Grain growth mechanism and thermal stability of Li2TiO3 pebbles fabricated by wet method

Abstract

Li2TiO3 ceramic pebbles with uniform structure, high density and good mechanical property were successfully fabricated by wet process. The Li2TiO3 pebbles sintered at 1000 °C for 4 h had satisfactory density (91% T.D.) and crush load (a.v. 27.1 N). The apparent activation energy of Li2TiO3 grain growth was 201 ± 7 kJ/mol. Accelerated densification was observed in a reducing atmosphere, this might be attributed to the oxygen vacancies generated by the reduction of Ti4+ to Ti3+ in 0.1%H2+He atmosphere, which facilitate the diffusion of ions through the lattice. The grain growth was controlled by lattice diffusion under reducing atmosphere, and the apparent activation energy was 168 ± 6 kJ/mol. The mechanical results show that the crush load of Li2TiO3 pebbles decreased with the increase of temperature, and the average crush load at 500 °C was 13.9 N. In addition, the thermal cycling and long-time annealing experiments suggested that Li2TiO3 pebbles have good structural and performance stability. The Li2TiO3 ceramics prepared by wet process were satisfactory tritium breeder materials with ideal application potential.