Design, synthesis and characterization of advanced tritium breeder: Li4Si1-xTixO4 ceramics

Lithium orthosilicate (Li 4 SiO 4 ) is an important tritium breeder for the fusion blanket concept. It was selected as the first candidate in China's test blanket model. In this study, in order to improve the thermal conductivity and mechanical properties of Li 4 SiO 4 , titanium was chosen to replace the silicon in it. This is because Ti has large atomic radius and the same charge as that of silicon. The fabrication and characterization of Li 4 Si 1-x Ti x O 4 solid solution was carried out. The Li 4 (Si,Ti)O 4 powders were synthesised via a solid-state reaction, and the pebbles were fabricated using the freeze-drying method. The structure, morphology, thermal conductivity, and mechanical properties of the Li 4 (Si,Ti)O 4 samples were analysed using X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy, a laser thermal conductivity meter, and a universal testing machine. Moreover, the thermal conductivity of Li 4 SiO 4 improved significantly after Ti doping, and the mechanical properties of the Li 4 (Si,Ti)O 4 pebbles sintered at 1000 °C were significantly better than those of Li 4 SiO 4 .