Crystal chemistry and thermal behavior of [(U0.3Th0.7)1-yNdy]O2+x; 0≤y≤0.4

Publication date: Available online 25 January 2020Source: Journal of Solid State ChemistryAuthor(s): Meera Keskar, S.K. Sali, Geeta P. Shelke, Muhammed Shafeeq, S. KannanAbstractSynthesis, X-ray, chemical analysis and thermal properties of Nd doped (U, Th)O2 mixed oxides of the formula [(U0.3Th0.7)1-yNdy]O2+x; (Where y = 0–0.4) are reported in this work. The Nd doped mixed (U, Th)O2 oxides were synthesized using gel combustion method followed by heating the precursors at 1673 K in reduced atmosphere. Powder X-ray Diffraction (XRD) patterns of the mixed oxides showed retention of a single FCC phase up to 40 mol% Nd. In order to show a relationship between lattice parameter of FCC phase with the concentrations of the dopant and oxygen non–stoichiometry, reduced mixed oxides were further heated in different atmospheres up to 1673 K. The relations between lattice parameter (a0) with oxygen non–stoichiometry (x) and dopant content (y) are expressed as:a0 (Ǻ) = 5.5580–0.112 x - 0.154 y for x > 0; 0≤ y ≤ 0.2.a0 (Ǻ) = 5.5580–0.300 x - 0.130 y for x < 0; 0.3≤y ≤ 0.4.Oxidation behavior of all the doped oxides was studied using thermogravimetric (TG) method in dry air. The kinetics of oxidation of [(U0.3Th0.7)1-yNdy]O2+x was studied using non-isothermal method and was found to be controlled by random nucleation. The specific heat capacities of the mixed oxides were measured using differential scanning calorimetry in the tempe...

Source: Journal of Solid State Chemistry - January 27, 2020 Category: Chemistry Source Type: research