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Information × Registration Number 0224U001839, (0121U108714) , R & D reports Title Study of the phenomena of thermal breakdown in systems that have a percolation threshold or are accompanied by chemical reactions during the transmission of electric current popup.stage_title Вивчення явищ теплового пробою в системах, що мають поріг перколяції, або супроводжуються хімічними реакціями під час пропускання електричного струму Head Rahulia Andrii V., д.т.н. Registration Date 31-01-2024 Organization Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine popup.description1 The aim of the study is to establish patterns of structure formation and formation of properties in systems in which the flow threshold exists or appears as a result of a chemical reaction, during the transmission of electric current in the process of spark-plasma and microwave sintering. popup.description2  The percolation effect under SPS in the conductor-insulator system (Si3N4–30vol.%ZrN)–5vol.%Y2O3 and (Si3N4–50vol.%ZrN)–5vol.%Y2O3 at different current densities was studied. The percolation effect of increased current density due to matrix isolation was revealed as a jump in heating power at ~1350 °С. Simulation of the current flow in the conductor-insulator system was carried out by the method of cellular automata with different 3D grids: it was found that when the number of contacts increases for a simple model, the percolation threshold decreases from 33% (26 contacts) to 9% (6 contacts). For the complex porous model, the number of interparticle contacts required for percolation decreases from 15 at 15% to 9 at 35%. The temperature dependence of the change in the Gibbs free energy of chemical reactions, possible during the reactive SPS of powder mixtures TiН2+ZrН2+HfН2+BN and TiН2+ZrН2+HfН2+BN+В in the temperature range from 300 to 2300 K, was carried out. The phase formation of the TiN-TiB2 composite was studied from a mixture of TiH2 (75 wt. %) and BN (25 wt. %), which corresponds to the final composition of TiN 64 wt.% and TiB2 36 wt.%, depending on the heating rate of 10 – 400 °С/min in SPS conditions. Ceramic-composite TiB2 – B4C, (70/30 vol. %) of high density (99.5 %), obtained by the IPS method and tested for bending in an Ar atmosphere at a temperature of 1800 °C showed a strength value of ~1,1 GPa It was established that the presence of Ti and Si3N4 in the composition of SiC-based composite powder contributes to the formation of low resistivity at the HP of ceramics due to carbide, silicide, and non-stoichiometric titanium oxide (Ti6O), which contributes to the possible formation of the MAX – Ti3SiC2 phase with high electrical conductivity. Product Description popup.authors Borodianska Hanna Yu. Petrovsky Vitaly Ya. Foya Oleksandr O. Vasiliev Оleksandr О. Bаrаnovskyi Dmytro I. Maryna S. Storozhenko Levina Diana A. Fedorova Nataliia Ye. Hadzyra Mykola P. Bystrenko Tetyana O Umerova Saide O. Denysiuk Nataliia M. Ilkiv Bogdan I. Brodnikovska Iryna Volodymyrivna Nadiia K. Davydchuk Andrii V. Rahulia Petukhov Oleksandr S. Kolesnichenko Valerii H. Tyshchenko Nadiia I. Olha A. Kovalenko Kravchuk Karyna L. Koshelev Mykhaylo V. Tulinova Alla S. Dranenko Oleksiy S. Synelnychenko Oleksiy K. Kopylova Kateryna I. Lysenko Nadija V. Verbycka Tetiana V. Petrovska Svitlana S. Itsenko Anatolii I. Zamula Maryna V. Tomila Tamara V. Haliamin Volodymyr B. Shуrokov Oleksandr V. Luzhnyi Ivan V Lobunets Tetiana F. Poznii Anatolii P. Patsui Viktor I. Bondarenko Serhii O. Makohon Viktor A. Lazhevskyi Viktor O. Zahornyi Maksym M. Pokhylko Bohdan A. Kushnir Vladyslav V. Derii Andrii A. Semeniuk Nataliia G. Manakina Diana M. Shulzhenko Volodymyr Ya. Tepliuk Olena V. Kozak Svitlana I. Pinchuk Мykyta O. Bystrenko Oleksiy V. Tymoshenko Yaroslav G. Ivanchenko Serhii E. Tkach Vіra P. Bilan Irina I. Maslova Galyna A. Pirnach Tetyana P. Kovalyova Liudmyla O. Liubchyk Ihor V. Hudymenko Tetiana V. Pavlovska Zhanna Yo. Kolomiiets Volodymyr V. Oleh Y. Khyzhun Appolinariy I. Stetsun popup.nrat_date 2024-01-31 Close