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Information × Registration Number 0219U100311, 0118U003797 , R & D reports Title Development of technology for manufacturing and research of electrodynamic characteristics of radio-transparent, high-strength, high-temperature ceramics for antenna complexes.Then second year of impiementation. popup.stage_title Head Prikhna Tetiana O., Доктор технічних наук Registration Date 05-02-2019 Organization Department for special training National academy of science of Ukraine at Kiev University popup.description2  The new composite materials based on AlN-Y2O3-1-5wt.%C (diamond / soot) and AlN-Y2O3-1-5% C(diamond)-Mo were obtained by free sintering at 1850 ºС (30 min.). The X-ray diffraction analysis showed that in the structure of composites with the addition of diamond / soot the presence of the main phases: hexagonal AlN, cubic AlN, graphite (C) and Y3Al5O12. The structure of materials consists of a matrix phase - aluminum nitride, which contains the inclusion of the conductive phase (graphite or molybdenum) along of the grains boundaries which the thin layers of Y3Al5O12 are placed. It has been established that increasing of the diamond content in the material from 1 to 5wt.% leads to a decrease in the average size of graphite grains in the material structure, to increase the mass fraction of graphite and to the formation of contacts between grains of graphite. It is determined that all developed composite materials are dielectrics and their resistivity is 1∙1011 - 1.25∙1011 Ohm∙sm. It is shown that the structural features of ceramics influence the electrodynamic characteristics, in particular, the real and imaginary parts of dielectric constant measured in the frequency range up to 70 GHz are ε = 3,2-7 and tgδ = 0,03-0,06 and almost do not change in the composites, which have a homogeneous structure, that is, the structure in which the conductive inclusions in the matrix phase are evenly distributed. The thermal conductivity of the composites obtained is 27-42 W / (m ∙ K), and the hardness is 12.0-15.3 GPa. The obtained characteristics indicate the possibility of using developed ceramics as radio-transparent materials. Product Description popup.authors popup.nrat_date 2020-04-02 Close