Speaker
Description
Qilai Zhou a, Yifu Xu a, Kaixuan Zhu a
a School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
Abstract:
Lithium orthosilicate (Li4SiO4) is considered as a promising solid tritium breeding material for fusion reactors due to its high lithium density and subsequent high tritium generation rate. However, its limited sinterability and inadequate mechanical properties present significant challenges. This study investigates the addition of neutron multiplier elements, Pb and Zr, to improve the sintering process and microstructure of Li4SiO4 ceramics, aiming at enhanced densification and improved mechanical performance. Pb was introduced into the precursor solution in the form of lead nitrate, Pb(NO3)2, and Li4SiO4-Pb ceramic powders were synthesized via a microwave-assisted solution combustion method. It was found that Pb existed as PbO in the ceramic. During sintering, PbO melted and accumulated at the Li4SiO4 grain boundaries, enhancing densification through liquid-phase sintering and improving mechanical properties. The Li4SiO4-10 wt.% Pb ceramic pebbles sintered at 1173 K achieved a relative density of 96.4% and a crush load of 106.3 N. However, PbO also promoted grain growth. In contrast, the addition of 10 wt.% ZrO2 led to the formation of Li2ZrO3, which induced a pinning effect, effectively refining the grain size. The ceramic pebbles exhibited a relative density of 86.2% and a crush load of 40.8 N. Furthermore, bending strength tests on ceramic bodies demonstrated a positive correlation between bending strength and densification. These findings suggest that Pb and Zr additions can effectively modify the microstructure and mechanical properties of Li4SiO4 ceramics, providing valuable insights for their application in fusion reactors.
