Search academic texts

Information × Registration Number 0220U104633, 0120U100665 , R & D reports Title Development of additive technologies and consolidation of ceramic nanocomposites under the influence of external electromagnetic fields popup.stage_title Head Ragulya Andrii V., Доктор технічних наук Registration Date 24-12-2020 Organization Institute of Problems of Materials Science named after IM Frantsevich of the National Academy of Sciences of Ukraine popup.description2  The initial composition of the mixtures for obtaining transparent Si3N4-based ceramics has been determined. Modes of mechanical processing of initial powders and modes of consolidation under the spark plasma sintering conditions have been developed. It was established that intense mechanical activation and doping with Y2O3 stimulate sintering and create conditions of →-phase transformation. Phase transformation was found to be faster in Si3N4 - BN composite ceramics doped with Y2O3. It was found that in the case of a significant amount of SiO2 (up to 7%), and its interaction with Si3N4 during sintering leads to the formation of  20 vol.% Si2N2O, which significantly stimulates shrinkage. The stages of consolidation were determined and the mechanisms of compaction been proposed. It was established that the addition of BN decreased the ceramic density, enhanced the dielectric characteristics of the material due to decreasing of both the dielectric constant and dielectric loss. The influence of ceramics structure on the mechanical properties and dielectric characteristics has been studied. The composite based on -Si3N4 (St) showed strength  1000 MPa (T = 20 С) and 400 MPa (1400 С), fracture toughness of about 5.5 MPa · m1/2. The MAX-phase Ti3SiC2 in SiC-Ti and SiC-Ti-C systems synthesis conditions were established. The influence of temperature on consolidation and formation of mechanical characteristics were studied. The ceramic with maximum density was consolidated at 1520 ° C, the specific resistivity was 2.7 10-6 Om m. Hot pressing contributes to a higher density and mechanical properties. The hardness reached 14.4 GPa, and the fracture toughness increased to 10.5 MPa m1/2 due to the change of phase composition, which is accompanied with the MAX phase decomposition and the growth of titanium carbide and silicide. It was found that materials based on nanosized powder of solid solution of carbon in SiC with a content of MAX phase Ti3SiC2 of 3 to 50% showed el Product Description popup.authors Ivanchenko Serhii E. Itsenko Anatolii I Bаrаnovskyi Dmytro I. Bondarenko Serhii O. Borodianska Hanna Yu. Havrysh Anatolii O Hadzyra Mykola P Haliamin Volodymyr B Davydchuk Nadiya K Derii Andrii I Domikhina Nataliia V Zagornyi Maksym M. Zahornyi Maksym M Zamula Maryna V Kovalenko Olha A. Kovalchuk Volodymyr V Kozak Svitlana I Kolesnichenko Valerii G Korniienko Oksana A. Korop Serhii M Koriak Oksana S Kravchuk Karyna L. Kuzʹmenko Lyudmyla M Kutranʹ Tamara M Kushnir Vladyslav V Lazhevskyi Viktor O Lobunetsʹ Tetiana F. Makohon Viktor A. Monakina Diana M Pinchuk Mykyta O. Patsui Viktor I. Petrovskiy Vitaly Ya Petukhov Oleksandr S. Poznii Anatolii P. Pokhylko Bohdan A Ragulya Andrey V Semeniuk Nataliia G Stepanenko Artur V Tepliuk Olena V Yaroslav Grygorovych H. Tyshchenko Nadiya I. Tomyla Tamara V. Tulinova Alla S Umerova Saide O. Fatov Ihor I Shyrokov Oleksandr V Shulzhenko Volodymyr Ya Yurchenko Yuriy V. popup.nrat_date 2020-12-24 Close