Search academic texts

Information × Registration Number 0221U107169, 0121U111175 , R & D reports Title Novel and traditional IR-transparent ceramics of complex architecture for extreme operating conditions popup.stage_title Head Yavetskyi Roman P., Доктор технічних наук Registration Date 28-12-2021 Organization Institute of Single Crystals of the National Academy of Sciences of Ukraine popup.description2  The aim of the project is to develop IR-transparent MgO–Y2O3 composite nanoceramics, Y2O3 transparent ceramics, as well as to obtain ceramic materials with complex geometry for infrared missile domes. The aim of the second stage of the project in 2021 is: – To develop the obtaining methods of highly-loaded powders suspensions enabling slip casting of green bodies of complex geometry; – To determine technological parameters of slip casting of green bodies of complex shapes on the basis of Y2O3 and Y2O3–MgO nanopowders; – To obtain Y2O3 and Y2O3–MgO green bodies by the cold isostatic pressing for infrared missile domes. Sedimentation stability and rheological properties of Y2O3, Y2O3–MgO nanopowder suspensions with different solid loading and Dolapix CE64 (molecular weight 350 g/mol) and PAANH4 (molecular weight ~1800 g/mol) dispersants were studied. Dolapix CE64 in the 1.25-2.0 wt.% concentration range shows higher stabilization efficiency compared to PAANH4 due to the difference in molecular weights. 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 and Dolapix CE64 or ammonium polyacrylate as dispersants. The rheological properties of suspensions correspond to the Newtonian liquid. The effect of isostatic pressure on relative density of green bodies, optical properties and microstructure of transparent Y2O3, Y2O3–MgO ceramics has been studied. Technological parameters of isostatic pressing of compacts of abovementioned model systems have been determined. Product Description popup.authors Balabanov Anton E. Vorona Igor O. Doroshenko Andrii H. Kryzhanovska Oleksandra S Safronova Nadiia A. Tymoshenko Arsenii D. Yavetskyi Roman P. popup.nrat_date 2022-03-09 Close