Thermophysical properties of thorium–praseodymium mixed oxides

Abstract

Thorium–Praseodymium mixed oxide solid solutions (Th1−yPry)O2−x (y = 0.15, 0.25, 0.4, 0.55) were prepared by co-precipitation method. These mixed oxides form single-phase fluorite solid solutions (fm3m). Heat capacity (Cp) measurements and lattice thermal expansion characteristics of these solid solutions were determined with differential scanning calorimeter in the temperature range of 298–800 K and high temperature X-ray diffractometer in the temperature range of 298–2,000 K, respectively. The Cp,298 of (Th 1−yPry)O2−x pertaining to the solid solutions with the compositions, y = 0.15, 0.25, 0.4, and 0.55, were found to be 65.2, 62.4, 60.1, and 57.1 J K−1 mol−1, respectively. The coefficients of lattice thermal expansion in the temperature range of 298–2,000 K of (Th1−yPry)O2−x for these solid solutions with the compositions y = 0.15, 0.25, 0.4, and 0.55 were found to be 16.97, 20.43, 25.63 and 30.82 × 10−6 K−1, respectively.