlimited. The comparison of the obtained kinetic characteristics with known values for coarse-grained powders shows that the nanopowders dissolution rate is 3 ÷ 5 times higher.

Resume : For chromium disilicide metallothermic synthesis realization, 0.02 mol of anhydrous chromium trichloride and 0.04 mol of sodium fluorosilicate are placed into quartz glass container. After addition of 0.22 mol of potassium metal, con¬tainer was placed into stainless steel reactor under argon atmosphere. Reactor was heated up to 923-1023 K during 10-15 h. After cooling reactor to room temperature, synthesis products were washed and dried for impurities removal. Generally, metallothermic reduction reaction process should be represented as follows. At temperature higher than 723 K, sodium fluorosilicate decomposes into sodium fluoride NaF and gaseous silicon fluoride SiF4. Chromium disilicide metal¬lothermic synthesis reaction is based upon interaction of chromium and silicon formed during reduction of chromium (III) chloride and silicon (IV) fluoride by potassium metal. We estimated the possibility of molybdenum and tungsten dicilicides obtaining by metallothermic reduction of metal chlorides and sodium fluorosilicate by potassium. As molybdenum and tungsten sources, MoCl3 and WCl6 were used respectively. Nascent powders thermal stability was determined in airflow at temperature up to 1273 K. According to thermogravimetric analysis (TGA) data, obtained disilicides mass does not change practically up to 973 K.

Resume : We studied the simultaneous electroreduction of carbonate and tungstate ions in oxide (Na2WO4) melts. It was difficult to detect the lithium tungstate reduction wave on the Na2WO4 background. This wave is detectable only at lithium tungstate concentrations above 20 mol %. The reduction wave of lithium tungstate is observed at its concentration 40 mol % at the potential -1.8 ÷ -1.9 V. Addition of lithium carbonate to the Na2WO4-Li2WO4 melt initially causes an increase in the height of the lithium tungstate reduction wave. The reduction wave of the carbonate ion, followed by lithium tungstate electroreduction, appears at lithium carbonate concentration 10 mol %. With the lithium carbonate concentration 15 mol %, the tungstate and carbonate reduction waves merge in a single broad electro¬reduction wave. Tungsten carbide was obtained from the electrolyte composed of 10-20 mol % Li2CO3, 30-45 mol % Na2WO4, and Li2WO4 at T= 1073-1173 K and i = 1.0-1.7 A/cm2. The product composition depends strongly on the synthesis temperature. A WC + W2C mixture formed below 1073 K, and a W2C or a W2C + W mixture was found at 1023 K and below. Raising the temperature above 1173 K is inexpedient because of the thermal instability of the carbonate ion and the increasing volatility of the melt components. Optimal conditions yielded tungsten carbide powders with a specific surface area of 10-20 m2/g.

Resume : A necessary condition for electrodeposition is that the cathode (or the surface layer of the pseudocathode) must possess electronic conductivity. This condition for the SiC(B4C) electrodes was checked by us using voltammetry method. During the electroreduction of CO2 at an elevated pressure, we observed an appreciable increase in the reduction current through these electrodes. According to our data on the MoO42-(WO42-) anions electroreduction in the NaCl-KCl melt at the platinum net silicon carbide (boron carbide) electrodes in the presence of Mg2+ cations, to determine the portion of the platinum net involved in the cathodic reaction, we studied the i(E) dependences with the empty and filled containers. The MO42- ions reduction rate at the empty container electrode is similar to that at a platinum pin electrode. After the platinum container was filled with SiC(B4C), its stationary potential shifted from the platinum net potential to -0.35 ÷ -0.40 V (vs. the platinum-oxygen electrode). A marked rise in the reduction current was also observed showing an increase in the working electrode surface area. From the observed currents difference between the Pt and SiC(B4C) electrodes, we were able to determine the partial MoO42- reduction current at the SiC(B4C) particles surface. We’ve calculated the working SiC(B4C) surface area which was in good agreement with the surface area for the SiC powder with the specified particle size calculated from literature data.

