Bulk and lattice thermal expansion of Th1-xCexO2

Bulk and lattice thermal expansion studies on Th1-xCexO2 (x = 0.0, 0.04, 0. 08 and 1.0) were carried out by dilatometry and high-temperature XRD from r oom temperature to 1123 K and to 1473 K, respectively. The average linear t hermal expansion coefficients, <(alpha)over bar>, of ThO2, Th0.96Ce0.04O2, Th0.92Ce0.08O2 and CeO2 were found to be 9.04 x 10(-6) 9.35 x 10(-6), 9.49 x 10(-6) and 11.58 x 10(-6) K-1, respectively, between 293 and 1123 K. The average lattice thermal expansion coefficients, <(alpha)over bar>(a), were 9.54 x 10(-6), 9.85 x 10(-6), 10.01 x 10(-6) and 12.06 x 10(-6) K-1, respec tively, between 293 and 1473 K in this series of compounds. The substitutio n of 4 and 8 mol% Ce4+ at Th4+ sites in ThO2 has a noticeable influence on the thermal expansion behavior. (C) 2000 Elsevier Science B.V. All rights r eserved.