Thermodynamic prediction of the nonstoichiometric phase Zr1–zCezO2–x in the ZrO2–CeO1.5–CeO2 system

A thermodynamic estimation of the ZrO2–CeO2 and ZrO2–CeO1.5 systems, as well as the cubic phase in the CeO1.5–CeO2 system has been developed and the complex relation between the nonstoichiometry, y, in CezO2–y and the oxygen partial pressure at different temperatures is evaluated. The behavior of the nonstoichiometry phase Zr1–zCezO2–x is described based on the thermodynamic estimation in the ZrO2–CeO2, CeO1.5–CeO2 and ZrO2–CeO1.5 systems. Additionally, the interdependence among miscellaneous factors, which can be used to describe the change in oxidation states of cerium such as the oxygen partial pressure, the CeO1.5 fraction in CeO1.5–CeO2 in the quasi-ternary system, the nonstoichiometry y and the difference between the activity of CeO2 and CeO1.5 are predicted. The calculated results are found to be very useful to explain the influence of pressureless sintering at different O2 partial pressures on the mechanical properties of CeO2-stabilised ZrO2 ceramics