Resume : We present a facile process to fabricate polymer micro- and nano-structures using ion-beam treatment, resulting in the dry adhesives of high adhesion strength. The polytetrafluoroethylene substrate was surface treated under argon ion irradiation. The morphology and average surface roughness of the etched substrate was investigated by scanning electron microscopy and atomic force microscopy, respectively. The micro- and nano-structures of spire with high aspect ratios were obtained. The bonding of the micro- and nano-structures on the polytetrafluoroethylene surface with silicone matrix was adjusted using releasing agent and the transferred structure was suitable to fabricate dry adhesives. The micro- and nano-structures also was stable over repeated uses and played a role to increase the adhesion strength.

Resume : The development of high-reliable nanostructured thick films and their multilayers based on spinel-type compounds for environment sensors operating as simultaneous negative temperature coeficiant (NTC) thermistors and integrated temperature/humidity sensors are very important task. In this work the temperature-sensitive thick films based on spinel-type semiconducting ceramics of different chemical composition Cu0.1Ni0.1Co1.6Mn1.2O4 (with p+-types of electrical conductivity), Cu0.1Ni0.8Co0.2Mn1.9O4 (with p-types of electrical conductivity) and their multilayers of p+-p and p-p+-p structures were fabricated and studied. It is established that these thick-film elements possess good electrophysical characteristics before and after long-term ageing test at 170 оС. It is shown that degradation processes connected with diffusion of metallic Ag into grain boundaries occur in one-layer p- and p+- conductive thick films. The p+-p structures were of high stability, the relative electrical drift being no more than 1 %. Positron trapping processes in so-called “free” thick-film structures based on spinel-type Cu0.1Ni0.8Co0.2Mn1.9O4 ceramics are studied. It is shown that two-state positron trapping model is appropriate for an adequate description of changes caused by additional glass phase in these materials. The observed behaviour of defect-related component in the fit of the experimentally measured positron lifetime spectra for thick films in comparison with bulk ceramics testifies in a favour of agglomeration of free volume entities during technological process.

Resume : Damage occurred in the water tightness test after installation of nuclear power plants HDPE (high density polyethylene) water pipe extruded with master batch compound (natural resin pigmented concentrate). “Window” (white dot) was observed on the surface of the broken HDPE pipe. Window is a master batch compound produced by uneven mixing between the additive and the HDPE resin during extrusion. The observed window defects seem to have a great effect on the safety of the pipe. To confirm the distribution of the window, the surface of the pipe was cut to 100μm, and then the light was transmitted. As a result, it was confirmed that the window was concentrated in the middle portion of the pipe. The tensile test was performed to confirm the effect of the window on the mechanical properties of the pipe, and the fracture cross section of the specimen was observed using a SEM (scanning electron microscope). It was confirmed that the window in the piping had no effect on the yield strength of the HDPE pipe but had a large effect on the elongation. Window appears to affect the safety of HDPE piping, and further research is required for that.

Resume : Generally, polyethylene pipes are welded with butt fusion welding. The butt fusion welding is an effective process for joining plastic pipes. The butt fusion welding is divided into two main stages : the heat soak stage and the coupling phase. Intrusion of foreign substances during this process or failure to accurately proceed with the fusion process can have a significant impact on pipe integrity. Therefore, it is not too much to say that the quality of the pipes that are welded together depends on the process of pipe fusion. In fact, pipe welding is often carried out directly on site, and there is a high possibility that foreign materials (dust, sand powder, etc.) may enter between the fusion joints when welding is performed in the field. Depending on the various situations in the field, foreign materials may enter during fusion, which is called Defects. Defects can have a significant impact on the pipe properties. We have so far assessed the integrity of the fusion joints and have not studied the effects of defects. Therefore, in this study, defects to be inserted into the polyethylene pipe joint are developed. And defects are introduced to evaluate the integrity of the piping to investigate the influence of the foreign material input during the welding process on the pipe life.

