Features of solid solution formation with a fluorite type structure in the system ZrO2-HfO2-Y2O3 with different synthesis methods

Abstract

X-ray phase, petrographic, and thermal analysis methods are used to study the properties of solid solutions with a fluorite type structure in the ternary system ZrO2-HfO2-Y2O3 in relationship to preparation method: mixing of the original powders followed by solid-phase sintering and melting in solar furnaces; hydrothermal synthesis of nanocrystalline powders followed by solid-phase sintering. It is shown that in specimens whose composition lies at the isoconcentrate of 10 mole% Y2O3 a single phase forms independent of preparation method, i.e. a solid solution with a fluorite type structure. The azeotrope, situated at the liquidus of the limiting binary system ZrO2-Y2O3 in the region of fluorite-like solid solutions, affects the melting temperature of ternary solid solutions and the lattice parameters of specimens after melting in a solar furnace.