Study of the Effect of Nanostructured Grains on the Radiation Resistance of Zirconium Dioxide Ceramics During Gas Swelling in the Case of High-Dose Irradiation with He²⁺ Ions

The paper is devoted to the study of the influence of variation of ZrO2 ceramics grain sizes on the resistance to radiation-induced swelling under irradiation with low-energy Не²⁺ ions. The choice of ZrO2 ceramics as objects of research is due to high levels of mechanical strength and hardness, as well as low rates of thermal expansion, which eliminates the effects of thermal expansion and destruction when operating at high temperatures, as well as good insulating properties, which makes it possible to use these ceramics both as radiation-resistant materials in nuclear energy in the manufacture of inert matrices of dispersed nuclear fuel, and as a basis for creation of fuel cells for the production of hydrogen. During the studies of the influence of mechanochemical grinding conditions on the change in dimensional factors in ZrO2 ceramics, it was found that increasing the grinding speed from 300 to 900 rpm does not lead to the initiation of polymorphic transformation processes of the m-ZrO2 → t-ZrO2 type, which are also not initiated during thermal annealing of samples at a temperature of 1500 °C, the choice of which was due to thermal relaxation of structural deformation distortions caused by mechanochemical grinding during grain crushing. In determining the influence of size effects (dislocation strengthening) on the resistance of ZrO2 ceramics to radiation-induced swelling under high-dose irradiation with He²⁺ ions, it was found that a decrease in grain size by 2.5 – 3 times leads to an increase in resistance to swelling and softening by 1.5 – 2 times. Moreover, for ZrO2 ceramic samples obtained at grinding speeds of 700 – 900 rpm, strengthening is not only due to dimensional factors, but also to the structural ordering of the crystal lattice, due to thermal relaxation of residual mechanical stresses.