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

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 O-2 atmosphere. Results revealed surprisingly low sintering onset temperature (similar to 715 degrees C) of un-doped Li2TiO3. Increasing sintering temperature to about 970 degrees 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 degrees 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.