Preparation and bulk thermal expansion studies in M 1− xCe xSiO 4 (M = Th, Zr) system, and stabilization of tetragonal ThSiO 4

Abstract

Two series of compositions with the general formula M 1− x Ce x SiO 4 (M = Th, Zr; x = 0.0–0.5; 1.0) were prepared by a standard solid state route and characterized by powder XRD. About 10 mol% of ceria could be dissolved in the lattice of ThSiO 4. A striking observation was the stabilization of tetragonal modification of ThSiO 4, which is metastable, by ceria substitution. There was no solubility of ceria in zircon (ZrSiO 4) lattice. The average linear thermal expansion coefficient (293–1123 K) of ZrSiO 4, ThSiO 4 and Th 0.9Ce 0.1SiO 4 are 4.65 × 10 −6, 4.97 × 10 −6 and 5.14 × 10 −6 K −1, respectively.