TY - CONF A1 - Gornushkin, Igor A1 - Kornev, R. A1 - Bulanov, A. A1 - Ermakov, A. T1 - Laser-Induced Dielectric Breakdown as a Novel Method for Obtaining Isotopically Enriched Nanoscale Substances N2 - The possibility of obtaining high-purity, isotopically modified and nanostructured elemental substances 29Si, 98Mo, and 100Mo, as well as 98Mox10By compounds from volatile halides under conditions of laser optical breakdown of a pulsed Nd:YAG laser is shown. Currently, research in the field of developing new methods for obtaining high-purity, isotopically modified and nanostructured substances is being actively conducted. Interest in Si and Mo combining these forms has noticeably increased. In nuclear medicine, 29Si-enriched nanoparticles can be used as contrast agents in magnetic resonance imaging (MRI), and 98Mo and 100Mo isotopes can be used to obtain the unstable 99mTc radioisotope. These applications do not require large amounts of isotopically modified Si and Mo. Their obtaining belongs to the problems of small chemistry. When obtaining isotopically modified Si and Mo, it is expedient to use their volatile fluorides, for which technologies of isotope enrichment and deep purification are well developed. These halides have high chemical and thermal stability; therefore, plasma-chemical methods based on the plasma of a pulsed discharge generated by laser breakdown can be promising for separating 29Si, 98Mo, and 100Mo from them. Laser breakdown in H2+Ar+SiF4 and H2+Ar+MoF6 mixtures in various stoichiometric ratios in the pressure range 30–760 Torr was carried out using a pulsed Nd:YAG laser. The pulse duration at a wavelength of 1064 nm was 15 ns, the repetition rate was 5 Hz. A pulse energy of 800 mJ was focused by a lens with a focal length of 5 cm. The energy density at the focus was 26 J/cm3 . It has been shown that when using a mixture based on 29SiF4, the sample contains a 29Si crystalline phase with an average grain size of 30–50 nm (Fig. 1a). When using a mixture based on 98MoF6, the sample contains a 98Mo crystalline phase with an average grain size of 70–100 nm (Fig. 1b). In this type of gas discharge, the possibility of forming superhard materials, isotopically modified molybdenum borides, was also studied. These substances in the form of nanosized particles have improved tribological properties. After ablation of metallic Mo in the H2 + BF3 mixture, the main phase was MoB2 in the form of a nanodispersed powder with an average grain size of 100 nm (Fig. 1c) [1]. A technique for modeling gas-dynamic and thermal conditions in a low-temperature chemically active plasma induced by laser breakdown is proposed. Using computational experiments, the features of gas mixture heating and the formation of nanoparticles in the LIBS reactor were studied T2 - 17the International Conference on Laser Applications in Life Sciences CY - Mugla, Turkey DA - 15.10.2023 KW - Laser induced plasma KW - Chemical vapor deposition KW - Isotopically enriched nanomaterials PY - 2023 AN - OPUS4-58888 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gornushkin, Igor A1 - Kornev, R.A. A1 - Shabarova, L.V. A1 - Ermakov, A.A. A1 - Mochalov, G.M. A1 - Rekunov, N.V. A1 - Medov, V.A. A1 - Chaschina, A.D. A1 - Kalinina, A.A. T1 - Features of Plasma-Chemical Hydrogen Reduction of Volatile Silicon and Germanium Chlorides in RF-arc Discharge T2 - Preprints.org N2 - The processes of hydrogen reduction of silicon and germanium chlorides under the conditions of radio-frequency (40.68 MHz) counteracted arc discharge stabilized between two rod electrodes were investigated. The main gas-phase and solid products of plasma-chemical transformations were determined. Thermodynamic analysis of SiCl4 + H2 and GeCl4 + H2 systems was carried out. It is shown that under the implemented experimental conditions, equilibrium components of the products are established. The detected spectra of chemical activity were studied, which gave reason to assume that the molecular mechanism of the hydrogen reduction process is the main one. The impurity composition of gas-phase and solid reaction products was investigated. The possibility of single-stage production of high-purity Si and Ge mainly in the form of compact ingots, as well as high-purity chlorosilanes and trichlorogermane, was shown. KW - RF-arc discharge KW - Hydrogen reduction KW - Silicon chloride KW - Germanium chloride KW - Thermodynamic KW - Silicon KW - Germanium PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588909 DO - https://doi.org/10.20944/preprints202311.1412.v1 SP - 1 EP - 14 AN - OPUS4-58890 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -