Structure of Nanocomposites in the ZrO2–Y2O3–Al2O3 System and Their Formation under Hydrothermal Conditions

The mutual influence of the components in the ZrO2–Y2O3–Al2O3 system on the formation of nanocomposites under hydrothermal treatment conditions has been studied. An analysis of the results obtained has shown that the presence of yttrium oxide in nanoparticles based on zirconium dioxide with a fluorite-like structure leads to active recrystallization of c-ZrO2(YO1.5) nanocrystals in the ZrO2(YO1.5)–AlO1.5 system under hydrothermal conditions. In this case, yttrium oxide partially passes from ZrO2(YO1.5) nanoparticles to an amorphous phase based on aluminum oxide. The most active transfer of yttrium oxide between ZrO2(YO1.5) nanoparticles and the amorphous phase is observed in cases where yttrium oxide is partially localized on the surface of c-ZrO2(YO1.5) nanocrystals, which is realized at a YO1.5 content in ZrO2(YO1.5) higher than ~27 mol %.