Topochemical Synthesis of Plate‐Like Na 0.5 Bi 0.5 TiO 3 from Aurivillius Precursor

Plate‐like Na 0.5 Bi 0.5 TiO 3 (NBT) particles with perovskite structure were synthesized by topochemical microcrystal conversion from plate‐like particles of layer‐structured Na 0.5 Bi 4.5 Ti 4 O 15 (NBIT) at 950°C in NaCl molten salt. As the precursors of NBT, plate‐like NBIT particles were first synthesized by molten salt process by the reaction of Bi 4 Ti 3 O 12 , Na 2 CO 3 , and TiO 2 . After the topochemical reactions, layer‐structured NBIT particles were transformed to the perovskite NBT platelets. NBT particles with a thickness of approximately 0.5 μm and a length of 10–15 μm retained the morphology feature of the precursor. High‐aspect‐ratio NBT platelets are suitable templates to obtain textured ceramics (especially NBT‐based ceramics) by (reactive) template grain growth process.