Resume : Over the last few decades new ingenious methods have been developed in the sol-gel processing of materials, combining knowledge and material processing methods from different fields of research and pushing the boundaries of conventional xerogel/oxide or aerogel preparation from a wet gel in a typical film, fiber or bulk material form. Notable examples of the reinvention of the sol-gel technique include the synthesis of oxide foams, which form an important class of materials due to their wide applicability for catalysis, electrochromic devices and high performance thermal insulation. This work reports a novel method for the preparation of thick silica foam films that combines an alkoxide-based hydrolytic sol-gel process and in situ catalytic decomposition of hydrogen peroxide on a catalyst-coated support. A hydrogen peroxide/nitric acid aqueous solution was used to carry out acid-catalysed hydrolysis of tetramethoxysilane. The H2O2-loaded sols were sprayed on MnO2-coated substrates, resulting in heterogeneous catalytic decomposition of H2O2 and effective foaming and simultaneous gel formation due to oxygen gas and water formation. Silica foam films with a well-defined closed-cell porosity were annealed at 600 °C without any damage to the closed-cell porous film morphology. Up to 530 µm thick films were prepared with macropore sizes in the range of 29–47 µm, exceptionally thin macropore wall thicknesses of 16–50 nm and a bulk density as low as 64 kg/m3, comparable to that of the aerogels. The lowest measured thermal conductivity of the prepared foams was 0.018±0.001 W/(m*K), which is also similar to silica aerogels, enabling the prepared foams to be used as efficient thermal insulation materials.

Resume : Nickel matrix composite coatings are used especially in the automotive and aerospace industries due to their very good mechanical properties and corrosion resistance. The paper presents the results of the studies of nickel-boron composite coatings deposited by the electrochemical reduction method. A bath with low concentration of nickel ions, boron as dispersed particles and organic compounds were used for deposition of the composite coatings nickel-boron. The results of investigations of coatings deposited from the electrolyte containing 2, 5 and 10 g/dm3 boron and five surface-active compounds were shown. The contents of particles in coatings was determined gravimetrically. The roughness of the layers was measured by TR 100 profilograph. The microhardness of the coatings was measured using the Vickers’ method at a load of 0.01 kg. The Amsler testing machine with system: block – ring was used for tribological tests with lubrication Lux oil. The obtained results suggest that the content of incorporated boron particles increases with an increasing amount of boron in plating bath. The coatings nickel-boron produced during investigation were distinguished by much better tribological properties than nickel coating.

Resume : Thermophysical and mechanical properties of Epoxy-520 resin compositions with unoxidized graphene particles were investigated. The particles were obtained by the electrochemical method and were blocks up to 50 nm. The particle concentrations in the composites were C = 1.0, 2.0 and 5.0% for thermophysical studies and 0.1, 0.2, 0.5 and 1.0% for mechanical measurements. Thermophysical measurements of the composite destruction are performed by method of thermo-programmable desorption with mass spectrometric recording of volatile products. The main effect of the introduction of unoxidized graphene particles is a sharp increase in the thermal stability of the composite and a decrease in the amount of the released volatile products Qi, with a low filling, when ?? 1.0%. Another effect of the introduction of unoxidized graphene is the fastening of atomic groups of the macromolecule on the carbon atoms of the particle side faces. The run of Qi for volatile fragments does not correlate with the dependence of their desorption energy on the concentration of graphene filler. Thus, with a sharp increase in the thermal stability of composites, the energy Ed of the destruction products, reduced. Determination of the mechanical loading parameters ? and the elastic modulus E was performed. It was found that the parameters vary in a narrow range of graphene concentration, at C?1% , whereas in the region of high concentrations ? and E do not change. The increase in the thermal stability of composites is attributed to the separation of the heat flux that propagates along the polymeric chains of the resin at the interphase boundary with graphene particles between two streams, namely phonon and electron, which carry the resulting heat in graphene particles.

Resume : Doped YAG polycrystalline ceramics are widely used for various applications including phosphors and solid-state lasers. The sintering process typically requires two or more stages which involve prolonged pressureless sintering at high temperatures (>1700°C) under vacuum or air atmosphere. In the present work, nano-powders were synthesized by a co-precipitation method. Spark plasma sintering (SPS) densification technique was used for the fabrication of dense, highly transparent polycrystalline Ce-doped YAG at relatively low temperatures (1300°C) and short dwell time. Ce:YAG samples with excellent optical properties were fabricated. Such material could be used, for example, as a yellow phosphor in white light emitting diodes. Post sintering treatments were applied in order to further improve optical properties.

