Fabrication of lanthanum-doped thorium dioxide by high-energy ball milling and spark plasma sintering

作者：Scott Spencer M; Yao Tiankai; Lu Fengyuan; Xin Guoqing; Zhu Weiguang; Lian Jie^*

来源：Journal of Nuclear Materials, 2017, 485: 207-215.

DOI：10.1016/j.jnucmat.2017.01.005

High-energy ball milling was used to synthesize Th1-xLaxO2-0.5x (x 0.09, 0.23) solid solutions, as well as improve the sinterability of ThO2 powders. Dense La-doped ThO2 pellets with theoretical density above 94% were consolidated by spark plasma sintering at temperatures above 1400 degrees C for 20 min, and the densification behavior and the non-equilibrium effects on phase and structure were investigated. A lattice contraction of the SPS-densified pellets occurred with increasing ball milling duration, and a secondary phase with increased La-content was Observed in La-doped pellets. A dependence on the La-content and sintering duration for the onset of localized phase segregation has been proposed. The effects of high-energy ball milling, La-content, and phase formation on the thermal diffusivity were also studied for La-doped ThO2 pellets by laser flash measurement. Increasing La-content and high energy ball milling time decreases thermal diffusivity; while the sintering peak temperature and holding time beyond 1600 degrees C dramatically altered the temperature dependence of the thermal diffusivity beyond 600 degrees C.

• 出版日期2017-3