Grain growth in BaTiO3 ceramics assisted by an intergranular glass film

This research demonstrates that BaTiO3 ceramics exhibit increased grain boundary mobility (Mb) triggered by an inter-granular glass film (IGF) as previously demonstrated in polycrystalline Al2O3 ceramics conversion to single-crystal sapphire upon annealing at high temperatures. These results suggest that secondary abnormal grain growth (SAGG) during sintering of BaTiO3 ceramics at 1365 °C, a temperature above the eutectic points in the BaTiO3–SiO2 and BaTiO3–TiO2 systems, is another example of faster Mb caused by IGF. Higher Mb magnified through an interface glass film of several nanometers thickness facilitates a faster grain growth rate that produces exceedingly large grains of ∼2.4 mm in size. The growth mechanism involving twin-plane re-entrant (TPRE) corners may not be the only route responsible for SAGG in BaTiO3, particularly when sintered at above eutectic temperatures. How this abnormal grain growth occurs through mechanisms involving liquid-phase-enhanced Mb and the {111} twins as a chemically induced growth fault is discussed.