Li vaporization behavior and mechanical properties of Li8ZrO6 under high temperature reducing atmosphere

Abstract

Li8ZrO6 sintered compacts are one of the promising candidates for innovative tritium breeding materials from the viewpoint of lithium density, but there are concerns such as a decrease in lithium atomic density and mechanical strength due to Li2O vaporization. In this study, we fabricated a two-phase mixed sintered body of Li8ZrO6 with a high lithium atomic density, as the main component, and relatively a large amount of Li2O, and thermally annealed it in an environment simulating actual use conditions to vaporize lithium. It is shown that this material is stable at 320°C, which is the main temperature in the blanket space, Li2O vaporizes and part of Li8ZrO6 changes to Li6Zr2O7 at least above 700°C, and vaporization of Li2O occurs more rapidly to finally become to a single phase of Li2ZrO3 at 800−900°C. In addition, it is shown that this material has a higher lithium density than Li2TiO3, one of the Japanese candidate materials, in a wide temperature range below 770 °C during the expected period of practical use of three years. Finally, it is concluded that loading Li8ZrO6-based material and Li2TiO3 in the high and low temperature regions, respectively, achieves the highest lithium density.