Resume : Dense boron carbide ceramics may be fabricated by a reaction bonding (RB) approach, which involves the infiltration of porous ceramic preforms with molten silicon or Al-Si alloy. Recently, it was suggested to fabricate RB composites using boron carbide as a source of carbon. This approach allows to improve functional properties of the composites by designing of their composition and by post processing heat treatments. The infiltration of boron carbide preforms with molten Al-Si alloy may be conducted at relatively low temperature (<1000°C) under Mg vapor (6.6kPa) atmosphere. Unfortunately, chemical interactions between boron carbide and Al-Si alloy at low temperatures is very slow and the formation of novel ceramic phases is limited. The prolonged holding time of the infiltrated composites under vacuum leads to a significant evaporation of metallic components and reducing mechanical properties. It was suggested to conduct an additional prolonged (up to 100 hours) thermal treatment in the 800-950°C temperature range in air furnace under protective media, based on oxides system. The thermal treatments allowed significantly to decrease the fracture of the residual metallic phase, to increase Young modulus from 320 to 400GPa and the average value of hardness from 1300 to 2300HV. Microstructure of the infiltrated and heat treated composites will be discussed.

Resume : The possibility of creating metal-matrix composites strengthened by nanolaminate MAX phases by Ti-Al-C systems was investigated. Methods of activation of the initial powder mixture, based on aluminum and titanium, by means of mechanoactivation (MA) or high-voltage electric discharge (HVED) powder processing in kerosene and its subsequent spark- plasma consolidation (SPS) were used. The effect of carbon allotropic forms presence on the formation of new phases during the SPS process is found out. In powder mixture after MA, which contains graphite, the formation of the MAX phase of Ti3AlC2 occurs, while the MAX phase of Ti2AlC composition and the triple Ti3AlC carbide are formed in powder mixture, activated by HVED, which contains C60 and C70. It is shown that the metal matrix composite of the Ti-Al-C system, which contains Ti2AlC MAX phase and the ternary Ti3AlC carbide has a Vickers hardness of 7 GPa, which is almost by 2 GPa higher than is the hardness of the samples that contain only Ti3AlC2MAX phase (5.1 GPa).

Resume : United need at the present stage of technological development in the filter material on the one hand, and their successful use in designs for each particular application, on the other, cause the presence of various kinds of materials with a wide range of performance properties. Advantages of filtering powder materials (FPM) with metal powders of nonmetallic lies in their relatively high filtering capacity, high performance, the possibility of multiple regeneration, light machining and long service life. The practice of using new materials on the basis of metal powders shows that the implementation in full volume of their strength and performance characteristics requires a significant increase in the level of prediction of physical and mechanical properties of materials and the development of new methods of modeling, which includes a comprehensive analysis of the processes of formation of materials. For the practical creation of the required porous structure of the FPM, which will fit the optimal combination of performance characteristics, it is necessary to establish a relationship between the technological modes of their obtaining and operational characteristics. Modeling of the porous structure of a concrete multilayer FPM from a steel powder BBS15 was carried out in the package of applications MatLab. Using the method described above, the authors of the article developed the software in the programming language C++ (the program "FiltrN"), which allowed to simulate the process of radial isostatic pressing with a given porosity of the FPM. Since the filter has the form of an elongated circular cylinder, the simulation was carried out for the following parameters of the technological process: the diameter of the mandrel - 40 mm, the diameter of the reinforced elastic shell - 80 mm. The powder poured into the space between the mandrel and the elastic shell. The relative bulk density of powder BBS15 was 20%, that is, the initial porosity was equal 0,8. Based on the results of our calculations, the distribution of porosity and radial velocity in the modeling of radial isostatic pressing of a multilayered FPM had been analyzed. The developed method of computer modeling allowed not only to determine the distribution of porosity and other characteristics of powder permeable material, but also to establish the relationship between the technological modes of their obtaining and operational characteristics. The radial velocity makes it possible to control the distribution of porosity in a multilayered FPM and allows you to analyze the factors that contribute to the heterogeneity of the density distribution.

