Thermal expansion and self-irradiation damage in curium nitride lattice

A powder sample of curium nitride (CmN) containing 0.35%-Pu and 3.59%-Am as actinide impurities was prepared by carbothermic nitridation of the oxide. The lattice expansion induced by self-irradiation damage at room temperature was measured as a function of time. The saturated Delta a/a(0) value was 0.43%, which is greater than those for transuranium dioxides available in literature. The undamaged lattice parameter at 297 +/- 1 K was determined to be 0.50261 +/- 0.00006 nm. Temperature dependence of the lattice parameter was measured by a high temperature X-ray diffractometer in the temperature range up to 1375 K. The linear thermal expansion from 293 to 1273 K was 0.964% and the corresponding thermal expansion coefficient was 9.84 Chi 10(-6) K-1. Comparing with the other actinide nitrides, it was found that CmN lies between the higher expansion nitrides (PuN and AmN) and the lower expansion nitrides (UN and NpN). (C) 2014 Elsevier B.V. All rights reserved.