Bulk and lattice thermal expansion in Ce_(1-x)Sr_xO_(2-x) (0.0 <= x <= 0.10)

摘要

In this communication, we report on the bulk and lattice thermal expansion studies on a number of compounds, within the homogeneity range of solid solutions, in a series with the general composition Ce_(1-x)Sr_xO_(2-x) (0.0 <= x<= 0.10). The XRD pattern of each product was refined to determine the solid solubility of SrO into the lattice of CeO_2, and the homogeneity range. The composition with maximum solid solubility limit of SrO in CeO_2 lattice, under the slow cooled conditions, was delineated as Ce_(0.91)Sr_(0.09)O_(1.91) (i.e. 9 mol. percent of SrO). The bulk thermal expansion measurements from ambient to 1123 K, as investigated by a dilatometer, revealed that the alpha _1 (293 to 1123 K) values for the compositions within the homogeneity range increase from 11.58 X 10~(-6) to 12.13 X 10~(-6) K~(-1) on increasing the Sr~(2+) content from 0 mol. percent (i.e. CeO_2) to 9 mol. percent, i.e. the upper solubility limit of SrO into the lattice of CeO_2. A similar trend was observed in the lattice thermal expansion coefficients alpha _a (293 to 1473 K) as obtained by a high temperature-XRD.