Resume : Powder metallurgy for every new developed technology process demonstrates advantages that allow creation of materials with advanced or new properties and at the same time ensure more economic ways of their production. Porous permeable materials (PPM) which can be used as nozzles for sandblasting processing are the main object of presented investigation. Study of structural properties of PPM is a basis of creation of new advanced properties of already existing materials. Metallographic images of such objects can be presented by the combination of various structural components. Combination of these structural components can give a very complicated picture for interpretation so using of special analysing program is very promising in that case. Therefore the basic requirement to the high quality analysis of images is correct presentation of superposition of structural components with their following classification in correspondence with brightness and size and shape. Presented results are based on the system understanding of morphology and microstructure of investigated samples. This knowledge has a primary estimation of the quality of finished products - a nozzle for sandblasting processing. For complete and quality estimation of a nozzle basic morphological parameters of sample structure such as amount of particles of different size and shape, structural defects of the samples, shape of pores and particles, general distribution of pores in separate section and in the whole sample volume and general distribution of certain shapes of particles in a perimeter and volume had been defined and investigated. During the investigation the whole sample of nozzle had been divided into five equal parts with the same height with the following morphological analysis of every part and production of final general characteristics. Conducted morphological analysis of a structure of nozzles for sandblasting processing showed a possibility of their application in practice. With the help of application programs of image processing AVIZO and SMART eye the structure and topology of sample surface had been investigated completely.

Resume : In the present work, the enthalpies of mixing of liquid alloys of the ternary Mn-Al-Gd system have been calculated using the regular solution model by the Redlich-Kister-Muggianu formula. Also a comparison was made of calculated values of enthalpies of mixing in this system with the experimentally determined thermochemical properties of liquid alloys of the Mn-In-Gd ternary system obtained previously. This comparison was made taking into consideration the main features of the component interaction in the boundary binary systems, their phase diagrams and also such important characteristics as electronegativity of the components, their electron work functions and their big difference in atomic size. For the two indicated ternary systems the size mismatch entropy has been calculated within the framework of hard spheres model and the parameter has been determined. On the basis of the comprehensive analysis carried out, the criteria for the probability of occurrence of regions of easy amorphization in these ternary systems are proposed. The determination of the topology of the mixing enthalpy surface and the parameter for the melts of studied ternary systems together with the data on binary and ternary compounds existing in these systems allowed to reasonably assume the concentration regions where the investigated ternary alloys have tendency for easy amorphization while rapid cooling of the melt.

Resume : A CoCrNi-Mn metal matrix composite produced by a combination of Mechanical Alloying and Spark Plasma Sintering is reported on the present study. The material is composed of a mechanically alloyed medium entropy alloy CoCrNi, as a matrix, and Mn powder, as reinforcement. The pre-alloyed powders were subject to mixture in a proportion of 2:1. The investigation of the microstructural features, chemical composition and basic mechanical properties of the bulk material were subject to study, by means of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDS) and Vickers microhardness testing. A full-density composite has been achieved with the selected sintering conditions, possessing an average hardness of 329 HV0.3 within a soft matrix of FCC solid solution and 828 HV0.3 within a hard reinforcement area, which mainly consists of β-Mn in a primitive cubic structure and Cr as BCC.

Resume : The work is devoted to the analysis of the structural state and structural sensitivity of the mechanical properties of ultra-hightemperature ceramics based on zirconium boride. The processes of phase interactions in the region of grain boundaries with the determination of the grain-boundary strength characteristics and the relationship between grain-boundary strength and the mechanical properties of composites have been studied. At temperatures below the eutectic melting temperature, sintering activation takes place in the systems under investigation due to the formation of diffusion zones with enhanced diffusion characteristics and phase transformations in the field of boundaries. The experimentally observed significant attenuation of interatomic bonds and an increase in the atoms thermal vibration amplitudes is the physical cause of diffusion activity in the grain boundary volumes in eutectic systems, which stimulates an increase in the rates of a number of high-temperature processes (powder sintering, creep, etc.). Correlation dependences between the ceramics basic mechanical characteristics, namely between grain boundary strength with fracture toughness, compressive strength, yielding strength, etc., have been found, which underlies the structural sensitivity of the mechanical properties of brittle materials.

