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Information × Registration Number 0220U101456, 0115U003688 , R & D reports Title Creation of methodological base for the development of the technology for the obtaining of oxide laser ceramics popup.stage_title Head Tolmachov Oleksandr V., Доктор фізико-математичних наук Registration Date 11-02-2020 Organization Institute for single crystals NASU popup.description2 The project aims to creating methodological platform for the development of technology for oxide laser ceramics by establishing and investigating factors of influence of technological processes and their significance on the properties of intermediate and final materials in the process of obtaining oxide laser ceramics on the example laser ceramics based on yttrium aluminum garnet and dopants (Nd3+, Yb3+, Cr4+). Production of laser ceramics YAG:Nd3+, YAG:Yb3+, YAG:Cr4+ using the developed approaches. Optimal conditions for homogenization of initial oxides mixture Al2O3, Y2O3, RE2O3 (RE: Nd, Gd, Yb, Er) with garnet stoichiometry, influence of initial mesostructure to powder compacts porosity, optical and laser properties of transparent ceramics Y3Al5O12:Nd3+ (porosity, 0,001 vol.%,  – 67%) are determined. Established that oxidation Yb and Cr ions in YAG:Me (Me =Yb,Cr) ceramics proceeds according Jander model. Activation energies of the oxidation processes are determined. It is shown that recharge Cr ions in ceramics Cr4+:YAG limited by diffusion of oxygen ions in the volume of ceramics. It was found that Cr2O3 functional impurity reduces the rate of YAP and YAG phase formation during sintering of YAG:Cr,Ca ceramics by forming YCrO3 or YCr1-xAlxO3 intermediate phases. It is found that sintering additives (MgO and CaO), it is advisable to introduce over stoichiometric composition of the garnet. Optimal conditions for synthesis of YAG:Cr,Mg,Ca ceramics (optical transmission - 79%) were determined (Tsynth= 1775 °C, Тoxidation= 1300 °C). The optimum temperature for producing YAG:Cr,Mg ceramics, doped with 0.5 at.% Cr and 0.5 at.% Mg ions is 1765 °C (average grain size ~ 3 μm, linear transmittance level above 80%). Thermal annealing of ceramics leads to transition of part of Cr3+ ions to Cr4+ charge state. Reducing the concentration of Cr4+ ions in tetrahedral environment with increasing sintering temperature is due to different mechanisms of charge compensation of Mg2+ Product Description popup.authors Vovk Oleg M. Vorona Igor O. Dobrotvorska Mariya V. Doroshenko Andrii H. Kosyanov Denys Yu. Matvieievska Neonila A. Mateichenko Pavlo V. Parkhomenko Sergij V. Tolmachov Oleksandr V. Yavetskiy Roman P. popup.nrat_date 2020-04-02 Close