Crystallographic Relationships of the {111} Growth Twins in Tetragonal Barium Titanate Determined by Electron-Backscatter Diffraction

The {111} growth twins are often found in sintered BaTiO3 ceramics with non‐stoichiometric TiO2‐excess compositions. The twin crystallographic orientation relationships studied in the past using transmission electron microscopy combined with the selected area diffraction patterns have now been determined directly from polished and etched samples using electron‐backscatter diffraction equipped with a scanning electron microscope. This technique is an effective way of determining orientation relationships for growth twins as well as transformation twins. The crystal poles of the Kikuchi patterns were determined automatically using a commercial electron‐backscatter diffraction system, INCACrystal™, supplied by Oxford Instruments. The automatic indexing, however, requires modification in order to ensure that the twin plane is consistent with previous findings by transmission electron microscopy and is of an identical index. The crystallographic relationships thus derived are in complete accord with those reported before.