Sub-solidus phase relations in CeO 2–YSZ and ThO 2–YSZ systems: XRD, high temperature-XRD and EPMA studies

Abstract

In the present manuscript, synthesis, XRD, high temperature-XRD as well as electron probe for microanalysis (EPMA) studies on CeO 2–YSZ and ThO 2–YSZ are being reported. It is found that CeO 2–YSZ system shows formation of a cubic solid solution throughout the homogeneity range. The lattice parameter of this cubic solid solution in CeO 2–YSZ system decreases linearly on going from CeO 2 to YSZ side. On the other hand ThO 2–YSZ system was bi-phasic throughout the range. XRD results indicate that YSZ has no solubility in ThO 2, however, EPMA studies revealed that a very small amount of YSZ is soluble in ThO 2. High Temperature XRD studies were performed on few representative compositions in CeO 2–YSZ system and the lattice thermal expansion coefficients (20–1200 °C) of the compositions YSZ, Ce 0.2(YSZ) 0.8O 1.90, Ce 0.4(YSZ) 0.6O 1.925 and Ce 0.6(YSZ) 0.4O 1.950 were observed as 11.32 × 10 −6, 11.38 × 10 −6, 11.43 × 10 −6 and 11.48 × 10 −6 °C −1, respectively.