Resume : The aim of this work was to produce a composite, combining high hardness, ability to efficiently dissipate thermal energy, and low specific weight, using aluminium dodecaboride AlB12 as a hard component and aluminum nitride AlN as a softer sintering-assisting component with high thermal conductivity. A mixture of nanocrystalline AlB12 and AlN was produced by vacuum thermal synthesis with CVD elements. To vary the ratio of components in the ceramics AlB12 was separated from AlN by wet chemistry. Initial mixtures containing 75, 50, 25, 15, 10, and 5 % AlN by mass were compacted into ceramics using conventional hot-pressing at 30 MPa and temperatures 1800-1900 C. Specific mass of the produced materials was in the range of 2,6-3 g/cm3. Microhardness (P=2N) demonstrated linear dependence from composition, as expected for composites with non-interacting components, and varied from 16 to 27 GPa with the decrease of AlN content. All compositions retained the hardness above 15 GPa at P=100 N. Estimated thermal conductivity of such ceramics may reach ~100 W/(m*K) at higher contents of AlN. But special precautions must be held during the hot pressing, as thermodynamic calculations show the possibility of AlN partial decomposition, resulting in alumina formation in oxygen containing environments.

Resume : The corrosion behavior of ZrB2-15% SiC, ZrB2-15% MoSi2 composites with 5% chromium diboride has been studied. It has been shown that CrB2 adding increases oxidation resistance in 1.85 times at temperatures of 1300-1400 °C and decreases it on about 15 % at a temperature of 1500 oC, which is connected with an increase in diffusion constants in the material layers, especially in the case of ZrB2-15% SiC-5% CrB2. It has been established that the beginning of the oxidation of ceramics ZrB2 to ZrO2 and B2O3 occurs at temperatures of about 750 °C. Above 1100 °C, the formation of SiO2 occurs due to the reaction of silicon-containing elements (MoSi2 and SiC) with oxygen. The formed borosilicate glass can protect from the aggressive medium impact. The X-ray diffraction analysis of oxidized ceramics has shown that monoclinic ZrO2 and amorphous phases based on SiO2 are the resulting products of oxidation It has been shown that the doping of the glass phase with the "heavy" elements Cr, Mo Zr reduces the distance in the first coordination sphere compared to the amorphous ZrB2-15% SiC glass, which is possibly due to the difference in the atomic radii of the elements (Cr -130 nm, Mo- 139 nm). Moreover, the ZrB2-15% MoSi2 ceramic includes ZrSiO4 phase that protects it from oxidation to temperatures of 1650 oC.

Resume : The ZrB2+15 vol.% MoSi2 plasma coating of 375 μm thick on a C / C substrate without pores and cracks closely adjacent to the substrate has been obtained. The coating has been subjected to the oxidizing in two-phase supersonic air / oxygen-kerosene jets with different oxygen content. The main phase of the oxidized coating is ZrO2mon (88%), responsible for low thermal conductivity. Inclusions of zircon ZrSiO4 (12%) inhibit the cracks spread. In an oxygen-kerosene jet with a high oxygen content, the coating is oxidized with a higher rate over the entire thickness, providing effective thermal protection of the C/C-substrate structural graphite. An oxidized coating layer with a thickness more of 100 μm provides effective thermal protection of the C/C-substrate, preventing its destruction.

