Study of Diffusion Expansion of Damaged Layer in Nd₂Zr₂O₇ Ceramics Under High-Temperature Irradiation

The main aim of this study is to determine the role of irradiation temperature on the mechanisms of softening of the surface layers of Nd₂Zr₂O₇ ceramics, as well as to identify the effect of stabilizing additives on enhancement of the resistance to high-temperature destabilization of the damaged layer. Analysis of the effect of variations in irradiation temperature on the change in the strength properties of Nd₂Zr₂O₇ ceramics and identification of the effect of addition of stabilizing MgO and Y₂O₃ additives on inhibition of the mechanisms of diffusion expansion of the damaged layer depth revealed that in the case of high-temperature irradiation, the effect of diffusion softening is more pronounced for unstabilized ceramics, while the formation of impurity inclusions in the composition inhibits the mechanisms of diffusion of point and vacancy defects. One of the key parameters for using the addition of stabilizing additives to ceramics is to contain the mechanisms of structural disorder associated with thermodynamic phase transitions of the “pyrochlore → highly defective fluorite” type, the formation of which leads to softening and degradation of the damaged layer. During the studies conducted, it was established that the addition of stabilizing additives to the composition of Nd₂Zr₂O₇ ceramics leads to an increase in resistance to high-temperature degradation of strength properties, consisting in an increase in the threshold for reducing hardness depending on the irradiation temperature for stabilized ceramics in comparison with nonstabilized Nd₂Zr₂O₇ ceramics.