Preparation and bulk thermal expansion studies in M1-xCexSiO4 (M = Th, Zr) system, and stabilization of tetragonal ThSiO4

Two series of compositions with the general formula M1-xCexSiO4 (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 ThSiO4. A striking observation was the stabilization of tetragonal modification of ThSiO4, which is metastable, by ceria substitution. There was no solubility of ceria in zircon (ZrSiO4) lattice. The average linear thermal expansion coefficient (293-1123 K) Of ZrSiO4, ThSiO4 and Th0.9Ce0.1SiO4 are 4.65 x 10(-6), 4.97 x 10(-6) and 5.14 x 10(-6) K-1, respectively. (C) 2004 Elsevier B.V. All rights reserved.