Thermodynamic Reassessment of ZrO₂–CaO System

Abstract

In this work, several thermodynamic assessments adopted widely for ZrO2–CaO system are reviewed and examined, the existing discrepancies are summarized, and a new assessment is carried out based on the formation enthalpy of two compounds (CaZr4O9 and Ca6Zr19O44) and experimental activity data concerning cubic solid solution. The thermodynamic parameters of all phases have been optimized by the least squares minimization procedure, a self consistent set of the optimized Gibbs energy parameters has been derived, which can be safely used to extrapolate into the multicomponent system. Compared with experimental data and the results in this work as well as the results reported previously, it is demonstrated that the present thermodynamic assessment is in better agreement with most of the experiments.

Compositional Dependence of Phase Formation Mechanisms at the Interface Between Titanium and Calcia‐Stabilized Zirconia at 1550°C

“…The thermodynamic values for the decomposition of 17C83Z are calculated as an example. In addition to four end solid solution phases, there are four intermediate stoichiometric compounds, i.e., o ‐CaZrO 3 , c ‐CaZrO 3 , CaZr 4 O 9 (Φ1), and Ca 6 Zr 19 O 44 (Φ2), in the CaO–ZrO 2 binary system 26 . The thermodynamic values acquired were mainly focused on the intermediate compounds CaZrO 3 in previous studies, 27–31 while those for the other two intermediate phases (Φ1 and Φ2) are relatively insufficient.…”

96Zr Tracer Diffusion in AZrO3 (A = Ca, Sr, Ba)

“…The crystal structure of CZ is orthorhombic compared to the cubic structure of BZ and SZ at 1300-1500 °C. The phase transition to cubic SZ has been reported at 1087 °C [26], while CZ is The crystal structure of CZ is orthorhombic compared to the cubic structure of BZ and SZ at 1300-1500 • C. The phase transition to cubic SZ has been reported at 1087 • C [26], while CZ is orthorhombic up to 2000 • C [27]. Thus, the diffusion mechanism for CZ cannot be argued for based on diffusion in cubic BZ or SZ.…”

“…Abbreviations: ppolycrystalline; sc-single crystal; c-cubic; b-bulk; gb-grain boundaries. (1) Ho in p BaTiO3 gb [11]; (2) Ho in p BaTiO3 b [11]; (3) Ni in p Ba(Ho,Ti)O3 [10]; (4) Ni in sc BaTiO3 [10]; (5) Ni in p BaTiO3 [10]; (6) Si in MgSiO3 [39]; (7) 49 Ti in sc (La,Sr)TiO3 [25]; (8) Zr in sc BaTiO3 [12]; (9) 141 Pr in LaFeO3 gb [40; (10) 141 Pr in LaCoO3 gb [40]; (11) Co in LaCoO3 gb [41]; (12) Cr in LaMnO3 [42];(13) Mn in LaCoO3 [43]; (14) Co in LaCoO3 b [41]; (15) 141 Pr in LaMnO3 [40]; (16) Co in GdCoO3 [44]; (17) Co in EuCoO3 [44]; (18) Co in SmCoO3 [44]; (19) Co in NdCoO3 [44]; (20) Co in PrCoO3 [44]; (21) 50 Cr in (La,Ca)CrO3 gb [45]; (22) Co in LaCoO3 [44]; (23) Mn in LaMnO3 b [42]; (24) Mn in LaMnO3 gb [42]; (25) Fe in LaFeO3 gb [46]; (26) Fe in LaFeO3 b [46]; (27) 141 Pr in LaCoO3 b [40]; (28) 141 Pr in LaFeO...…”

On the Modification of Hydration Resistance of CaO with ZrO2 Additive

“…The CaO–ZrO 2 equilibrium phase diagram was shown in Fig. ; there existed three intermediate compound, CaZr 4 O 9 , Ca 6 Zr 19 O 44 , and CaZrO 3 , and the solid solubility of ZrO 2 in CaO was very small.…”