A simple method for preparing ThO ₂ ceramics with high density

Abstract A simple and effective method for preparing ThO ₂ 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 ThO ₂ ceramics. The XRD analyses confirm that the ThO ₂ ceramics sintered at 1590°C were composed of cubic fluorite phase. The effect of sintering temperature on the density of ThO ₂ 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 mm ² /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.