Anomalous phase transformation of Li2TiO3 during sintering in oxygen atmosphere: A dilatometry study

Highlights: • Remarkably improved sinterability was observed in BeO doped Li₂TiO₃. • For the first time, monoclinic-to-cubic phase transformation in Li₂TiO₃ was observed at unusually low sintering temperature. • Monoclinic-to-cubic phase transformation was not observed after small quantity of BeO doping in Li₂TiO₃. Augmenting the sinter-ability of powder is helpful to address problems such as Li sublimation and rapid grain growth related to the sintering of lithium-bearing ceramics as tritium breeder materials. In the present work, the sintering behavior of pure phase Li₂TiO₃ powders with and without BeO doping synthesized by urea assisted solid-state method was probed employing dilatometry analysis in the O₂ atmosphere. Results revealed surprisingly low sintering onset temperature (∼715 °C) of un-doped Li₂TiO₃. Increasing sintering temperature to about 970 °C resulted in an anomalous monoclinic-to-cubic phase transformation characterized by unusually low transformation temperature and irreversible nature. Such phase transformation of Li₂TiO₃ has been usually reported in temperature range 1150–1250 °C which is significantly higher than observed in the present work. Interestingly, after BeO doping, a further reduction in sintering temperature with improved densification and suppression of the phase transformation was observed.