Registration Number
0223U004800,
(0123U102633)
, R & D reports
Title
Novel and traditional IR-transparent ceramics of complex architecture for extreme operating conditions
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Масштабування технології компактування заготівок обтічників Y2O3 та Y2O3–MgO
Head
Yavetskyi Roman P., Доктор технічних наук
Registration Date
05-12-2023
Organization
Institute of Single Crystals of the National Academy of Sciences of Ukraine
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The goal of the project is to create IR-transparent composite nanoceramics MgO-Y2O3 and to obtain ceramic products of complex geometry, which in terms of optical and thermomechanical parameters meet the requirements for heat-guided missile domes. The project also envisages refinement of the technology of creating traditional transparent ceramics Y2O3 of complex geometry, which has the lowest emissivity among IR materials and is not available as a commercial material. Solving the tasks set in the project will increase the country's defense potential and contribute to the creation of the latest science-intensive technologies.
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The optimal synthesis conditions of Y2O3 powder precursor by the high-energy planetary ball milling were determined (v=140 rpm, t=15-24 h). Milling of Y2O3 powders allows one to shift the average particle size into the submicron range and to obtain nanopowders with average particle size of 0.4-0.5 μm and agglomeration degree of 6.6-8.3. The optimal synthesis conditions of Y2O3–MgO powder precursor by the high-temperature self-propagating synthesis have been established. Annealing of powders at T=600°С for 2 hours leads to formation of 40 nm Y2O3, MgO isolated nanocrystals.
Sedimentation stability and rheological properties of Y2O3, Y2O3–MgO nanopowder were studied. Optimal conditions for obtaining near Newtonian liquid suspensions were determined: 1.5 wt.% Dolapix CE64 and 30 wt.% solid loading of Y2O3; 2.0 wt.% Dolapix CE64 and 30 wt.% solid loading of Y2O3–MgO. Y2O3 and Y2O3–MgO green bodies of complex geometry with 40 to 46% relative density were obtained by slip casting using suspensions based on highly dispersed Y2O3, Y2O3–MgO nanopowders.
The temperature-time sintering route for Y2O3 optical ceramics was optimized (Т=1800С, 10 h), which allows to obtain of yttria ceramics having relative density of 99.999%, average grain size of 7 μm, and optical transmittance higher than 80% at 5 μm. It was shown that La3+(0.5 аt.%) + Zr4+ (1.5 аt.%) complex sintering aid effectively suppresses the grain boundary mobility of Y2O3 and activates diffusion transport along the grain boundaries subsystem. The vacuum sintering route to transparent 50:50 vol.% MgO–Y2O3nanocomposites were optimized (Т=1300С, t=10 h). It was shown that the in-line optical transmittance of the composite T60% at =5 μm could be realized via formation of a homogeneous two-phase structure, the spatial limitation of the coarsening of components and the preservation of the grain size at the 200-250 nm level making light scattering at the interphase boundaries negligible.
Product Description
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Balabanov Anton E.
Vorona Ihor O
Kapustnik Oleksiy K.
Matvienko Oksana O.
Sofronov Dmytro S.
Tymoshenko Arsenii D.
Yavetskyi Roman P.
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2026-06-23
