Synthesis, Phase Transformations and Strength Properties of Nanostructured (1 − x)ZrO(2) − xCeO(2) Composite Ceramics

The aim of this work is to study the properties of nanostructured (1 − x)ZrO(2) − xCeO(2) composite ceramics, depending on the content of oxide components, as well as to establish the relationship between the phase composition of ceramics and strength properties. The choice of (1− x)ZrO(2) − xCeO(2) composite ceramics as objects of study is due to the great prospects for using them as the basis for inert matrix materials for nuclear dispersed fuel, which can replace traditional uranium fuel in high-temperature nuclear reactors. Using X-ray diffraction, it was found that the variation of the oxide components leads to phase transformations of the Monoclinic-ZrO(2) → Monoclinic − Zr(0.98)Ce(0.02)O(2)/Tetragonal − ZrO(2) → Tetragonal − Zr(0.85)Ce(0.15)O(2) → Tetragonal − ZrCeO(4)/Ce(0.1)Zr(0.9)O(2) type. As a result of mechanical tests, it was found that the formation of tetragonal phases in the structure of ceramics leads to strengthening of ceramics and an increase in crack resistance, which is due not only to an increase in the crystallinity degree, but also to the effect of dislocation hardening associated with a decrease in grain size. It has been established that a change in the phase composition due to phase transformations and displacement of the ZrO(2) phase from the ceramic structure with its transformation into the phase of partial replacement of Zr(0.85)Ce(0.15)O(2) or Ce(0.1)Zr(0.9)O(2) leads to the strengthening of ceramics by more than 3.5–4 times. The results of resistance to crack formation under single compression showed that the formation of the ZrCeO(4) phase in the structure of ceramics leads to an increase in the resistance of ceramics to cracking by more than 2.5 times.