Fabrication of high strength Li-rich 2Li2TiO3–Li4SiO4 composite breeding ceramics at low-temperature by two-step sintering

Abstract

In this study, Li-rich 2Li2TiO3–Li4SiO4 composite breeding ceramics were prepared for the first time through a two-step low-temperature sintering route to meet the increasingly stringent performance requirements of tritium breeding materials. The effects of excess Li addition and sintering atmosphere on the phase composition, mechanical properties, and microstructure of the composite breeding ceramics were systematically studied. A two-step low-temperature sintering method was proposed to integrate the advantages of different sintering environments. The results show that moderate Li addition can significantly enhance the crushing load of composite ceramics while maintaining the nanostructure. However, further increasing the amount of Li addition does not continue to increase the crushing load, and will even affect the structural uniformity of the composite breeding ceramics. Most importantly, the S2.5 (2Li2.5TiO3–Li4SiO4, molar ratio) composite breeding ceramics sintered at 750 °C in an air-vacuum environment exhibited a grain size of ∼86 nm and a crushing load of ∼66.9 N, which has not been achieved by previous studies.