Zr(1-x)Ln(x)W(2)O(8-x/2) (Ln = Eu, Er, Yb): Solid solutions of negative thermal expansion-synthesis, characterization and limited solid solubility

摘要

Zr(1-x)Ln(x)W(2)O(8-x/2) solid solutions (Ln = Eu, Er, Yb) of different substitution fractions x have been synthesized. Their X-ray diffraction (XRD) patterns have been indexed and lattice parameters calculated based on the alpha-ZrW2O8 structure. The coefficients of thermal expansion (CTEs) of these solid solutions were estimated to be -10.3 x 10(-6) K-1 in temperature range of 30-100 degrees C. The solubility of lanthanide ions in these solid solutions decreases linearly with the increase in the radius of substituted lanthanide ions. Based on the concentration dependence of phase transition temperatures, a novel method for determination of solubility of the lanthanide ions in Zr(1-x)Ln(x)W(2)O(8-x/2) solid solutions has been developed. This method seems to be more sensitive as compared with that based on XRD technique. (c) 2006 Elsevier Inc. All rights reserved.