Thermodynamic Calculation of the Zirconia–Calcia System

Abstract

An optimal thermodynamic data set for the zirconia-calcia system is evaluated by the CALPHAD (CALculation of PHAse Diagrams) method applied to experimental phase diagram and thermodynamic data. The liquid and C,, (cubic ZrO, solid solution) are described by a subregular solution model. Three compounds, CaZr,O,, Ca6ZrlYOU, and CaZrO,, are modeled as stoichiometric compounds. A regular solution model is applied to the other phases. Comparisons between calculated and measured phase diagrams and thermodynamic quantities show that most of experimental information is satisfactorily accounted for by thermodynamic calculations. The calculations also reasonably predict the measured electromotive force concerning the metastable Css.

Microwave-assisted hydrothermal synthesis followed by heat treatment: A new route to obtain CaZrO3

“…CaZrO 3 can be used as a semiconductor, with applications in high-temperature water sensors, photoluminescent emitter at 450 and 700 nm, solid electrolyte, proton conductor and photocatalytic material (for molecules such as rhodamine B) [5][6][7][8][9][10]. In addition, CaZrO 3 can be used in various areas due to its refractory character (melting point of 2340°C), relative high electrical permittivity and low dissipation factor [11].…”

Thermodynamic assessment of the system ZrO2–CaO–MgO using new experimental results

“…There are really a lot of experimental data related to this system and a very exhaustive revision is collected in a thermodynamic approach by Du et al 31 The ZrO 2 -CaO system presents an intermediate compound CaZrO 3 stable up to 2365 • C. The existence of another two intermediate compounds 1 (CaZr 4 O 9 ) and 2 (Ca 6 Zr 19 O 44 ) have been established for the system, but their range of stability is currently a controversial question. In this paper the stability of the 1 and 2 phases was considered, according to what was proposed by Hellman and Stubican 32 and Yin and Arget 33 so that only two compounds have been considered as stable and included in the calculation: CaZrO 3 and 2 (Ca 6 Zr 19 O 44 ).…”

Thermochemistry of the ZrO2–SrO System: From enthalpies of formation and heat capacities of the compounds to the phase diagram

“…During the optimization process, the aforementioned Gibbs energy functions of four compounds were included in the analysis of phase diagram data 10,11 for the derivation of the model parameters a 0 , a 1 and b 0 , b 1 in Equation (7) for liquid. It was noticed that the steep liquidus curves near the two high melting compounds, SrZrO 3 and Sr 4 Zr 3 O 10 (2)(3)(4)(5) so that the C SS , T SS structures of SrO and RS SS structure of ZrO 2 became metastable in the temperature and composition ranges of interest. Finally, the whole system was optimized using all the selected data simultaneously.…”

“…A small amount of alkaline earth oxides MgO, CaO, SrO, and BaO can stabilize the high‐temperature cubic form of ZrO 2 or partially stabilize a mixture of monoclinic and tetragonal phases . There has been a significant amount of work on the phase diagrams of the ZrO 2 –MgO and ZrO 2 –CaO systems . However, phase diagram information for the ZrO 2 –SrO system is still very limited and inconsistent .…”