A simple method for preparing ThO₂ ceramics with high density

Abstract

A simple and effective method for preparing ThO2 ceramics with high density has been proposed. It mainly includes a positive precipitation approach and a conventional sintering process. The SEM images and laser particle size analysis show that the prepared powder exhibits a round‐plated shape with a uniform and narrow particle size distribution, which is the key to the densification sintering of ThO2 ceramics. The XRD analyses confirm that the ThO2 ceramics sintered at 1590°C were composed of cubic fluorite phase. The effect of sintering temperature on the density of ThO2 ceramics was also investigated, and a relative density higher than 95% were achieved after sintering at 1590°C for 6 h in an air atmosphere. Moreover, the Vickers hardness was up to 8.49 GPa, the average linear expansion coefficient within 40–800°C was low to 10.97 × 10−6/K, and the thermal conductivity and the thermal diffusivity were both higher than most of traditional ceramic materials (16.94–5.86 W/m K and 7.28–1.28 mm2/s, respectively, within the temperature range of 25–800°C). The previous great performances are closely related to its high density, which enables it to be a great candidate for nuclear fuels and other potential application fields.

Crystal structure and magnetism of actinide oxides: a review

“…The lattice parameters reported are at room temperature unless otherwise stated in the text. Polycrystalline samples of actinide oxides are most commonly synthesized by calcination of various precursors including the oxalates [50,156] nitrates [103] and hydroxides [129]. Controlling the atmosphere during calcination, or post-synthetic oxidation/reduction, allows for control over the specific actinide oxide produced.…”