Bulk and lattice thermal expansion of Th 1− xCe xO 2

Abstract

Bulk and lattice thermal expansion studies on Th 1 − x Ce x O 2 ( x=0.0, 0.04, 0.08 and 1.0) were carried out by dilatometry and high-temperature XRD from room temperature to 1123 K and to 1473 K, respectively. The average linear thermal expansion coefficients, α ̄ , of ThO 2, Th 0.96Ce 0.04O 2, Th 0.92Ce 0.08O 2 and CeO 2 were found to be 9.04×10 −6, 9.35×10 −6, 9.49×10 −6 and 11.58×10 −6 K −1, respectively, between 293 and 1123 K. The average lattice thermal expansion coefficients, α ̄ a , were 9.54×10 −6, 9.85×10 −6, 10.01×10 −6 and 12.06×10 −6 K −1 , respectively, between 293 and 1473 K in this series of compounds. The substitution of 4 and 8 mol% Ce 4+ at Th 4+ sites in ThO 2 has a noticeable influence on the thermal expansion behavior.