Template-free aqueous tape casting of hydrothermally synthesized barium titanate powder and the fabrication of highly {001}-{100} textured tapes

Aqueous slurries of hydrothermally prepared barium titanate (BaTiO3) powders were tape casted without the use of large anisotropic template materials. The tapes were sintered at 1400 degrees C or 1500 degrees C, and at different furnace parameters. The texture of the sintered tapes was evaluated by the semi-quantitative XRD Lotgering method and the microstructure was studied by SEM. The Lotgering factor (f) of the sintered tapes was positively influenced by two main variables. First, directly heating to the sintering temperature resulted in a 22-30% increase. Second, sintering in the liquid-phase (Ti-excess) temperature region and at a high enough temperature (1500 degrees C) drastically improved the relative intensity of the {100} and {001} lines by 72%, at the expense of the {101}- and {111}-lines. The average volume weighted grain-size of the tape, which was directly heated to the sintering temperature (i.e., skipping the calcination step), was decreased by 77%.