Phase Formation of Sodium Bismuth Titanate Perovskite During Solid‐State Processing

Phase formation of sodium bismuth titanate (Na 0.5 Bi 0.5 TiO 3 or NBT) during the calcination process is investigated using in situ high‐temperature diffraction. Reactant oxide and carbonate powders were heated from room temperature to 700°C and diffraction patterns were measured sequentially and continuously in 60 s intervals during heating using a laboratory X‐ray powder diffractometer with a curved position‐sensitive detector. A small fraction of a transient phase was observed in the range of 500°–650°C and attributed to a reaction between Bi 2 O 3 and TiO 2 . A diffusion‐dependent particle conversion mechanism is proposed for the formation of NBT in which the Bi 2 O 3 particle and structure transforms into the perovskite phase.