Nassyrbayev, A. R.

Pogorelova, S. O.

Shanenkov, Ivan Igorevich

Electronic archive of Tomsk Polytechnic University

 Секция 7.  Химия и химическая технология на иностранном языке497References1. Andrievski R.A. Nano-sized silicon carbide: synthesis, structure and properties // Russian Chemical	Reviews,	2009.–	V.78.–	№9.–	P.821.2. Klabunde K.J. Introduction to nanotechnology // Nanoscale Materials in Chemistry, 2001.– P.1–13.3. Sivkov A.A., Pak A.Y. Coaxial magnetoplasma accelerator	//	RF	Patent,	2011.–	№	2431947.DEPENDENCE OF THE PRODUCT'S PHASE COMPOSITION ON THE RATIO OF PRECURSORS IN PLASMODYNAMIC SYNTHESIS OF TITANIUM DIBORIDES.O. Pogorelova, A.R. Nassyrbayev, I.I. ShanenkovScientific adviser – PhD in Engineering sciences, Prof. of ISE TPU A.A. SivkovNational Research Tomsk Polytechnic University 634050, Russia, Tomsk, 30 Lenin Avenue, sop2@tpu.ruIn present time materials with high physic-me-chanical properties are in demand. Materials based on nanostructured powder show higher properties than coarse-grained analogs. Titanium diboride (TiB2) is an excellent powder for functional ceram-ics, which needs in a lot of application in industry, for example, metallurgy, mechanical engineering [1]. It can be used as surface coatings on iron, steels, refractory metals, because TiB2 has high hardness, good wear and corrosion resistance [2].In this paper presents one of a possible way of obtaining TiB2 – plasmodynamic synthesis us-ing coaxial magnetoplasma accelerator (CMPA). The aim of this work was to find the optimal ra-tio of precursors to synthesize the phase of titani-um diboride hexagonal syngony with spatial group P6/mmm. The possibility of synthesis nanopowders was shown in the work [3].According to the aim series of experiments with different mass ratio of Ti:B precursors were implemented (26.7 : 73.3; 45.5 : 54.5; 61.1 : 38.9; 86.4 : 13.6). Synthesized powder products without any pretreatment were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM). Quantitative X-ray analysis was performed using the PowderCell program. The highest yield of the ti-tanium diboride phase (96.2 %) was achieved in the experiment with a Ti : B ratio of 45.5 : 54.5, bur the average size of particles is 67.8 nm. The experiment with a boron percentage of 73 % was implemented, which from the Ti-B state diagram is the region for the production of titanium diboride. The yield of TiB2 is 93.2 % and the particle size is the smallest in comparison with the other experiments – 56.1 nm.The analysis of the crystal forms of the product was carried out on the basis of a set of light-field TEM and HRTEM images. There is typical bright-field image of transmission electron microscopy in figure 1. It can be seen that the product basically includes at least two types of particles. The first type is prismatic crystals of a hexagonal and dihexagonal forms, which looks like a circle in a plan. This form corresponds to the spatial group P6/mmm of the hexagonal system. The habit of a crystal can exist in several simple forms: hexagonal and dihexago-nal prisms and pyramids. In other areas they can be related to the second type – crystals in the form of a cube that corresponds to the spatial group Fm3m for the corresponding phase of titanium diboride TiB cubic syngony. This product consists only of particles of two fractions: cubes and hexagons with a narrow width distribution up to 100 nm in size.Thus, plasmodynamic synthesis of nanocrys-talline particles of titanium diboride with hexagonal syngony with the spatial group P6/mmm was car-Fig. 1.		Typical	bright-field	image	of	transmission electron microscopyXIX Международная научно-практическая конференция имени профессора Л.П. Кулёва498ried out. The optimal ratio of precursors Ti:B with the smallest particles 56.1 nm is 26.7 : 73.3. In the synthesized product, the predominant content of hexagonal and cubic titanium diboride particles was found. References1. A.B. Zou, C. Hyang, J. Song, Z. Liu, L. Liu, Y. Zhao Mechanical properties and microstructure of TiB2-TiC composite ceramic cutting tool ma-terial. J. Eur. Ceram. Soc., 2012.– P.1–9.2. M. Masanta, P. Ganesh, R. Kaul, A.R. Choud-hury Microstructure and mechanical proper-ties of TiB2–TiC–Al2O3–SiC composite coatings developed by combined SHS, sol–gel and laser technology. Surf. Coat. Technol., 2010. 3. A.A. Sivkov, D.S. Nikitin, A.Ya. Pak, I.A. Ra-khmatullin Production of ultradispersed crys-talline silicon carbide by plasmodynamic syn-thesis. J. Superhard Mater, 2013.– P.137–142.FLUSHING CATHODE DEPOSIT FROM SODIUM, POTASSIUM AND LITHIUM FLUORIDESM.A. Shipeykina, S.A. Tyurpeko, S. Seytkazy, E.Y. KonovalovaResearch advisor – assistant professor F.A. VoroshilovNational Research Tomsk Polytechnic University 634050, Russia, Tomsk, 30 Lenin Avenue, mas49@tpu.ruAs a result of electrolysis of UF4 in the molten salt FLiNaK (the composition is given in Table 1), metallic uranium is obtained [1].In order to obtain pure uranium powder, it is necessary to separate it from fluoride salts of elec-trolyte (LiF, NaF, KF), complex uranium-containing salts, micro impurities that are contained because of the primary components, and also because of corro-sion processes.FLiNaK melt salts must be extracted from an economic point of view. They can be returned to the cycle, thereby reducing the cost of the resulting me-tallic uranium.To solve these problems, we can offer several methods of flushing:1) "Aqueous" way of separating the cathode deposit.It is necessary to thoroughly reground the pre-formed precipitate to create a larger reaction sur-face.The quantity of substance is mixed with dis-tilled water upon the application of heat. After filtra-tion, the residue is mixed with HCl and AlCl3. The resulting solution will contain fluoride salts.After this, it is necessary to evaporate the water in order to separate the salts. The costs of heating and evaporation of water significantly increase the cost of uranium. Therefore, it is necessary to find another, more cost-effective way of flushing the cathode deposit.Moreover, the difficulty of this method is that it is possible to form an oxide film on metallic ura-nium. It is necessary to take additional measures to destroy it.2) Flushing the cathode deposit with ethyl hy-droxide.The cathode deposit is comminuted. Quantity Table 1. FLiNaK salt compositionFluoride Content, % wt.LiF 29.21NaF 11.7KF 59.09Table 2. Mass values for salt dissolution in ethanol at room temperatureFluorideWeight of the sample before dissolution, gWeight after disso-lution in ethanol, gKF 0.4 0.39LiF 0.4 0.38NaF 0.4 0.15Table 3. Mass values for salt dissolution in ethanol upon the application of heatFluorideWeight of the sample before dissolution, gWeight after disso-lution in ethanol, gKF 0.2 0.2LiF 0.2 0.18NaF 0.2 0.06

Dependence of the product's phase composition on the ratio of precursors in plasmodynamic synthesis of titanium diboride

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Dependence of the product's phase composition on the ratio of precursors in plasmodynamic synthesis of titanium diboride

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