Preparation of Li2TiO3-Li4SiO4 core-shell ceramic pebbles with enhanced crush load by graphite bed process

Abstract Li 4 SiO 4 and Li 2 TiO 3 have been regarded as the most favored ceramic breeders of the test blanket modules (TBMs). The lithium density of Li 4 SiO 4 is higher than that of Li 2 TiO 3 ; however, the thermo-mechanical stability of Li 2 TiO 3 is better than that of Li 4 SiO 4 . Hence, the biphasic y Li 2 TiO 3 –(1− y )Li 4 SiO 4 ( y  = 25%, 50%, 75%, molar ratio) pebbles were fabricated by a graphite bed process for the next generation of advanced tritium breeder materials. The pebbles with interesting core–shell structure (core: Li 2 TiO 3 and Li 4 SiO 4 , shell: Li 2 TiO 3 ) were fabricated for the first time. The thickness of Li 2 TiO 3 shell can be controlled by sintering time. Crystal structure, microstructure, and mechanical properties of the biphasic pebbles were investigated. The experimental results showed that the core–shell structure improved the crush load dramatically. The average crush load of 50%Li 2 TiO 3 –50%Li 4 SiO 4 pebbles sintered at 1100 °C for 5 h was up to104.79 N.