Resume : The wear of new composite materials on the base of titanium nitride in friction without lubricant in pair with steel in air has been investigated by electron scanning microscopy, Auger spectroscopy, and X-ray diffraction analysis. It is established that, independently of the composition of the binder in the composites, the value of the lattice constant of TiN decreases in the process of friction. Such titanium nitride lattice constant change in the contact zone is caused by the substitution of nitrogen atoms by oxygen atoms and by the formation of titanium oxynitride. It is shown that the interaction which occurs in the Ti-N-O system on the atomic level with the formation of titanium oxynitride is responsible for a substantial increase in the wear resistance of the investigated materials.

Resume : Photoelectrochemical water splitting is a promising process for obtaining of hydrogen as renewable energy source. Titanium dioxide is one of the most common photoanode materials, but the photocatalytic activity of TiO2 is greatly limited by its wide band gap of 3.2 eV, which leads to the extremely low absorption in the visible region of solar spectrum. Recently, graphite-like carbon nitride, as a metal-free polymeric semiconductor with inherent chemical and thermal stability, and a moderate band gap of 2.7 eV, has generated a lot of interest as photoelectrode material for the evolution of hydrogen from water in visible light. In this work, we introduce a facile procedure to obtaining of g-C3N4/TiO2 binary composite films on titanium foil substrate by one-step CVD approach using melamine as precursor under air atmosphere. To produce oxidized Ti surface we carried out the pyrolysis (580°C) of melamine at the presence of a fixed volume of air. The g-C3N4/TiO2 films were analyzed by SEM, XRD and IR spectroscopy. It was found that the visible-light-induced photodegradation of methylene blue was remarkably increased upon coupling TiO2 with g-C3N4, possibly due to heterojunctions which enhanced electron-hole separation efficiency as a result of effective interfacial electron transfer between TiO2 and g-C3N4. The facile deposition method can be promising for the fabrication of efficient and low-cost photoanodes based on g-C3N4/TiO2 composite films for renewable energy applications.

Resume : The work is devoted to the comparative study of the zirconia ceramic properties depends on its structure. The structure formation of the zirconia was achieved by sintering at different temperatures (1100-1500 °C). Zirconia stabilized with 8-mol. % Y2O3 (8YSZ) powder manufactured mainly by ?Tosoh?, ?DKKK? (Japan) companies is the state-of-the-art material for SOFC electrolyte and electrodes due to its high ionic conductivity, mechanical and chemical stability in both oxidation and reduction medias. It is known that Ukraine has own zirconia-sand deposit that is the third in the World and practically the only in the Northern hemisphere. Ukrainian companies, Science & Technology Centre ?NOVITECH? and Zirconia Ukraine Ltd., are starting their own pilot productions of zirconia powders with different stabilization, currently 8YSZ and 1Ce10ScSZ to be optimized for electrolyte and electrode applications. In context of the Work mechanical behavior and electrical properties of 8YSZ ceramic made from ?NOVITECH? and (TOSOH) powders were studied. Comparative study of two powders showed that ?NOVITECH? 8YSZ powder ensured higher values of mechanical strength and electrical conductivity comparing to the ?Tosoh? powder. Namely, at the same level of porosity (~4 %) ceramic samples made under the same conditions from ?NOVITECH? and ?Tosoh? powders demonstrated mechanical strength of 181 and 114 MPa and electrical conductivity of 2.34?10-3 and 1.2?10-3 S/cm, respectively.

Resume : A compact 5-kg device was developed in which a small portion of a hard powder was converted into an aerosol, which was further analyzed by means of a laser technology based on single particle optical sizing (SPOS) method for the registration of the obscuration of individual particles. Two-beam illumination system of a particle stream provided high accuracy of measurements. The particle size distribution function was automatically displayed on a monitor or an external computer. The instrument was calibrated using calibration powders from Particle Technology Ltd (United Kingdom). Test measurements were performed using composite powders of the BK and KХН types as well as using mixtures of powder fractions with average particle sizes of 26 μm and 63 μm, which produced particle distributions displaying two maxima as expected. The device covers particle size range from 5 to 300 μm and requires only 5 to 10 mg of a sample with a measurement time of 2 to 3 minutes, being able to resolve up to 100 fractions according to particle size. These data reveal that our device can be useful for detailed characterization of powders in scientific and industrial applications.