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The key objective of this study is to determine the effect of interphase boundaries, the formation of which is caused by the variation of Li2ZrO3/MgLi2ZrO4 phases in lithium-containing ceramics based on lithium metazirconate, on the resistance to near-surface layer destruction processes associated with irradiation with He2+ ions. During the observation of the deformation effects that have an adverse impact on the volumetric swelling of the near-surface layers of ceramics, the thermal expansion factor caused by high-temperature irradiation was considered, simulating conditions as close as possible to the operating conditions of these materials as blankets for tritium propagation. During the studies conducted, it was established that an elevation in the contribution of MgLi2ZrO4 in the composition of ceramics leads to a rise in resistance to deformation swelling caused by structural distortions of the crystal lattice, due to a decrease in the effect of thermal expansion, alongside the presence of interphase boundaries. The established dependencies of the change in the hardness of the near-surface layer of the studied ceramics made it possible to establish the kinetics of softening caused by the deformation distortion of the crystalline structure, as well as to determine the relationship between volumetric swelling and softening (change in hardness) and a decrease in crack resistance (change in the value of resistance to single compression).

The aim of this work is to study the hydrogenation processes in lithium-containing ceramics under high-temperature irradiation. Irradiation was carried out with protons with an energy of 1 MeV and fluences of 1015–1017 ion/cm2 at irradiation temperatures of 300–1000 K. The choice of irradiation conditions is due to the possibility of simulation of the radiation damage accumulation processes in the near-surface layer of Li2TiO3 ceramics, as well as establishing the dependences of changes in structural parameters during temperature heating of samples during irradiation. It has been established that at irradiation fluences of 1015–1016 ion/cm2, the formation of dislocation defects is observed, the density of which has a pronounced dependence on the irradiation temperature. At irradiation fluence above 5 × 1016 ion/cm2, an increase in the crystal structure deformation is observed, due to swelling processes as a result of implanted hydrogen accumulation in the near-surface layer structure. At the same time, an increase in the irradiation temperature leads to a decrease in the swelling value, which is due to the accelerated migration of implanted hydrogen in the near-surface layer and its release through the existing pores. Results of mechanical tests showed that the swelling of the crystal structure and its deformation leads to embrittlement and a partial decrease in the strength of the near-surface layer. The obtained research results will further allow us to evaluate the resistance of lithium ceramics to the processes of hydrogenation and destruction as a result of the formation of gas-filled cavities in the structure of the near-surface layer.

The paper considers the hydrogenation processes in Li2TiO3 ceramics under irradiation with protons with an energy of 500 keV and fluences of 1 × 1010–5 × 1017 ion/cm2. The choice of the type of irradiation, as well as the irradiation fluences, is based on the possibilities of modeling hydrogenation processes and studying the kinetics of structural changes caused by the accumulation of radiation damage. The choice of Li2TiO3 ceramics as objects of research is due to their prospects for using as blanket materials of thermonuclear reactors for the tritium production and accumulation. It was found that the formation of point defects and their subsequent evolution associated with the formation of complex compounds and the filling of pores, followed by the formation of gas-filled bubbles, the presence of which leads to a decrease in crack resistance and resistance to destruction of the near-surface layer. Based on the data on structural changes and evolution of the crystal lattice parameters, its swelling, a description of the destruction processes associated with hydrogenation in Li2TiO3 ceramics was proposed. Also, during the studies, it was found that at irradiation fluences above 1 × 1017 ion/cm2, the appearance of impurity inclusions characteristic of the TiO2 phase was observed, the presence of which indicates the crystal lattice destruction processes because of accumulation of radiation damage and deformations caused by them. Critical doses are established at which there is a sharp deterioration in strength and crack resistance, reflecting the resistance of ceramics to mechanical external influences.

In this work, we consider the effect of irradiation with heavy Kr15+ and Xe22+ ions on the change in the structural and strength properties of WO3 microparticles, which are among the candidates for inert matrix materials. Irradiation with heavy Kr15+ and Xe22+ ions was chosen to determine the possibility of simulation of radiation damage comparable to the impact of fission fragments. During the studies, it was found that the main changes in the structural properties with an increase in the irradiation fluence are associated with the crystal lattice deformation and its anisotropic distortion, which is most pronounced during irradiation with heavy Kr15+ ions. An assessment of the gaseous swelling effect due to the radiation damage accumulation showed that a change in the ion type during irradiation leads to an increase in the swelling value by more than 8–10%. Results of strength changes showed that the most intense decrease in the hardness of the near-surface layer is observed when the fluence reaches more than 1012 ion/cm2, which is typical for the effect of overlapping radiation damage in the material. The dependences obtained for the change in structural and strength properties can later be used to evaluate the effectiveness of the use of refractory oxide materials for their use in the creation of inert matrices of nuclear fuel.

Lithium-containing ceramics have several great potential uses for tritium production, as well as its accumulation. However, their use is limited due to their poor resistance to external influences, mechanical pressure, and temperature changes. In this work, initial nanostructured ceramic powders were obtained using the sol-gel method, by mixing TiO2 and LiClO4·3H2O with the subsequent addition of NiO nanoparticles to the reaction mixture; these powders were subsequently subjected to thermal annealing at a temperature of 1000 °C for 10 h. Thermal annealing was used to initiate the phase transformation processes, and to remove structural distortions resulting from synthesis. During the study, it was found that the addition of NiO nanoparticles leads to the formation of solid solutions by a type of Li0.94Ni1.04Ti2.67O7 substitution, which leads to an increase in the crystallinity and structural ordering degree. At the same time, the grain sizes of the synthesized ceramics change their shape from rhomboid to spherical. During analysis of the strength characteristics, it was found that the formation of Li0.94Ni1.04Ti2.67O7 in the structure leads to an increase in hardness and crack resistance; this change is associated with dislocation. When analyzing changes in resistance to cracking, it was found that, during the formation of the Li0.94Ni1.04Ti2.67O7 phase in the structure and the subsequent displacement of the Li2TiO3 phase from the composition, the crack resistance increases by 15% and 37%, respectively, which indicates an increase in the resistance of ceramics to cracking and the formation of microcracks under external influences. This hardening and the reinforcing effect are associated with the replacement of lithium ions by nickel ions in the crystal lattice structure.

The aim of this work is to study the properties of nanostructured (1 − x)ZrO2 − xCeO2 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)ZrO2 − xCeO2 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-ZrO2 → Monoclinic − Zr0.98Ce0.02O2/Tetragonal − ZrO2 → Tetragonal − Zr0.85Ce0.15O2 → Tetragonal − ZrCeO4/Ce0.1Zr0.9O2 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 ZrO2 phase from the ceramic structure with its transformation into the phase of partial replacement of Zr0.85Ce0.15O2 or Ce0.1Zr0.9O2 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 ZrCeO4 phase in the structure of ceramics leads to an increase in the resistance of ceramics to cracking by more than 2.5 times.