Influence of sintering atmosphere on phase,microstructure and mechanical properties of Li4Si0.7Ti0.3O4 tritium breeding ceramics

Li₄Si_1–xTi_xO₄ ceramic solid solution was considered as a promising tritium breeding material for fusion reactor blanket. In this work, the effects of the sintering atmosphere on the phase composition, microstructure, and mechanical properties of Li₄Si_0.7Ti_0.3O₄ ceramic pebbles were investigated for the first time, aiming to explore the optimal sintering atmosphere for this solid solution. The results show that compared with air and argon atmosphere, the negative pressure of vacuum atmosphere was more favorable for Ti to enter the Li₄SiO₄ crystal structure as a substitute for Si atom to form a solid solution. More importantly, sintering in argon-vacuum atmosphere can ensure the formation of solid solution while fully exerting the liquid phase sintering effect. The crushing load of the Li₄Si_0.7Ti_0.3O₄ ceramic pebbles sintered at 800 °C in argon-vacuum atmosphere reaches 30.3 ± 3.2 N. In general, the appropriate sintering atmosphere was of great significance for obtaining Li₄Si_0.7Ti_0.3O₄ solid solution to meet the performance requirements of tritium breeding blanket.