Phase equilibria and materials in the TiO2-SiO2-ZrO2 system: a review

Abstract

This paper analyzes the available data on phase equilibria in the TiO 2 -SiO 2 -ZrO 2 system. The advantages of specialized databases and software systems for the analysis of information on phase equilibria are pointed. Phase diagrams are kind of a roadmap for the design of materials. As shown in the review, nanomaterials are no exception to this. Data on phase equilibria, such as eutectic points, solubility limits, binodal and spinodal curves, make it possible to predict the possibility of the formation of nanoscale structures and materials based on them. In its turn during the transition to the nanoscale state, the mutual component solubility, the temperature of phase transformation may change significantly, and other features may become observable. This provides additional variability when choosing compositions and material design based on the phases of a given system. As an example, for design of nuclear fuel assemblies that are tolerant to severe accidents at nuclear power plants, mixed carbides (so-called MAX-phases) are considered as one of the most promising options as nanoscale layers on fuel cladding. It is suggested that the materials of the TiO 2 -SiO 2 -ZrO 2 system, which are the product of oxidation of some MAX-phases, can serve as an inhibitor of their further corrosion. Ensuring the stability of materials based on MAX-phases expands their prospects in nuclear power. This requires comprehensive information about phase equilibria and formation conditions of nanostructured states in the analyzed system.

High‐temperature Mass Spectrometric Study and Modeling of the Thermodynamic Properties of the TiO2‐SiO2‐ZrO2 System

“…Similar effects were observed for the samples of the SiO 2 -ZrO 2 system at the temperature 1973 K. The available data on the phase relations in the SiO 2 -ZrO 2 system [1,7,8] and evaluation of the possible error of the temperature measurements in the mass spectrometric experiments (� 10 K) imply that the SiO 2 [11] activity data in Tables 2 and S2 refer to the (ZrO 2 + melt) region of the phase diagram. Comparing Figure 6 with the latest version of the SiO 2 -ZrO 2 phase diagram, [8] one may conclude that the measured SiO 2 activity values in the whole concentration range should be determined by the SiO 2 activity in the melt with x(SiO 2 ) = 0.90-0.95 mole fraction.…”

“…The concentration dependence of the measured activities, Table 2, exhibited irregularities at some points and was not fully compatible with the phase diagrams of the TiO 2 -SiO 2 , TiO 2 -ZrO 2 , and SiO 2 -ZrO 2 systems. [1] Nevertheless, the component activity data were considered suitable as an experimental basis for the rough evaluation of the thermodynamic description of the TiO 2 -SiO 2 -ZrO 2 system using GLTAS.…”

“…Promising nuclear fuel cladding ceramics can form materials based on the TiO 2 -SiO 2 -ZrO 2 system in the course of oxidation of their constituent MAX-phases, thereby providing the protective layer for the reactor core against further corrosion. [1] The TiO 2 -SiO 2 -ZrO 2 system can be taken as a basis for the synthesis of the new materials composed of nanoscale hierarchically organized structures. [2] It may also be used to replace the toxic components in the presently developed luminescent glasses with high thermal stability.…”

“…For instance, the information on the properties of the TiO 2 ‐SiO 2 ‐ZrO 2 system is of great interest for solution of the safety issues in the nuclear power technologies. Promising nuclear fuel cladding ceramics can form materials based on the TiO 2 ‐SiO 2 ‐ZrO 2 system in the course of oxidation of their constituent MAX‐phases, thereby providing the protective layer for the reactor core against further corrosion [1] . The TiO 2 ‐SiO 2 ‐ZrO 2 system can be taken as a basis for the synthesis of the new materials composed of nanoscale hierarchically organized structures [2] .…”

“…One of the key points in these studies was the determination of the immiscibility gaps, which are known to exist in the system. A comprehensive and detailed analysis of the presently available data on the phase equilibria in the TiO 2 ‐SiO 2 ‐ZrO 2 system and its boundary systems was carried out by Kirillova et al [1] . (120 citations).…”